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 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1476 #ifdef USE_MBEDTLS_FOR_ECDH 1477 // da * Pb 1478 mbedtls_ecp_group grp; 1479 mbedtls_ecp_group_init( &grp ); 1480 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 1481 mbedtls_ecp_point Q; 1482 mbedtls_ecp_point_init( &Q ); 1483 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1484 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1485 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1486 mbedtls_ecp_point DH; 1487 mbedtls_ecp_point_init( &DH ); 1488 mbedtls_ecp_mul(&grp, &DH, &le_keypair.d, &Q, NULL, NULL); 1489 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1490 #endif 1491 log_info("dhkey"); 1492 log_info_hexdump(dhkey, 32); 1493 } 1494 1495 #endif 1496 1497 static void sm_run(void){ 1498 1499 btstack_linked_list_iterator_t it; 1500 1501 // assert that we can send at least commands 1502 if (!hci_can_send_command_packet_now()) return; 1503 1504 // 1505 // non-connection related behaviour 1506 // 1507 1508 // distributed key generation 1509 switch (dkg_state){ 1510 case DKG_CALC_IRK: 1511 // already busy? 1512 if (sm_aes128_state == SM_AES128_IDLE) { 1513 // IRK = d1(IR, 1, 0) 1514 sm_key_t d1_prime; 1515 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1516 dkg_next_state(); 1517 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1518 return; 1519 } 1520 break; 1521 case DKG_CALC_DHK: 1522 // already busy? 1523 if (sm_aes128_state == SM_AES128_IDLE) { 1524 // DHK = d1(IR, 3, 0) 1525 sm_key_t d1_prime; 1526 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1527 dkg_next_state(); 1528 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1529 return; 1530 } 1531 break; 1532 default: 1533 break; 1534 } 1535 1536 // random address updates 1537 switch (rau_state){ 1538 case RAU_GET_RANDOM: 1539 rau_next_state(); 1540 sm_random_start(NULL); 1541 return; 1542 case RAU_GET_ENC: 1543 // already busy? 1544 if (sm_aes128_state == SM_AES128_IDLE) { 1545 sm_key_t r_prime; 1546 sm_ah_r_prime(sm_random_address, r_prime); 1547 rau_next_state(); 1548 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1549 return; 1550 } 1551 break; 1552 case RAU_SET_ADDRESS: 1553 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1554 rau_state = RAU_IDLE; 1555 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1556 return; 1557 default: 1558 break; 1559 } 1560 1561 // CMAC 1562 switch (sm_cmac_state){ 1563 case CMAC_CALC_SUBKEYS: 1564 case CMAC_CALC_MI: 1565 case CMAC_CALC_MLAST: 1566 // already busy? 1567 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1568 sm_cmac_handle_aes_engine_ready(); 1569 return; 1570 default: 1571 break; 1572 } 1573 1574 // CSRK Lookup 1575 // -- if csrk lookup ready, find connection that require csrk lookup 1576 if (sm_address_resolution_idle()){ 1577 hci_connections_get_iterator(&it); 1578 while(btstack_linked_list_iterator_has_next(&it)){ 1579 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1580 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1581 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1582 // and start lookup 1583 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); 1584 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1585 break; 1586 } 1587 } 1588 } 1589 1590 // -- if csrk lookup ready, resolved addresses for received addresses 1591 if (sm_address_resolution_idle()) { 1592 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1593 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1594 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1595 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1596 btstack_memory_sm_lookup_entry_free(entry); 1597 } 1598 } 1599 1600 // -- Continue with CSRK device lookup by public or resolvable private address 1601 if (!sm_address_resolution_idle()){ 1602 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1603 while (sm_address_resolution_test < le_device_db_count()){ 1604 int addr_type; 1605 bd_addr_t addr; 1606 sm_key_t irk; 1607 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1608 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1609 1610 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1611 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1612 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1613 break; 1614 } 1615 1616 if (sm_address_resolution_addr_type == 0){ 1617 sm_address_resolution_test++; 1618 continue; 1619 } 1620 1621 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1622 1623 log_info("LE Device Lookup: calculate AH"); 1624 log_info_key("IRK", irk); 1625 1626 sm_key_t r_prime; 1627 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1628 sm_address_resolution_ah_calculation_active = 1; 1629 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1630 return; 1631 } 1632 1633 if (sm_address_resolution_test >= le_device_db_count()){ 1634 log_info("LE Device Lookup: not found"); 1635 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1636 } 1637 } 1638 1639 1640 // 1641 // active connection handling 1642 // -- use loop to handle next connection if lock on setup context is released 1643 1644 while (1) { 1645 1646 // Find connections that requires setup context and make active if no other is locked 1647 hci_connections_get_iterator(&it); 1648 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1649 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1650 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1651 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1652 int done = 1; 1653 int err; 1654 int encryption_key_size; 1655 int authenticated; 1656 int authorized; 1657 switch (sm_connection->sm_engine_state) { 1658 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1659 // send packet if possible, 1660 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1661 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1662 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1663 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1664 } else { 1665 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1666 } 1667 // don't lock setup context yet 1668 done = 0; 1669 break; 1670 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1671 sm_init_setup(sm_connection); 1672 // recover pairing request 1673 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1674 err = sm_stk_generation_init(sm_connection); 1675 if (err){ 1676 setup->sm_pairing_failed_reason = err; 1677 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1678 break; 1679 } 1680 sm_timeout_start(sm_connection); 1681 // generate random number first, if we need to show passkey 1682 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1683 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1684 break; 1685 } 1686 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1687 break; 1688 case SM_INITIATOR_PH0_HAS_LTK: 1689 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1690 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1691 &encryption_key_size, &authenticated, &authorized); 1692 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1693 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1694 sm_connection->sm_connection_authenticated = authenticated; 1695 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1696 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1697 break; 1698 case SM_RESPONDER_PH0_RECEIVED_LTK: 1699 // re-establish previously used LTK using Rand and EDIV 1700 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1701 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1702 // re-establish used key encryption size 1703 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1704 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1705 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1706 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1707 log_info("sm: received ltk request with key size %u, authenticated %u", 1708 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1709 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1710 break; 1711 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1712 sm_init_setup(sm_connection); 1713 sm_timeout_start(sm_connection); 1714 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1715 break; 1716 default: 1717 done = 0; 1718 break; 1719 } 1720 if (done){ 1721 sm_active_connection = sm_connection->sm_handle; 1722 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1723 } 1724 } 1725 1726 // 1727 // active connection handling 1728 // 1729 1730 if (sm_active_connection == 0) return; 1731 1732 // assert that we could send a SM PDU - not needed for all of the following 1733 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1734 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1735 return; 1736 } 1737 1738 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1739 if (!connection) return; 1740 1741 sm_key_t plaintext; 1742 int key_distribution_flags; 1743 1744 log_info("sm_run: state %u", connection->sm_engine_state); 1745 1746 // responding state 1747 switch (connection->sm_engine_state){ 1748 1749 // general 1750 case SM_GENERAL_SEND_PAIRING_FAILED: { 1751 uint8_t buffer[2]; 1752 buffer[0] = SM_CODE_PAIRING_FAILED; 1753 buffer[1] = setup->sm_pairing_failed_reason; 1754 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1755 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1756 sm_done_for_handle(connection->sm_handle); 1757 break; 1758 } 1759 1760 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1761 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 1762 if (!sm_cmac_ready()) break; 1763 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 1764 sm_sc_calculate_local_confirm(connection); 1765 break; 1766 1767 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 1768 if (!sm_cmac_ready()) break; 1769 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 1770 sm_sc_calculate_remote_confirm(connection); 1771 break; 1772 #endif 1773 // initiator side 1774 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1775 sm_key_t peer_ltk_flipped; 1776 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1777 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1778 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1779 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1780 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1781 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1782 return; 1783 } 1784 1785 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1786 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 1787 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1788 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1789 sm_timeout_reset(connection); 1790 break; 1791 1792 // responder side 1793 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1794 connection->sm_engine_state = SM_RESPONDER_IDLE; 1795 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1796 return; 1797 1798 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1799 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 1800 uint8_t buffer[65]; 1801 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 1802 // 1803 #ifdef USE_MBEDTLS_FOR_ECDH 1804 uint8_t value[32]; 1805 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1806 reverse_256(value, &buffer[1]); 1807 mbedtls_mpi_write_binary(&le_keypair.Q.Y, value, sizeof(value)); 1808 reverse_256(value, &buffer[33]); 1809 #endif 1810 // TODO: use random generator to generate nonce 1811 1812 // generate 128-bit nonce 1813 int i; 1814 for (i=0;i<16;i++){ 1815 setup->sm_local_nonce[i] = rand() & 0xff; 1816 } 1817 1818 // stk generation method 1819 // passkey entry: notify app to show passkey or to request passkey 1820 switch (setup->sm_stk_generation_method){ 1821 case JUST_WORKS: 1822 case NK_BOTH_INPUT: 1823 if (connection->sm_role){ 1824 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1825 } else { 1826 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1827 } 1828 break; 1829 case PK_INIT_INPUT: 1830 case PK_RESP_INPUT: 1831 case OK_BOTH_INPUT: 1832 // hack for testing: assume user entered '000000' 1833 // memset(setup->sm_tk, 0, 16); 1834 memcpy(setup->sm_ra, setup->sm_tk, 16); 1835 memcpy(setup->sm_rb, setup->sm_tk, 16); 1836 setup->sm_passkey_bit = 0; 1837 if (connection->sm_role){ 1838 // responder 1839 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1840 } else { 1841 // initiator 1842 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1843 } 1844 sm_trigger_user_response(connection); 1845 break; 1846 case OOB: 1847 // TODO: implement SC OOB 1848 break; 1849 } 1850 1851 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1852 sm_timeout_reset(connection); 1853 break; 1854 } 1855 case SM_SC_SEND_CONFIRMATION: { 1856 uint8_t buffer[17]; 1857 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1858 reverse_128(setup->sm_local_confirm, &buffer[1]); 1859 if (connection->sm_role){ 1860 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1861 } else { 1862 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1863 } 1864 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1865 sm_timeout_reset(connection); 1866 break; 1867 } 1868 case SM_SC_SEND_PAIRING_RANDOM: { 1869 uint8_t buffer[17]; 1870 buffer[0] = SM_CODE_PAIRING_RANDOM; 1871 reverse_128(setup->sm_local_nonce, &buffer[1]); 1872 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 1873 if (connection->sm_role){ 1874 // responder 1875 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1876 } else { 1877 // initiator 1878 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1879 } 1880 } else { 1881 if (connection->sm_role){ 1882 // responder 1883 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1884 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 1885 // calc Vb if numeric comparison 1886 // TODO: use AES Engine to calculate g2 1887 uint8_t value[32]; 1888 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1889 uint32_t vb = g2(setup->sm_peer_qx, value, setup->sm_peer_nonce, setup->sm_local_nonce) % 1000000; 1890 big_endian_store_32(setup->sm_tk, 12, vb); 1891 sm_trigger_user_response(connection); 1892 } 1893 } else { 1894 // initiator 1895 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1896 } 1897 } 1898 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1899 sm_timeout_reset(connection); 1900 break; 1901 } 1902 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 1903 1904 // calculate DHKEY 1905 sm_key256_t dhkey; 1906 sm_sc_calculate_dhkey(dhkey); 1907 1908 // calculate LTK + MacKey 1909 sm_key256_t ltk_mackey; 1910 sm_key56_t bd_addr_master, bd_addr_slave; 1911 bd_addr_master[0] = setup->sm_m_addr_type; 1912 bd_addr_slave[0] = setup->sm_s_addr_type; 1913 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1914 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1915 if (connection->sm_role){ 1916 // responder 1917 f5(ltk_mackey, dhkey, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1918 } else { 1919 // initiator 1920 f5(ltk_mackey, dhkey, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1921 } 1922 // store LTK 1923 memcpy(setup->sm_ltk, <k_mackey[16], 16); 1924 1925 // calc DHKCheck 1926 memcpy(setup->sm_mackey, <k_mackey[0], 16); 1927 1928 // TODO: checks 1929 1930 uint8_t iocap_a[3]; 1931 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1932 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1933 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1934 uint8_t iocap_b[3]; 1935 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1936 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1937 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1938 if (connection->sm_role){ 1939 // responder 1940 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); 1941 } else { 1942 // initiator 1943 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); 1944 } 1945 1946 uint8_t buffer[17]; 1947 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 1948 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 1949 if (connection->sm_role){ 1950 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 1951 } else { 1952 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1953 } 1954 1955 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1956 sm_timeout_reset(connection); 1957 break; 1958 } 1959 1960 #endif 1961 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 1962 // echo initiator for now 1963 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 1964 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1965 1966 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 1967 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1968 if (setup->sm_use_secure_connections){ 1969 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1970 // skip LTK/EDIV for SC 1971 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 1972 } 1973 #endif 1974 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); 1975 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); 1976 1977 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 1978 sm_timeout_reset(connection); 1979 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 1980 if (setup->sm_stk_generation_method == JUST_WORKS){ 1981 sm_trigger_user_response(connection); 1982 } 1983 return; 1984 1985 case SM_PH2_SEND_PAIRING_RANDOM: { 1986 uint8_t buffer[17]; 1987 buffer[0] = SM_CODE_PAIRING_RANDOM; 1988 reverse_128(setup->sm_local_random, &buffer[1]); 1989 if (connection->sm_role){ 1990 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 1991 } else { 1992 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 1993 } 1994 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1995 sm_timeout_reset(connection); 1996 break; 1997 } 1998 1999 case SM_PH2_GET_RANDOM_TK: 2000 case SM_PH2_C1_GET_RANDOM_A: 2001 case SM_PH2_C1_GET_RANDOM_B: 2002 case SM_PH3_GET_RANDOM: 2003 case SM_PH3_GET_DIV: 2004 sm_next_responding_state(connection); 2005 sm_random_start(connection); 2006 return; 2007 2008 case SM_PH2_C1_GET_ENC_B: 2009 case SM_PH2_C1_GET_ENC_D: 2010 // already busy? 2011 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2012 sm_next_responding_state(connection); 2013 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2014 return; 2015 2016 case SM_PH3_LTK_GET_ENC: 2017 case SM_RESPONDER_PH4_LTK_GET_ENC: 2018 // already busy? 2019 if (sm_aes128_state == SM_AES128_IDLE) { 2020 sm_key_t d_prime; 2021 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2022 sm_next_responding_state(connection); 2023 sm_aes128_start(sm_persistent_er, d_prime, connection); 2024 return; 2025 } 2026 break; 2027 2028 case SM_PH3_CSRK_GET_ENC: 2029 // already busy? 2030 if (sm_aes128_state == SM_AES128_IDLE) { 2031 sm_key_t d_prime; 2032 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2033 sm_next_responding_state(connection); 2034 sm_aes128_start(sm_persistent_er, d_prime, connection); 2035 return; 2036 } 2037 break; 2038 2039 case SM_PH2_C1_GET_ENC_C: 2040 // already busy? 2041 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2042 // calculate m_confirm using aes128 engine - step 1 2043 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); 2044 sm_next_responding_state(connection); 2045 sm_aes128_start(setup->sm_tk, plaintext, connection); 2046 break; 2047 case SM_PH2_C1_GET_ENC_A: 2048 // already busy? 2049 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2050 // calculate confirm using aes128 engine - step 1 2051 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); 2052 sm_next_responding_state(connection); 2053 sm_aes128_start(setup->sm_tk, plaintext, connection); 2054 break; 2055 case SM_PH2_CALC_STK: 2056 // already busy? 2057 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2058 // calculate STK 2059 if (connection->sm_role){ 2060 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2061 } else { 2062 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2063 } 2064 sm_next_responding_state(connection); 2065 sm_aes128_start(setup->sm_tk, plaintext, connection); 2066 break; 2067 case SM_PH3_Y_GET_ENC: 2068 // already busy? 2069 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2070 // PH3B2 - calculate Y from - enc 2071 // Y = dm(DHK, Rand) 2072 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2073 sm_next_responding_state(connection); 2074 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2075 return; 2076 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2077 uint8_t buffer[17]; 2078 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2079 reverse_128(setup->sm_local_confirm, &buffer[1]); 2080 if (connection->sm_role){ 2081 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2082 } else { 2083 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2084 } 2085 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2086 sm_timeout_reset(connection); 2087 return; 2088 } 2089 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2090 sm_key_t stk_flipped; 2091 reverse_128(setup->sm_ltk, stk_flipped); 2092 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2093 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2094 return; 2095 } 2096 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2097 sm_key_t stk_flipped; 2098 reverse_128(setup->sm_ltk, stk_flipped); 2099 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2100 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2101 return; 2102 } 2103 case SM_RESPONDER_PH4_SEND_LTK: { 2104 sm_key_t ltk_flipped; 2105 reverse_128(setup->sm_ltk, ltk_flipped); 2106 connection->sm_engine_state = SM_RESPONDER_IDLE; 2107 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2108 return; 2109 } 2110 case SM_RESPONDER_PH4_Y_GET_ENC: 2111 // already busy? 2112 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2113 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2114 // Y = dm(DHK, Rand) 2115 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2116 sm_next_responding_state(connection); 2117 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2118 return; 2119 2120 case SM_PH3_DISTRIBUTE_KEYS: 2121 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2122 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2123 uint8_t buffer[17]; 2124 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2125 reverse_128(setup->sm_ltk, &buffer[1]); 2126 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2127 sm_timeout_reset(connection); 2128 return; 2129 } 2130 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2131 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2132 uint8_t buffer[11]; 2133 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2134 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2135 reverse_64(setup->sm_local_rand, &buffer[3]); 2136 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2137 sm_timeout_reset(connection); 2138 return; 2139 } 2140 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2141 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2142 uint8_t buffer[17]; 2143 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2144 reverse_128(sm_persistent_irk, &buffer[1]); 2145 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2146 sm_timeout_reset(connection); 2147 return; 2148 } 2149 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2150 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2151 bd_addr_t local_address; 2152 uint8_t buffer[8]; 2153 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2154 gap_advertisements_get_address(&buffer[1], local_address); 2155 reverse_bd_addr(local_address, &buffer[2]); 2156 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2157 sm_timeout_reset(connection); 2158 return; 2159 } 2160 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2161 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2162 2163 // hack to reproduce test runs 2164 if (test_use_fixed_local_csrk){ 2165 memset(setup->sm_local_csrk, 0xcc, 16); 2166 } 2167 2168 uint8_t buffer[17]; 2169 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2170 reverse_128(setup->sm_local_csrk, &buffer[1]); 2171 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2172 sm_timeout_reset(connection); 2173 return; 2174 } 2175 2176 // keys are sent 2177 if (connection->sm_role){ 2178 // slave -> receive master keys if any 2179 if (sm_key_distribution_all_received(connection)){ 2180 sm_key_distribution_handle_all_received(connection); 2181 connection->sm_engine_state = SM_RESPONDER_IDLE; 2182 sm_done_for_handle(connection->sm_handle); 2183 } else { 2184 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2185 } 2186 } else { 2187 // master -> all done 2188 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2189 sm_done_for_handle(connection->sm_handle); 2190 } 2191 break; 2192 2193 default: 2194 break; 2195 } 2196 2197 // check again if active connection was released 2198 if (sm_active_connection) break; 2199 } 2200 } 2201 2202 // note: aes engine is ready as we just got the aes result 2203 static void sm_handle_encryption_result(uint8_t * data){ 2204 2205 sm_aes128_state = SM_AES128_IDLE; 2206 2207 if (sm_address_resolution_ah_calculation_active){ 2208 sm_address_resolution_ah_calculation_active = 0; 2209 // compare calulated address against connecting device 2210 uint8_t hash[3]; 2211 reverse_24(data, hash); 2212 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2213 log_info("LE Device Lookup: matched resolvable private address"); 2214 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2215 return; 2216 } 2217 // no match, try next 2218 sm_address_resolution_test++; 2219 return; 2220 } 2221 2222 switch (dkg_state){ 2223 case DKG_W4_IRK: 2224 reverse_128(data, sm_persistent_irk); 2225 log_info_key("irk", sm_persistent_irk); 2226 dkg_next_state(); 2227 return; 2228 case DKG_W4_DHK: 2229 reverse_128(data, sm_persistent_dhk); 2230 log_info_key("dhk", sm_persistent_dhk); 2231 dkg_next_state(); 2232 // SM Init Finished 2233 return; 2234 default: 2235 break; 2236 } 2237 2238 switch (rau_state){ 2239 case RAU_W4_ENC: 2240 reverse_24(data, &sm_random_address[3]); 2241 rau_next_state(); 2242 return; 2243 default: 2244 break; 2245 } 2246 2247 switch (sm_cmac_state){ 2248 case CMAC_W4_SUBKEYS: 2249 case CMAC_W4_MI: 2250 case CMAC_W4_MLAST: 2251 { 2252 sm_key_t t; 2253 reverse_128(data, t); 2254 sm_cmac_handle_encryption_result(t); 2255 } 2256 return; 2257 default: 2258 break; 2259 } 2260 2261 // retrieve sm_connection provided to sm_aes128_start_encryption 2262 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2263 if (!connection) return; 2264 switch (connection->sm_engine_state){ 2265 case SM_PH2_C1_W4_ENC_A: 2266 case SM_PH2_C1_W4_ENC_C: 2267 { 2268 sm_key_t t2; 2269 reverse_128(data, t2); 2270 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2271 } 2272 sm_next_responding_state(connection); 2273 return; 2274 case SM_PH2_C1_W4_ENC_B: 2275 reverse_128(data, setup->sm_local_confirm); 2276 log_info_key("c1!", setup->sm_local_confirm); 2277 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2278 return; 2279 case SM_PH2_C1_W4_ENC_D: 2280 { 2281 sm_key_t peer_confirm_test; 2282 reverse_128(data, peer_confirm_test); 2283 log_info_key("c1!", peer_confirm_test); 2284 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2285 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2286 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2287 return; 2288 } 2289 if (connection->sm_role){ 2290 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2291 } else { 2292 connection->sm_engine_state = SM_PH2_CALC_STK; 2293 } 2294 } 2295 return; 2296 case SM_PH2_W4_STK: 2297 reverse_128(data, setup->sm_ltk); 2298 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2299 log_info_key("stk", setup->sm_ltk); 2300 if (connection->sm_role){ 2301 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2302 } else { 2303 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2304 } 2305 return; 2306 case SM_PH3_Y_W4_ENC:{ 2307 sm_key_t y128; 2308 reverse_128(data, y128); 2309 setup->sm_local_y = big_endian_read_16(y128, 14); 2310 log_info_hex16("y", setup->sm_local_y); 2311 // PH3B3 - calculate EDIV 2312 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2313 log_info_hex16("ediv", setup->sm_local_ediv); 2314 // PH3B4 - calculate LTK - enc 2315 // LTK = d1(ER, DIV, 0)) 2316 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2317 return; 2318 } 2319 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2320 sm_key_t y128; 2321 reverse_128(data, y128); 2322 setup->sm_local_y = big_endian_read_16(y128, 14); 2323 log_info_hex16("y", setup->sm_local_y); 2324 2325 // PH3B3 - calculate DIV 2326 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2327 log_info_hex16("ediv", setup->sm_local_ediv); 2328 // PH3B4 - calculate LTK - enc 2329 // LTK = d1(ER, DIV, 0)) 2330 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2331 return; 2332 } 2333 case SM_PH3_LTK_W4_ENC: 2334 reverse_128(data, setup->sm_ltk); 2335 log_info_key("ltk", setup->sm_ltk); 2336 // calc CSRK next 2337 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2338 return; 2339 case SM_PH3_CSRK_W4_ENC: 2340 reverse_128(data, setup->sm_local_csrk); 2341 log_info_key("csrk", setup->sm_local_csrk); 2342 if (setup->sm_key_distribution_send_set){ 2343 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2344 } else { 2345 // no keys to send, just continue 2346 if (connection->sm_role){ 2347 // slave -> receive master keys 2348 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2349 } else { 2350 // master -> all done 2351 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2352 sm_done_for_handle(connection->sm_handle); 2353 } 2354 } 2355 return; 2356 case SM_RESPONDER_PH4_LTK_W4_ENC: 2357 reverse_128(data, setup->sm_ltk); 2358 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2359 log_info_key("ltk", setup->sm_ltk); 2360 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 2361 return; 2362 default: 2363 break; 2364 } 2365 } 2366 2367 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2368 static void sm_handle_random_result(uint8_t * data){ 2369 2370 switch (rau_state){ 2371 case RAU_W4_RANDOM: 2372 // non-resolvable vs. resolvable 2373 switch (gap_random_adress_type){ 2374 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2375 // resolvable: use random as prand and calc address hash 2376 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2377 memcpy(sm_random_address, data, 3); 2378 sm_random_address[0] &= 0x3f; 2379 sm_random_address[0] |= 0x40; 2380 rau_state = RAU_GET_ENC; 2381 break; 2382 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2383 default: 2384 // "The two most significant bits of the address shall be equal to ‘0’"" 2385 memcpy(sm_random_address, data, 6); 2386 sm_random_address[0] &= 0x3f; 2387 rau_state = RAU_SET_ADDRESS; 2388 break; 2389 } 2390 return; 2391 default: 2392 break; 2393 } 2394 2395 // retrieve sm_connection provided to sm_random_start 2396 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2397 if (!connection) return; 2398 switch (connection->sm_engine_state){ 2399 case SM_PH2_W4_RANDOM_TK: 2400 { 2401 // map random to 0-999999 without speding much cycles on a modulus operation 2402 uint32_t tk = little_endian_read_32(data,0); 2403 tk = tk & 0xfffff; // 1048575 2404 if (tk >= 999999){ 2405 tk = tk - 999999; 2406 } 2407 sm_reset_tk(); 2408 big_endian_store_32(setup->sm_tk, 12, tk); 2409 if (connection->sm_role){ 2410 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2411 } else { 2412 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2413 sm_trigger_user_response(connection); 2414 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2415 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2416 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2417 } 2418 } 2419 return; 2420 } 2421 case SM_PH2_C1_W4_RANDOM_A: 2422 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2423 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2424 return; 2425 case SM_PH2_C1_W4_RANDOM_B: 2426 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2427 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2428 return; 2429 case SM_PH3_W4_RANDOM: 2430 reverse_64(data, setup->sm_local_rand); 2431 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2432 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2433 // no db for authenticated flag hack: store flag in bit 4 of LSB 2434 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2435 connection->sm_engine_state = SM_PH3_GET_DIV; 2436 return; 2437 case SM_PH3_W4_DIV: 2438 // use 16 bit from random value as div 2439 setup->sm_local_div = big_endian_read_16(data, 0); 2440 log_info_hex16("div", setup->sm_local_div); 2441 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2442 return; 2443 default: 2444 break; 2445 } 2446 } 2447 2448 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2449 2450 sm_connection_t * sm_conn; 2451 hci_con_handle_t con_handle; 2452 2453 switch (packet_type) { 2454 2455 case HCI_EVENT_PACKET: 2456 switch (hci_event_packet_get_type(packet)) { 2457 2458 case BTSTACK_EVENT_STATE: 2459 // bt stack activated, get started 2460 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2461 log_info("HCI Working!"); 2462 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2463 rau_state = RAU_IDLE; 2464 sm_run(); 2465 } 2466 break; 2467 2468 case HCI_EVENT_LE_META: 2469 switch (packet[2]) { 2470 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2471 2472 log_info("sm: connected"); 2473 2474 if (packet[3]) return; // connection failed 2475 2476 con_handle = little_endian_read_16(packet, 4); 2477 sm_conn = sm_get_connection_for_handle(con_handle); 2478 if (!sm_conn) break; 2479 2480 sm_conn->sm_handle = con_handle; 2481 sm_conn->sm_role = packet[6]; 2482 sm_conn->sm_peer_addr_type = packet[7]; 2483 reverse_bd_addr(&packet[8], 2484 sm_conn->sm_peer_address); 2485 2486 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2487 2488 // reset security properties 2489 sm_conn->sm_connection_encrypted = 0; 2490 sm_conn->sm_connection_authenticated = 0; 2491 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2492 sm_conn->sm_le_db_index = -1; 2493 2494 // prepare CSRK lookup (does not involve setup) 2495 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2496 2497 // just connected -> everything else happens in sm_run() 2498 if (sm_conn->sm_role){ 2499 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2500 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2501 if (sm_slave_request_security) { 2502 // request security if requested by app 2503 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2504 } else { 2505 // otherwise, wait for pairing request 2506 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2507 } 2508 } 2509 break; 2510 } else { 2511 // master 2512 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2513 } 2514 break; 2515 2516 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2517 con_handle = little_endian_read_16(packet, 3); 2518 sm_conn = sm_get_connection_for_handle(con_handle); 2519 if (!sm_conn) break; 2520 2521 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2522 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2523 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2524 break; 2525 } 2526 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2527 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2528 break; 2529 } 2530 2531 // assume that we don't have a LTK for ediv == 0 and random == null 2532 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 2533 log_info("LTK Request: ediv & random are empty"); 2534 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2535 break; 2536 } 2537 2538 // store rand and ediv 2539 reverse_64(&packet[5], sm_conn->sm_local_rand); 2540 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2541 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 2542 break; 2543 2544 default: 2545 break; 2546 } 2547 break; 2548 2549 case HCI_EVENT_ENCRYPTION_CHANGE: 2550 con_handle = little_endian_read_16(packet, 3); 2551 sm_conn = sm_get_connection_for_handle(con_handle); 2552 if (!sm_conn) break; 2553 2554 sm_conn->sm_connection_encrypted = packet[5]; 2555 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2556 sm_conn->sm_actual_encryption_key_size); 2557 log_info("event handler, state %u", sm_conn->sm_engine_state); 2558 if (!sm_conn->sm_connection_encrypted) break; 2559 // continue if part of initial pairing 2560 switch (sm_conn->sm_engine_state){ 2561 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2562 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2563 sm_done_for_handle(sm_conn->sm_handle); 2564 break; 2565 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2566 if (sm_conn->sm_role){ 2567 // slave 2568 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2569 } else { 2570 // master 2571 if (sm_key_distribution_all_received(sm_conn)){ 2572 // skip receiving keys as there are none 2573 sm_key_distribution_handle_all_received(sm_conn); 2574 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2575 } else { 2576 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2577 } 2578 } 2579 break; 2580 default: 2581 break; 2582 } 2583 break; 2584 2585 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2586 con_handle = little_endian_read_16(packet, 3); 2587 sm_conn = sm_get_connection_for_handle(con_handle); 2588 if (!sm_conn) break; 2589 2590 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2591 log_info("event handler, state %u", sm_conn->sm_engine_state); 2592 // continue if part of initial pairing 2593 switch (sm_conn->sm_engine_state){ 2594 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2595 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2596 sm_done_for_handle(sm_conn->sm_handle); 2597 break; 2598 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2599 if (sm_conn->sm_role){ 2600 // slave 2601 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2602 } else { 2603 // master 2604 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2605 } 2606 break; 2607 default: 2608 break; 2609 } 2610 break; 2611 2612 2613 case HCI_EVENT_DISCONNECTION_COMPLETE: 2614 con_handle = little_endian_read_16(packet, 3); 2615 sm_done_for_handle(con_handle); 2616 sm_conn = sm_get_connection_for_handle(con_handle); 2617 if (!sm_conn) break; 2618 2619 // delete stored bonding on disconnect with authentication failure in ph0 2620 if (sm_conn->sm_role == 0 2621 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2622 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2623 le_device_db_remove(sm_conn->sm_le_db_index); 2624 } 2625 2626 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2627 sm_conn->sm_handle = 0; 2628 break; 2629 2630 case HCI_EVENT_COMMAND_COMPLETE: 2631 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2632 sm_handle_encryption_result(&packet[6]); 2633 break; 2634 } 2635 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2636 sm_handle_random_result(&packet[6]); 2637 break; 2638 } 2639 break; 2640 default: 2641 break; 2642 } 2643 break; 2644 default: 2645 break; 2646 } 2647 2648 sm_run(); 2649 } 2650 2651 static inline int sm_calc_actual_encryption_key_size(int other){ 2652 if (other < sm_min_encryption_key_size) return 0; 2653 if (other < sm_max_encryption_key_size) return other; 2654 return sm_max_encryption_key_size; 2655 } 2656 2657 static int sm_passkey_used(stk_generation_method_t method){ 2658 switch (method){ 2659 case PK_RESP_INPUT: 2660 case PK_INIT_INPUT: 2661 case OK_BOTH_INPUT: 2662 return 1; 2663 default: 2664 return 0; 2665 } 2666 } 2667 2668 /** 2669 * @return ok 2670 */ 2671 static int sm_validate_stk_generation_method(void){ 2672 // check if STK generation method is acceptable by client 2673 switch (setup->sm_stk_generation_method){ 2674 case JUST_WORKS: 2675 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2676 case PK_RESP_INPUT: 2677 case PK_INIT_INPUT: 2678 case OK_BOTH_INPUT: 2679 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2680 case OOB: 2681 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2682 case NK_BOTH_INPUT: 2683 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 2684 return 1; 2685 default: 2686 return 0; 2687 } 2688 } 2689 2690 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2691 2692 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 2693 sm_run(); 2694 } 2695 2696 if (packet_type != SM_DATA_PACKET) return; 2697 2698 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2699 if (!sm_conn) return; 2700 2701 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2702 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2703 return; 2704 } 2705 2706 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2707 2708 int err; 2709 2710 switch (sm_conn->sm_engine_state){ 2711 2712 // a sm timeout requries a new physical connection 2713 case SM_GENERAL_TIMEOUT: 2714 return; 2715 2716 // Initiator 2717 case SM_INITIATOR_CONNECTED: 2718 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2719 sm_pdu_received_in_wrong_state(sm_conn); 2720 break; 2721 } 2722 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2723 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2724 break; 2725 } 2726 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2727 uint16_t ediv; 2728 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2729 if (ediv){ 2730 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2731 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2732 } else { 2733 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2734 } 2735 break; 2736 } 2737 // otherwise, store security request 2738 sm_conn->sm_security_request_received = 1; 2739 break; 2740 2741 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2742 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2743 sm_pdu_received_in_wrong_state(sm_conn); 2744 break; 2745 } 2746 // store pairing request 2747 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2748 err = sm_stk_generation_init(sm_conn); 2749 if (err){ 2750 setup->sm_pairing_failed_reason = err; 2751 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2752 break; 2753 } 2754 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2755 if (setup->sm_use_secure_connections){ 2756 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2757 if (setup->sm_stk_generation_method == JUST_WORKS){ 2758 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2759 sm_trigger_user_response(sm_conn); 2760 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2761 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2762 } 2763 } else { 2764 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2765 } 2766 break; 2767 } 2768 #endif 2769 // generate random number first, if we need to show passkey 2770 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2771 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2772 break; 2773 } 2774 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2775 sm_trigger_user_response(sm_conn); 2776 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2777 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2778 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2779 } 2780 break; 2781 2782 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2783 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2784 sm_pdu_received_in_wrong_state(sm_conn); 2785 break; 2786 } 2787 2788 // store s_confirm 2789 reverse_128(&packet[1], setup->sm_peer_confirm); 2790 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2791 break; 2792 2793 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2794 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2795 sm_pdu_received_in_wrong_state(sm_conn); 2796 break;; 2797 } 2798 2799 // received random value 2800 reverse_128(&packet[1], setup->sm_peer_random); 2801 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2802 break; 2803 2804 // Responder 2805 case SM_RESPONDER_IDLE: 2806 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2807 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2808 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2809 sm_pdu_received_in_wrong_state(sm_conn); 2810 break;; 2811 } 2812 2813 // store pairing request 2814 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2815 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2816 break; 2817 2818 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2819 case SM_SC_W4_PUBLIC_KEY_COMMAND: 2820 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 2821 sm_pdu_received_in_wrong_state(sm_conn); 2822 break; 2823 } 2824 2825 // store public key for DH Key calculation 2826 reverse_256(&packet[01], setup->sm_peer_qx); 2827 reverse_256(&packet[33], setup->sm_peer_qy); 2828 2829 #ifdef USE_MBEDTLS_FOR_ECDH 2830 // validate public key 2831 mbedtls_ecp_group grp; 2832 mbedtls_ecp_group_init( &grp ); 2833 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 2834 2835 mbedtls_ecp_point Q; 2836 mbedtls_ecp_point_init( &Q ); 2837 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 2838 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 2839 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 2840 err = mbedtls_ecp_check_pubkey(&grp, &Q); 2841 if (err){ 2842 log_error("sm: peer public key invalid %x", err); 2843 // uses "unspecified reason", there is no "public key invalid" error code 2844 sm_pdu_received_in_wrong_state(sm_conn); 2845 break; 2846 } 2847 #endif 2848 if (sm_conn->sm_role){ 2849 // responder 2850 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2851 } else { 2852 // initiator 2853 // stk generation method 2854 // passkey entry: notify app to show passkey or to request passkey 2855 switch (setup->sm_stk_generation_method){ 2856 case JUST_WORKS: 2857 case NK_BOTH_INPUT: 2858 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 2859 break; 2860 case PK_INIT_INPUT: 2861 case PK_RESP_INPUT: 2862 case OK_BOTH_INPUT: 2863 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2864 break; 2865 case OOB: 2866 // TODO: implement SC OOB 2867 break; 2868 } 2869 } 2870 break; 2871 2872 case SM_SC_W4_CONFIRMATION: 2873 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2874 sm_pdu_received_in_wrong_state(sm_conn); 2875 break; 2876 } 2877 // received confirm value 2878 reverse_128(&packet[1], setup->sm_peer_confirm); 2879 2880 if (sm_conn->sm_role){ 2881 // responder 2882 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2883 } else { 2884 // initiator 2885 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2886 } 2887 break; 2888 2889 case SM_SC_W4_PAIRING_RANDOM: 2890 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2891 sm_pdu_received_in_wrong_state(sm_conn); 2892 break; 2893 } 2894 2895 // received random value 2896 reverse_128(&packet[1], setup->sm_peer_nonce); 2897 2898 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 2899 // only check for JUST WORK/NC in initiator role AND passkey entry 2900 int passkey_entry = sm_passkey_used(setup->sm_stk_generation_method); 2901 if (sm_conn->sm_role || passkey_entry) { 2902 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 2903 } 2904 2905 sm_sc_state_after_receiving_random(sm_conn); 2906 break; 2907 2908 case SM_SC_W4_DHKEY_CHECK_COMMAND: 2909 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 2910 sm_pdu_received_in_wrong_state(sm_conn); 2911 break; 2912 } 2913 // store DHKey Check 2914 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 2915 2916 // validate E = f6() 2917 sm_key56_t bd_addr_master, bd_addr_slave; 2918 bd_addr_master[0] = setup->sm_m_addr_type; 2919 bd_addr_slave[0] = setup->sm_s_addr_type; 2920 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 2921 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 2922 2923 uint8_t iocap_a[3]; 2924 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 2925 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 2926 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 2927 uint8_t iocap_b[3]; 2928 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 2929 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 2930 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 2931 sm_key_t peer_dhkey_check; 2932 if (sm_conn->sm_role){ 2933 // responder 2934 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); 2935 } else { 2936 // initiator 2937 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); 2938 } 2939 2940 if (0 != memcmp(setup->sm_peer_dhkey_check, peer_dhkey_check, 16) ){ 2941 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 2942 break; 2943 } 2944 2945 if (sm_conn->sm_role){ 2946 // responder 2947 // for numeric comparison, we need to wait for user confirm 2948 if (setup->sm_stk_generation_method == NK_BOTH_INPUT && setup->sm_user_response != SM_USER_RESPONSE_CONFIRM){ 2949 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 2950 } else { 2951 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 2952 } 2953 } else { 2954 // initiator 2955 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2956 } 2957 break; 2958 #endif 2959 2960 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 2961 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2962 sm_pdu_received_in_wrong_state(sm_conn); 2963 break; 2964 } 2965 2966 // received confirm value 2967 reverse_128(&packet[1], setup->sm_peer_confirm); 2968 2969 // notify client to hide shown passkey 2970 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2971 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 2972 } 2973 2974 // handle user cancel pairing? 2975 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 2976 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2977 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2978 break; 2979 } 2980 2981 // wait for user action? 2982 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 2983 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2984 break; 2985 } 2986 2987 // calculate and send local_confirm 2988 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2989 break; 2990 2991 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 2992 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2993 sm_pdu_received_in_wrong_state(sm_conn); 2994 break;; 2995 } 2996 2997 // received random value 2998 reverse_128(&packet[1], setup->sm_peer_random); 2999 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3000 break; 3001 3002 case SM_PH3_RECEIVE_KEYS: 3003 switch(packet[0]){ 3004 case SM_CODE_ENCRYPTION_INFORMATION: 3005 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3006 reverse_128(&packet[1], setup->sm_peer_ltk); 3007 break; 3008 3009 case SM_CODE_MASTER_IDENTIFICATION: 3010 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3011 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3012 reverse_64(&packet[3], setup->sm_peer_rand); 3013 break; 3014 3015 case SM_CODE_IDENTITY_INFORMATION: 3016 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3017 reverse_128(&packet[1], setup->sm_peer_irk); 3018 break; 3019 3020 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3021 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3022 setup->sm_peer_addr_type = packet[1]; 3023 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3024 break; 3025 3026 case SM_CODE_SIGNING_INFORMATION: 3027 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3028 reverse_128(&packet[1], setup->sm_peer_csrk); 3029 break; 3030 default: 3031 // Unexpected PDU 3032 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3033 break; 3034 } 3035 // done with key distribution? 3036 if (sm_key_distribution_all_received(sm_conn)){ 3037 3038 sm_key_distribution_handle_all_received(sm_conn); 3039 3040 if (sm_conn->sm_role){ 3041 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3042 sm_done_for_handle(sm_conn->sm_handle); 3043 } else { 3044 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3045 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3046 if (setup->sm_use_secure_connections){ 3047 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3048 } 3049 #endif 3050 } 3051 } 3052 break; 3053 default: 3054 // Unexpected PDU 3055 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3056 break; 3057 } 3058 3059 // try to send preparared packet 3060 sm_run(); 3061 } 3062 3063 // Security Manager Client API 3064 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3065 sm_get_oob_data = get_oob_data_callback; 3066 } 3067 3068 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3069 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3070 } 3071 3072 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3073 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3074 } 3075 3076 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3077 sm_min_encryption_key_size = min_size; 3078 sm_max_encryption_key_size = max_size; 3079 } 3080 3081 void sm_set_authentication_requirements(uint8_t auth_req){ 3082 sm_auth_req = auth_req; 3083 } 3084 3085 void sm_set_io_capabilities(io_capability_t io_capability){ 3086 sm_io_capabilities = io_capability; 3087 } 3088 3089 void sm_set_request_security(int enable){ 3090 sm_slave_request_security = enable; 3091 } 3092 3093 void sm_set_er(sm_key_t er){ 3094 memcpy(sm_persistent_er, er, 16); 3095 } 3096 3097 void sm_set_ir(sm_key_t ir){ 3098 memcpy(sm_persistent_ir, ir, 16); 3099 } 3100 3101 // Testing support only 3102 void sm_test_set_irk(sm_key_t irk){ 3103 memcpy(sm_persistent_irk, irk, 16); 3104 sm_persistent_irk_ready = 1; 3105 } 3106 3107 void sm_test_use_fixed_local_csrk(void){ 3108 test_use_fixed_local_csrk = 1; 3109 } 3110 3111 void sm_init(void){ 3112 // set some (BTstack default) ER and IR 3113 int i; 3114 sm_key_t er; 3115 sm_key_t ir; 3116 for (i=0;i<16;i++){ 3117 er[i] = 0x30 + i; 3118 ir[i] = 0x90 + i; 3119 } 3120 sm_set_er(er); 3121 sm_set_ir(ir); 3122 // defaults 3123 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3124 | SM_STK_GENERATION_METHOD_OOB 3125 | SM_STK_GENERATION_METHOD_PASSKEY 3126 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3127 3128 sm_max_encryption_key_size = 16; 3129 sm_min_encryption_key_size = 7; 3130 3131 sm_cmac_state = CMAC_IDLE; 3132 dkg_state = DKG_W4_WORKING; 3133 rau_state = RAU_W4_WORKING; 3134 sm_aes128_state = SM_AES128_IDLE; 3135 sm_address_resolution_test = -1; // no private address to resolve yet 3136 sm_address_resolution_ah_calculation_active = 0; 3137 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3138 sm_address_resolution_general_queue = NULL; 3139 3140 gap_random_adress_update_period = 15 * 60 * 1000L; 3141 3142 sm_active_connection = 0; 3143 3144 test_use_fixed_local_csrk = 0; 3145 3146 // register for HCI Events from HCI 3147 hci_event_callback_registration.callback = &sm_event_packet_handler; 3148 hci_add_event_handler(&hci_event_callback_registration); 3149 3150 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3151 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3152 3153 #ifdef USE_MBEDTLS_FOR_ECDH 3154 // TODO: calculate keypair using LE Random Number Generator 3155 // use test keypair from spec initially 3156 mbedtls_ecp_keypair_init(&le_keypair); 3157 mbedtls_ecp_group_load(&le_keypair.grp, MBEDTLS_ECP_DP_SECP256R1); 3158 mbedtls_mpi_read_string( &le_keypair.d, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3159 mbedtls_mpi_read_string( &le_keypair.Q.X, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3160 mbedtls_mpi_read_string( &le_keypair.Q.Y, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3161 mbedtls_mpi_read_string( &le_keypair.Q.Z, 16, "1"); 3162 // print keypair 3163 char buffer[100]; 3164 size_t len; 3165 mbedtls_mpi_write_string( &le_keypair.d, 16, buffer, sizeof(buffer), &len); 3166 log_info("d: %s", buffer); 3167 mbedtls_mpi_write_string( &le_keypair.Q.X, 16, buffer, sizeof(buffer), &len); 3168 log_info("X: %s", buffer); 3169 mbedtls_mpi_write_string( &le_keypair.Q.Y, 16, buffer, sizeof(buffer), &len); 3170 log_info("Y: %s", buffer); 3171 #endif 3172 } 3173 3174 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3175 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3176 if (!hci_con) return NULL; 3177 return &hci_con->sm_connection; 3178 } 3179 3180 // @returns 0 if not encrypted, 7-16 otherwise 3181 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3182 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3183 if (!sm_conn) return 0; // wrong connection 3184 if (!sm_conn->sm_connection_encrypted) return 0; 3185 return sm_conn->sm_actual_encryption_key_size; 3186 } 3187 3188 int sm_authenticated(hci_con_handle_t con_handle){ 3189 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3190 if (!sm_conn) return 0; // wrong connection 3191 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3192 return sm_conn->sm_connection_authenticated; 3193 } 3194 3195 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3196 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3197 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3198 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3199 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3200 return sm_conn->sm_connection_authorization_state; 3201 } 3202 3203 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3204 switch (sm_conn->sm_engine_state){ 3205 case SM_GENERAL_IDLE: 3206 case SM_RESPONDER_IDLE: 3207 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3208 sm_run(); 3209 break; 3210 default: 3211 break; 3212 } 3213 } 3214 3215 /** 3216 * @brief Trigger Security Request 3217 */ 3218 void sm_send_security_request(hci_con_handle_t con_handle){ 3219 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3220 if (!sm_conn) return; 3221 sm_send_security_request_for_connection(sm_conn); 3222 } 3223 3224 // request pairing 3225 void sm_request_pairing(hci_con_handle_t con_handle){ 3226 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3227 if (!sm_conn) return; // wrong connection 3228 3229 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3230 if (sm_conn->sm_role){ 3231 sm_send_security_request_for_connection(sm_conn); 3232 } else { 3233 // used as a trigger to start central/master/initiator security procedures 3234 uint16_t ediv; 3235 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3236 switch (sm_conn->sm_irk_lookup_state){ 3237 case IRK_LOOKUP_FAILED: 3238 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3239 break; 3240 case IRK_LOOKUP_SUCCEEDED: 3241 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 3242 if (ediv){ 3243 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3244 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3245 } else { 3246 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3247 } 3248 break; 3249 default: 3250 sm_conn->sm_bonding_requested = 1; 3251 break; 3252 } 3253 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3254 sm_conn->sm_bonding_requested = 1; 3255 } 3256 } 3257 sm_run(); 3258 } 3259 3260 // called by client app on authorization request 3261 void sm_authorization_decline(hci_con_handle_t con_handle){ 3262 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3263 if (!sm_conn) return; // wrong connection 3264 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3265 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3266 } 3267 3268 void sm_authorization_grant(hci_con_handle_t con_handle){ 3269 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3270 if (!sm_conn) return; // wrong connection 3271 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3272 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3273 } 3274 3275 // GAP Bonding API 3276 3277 void sm_bonding_decline(hci_con_handle_t con_handle){ 3278 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3279 if (!sm_conn) return; // wrong connection 3280 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3281 3282 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3283 switch (setup->sm_stk_generation_method){ 3284 case PK_RESP_INPUT: 3285 case PK_INIT_INPUT: 3286 case OK_BOTH_INPUT: 3287 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3288 break; 3289 case NK_BOTH_INPUT: 3290 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3291 break; 3292 case JUST_WORKS: 3293 case OOB: 3294 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3295 break; 3296 } 3297 } 3298 sm_run(); 3299 } 3300 3301 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3302 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3303 if (!sm_conn) return; // wrong connection 3304 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3305 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3306 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3307 3308 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3309 if (setup->sm_use_secure_connections){ 3310 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3311 } 3312 #endif 3313 } 3314 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3315 if (sm_conn->sm_role){ 3316 // responder 3317 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 3318 } else { 3319 // initiator 3320 // TODO handle intiator role 3321 } 3322 } 3323 sm_run(); 3324 } 3325 3326 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3327 // for now, it's the same 3328 sm_just_works_confirm(con_handle); 3329 } 3330 3331 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3332 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3333 if (!sm_conn) return; // wrong connection 3334 sm_reset_tk(); 3335 big_endian_store_32(setup->sm_tk, 12, passkey); 3336 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3337 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3338 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3339 } 3340 sm_run(); 3341 } 3342 3343 /** 3344 * @brief Identify device in LE Device DB 3345 * @param handle 3346 * @returns index from le_device_db or -1 if not found/identified 3347 */ 3348 int sm_le_device_index(hci_con_handle_t con_handle ){ 3349 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3350 if (!sm_conn) return -1; 3351 return sm_conn->sm_le_db_index; 3352 } 3353 3354 // GAP LE API 3355 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3356 gap_random_address_update_stop(); 3357 gap_random_adress_type = random_address_type; 3358 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3359 gap_random_address_update_start(); 3360 gap_random_address_trigger(); 3361 } 3362 3363 gap_random_address_type_t gap_random_address_get_mode(void){ 3364 return gap_random_adress_type; 3365 } 3366 3367 void gap_random_address_set_update_period(int period_ms){ 3368 gap_random_adress_update_period = period_ms; 3369 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3370 gap_random_address_update_stop(); 3371 gap_random_address_update_start(); 3372 } 3373 3374 void gap_random_address_set(bd_addr_t addr){ 3375 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3376 memcpy(sm_random_address, addr, 6); 3377 rau_state = RAU_SET_ADDRESS; 3378 sm_run(); 3379 } 3380 3381 /* 3382 * @brief Set Advertisement Paramters 3383 * @param adv_int_min 3384 * @param adv_int_max 3385 * @param adv_type 3386 * @param direct_address_type 3387 * @param direct_address 3388 * @param channel_map 3389 * @param filter_policy 3390 * 3391 * @note own_address_type is used from gap_random_address_set_mode 3392 */ 3393 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3394 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3395 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3396 direct_address_typ, direct_address, channel_map, filter_policy); 3397 } 3398 3399