1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "ble/le_device_db.h" 43 #include "ble/core.h" 44 #include "ble/sm.h" 45 #include "btstack_debug.h" 46 #include "btstack_event.h" 47 #include "btstack_linked_list.h" 48 #include "btstack_memory.h" 49 #include "gap.h" 50 #include "hci.h" 51 #include "l2cap.h" 52 53 #ifdef ENABLE_LE_SECURE_CONNECTIONS 54 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT 55 #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" 56 #else 57 #define USE_MBEDTLS_FOR_ECDH 58 #endif 59 #endif 60 61 62 // Software ECDH implementation provided by mbedtls 63 #ifdef USE_MBEDTLS_FOR_ECDH 64 #include "mbedtls/config.h" 65 #include "mbedtls/platform.h" 66 #include "mbedtls/ecp.h" 67 #include "sm_mbedtls_allocator.h" 68 #endif 69 70 // 71 // SM internal types and globals 72 // 73 74 typedef enum { 75 DKG_W4_WORKING, 76 DKG_CALC_IRK, 77 DKG_W4_IRK, 78 DKG_CALC_DHK, 79 DKG_W4_DHK, 80 DKG_READY 81 } derived_key_generation_t; 82 83 typedef enum { 84 RAU_W4_WORKING, 85 RAU_IDLE, 86 RAU_GET_RANDOM, 87 RAU_W4_RANDOM, 88 RAU_GET_ENC, 89 RAU_W4_ENC, 90 RAU_SET_ADDRESS, 91 } random_address_update_t; 92 93 typedef enum { 94 CMAC_IDLE, 95 CMAC_CALC_SUBKEYS, 96 CMAC_W4_SUBKEYS, 97 CMAC_CALC_MI, 98 CMAC_W4_MI, 99 CMAC_CALC_MLAST, 100 CMAC_W4_MLAST 101 } cmac_state_t; 102 103 typedef enum { 104 JUST_WORKS, 105 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 106 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 107 OK_BOTH_INPUT, // Only input on both, both input PK 108 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 109 OOB // OOB available on both sides 110 } stk_generation_method_t; 111 112 typedef enum { 113 SM_USER_RESPONSE_IDLE, 114 SM_USER_RESPONSE_PENDING, 115 SM_USER_RESPONSE_CONFIRM, 116 SM_USER_RESPONSE_PASSKEY, 117 SM_USER_RESPONSE_DECLINE 118 } sm_user_response_t; 119 120 typedef enum { 121 SM_AES128_IDLE, 122 SM_AES128_ACTIVE 123 } sm_aes128_state_t; 124 125 typedef enum { 126 ADDRESS_RESOLUTION_IDLE, 127 ADDRESS_RESOLUTION_GENERAL, 128 ADDRESS_RESOLUTION_FOR_CONNECTION, 129 } address_resolution_mode_t; 130 131 typedef enum { 132 ADDRESS_RESOLUTION_SUCEEDED, 133 ADDRESS_RESOLUTION_FAILED, 134 } address_resolution_event_t; 135 136 typedef enum { 137 EC_KEY_GENERATION_IDLE, 138 EC_KEY_GENERATION_ACTIVE, 139 EC_KEY_GENERATION_DONE, 140 } ec_key_generation_state_t; 141 142 typedef enum { 143 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 144 } sm_state_var_t; 145 146 // 147 // GLOBAL DATA 148 // 149 150 static uint8_t test_use_fixed_local_csrk; 151 152 // configuration 153 static uint8_t sm_accepted_stk_generation_methods; 154 static uint8_t sm_max_encryption_key_size; 155 static uint8_t sm_min_encryption_key_size; 156 static uint8_t sm_auth_req = 0; 157 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 158 static uint8_t sm_slave_request_security; 159 #ifdef ENABLE_LE_SECURE_CONNECTIONS 160 static uint8_t sm_have_ec_keypair; 161 #endif 162 163 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 164 static sm_key_t sm_persistent_er; 165 static sm_key_t sm_persistent_ir; 166 167 // derived from sm_persistent_ir 168 static sm_key_t sm_persistent_dhk; 169 static sm_key_t sm_persistent_irk; 170 static uint8_t sm_persistent_irk_ready = 0; // used for testing 171 static derived_key_generation_t dkg_state; 172 173 // derived from sm_persistent_er 174 // .. 175 176 // random address update 177 static random_address_update_t rau_state; 178 static bd_addr_t sm_random_address; 179 180 // CMAC Calculation: General 181 static cmac_state_t sm_cmac_state; 182 static uint16_t sm_cmac_message_len; 183 static sm_key_t sm_cmac_k; 184 static sm_key_t sm_cmac_x; 185 static sm_key_t sm_cmac_m_last; 186 static uint8_t sm_cmac_block_current; 187 static uint8_t sm_cmac_block_count; 188 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 189 static void (*sm_cmac_done_handler)(uint8_t * hash); 190 191 // CMAC for ATT Signed Writes 192 static uint8_t sm_cmac_header[3]; 193 static const uint8_t * sm_cmac_message; 194 static uint8_t sm_cmac_sign_counter[4]; 195 196 // CMAC for Secure Connection functions 197 #ifdef ENABLE_LE_SECURE_CONNECTIONS 198 static sm_connection_t * sm_cmac_connection; 199 static uint8_t sm_cmac_sc_buffer[80]; 200 #endif 201 202 // resolvable private address lookup / CSRK calculation 203 static int sm_address_resolution_test; 204 static int sm_address_resolution_ah_calculation_active; 205 static uint8_t sm_address_resolution_addr_type; 206 static bd_addr_t sm_address_resolution_address; 207 static void * sm_address_resolution_context; 208 static address_resolution_mode_t sm_address_resolution_mode; 209 static btstack_linked_list_t sm_address_resolution_general_queue; 210 211 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 212 static sm_aes128_state_t sm_aes128_state; 213 static void * sm_aes128_context; 214 215 // random engine. store context (ususally sm_connection_t) 216 static void * sm_random_context; 217 218 // to receive hci events 219 static btstack_packet_callback_registration_t hci_event_callback_registration; 220 221 /* to dispatch sm event */ 222 static btstack_linked_list_t sm_event_handlers; 223 224 225 // Software ECDH implementation provided by mbedtls 226 #ifdef USE_MBEDTLS_FOR_ECDH 227 // group is always valid 228 static mbedtls_ecp_group mbedtls_ec_group; 229 static ec_key_generation_state_t ec_key_generation_state; 230 static uint8_t ec_qx[32]; 231 static uint8_t ec_qy[32]; 232 static uint8_t ec_d[32]; 233 #ifndef HAVE_MALLOC 234 // COMP Method with Window 2 235 // 1300 bytes with 23 allocations 236 // #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) 237 // NAIVE Method with safe cond assignments (without safe cond, order changes and allocations fail) 238 #define MBEDTLS_ALLOC_BUFFER_SIZE (700+18*sizeof(void *)) 239 static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; 240 #endif 241 #endif 242 243 // 244 // Volume 3, Part H, Chapter 24 245 // "Security shall be initiated by the Security Manager in the device in the master role. 246 // The device in the slave role shall be the responding device." 247 // -> master := initiator, slave := responder 248 // 249 250 // data needed for security setup 251 typedef struct sm_setup_context { 252 253 btstack_timer_source_t sm_timeout; 254 255 // used in all phases 256 uint8_t sm_pairing_failed_reason; 257 258 // user response, (Phase 1 and/or 2) 259 uint8_t sm_user_response; 260 uint8_t sm_keypress_notification; 261 262 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 263 int sm_key_distribution_send_set; 264 int sm_key_distribution_received_set; 265 266 // Phase 2 (Pairing over SMP) 267 stk_generation_method_t sm_stk_generation_method; 268 sm_key_t sm_tk; 269 uint8_t sm_use_secure_connections; 270 271 sm_key_t sm_c1_t3_value; // c1 calculation 272 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 273 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 274 sm_key_t sm_local_random; 275 sm_key_t sm_local_confirm; 276 sm_key_t sm_peer_random; 277 sm_key_t sm_peer_confirm; 278 uint8_t sm_m_addr_type; // address and type can be removed 279 uint8_t sm_s_addr_type; // '' 280 bd_addr_t sm_m_address; // '' 281 bd_addr_t sm_s_address; // '' 282 sm_key_t sm_ltk; 283 284 uint8_t sm_state_vars; 285 #ifdef ENABLE_LE_SECURE_CONNECTIONS 286 uint8_t sm_peer_qx[32]; // also stores random for EC key generation during init 287 uint8_t sm_peer_qy[32]; // '' 288 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 289 sm_key_t sm_local_nonce; // might be combined with sm_local_random 290 sm_key_t sm_peer_dhkey_check; 291 sm_key_t sm_local_dhkey_check; 292 sm_key_t sm_ra; 293 sm_key_t sm_rb; 294 sm_key_t sm_t; // used for f5 and h6 295 sm_key_t sm_mackey; 296 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 297 #endif 298 299 // Phase 3 300 301 // key distribution, we generate 302 uint16_t sm_local_y; 303 uint16_t sm_local_div; 304 uint16_t sm_local_ediv; 305 uint8_t sm_local_rand[8]; 306 sm_key_t sm_local_ltk; 307 sm_key_t sm_local_csrk; 308 sm_key_t sm_local_irk; 309 // sm_local_address/addr_type not needed 310 311 // key distribution, received from peer 312 uint16_t sm_peer_y; 313 uint16_t sm_peer_div; 314 uint16_t sm_peer_ediv; 315 uint8_t sm_peer_rand[8]; 316 sm_key_t sm_peer_ltk; 317 sm_key_t sm_peer_irk; 318 sm_key_t sm_peer_csrk; 319 uint8_t sm_peer_addr_type; 320 bd_addr_t sm_peer_address; 321 322 } sm_setup_context_t; 323 324 // 325 static sm_setup_context_t the_setup; 326 static sm_setup_context_t * setup = &the_setup; 327 328 // active connection - the one for which the_setup is used for 329 static uint16_t sm_active_connection = 0; 330 331 // @returns 1 if oob data is available 332 // stores oob data in provided 16 byte buffer if not null 333 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 334 335 // horizontal: initiator capabilities 336 // vertial: responder capabilities 337 static const stk_generation_method_t stk_generation_method [5] [5] = { 338 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 339 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 340 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 341 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 342 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 343 }; 344 345 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 346 #ifdef ENABLE_LE_SECURE_CONNECTIONS 347 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 348 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 349 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 350 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 351 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 352 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 353 }; 354 #endif 355 356 static void sm_run(void); 357 static void sm_done_for_handle(hci_con_handle_t con_handle); 358 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 359 static inline int sm_calc_actual_encryption_key_size(int other); 360 static int sm_validate_stk_generation_method(void); 361 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 362 363 static void log_info_hex16(const char * name, uint16_t value){ 364 log_info("%-6s 0x%04x", name, value); 365 } 366 367 // @returns 1 if all bytes are 0 368 static int sm_is_null(uint8_t * data, int size){ 369 int i; 370 for (i=0; i < size ; i++){ 371 if (data[i]) return 0; 372 } 373 return 1; 374 } 375 376 static int sm_is_null_random(uint8_t random[8]){ 377 return sm_is_null(random, 8); 378 } 379 380 static int sm_is_null_key(uint8_t * key){ 381 return sm_is_null(key, 16); 382 } 383 384 // Key utils 385 static void sm_reset_tk(void){ 386 int i; 387 for (i=0;i<16;i++){ 388 setup->sm_tk[i] = 0; 389 } 390 } 391 392 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 393 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 394 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 395 int i; 396 for (i = max_encryption_size ; i < 16 ; i++){ 397 key[15-i] = 0; 398 } 399 } 400 401 // SMP Timeout implementation 402 403 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 404 // the Security Manager Timer shall be reset and started. 405 // 406 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 407 // 408 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 409 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 410 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 411 // established. 412 413 static void sm_timeout_handler(btstack_timer_source_t * timer){ 414 log_info("SM timeout"); 415 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 416 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 417 sm_done_for_handle(sm_conn->sm_handle); 418 419 // trigger handling of next ready connection 420 sm_run(); 421 } 422 static void sm_timeout_start(sm_connection_t * sm_conn){ 423 btstack_run_loop_remove_timer(&setup->sm_timeout); 424 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 425 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 426 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 427 btstack_run_loop_add_timer(&setup->sm_timeout); 428 } 429 static void sm_timeout_stop(void){ 430 btstack_run_loop_remove_timer(&setup->sm_timeout); 431 } 432 static void sm_timeout_reset(sm_connection_t * sm_conn){ 433 sm_timeout_stop(); 434 sm_timeout_start(sm_conn); 435 } 436 437 // end of sm timeout 438 439 // GAP Random Address updates 440 static gap_random_address_type_t gap_random_adress_type; 441 static btstack_timer_source_t gap_random_address_update_timer; 442 static uint32_t gap_random_adress_update_period; 443 444 static void gap_random_address_trigger(void){ 445 if (rau_state != RAU_IDLE) return; 446 log_info("gap_random_address_trigger"); 447 rau_state = RAU_GET_RANDOM; 448 sm_run(); 449 } 450 451 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 452 log_info("GAP Random Address Update due"); 453 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 454 btstack_run_loop_add_timer(&gap_random_address_update_timer); 455 gap_random_address_trigger(); 456 } 457 458 static void gap_random_address_update_start(void){ 459 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 460 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 461 btstack_run_loop_add_timer(&gap_random_address_update_timer); 462 } 463 464 static void gap_random_address_update_stop(void){ 465 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 466 } 467 468 469 static void sm_random_start(void * context){ 470 sm_random_context = context; 471 hci_send_cmd(&hci_le_rand); 472 } 473 474 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 475 // context is made availabe to aes128 result handler by this 476 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 477 sm_aes128_state = SM_AES128_ACTIVE; 478 sm_key_t key_flipped, plaintext_flipped; 479 reverse_128(key, key_flipped); 480 reverse_128(plaintext, plaintext_flipped); 481 sm_aes128_context = context; 482 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 483 } 484 485 // ah(k,r) helper 486 // r = padding || r 487 // r - 24 bit value 488 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 489 // r'= padding || r 490 memset(r_prime, 0, 16); 491 memcpy(&r_prime[13], r, 3); 492 } 493 494 // d1 helper 495 // d' = padding || r || d 496 // d,r - 16 bit values 497 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 498 // d'= padding || r || d 499 memset(d1_prime, 0, 16); 500 big_endian_store_16(d1_prime, 12, r); 501 big_endian_store_16(d1_prime, 14, d); 502 } 503 504 // dm helper 505 // r’ = padding || r 506 // r - 64 bit value 507 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 508 memset(r_prime, 0, 16); 509 memcpy(&r_prime[8], r, 8); 510 } 511 512 // calculate arguments for first AES128 operation in C1 function 513 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, sm_key_t t1){ 514 515 // p1 = pres || preq || rat’ || iat’ 516 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 517 // cant octet of pres becomes the most significant octet of p1. 518 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 519 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 520 // p1 is 0x05000800000302070710000001010001." 521 522 sm_key_t p1; 523 reverse_56(pres, &p1[0]); 524 reverse_56(preq, &p1[7]); 525 p1[14] = rat; 526 p1[15] = iat; 527 log_info_key("p1", p1); 528 log_info_key("r", r); 529 530 // t1 = r xor p1 531 int i; 532 for (i=0;i<16;i++){ 533 t1[i] = r[i] ^ p1[i]; 534 } 535 log_info_key("t1", t1); 536 } 537 538 // calculate arguments for second AES128 operation in C1 function 539 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 540 // p2 = padding || ia || ra 541 // "The least significant octet of ra becomes the least significant octet of p2 and 542 // the most significant octet of padding becomes the most significant octet of p2. 543 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 544 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 545 546 sm_key_t p2; 547 memset(p2, 0, 16); 548 memcpy(&p2[4], ia, 6); 549 memcpy(&p2[10], ra, 6); 550 log_info_key("p2", p2); 551 552 // c1 = e(k, t2_xor_p2) 553 int i; 554 for (i=0;i<16;i++){ 555 t3[i] = t2[i] ^ p2[i]; 556 } 557 log_info_key("t3", t3); 558 } 559 560 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 561 log_info_key("r1", r1); 562 log_info_key("r2", r2); 563 memcpy(&r_prime[8], &r2[8], 8); 564 memcpy(&r_prime[0], &r1[8], 8); 565 } 566 567 #ifdef ENABLE_LE_SECURE_CONNECTIONS 568 // Software implementations of crypto toolbox for LE Secure Connection 569 // TODO: replace with code to use AES Engine of HCI Controller 570 typedef uint8_t sm_key24_t[3]; 571 typedef uint8_t sm_key56_t[7]; 572 typedef uint8_t sm_key256_t[32]; 573 574 #if 0 575 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 576 uint32_t rk[RKLENGTH(KEYBITS)]; 577 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 578 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 579 } 580 581 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 582 memcpy(k1, k0, 16); 583 sm_shift_left_by_one_bit_inplace(16, k1); 584 if (k0[0] & 0x80){ 585 k1[15] ^= 0x87; 586 } 587 memcpy(k2, k1, 16); 588 sm_shift_left_by_one_bit_inplace(16, k2); 589 if (k1[0] & 0x80){ 590 k2[15] ^= 0x87; 591 } 592 } 593 594 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 595 sm_key_t k0, k1, k2, zero; 596 memset(zero, 0, 16); 597 598 aes128_calc_cyphertext(key, zero, k0); 599 calc_subkeys(k0, k1, k2); 600 601 int cmac_block_count = (cmac_message_len + 15) / 16; 602 603 // step 3: .. 604 if (cmac_block_count==0){ 605 cmac_block_count = 1; 606 } 607 608 // step 4: set m_last 609 sm_key_t cmac_m_last; 610 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 611 int i; 612 if (sm_cmac_last_block_complete){ 613 for (i=0;i<16;i++){ 614 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 615 } 616 } else { 617 int valid_octets_in_last_block = cmac_message_len & 0x0f; 618 for (i=0;i<16;i++){ 619 if (i < valid_octets_in_last_block){ 620 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 621 continue; 622 } 623 if (i == valid_octets_in_last_block){ 624 cmac_m_last[i] = 0x80 ^ k2[i]; 625 continue; 626 } 627 cmac_m_last[i] = k2[i]; 628 } 629 } 630 631 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 632 // LOG_KEY(cmac_m_last); 633 634 // Step 5 635 sm_key_t cmac_x; 636 memset(cmac_x, 0, 16); 637 638 // Step 6 639 sm_key_t sm_cmac_y; 640 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 641 for (i=0;i<16;i++){ 642 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 643 } 644 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 645 } 646 for (i=0;i<16;i++){ 647 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 648 } 649 650 // Step 7 651 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 652 } 653 #endif 654 #endif 655 656 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 657 event[0] = type; 658 event[1] = event_size - 2; 659 little_endian_store_16(event, 2, con_handle); 660 event[4] = addr_type; 661 reverse_bd_addr(address, &event[5]); 662 } 663 664 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 665 // dispatch to all event handlers 666 btstack_linked_list_iterator_t it; 667 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 668 while (btstack_linked_list_iterator_has_next(&it)){ 669 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 670 entry->callback(packet_type, 0, packet, size); 671 } 672 } 673 674 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 675 uint8_t event[11]; 676 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 677 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 678 } 679 680 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 681 uint8_t event[15]; 682 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 683 little_endian_store_32(event, 11, passkey); 684 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 685 } 686 687 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 688 uint8_t event[13]; 689 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 690 little_endian_store_16(event, 11, index); 691 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 692 } 693 694 static void sm_notify_client_authorization(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t result){ 695 696 uint8_t event[18]; 697 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 698 event[11] = result; 699 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 700 } 701 702 // decide on stk generation based on 703 // - pairing request 704 // - io capabilities 705 // - OOB data availability 706 static void sm_setup_tk(void){ 707 708 // default: just works 709 setup->sm_stk_generation_method = JUST_WORKS; 710 711 #ifdef ENABLE_LE_SECURE_CONNECTIONS 712 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 713 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 714 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 715 memset(setup->sm_ra, 0, 16); 716 memset(setup->sm_rb, 0, 16); 717 #else 718 setup->sm_use_secure_connections = 0; 719 #endif 720 721 // If both devices have not set the MITM option in the Authentication Requirements 722 // Flags, then the IO capabilities shall be ignored and the Just Works association 723 // model shall be used. 724 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 725 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 726 log_info("SM: MITM not required by both -> JUST WORKS"); 727 return; 728 } 729 730 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 731 732 // If both devices have out of band authentication data, then the Authentication 733 // Requirements Flags shall be ignored when selecting the pairing method and the 734 // Out of Band pairing method shall be used. 735 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 736 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 737 log_info("SM: have OOB data"); 738 log_info_key("OOB", setup->sm_tk); 739 setup->sm_stk_generation_method = OOB; 740 return; 741 } 742 743 // Reset TK as it has been setup in sm_init_setup 744 sm_reset_tk(); 745 746 // Also use just works if unknown io capabilites 747 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 748 return; 749 } 750 751 // Otherwise the IO capabilities of the devices shall be used to determine the 752 // pairing method as defined in Table 2.4. 753 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 754 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 755 756 #ifdef ENABLE_LE_SECURE_CONNECTIONS 757 // table not define by default 758 if (setup->sm_use_secure_connections){ 759 generation_method = stk_generation_method_with_secure_connection; 760 } 761 #endif 762 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 763 764 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 765 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 766 } 767 768 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 769 int flags = 0; 770 if (key_set & SM_KEYDIST_ENC_KEY){ 771 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 772 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 773 } 774 if (key_set & SM_KEYDIST_ID_KEY){ 775 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 776 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 777 } 778 if (key_set & SM_KEYDIST_SIGN){ 779 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 780 } 781 return flags; 782 } 783 784 static void sm_setup_key_distribution(uint8_t key_set){ 785 setup->sm_key_distribution_received_set = 0; 786 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 787 } 788 789 // CSRK Key Lookup 790 791 792 static int sm_address_resolution_idle(void){ 793 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 794 } 795 796 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 797 memcpy(sm_address_resolution_address, addr, 6); 798 sm_address_resolution_addr_type = addr_type; 799 sm_address_resolution_test = 0; 800 sm_address_resolution_mode = mode; 801 sm_address_resolution_context = context; 802 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 803 } 804 805 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 806 // check if already in list 807 btstack_linked_list_iterator_t it; 808 sm_lookup_entry_t * entry; 809 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 810 while(btstack_linked_list_iterator_has_next(&it)){ 811 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 812 if (entry->address_type != address_type) continue; 813 if (memcmp(entry->address, address, 6)) continue; 814 // already in list 815 return BTSTACK_BUSY; 816 } 817 entry = btstack_memory_sm_lookup_entry_get(); 818 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 819 entry->address_type = (bd_addr_type_t) address_type; 820 memcpy(entry->address, address, 6); 821 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 822 sm_run(); 823 return 0; 824 } 825 826 // CMAC Implementation using AES128 engine 827 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 828 int i; 829 int carry = 0; 830 for (i=len-1; i >= 0 ; i--){ 831 int new_carry = data[i] >> 7; 832 data[i] = data[i] << 1 | carry; 833 carry = new_carry; 834 } 835 } 836 837 // while x_state++ for an enum is possible in C, it isn't in C++. we use this helpers to avoid compile errors for now 838 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 839 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 840 } 841 static inline void dkg_next_state(void){ 842 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 843 } 844 static inline void rau_next_state(void){ 845 rau_state = (random_address_update_t) (((int)rau_state) + 1); 846 } 847 848 // CMAC calculation using AES Engine 849 850 static inline void sm_cmac_next_state(void){ 851 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 852 } 853 854 static int sm_cmac_last_block_complete(void){ 855 if (sm_cmac_message_len == 0) return 0; 856 return (sm_cmac_message_len & 0x0f) == 0; 857 } 858 859 int sm_cmac_ready(void){ 860 return sm_cmac_state == CMAC_IDLE; 861 } 862 863 // generic cmac calculation 864 void sm_cmac_general_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t hash[8])){ 865 // Generalized CMAC 866 memcpy(sm_cmac_k, key, 16); 867 memset(sm_cmac_x, 0, 16); 868 sm_cmac_block_current = 0; 869 sm_cmac_message_len = message_len; 870 sm_cmac_done_handler = done_callback; 871 sm_cmac_get_byte = get_byte_callback; 872 873 // step 2: n := ceil(len/const_Bsize); 874 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 875 876 // step 3: .. 877 if (sm_cmac_block_count==0){ 878 sm_cmac_block_count = 1; 879 } 880 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 881 882 // first, we need to compute l for k1, k2, and m_last 883 sm_cmac_state = CMAC_CALC_SUBKEYS; 884 885 // let's go 886 sm_run(); 887 } 888 889 // cmac for ATT Message signing 890 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 891 if (offset >= sm_cmac_message_len) { 892 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 893 return 0; 894 } 895 896 offset = sm_cmac_message_len - 1 - offset; 897 898 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 899 if (offset < 3){ 900 return sm_cmac_header[offset]; 901 } 902 int actual_message_len_incl_header = sm_cmac_message_len - 4; 903 if (offset < actual_message_len_incl_header){ 904 return sm_cmac_message[offset - 3]; 905 } 906 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 907 } 908 909 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 910 // ATT Message Signing 911 sm_cmac_header[0] = opcode; 912 little_endian_store_16(sm_cmac_header, 1, con_handle); 913 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 914 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 915 sm_cmac_message = message; 916 sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 917 } 918 919 920 static void sm_cmac_handle_aes_engine_ready(void){ 921 switch (sm_cmac_state){ 922 case CMAC_CALC_SUBKEYS: { 923 sm_key_t const_zero; 924 memset(const_zero, 0, 16); 925 sm_cmac_next_state(); 926 sm_aes128_start(sm_cmac_k, const_zero, NULL); 927 break; 928 } 929 case CMAC_CALC_MI: { 930 int j; 931 sm_key_t y; 932 for (j=0;j<16;j++){ 933 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 934 } 935 sm_cmac_block_current++; 936 sm_cmac_next_state(); 937 sm_aes128_start(sm_cmac_k, y, NULL); 938 break; 939 } 940 case CMAC_CALC_MLAST: { 941 int i; 942 sm_key_t y; 943 for (i=0;i<16;i++){ 944 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 945 } 946 log_info_key("Y", y); 947 sm_cmac_block_current++; 948 sm_cmac_next_state(); 949 sm_aes128_start(sm_cmac_k, y, NULL); 950 break; 951 } 952 default: 953 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 954 break; 955 } 956 } 957 958 static void sm_cmac_handle_encryption_result(sm_key_t data){ 959 switch (sm_cmac_state){ 960 case CMAC_W4_SUBKEYS: { 961 sm_key_t k1; 962 memcpy(k1, data, 16); 963 sm_shift_left_by_one_bit_inplace(16, k1); 964 if (data[0] & 0x80){ 965 k1[15] ^= 0x87; 966 } 967 sm_key_t k2; 968 memcpy(k2, k1, 16); 969 sm_shift_left_by_one_bit_inplace(16, k2); 970 if (k1[0] & 0x80){ 971 k2[15] ^= 0x87; 972 } 973 974 log_info_key("k", sm_cmac_k); 975 log_info_key("k1", k1); 976 log_info_key("k2", k2); 977 978 // step 4: set m_last 979 int i; 980 if (sm_cmac_last_block_complete()){ 981 for (i=0;i<16;i++){ 982 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 983 } 984 } else { 985 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 986 for (i=0;i<16;i++){ 987 if (i < valid_octets_in_last_block){ 988 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 989 continue; 990 } 991 if (i == valid_octets_in_last_block){ 992 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 993 continue; 994 } 995 sm_cmac_m_last[i] = k2[i]; 996 } 997 } 998 999 // next 1000 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1001 break; 1002 } 1003 case CMAC_W4_MI: 1004 memcpy(sm_cmac_x, data, 16); 1005 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1006 break; 1007 case CMAC_W4_MLAST: 1008 // done 1009 log_info("Setting CMAC Engine to IDLE"); 1010 sm_cmac_state = CMAC_IDLE; 1011 log_info_key("CMAC", data); 1012 sm_cmac_done_handler(data); 1013 break; 1014 default: 1015 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1016 break; 1017 } 1018 } 1019 1020 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1021 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1022 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1023 switch (setup->sm_stk_generation_method){ 1024 case PK_RESP_INPUT: 1025 if (sm_conn->sm_role){ 1026 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1027 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1028 } else { 1029 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1030 } 1031 break; 1032 case PK_INIT_INPUT: 1033 if (sm_conn->sm_role){ 1034 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1035 } else { 1036 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1037 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1038 } 1039 break; 1040 case OK_BOTH_INPUT: 1041 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1042 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1043 break; 1044 case NK_BOTH_INPUT: 1045 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1046 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1047 break; 1048 case JUST_WORKS: 1049 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1050 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1051 break; 1052 case OOB: 1053 // client already provided OOB data, let's skip notification. 1054 break; 1055 } 1056 } 1057 1058 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1059 int recv_flags; 1060 if (sm_conn->sm_role){ 1061 // slave / responder 1062 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1063 } else { 1064 // master / initiator 1065 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1066 } 1067 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1068 return recv_flags == setup->sm_key_distribution_received_set; 1069 } 1070 1071 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1072 if (sm_active_connection == con_handle){ 1073 sm_timeout_stop(); 1074 sm_active_connection = 0; 1075 log_info("sm: connection 0x%x released setup context", con_handle); 1076 } 1077 } 1078 1079 static int sm_key_distribution_flags_for_auth_req(void){ 1080 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1081 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1082 // encryption information only if bonding requested 1083 flags |= SM_KEYDIST_ENC_KEY; 1084 } 1085 return flags; 1086 } 1087 1088 static void sm_reset_setup(void){ 1089 // fill in sm setup 1090 setup->sm_state_vars = 0; 1091 setup->sm_keypress_notification = 0xff; 1092 sm_reset_tk(); 1093 } 1094 1095 static void sm_init_setup(sm_connection_t * sm_conn){ 1096 1097 // fill in sm setup 1098 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1099 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1100 1101 // query client for OOB data 1102 int have_oob_data = 0; 1103 if (sm_get_oob_data) { 1104 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1105 } 1106 1107 sm_pairing_packet_t * local_packet; 1108 if (sm_conn->sm_role){ 1109 // slave 1110 local_packet = &setup->sm_s_pres; 1111 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1112 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1113 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1114 } else { 1115 // master 1116 local_packet = &setup->sm_m_preq; 1117 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1118 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1119 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1120 1121 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1122 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1123 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1124 } 1125 1126 uint8_t auth_req = sm_auth_req; 1127 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1128 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1129 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1130 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1131 } 1132 1133 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1134 1135 sm_pairing_packet_t * remote_packet; 1136 int remote_key_request; 1137 if (sm_conn->sm_role){ 1138 // slave / responder 1139 remote_packet = &setup->sm_m_preq; 1140 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1141 } else { 1142 // master / initiator 1143 remote_packet = &setup->sm_s_pres; 1144 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1145 } 1146 1147 // check key size 1148 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1149 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1150 1151 // decide on STK generation method 1152 sm_setup_tk(); 1153 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1154 1155 // check if STK generation method is acceptable by client 1156 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1157 1158 // identical to responder 1159 sm_setup_key_distribution(remote_key_request); 1160 1161 // JUST WORKS doens't provide authentication 1162 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1163 1164 return 0; 1165 } 1166 1167 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1168 1169 // cache and reset context 1170 int matched_device_id = sm_address_resolution_test; 1171 address_resolution_mode_t mode = sm_address_resolution_mode; 1172 void * context = sm_address_resolution_context; 1173 1174 // reset context 1175 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1176 sm_address_resolution_context = NULL; 1177 sm_address_resolution_test = -1; 1178 hci_con_handle_t con_handle = 0; 1179 1180 sm_connection_t * sm_connection; 1181 sm_key_t ltk; 1182 switch (mode){ 1183 case ADDRESS_RESOLUTION_GENERAL: 1184 break; 1185 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1186 sm_connection = (sm_connection_t *) context; 1187 con_handle = sm_connection->sm_handle; 1188 switch (event){ 1189 case ADDRESS_RESOLUTION_SUCEEDED: 1190 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1191 sm_connection->sm_le_db_index = matched_device_id; 1192 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1193 if (sm_connection->sm_role) break; 1194 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1195 sm_connection->sm_security_request_received = 0; 1196 sm_connection->sm_bonding_requested = 0; 1197 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 1198 if (!sm_is_null_key(ltk)){ 1199 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1200 } else { 1201 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1202 } 1203 break; 1204 case ADDRESS_RESOLUTION_FAILED: 1205 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1206 if (sm_connection->sm_role) break; 1207 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1208 sm_connection->sm_security_request_received = 0; 1209 sm_connection->sm_bonding_requested = 0; 1210 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1211 break; 1212 } 1213 break; 1214 default: 1215 break; 1216 } 1217 1218 switch (event){ 1219 case ADDRESS_RESOLUTION_SUCEEDED: 1220 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1221 break; 1222 case ADDRESS_RESOLUTION_FAILED: 1223 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1224 break; 1225 } 1226 } 1227 1228 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1229 1230 int le_db_index = -1; 1231 1232 // lookup device based on IRK 1233 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1234 int i; 1235 for (i=0; i < le_device_db_count(); i++){ 1236 sm_key_t irk; 1237 bd_addr_t address; 1238 int address_type; 1239 le_device_db_info(i, &address_type, address, irk); 1240 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1241 log_info("sm: device found for IRK, updating"); 1242 le_db_index = i; 1243 break; 1244 } 1245 } 1246 } 1247 1248 // if not found, lookup via public address if possible 1249 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1250 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1251 int i; 1252 for (i=0; i < le_device_db_count(); i++){ 1253 bd_addr_t address; 1254 int address_type; 1255 le_device_db_info(i, &address_type, address, NULL); 1256 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1257 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1258 log_info("sm: device found for public address, updating"); 1259 le_db_index = i; 1260 break; 1261 } 1262 } 1263 } 1264 1265 // if not found, add to db 1266 if (le_db_index < 0) { 1267 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1268 } 1269 1270 if (le_db_index >= 0){ 1271 1272 // store local CSRK 1273 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1274 log_info("sm: store local CSRK"); 1275 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1276 le_device_db_local_counter_set(le_db_index, 0); 1277 } 1278 1279 // store remote CSRK 1280 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1281 log_info("sm: store remote CSRK"); 1282 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1283 le_device_db_remote_counter_set(le_db_index, 0); 1284 } 1285 1286 // store encryption information for secure connections: LTK generated by ECDH 1287 if (setup->sm_use_secure_connections){ 1288 log_info("sm: store SC LTK (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1289 uint8_t zero_rand[8]; 1290 memset(zero_rand, 0, 8); 1291 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1292 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1293 } 1294 1295 // store encryption infromation for legacy pairing: peer LTK, EDIV, RAND 1296 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1297 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1298 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1299 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1300 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1301 1302 } 1303 } 1304 1305 // keep le_db_index 1306 sm_conn->sm_le_db_index = le_db_index; 1307 } 1308 1309 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1310 setup->sm_pairing_failed_reason = reason; 1311 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1312 } 1313 1314 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1315 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1316 } 1317 1318 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1319 1320 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1321 static int sm_passkey_used(stk_generation_method_t method); 1322 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1323 1324 static void sm_log_ec_keypair(void){ 1325 log_info("Elliptic curve: d"); 1326 log_info_hexdump(ec_d,32); 1327 log_info("Elliptic curve: X"); 1328 log_info_hexdump(ec_qx,32); 1329 log_info("Elliptic curve: Y"); 1330 log_info_hexdump(ec_qy,32); 1331 } 1332 1333 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1334 if (sm_passkey_used(setup->sm_stk_generation_method)){ 1335 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 1336 } else { 1337 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1338 } 1339 } 1340 1341 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1342 if (sm_conn->sm_role){ 1343 // Responder 1344 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1345 } else { 1346 // Initiator role 1347 switch (setup->sm_stk_generation_method){ 1348 case JUST_WORKS: 1349 sm_sc_prepare_dhkey_check(sm_conn); 1350 break; 1351 1352 case NK_BOTH_INPUT: 1353 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1354 break; 1355 case PK_INIT_INPUT: 1356 case PK_RESP_INPUT: 1357 case OK_BOTH_INPUT: 1358 if (setup->sm_passkey_bit < 20) { 1359 sm_sc_start_calculating_local_confirm(sm_conn); 1360 } else { 1361 sm_sc_prepare_dhkey_check(sm_conn); 1362 } 1363 break; 1364 case OOB: 1365 // TODO: implement SC OOB 1366 break; 1367 } 1368 } 1369 } 1370 1371 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1372 return sm_cmac_sc_buffer[offset]; 1373 } 1374 1375 static void sm_sc_cmac_done(uint8_t * hash){ 1376 log_info("sm_sc_cmac_done: "); 1377 log_info_hexdump(hash, 16); 1378 1379 sm_connection_t * sm_conn = sm_cmac_connection; 1380 sm_cmac_connection = NULL; 1381 link_key_type_t link_key_type; 1382 1383 switch (sm_conn->sm_engine_state){ 1384 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1385 memcpy(setup->sm_local_confirm, hash, 16); 1386 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1387 break; 1388 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1389 // check 1390 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1391 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1392 break; 1393 } 1394 sm_sc_state_after_receiving_random(sm_conn); 1395 break; 1396 case SM_SC_W4_CALCULATE_G2: { 1397 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1398 big_endian_store_32(setup->sm_tk, 12, vab); 1399 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1400 sm_trigger_user_response(sm_conn); 1401 break; 1402 } 1403 case SM_SC_W4_CALCULATE_F5_SALT: 1404 memcpy(setup->sm_t, hash, 16); 1405 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1406 break; 1407 case SM_SC_W4_CALCULATE_F5_MACKEY: 1408 memcpy(setup->sm_mackey, hash, 16); 1409 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1410 break; 1411 case SM_SC_W4_CALCULATE_F5_LTK: 1412 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1413 // Errata Service Release to the Bluetooth Specification: ESR09 1414 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1415 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1416 memcpy(setup->sm_ltk, hash, 16); 1417 memcpy(setup->sm_local_ltk, hash, 16); 1418 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1419 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1420 break; 1421 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1422 memcpy(setup->sm_local_dhkey_check, hash, 16); 1423 if (sm_conn->sm_role){ 1424 // responder 1425 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1426 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1427 } else { 1428 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1429 } 1430 } else { 1431 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1432 } 1433 break; 1434 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1435 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1436 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1437 break; 1438 } 1439 if (sm_conn->sm_role){ 1440 // responder 1441 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1442 } else { 1443 // initiator 1444 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1445 } 1446 break; 1447 case SM_SC_W4_CALCULATE_H6_ILK: 1448 memcpy(setup->sm_t, hash, 16); 1449 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1450 break; 1451 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1452 reverse_128(hash, setup->sm_t); 1453 link_key_type = sm_conn->sm_connection_authenticated ? 1454 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1455 if (sm_conn->sm_role){ 1456 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1457 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1458 } else { 1459 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1460 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1461 } 1462 sm_done_for_handle(sm_conn->sm_handle); 1463 break; 1464 default: 1465 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1466 break; 1467 } 1468 sm_run(); 1469 } 1470 1471 static void f4_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, uint8_t z){ 1472 const uint16_t message_len = 65; 1473 sm_cmac_connection = sm_conn; 1474 memcpy(sm_cmac_sc_buffer, u, 32); 1475 memcpy(sm_cmac_sc_buffer+32, v, 32); 1476 sm_cmac_sc_buffer[64] = z; 1477 log_info("f4 key"); 1478 log_info_hexdump(x, 16); 1479 log_info("f4 message"); 1480 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1481 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1482 } 1483 1484 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1485 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1486 static const uint8_t f5_length[] = { 0x01, 0x00}; 1487 1488 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1489 #ifdef USE_MBEDTLS_FOR_ECDH 1490 // da * Pb 1491 mbedtls_mpi d; 1492 mbedtls_ecp_point Q; 1493 mbedtls_ecp_point DH; 1494 mbedtls_mpi_init(&d); 1495 mbedtls_ecp_point_init(&Q); 1496 mbedtls_ecp_point_init(&DH); 1497 mbedtls_mpi_read_binary(&d, ec_d, 32); 1498 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1499 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1500 mbedtls_mpi_lset(&Q.Z, 1); 1501 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1502 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1503 mbedtls_ecp_point_free(&DH); 1504 mbedtls_mpi_free(&d); 1505 mbedtls_ecp_point_free(&Q); 1506 #endif 1507 log_info("dhkey"); 1508 log_info_hexdump(dhkey, 32); 1509 } 1510 1511 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1512 // calculate DHKEY 1513 sm_key256_t dhkey; 1514 sm_sc_calculate_dhkey(dhkey); 1515 1516 // calculate salt for f5 1517 const uint16_t message_len = 32; 1518 sm_cmac_connection = sm_conn; 1519 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1520 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1521 } 1522 1523 static inline void f5_mackkey(sm_connection_t * sm_conn, sm_key_t t, const sm_key_t n1, const sm_key_t n2, const sm_key56_t a1, const sm_key56_t a2){ 1524 const uint16_t message_len = 53; 1525 sm_cmac_connection = sm_conn; 1526 1527 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1528 sm_cmac_sc_buffer[0] = 0; 1529 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1530 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1531 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1532 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1533 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1534 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1535 log_info("f5 key"); 1536 log_info_hexdump(t, 16); 1537 log_info("f5 message for MacKey"); 1538 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1539 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1540 } 1541 1542 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1543 sm_key56_t bd_addr_master, bd_addr_slave; 1544 bd_addr_master[0] = setup->sm_m_addr_type; 1545 bd_addr_slave[0] = setup->sm_s_addr_type; 1546 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1547 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1548 if (sm_conn->sm_role){ 1549 // responder 1550 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1551 } else { 1552 // initiator 1553 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1554 } 1555 } 1556 1557 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1558 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1559 const uint16_t message_len = 53; 1560 sm_cmac_connection = sm_conn; 1561 sm_cmac_sc_buffer[0] = 1; 1562 // 1..52 setup before 1563 log_info("f5 key"); 1564 log_info_hexdump(t, 16); 1565 log_info("f5 message for LTK"); 1566 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1567 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1568 } 1569 1570 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1571 f5_ltk(sm_conn, setup->sm_t); 1572 } 1573 1574 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w, const sm_key_t n1, const sm_key_t n2, const sm_key_t r, const sm_key24_t io_cap, const sm_key56_t a1, const sm_key56_t a2){ 1575 const uint16_t message_len = 65; 1576 sm_cmac_connection = sm_conn; 1577 memcpy(sm_cmac_sc_buffer, n1, 16); 1578 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1579 memcpy(sm_cmac_sc_buffer+32, r, 16); 1580 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1581 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1582 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1583 log_info("f6 key"); 1584 log_info_hexdump(w, 16); 1585 log_info("f6 message"); 1586 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1587 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1588 } 1589 1590 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1591 // - U is 256 bits 1592 // - V is 256 bits 1593 // - X is 128 bits 1594 // - Y is 128 bits 1595 static void g2_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 1596 const uint16_t message_len = 80; 1597 sm_cmac_connection = sm_conn; 1598 memcpy(sm_cmac_sc_buffer, u, 32); 1599 memcpy(sm_cmac_sc_buffer+32, v, 32); 1600 memcpy(sm_cmac_sc_buffer+64, y, 16); 1601 log_info("g2 key"); 1602 log_info_hexdump(x, 16); 1603 log_info("g2 message"); 1604 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1605 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1606 } 1607 1608 static void g2_calculate(sm_connection_t * sm_conn) { 1609 // calc Va if numeric comparison 1610 if (sm_conn->sm_role){ 1611 // responder 1612 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1613 } else { 1614 // initiator 1615 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1616 } 1617 } 1618 1619 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1620 uint8_t z = 0; 1621 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1622 // some form of passkey 1623 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1624 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1625 setup->sm_passkey_bit++; 1626 } 1627 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1628 } 1629 1630 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1631 uint8_t z = 0; 1632 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1633 // some form of passkey 1634 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1635 // sm_passkey_bit was increased before sending confirm value 1636 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1637 } 1638 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1639 } 1640 1641 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1642 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1643 } 1644 1645 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1646 // calculate DHKCheck 1647 sm_key56_t bd_addr_master, bd_addr_slave; 1648 bd_addr_master[0] = setup->sm_m_addr_type; 1649 bd_addr_slave[0] = setup->sm_s_addr_type; 1650 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1651 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1652 uint8_t iocap_a[3]; 1653 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1654 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1655 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1656 uint8_t iocap_b[3]; 1657 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1658 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1659 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1660 if (sm_conn->sm_role){ 1661 // responder 1662 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1663 } else { 1664 // initiator 1665 f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1666 } 1667 } 1668 1669 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1670 // validate E = f6() 1671 sm_key56_t bd_addr_master, bd_addr_slave; 1672 bd_addr_master[0] = setup->sm_m_addr_type; 1673 bd_addr_slave[0] = setup->sm_s_addr_type; 1674 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1675 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1676 1677 uint8_t iocap_a[3]; 1678 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1679 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1680 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1681 uint8_t iocap_b[3]; 1682 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1683 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1684 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1685 if (sm_conn->sm_role){ 1686 // responder 1687 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1688 } else { 1689 // initiator 1690 f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1691 } 1692 } 1693 1694 1695 // 1696 // Link Key Conversion Function h6 1697 // 1698 // h6(W, keyID) = AES-CMACW(keyID) 1699 // - W is 128 bits 1700 // - keyID is 32 bits 1701 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1702 const uint16_t message_len = 4; 1703 sm_cmac_connection = sm_conn; 1704 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1705 log_info("h6 key"); 1706 log_info_hexdump(w, 16); 1707 log_info("h6 message"); 1708 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1709 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1710 } 1711 1712 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1713 // Errata Service Release to the Bluetooth Specification: ESR09 1714 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1715 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1716 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1717 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1718 } 1719 1720 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1721 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1722 } 1723 1724 #endif 1725 1726 // key management legacy connections: 1727 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1728 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1729 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1730 // - responder reconnects: responder uses LTK receveived from master 1731 1732 // key management secure connections: 1733 // - both devices store same LTK from ECDH key exchange. 1734 1735 static void sm_load_security_info(sm_connection_t * sm_connection){ 1736 int encryption_key_size; 1737 int authenticated; 1738 int authorized; 1739 1740 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1741 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1742 &encryption_key_size, &authenticated, &authorized); 1743 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1744 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1745 sm_connection->sm_connection_authenticated = authenticated; 1746 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1747 } 1748 1749 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1750 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1751 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1752 // re-establish used key encryption size 1753 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1754 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1755 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1756 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1757 log_info("sm: received ltk request with key size %u, authenticated %u", 1758 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1759 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1760 } 1761 1762 static void sm_run(void){ 1763 1764 btstack_linked_list_iterator_t it; 1765 1766 // assert that we can send at least commands 1767 if (!hci_can_send_command_packet_now()) return; 1768 1769 // 1770 // non-connection related behaviour 1771 // 1772 1773 // distributed key generation 1774 switch (dkg_state){ 1775 case DKG_CALC_IRK: 1776 // already busy? 1777 if (sm_aes128_state == SM_AES128_IDLE) { 1778 // IRK = d1(IR, 1, 0) 1779 sm_key_t d1_prime; 1780 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1781 dkg_next_state(); 1782 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1783 return; 1784 } 1785 break; 1786 case DKG_CALC_DHK: 1787 // already busy? 1788 if (sm_aes128_state == SM_AES128_IDLE) { 1789 // DHK = d1(IR, 3, 0) 1790 sm_key_t d1_prime; 1791 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1792 dkg_next_state(); 1793 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1794 return; 1795 } 1796 break; 1797 default: 1798 break; 1799 } 1800 1801 #ifdef USE_MBEDTLS_FOR_ECDH 1802 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1803 sm_random_start(NULL); 1804 return; 1805 } 1806 #endif 1807 1808 // random address updates 1809 switch (rau_state){ 1810 case RAU_GET_RANDOM: 1811 rau_next_state(); 1812 sm_random_start(NULL); 1813 return; 1814 case RAU_GET_ENC: 1815 // already busy? 1816 if (sm_aes128_state == SM_AES128_IDLE) { 1817 sm_key_t r_prime; 1818 sm_ah_r_prime(sm_random_address, r_prime); 1819 rau_next_state(); 1820 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1821 return; 1822 } 1823 break; 1824 case RAU_SET_ADDRESS: 1825 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1826 rau_state = RAU_IDLE; 1827 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1828 return; 1829 default: 1830 break; 1831 } 1832 1833 // CMAC 1834 switch (sm_cmac_state){ 1835 case CMAC_CALC_SUBKEYS: 1836 case CMAC_CALC_MI: 1837 case CMAC_CALC_MLAST: 1838 // already busy? 1839 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1840 sm_cmac_handle_aes_engine_ready(); 1841 return; 1842 default: 1843 break; 1844 } 1845 1846 // CSRK Lookup 1847 // -- if csrk lookup ready, find connection that require csrk lookup 1848 if (sm_address_resolution_idle()){ 1849 hci_connections_get_iterator(&it); 1850 while(btstack_linked_list_iterator_has_next(&it)){ 1851 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1852 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1853 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1854 // and start lookup 1855 sm_address_resolution_start_lookup(sm_connection->sm_peer_addr_type, sm_connection->sm_handle, sm_connection->sm_peer_address, ADDRESS_RESOLUTION_FOR_CONNECTION, sm_connection); 1856 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1857 break; 1858 } 1859 } 1860 } 1861 1862 // -- if csrk lookup ready, resolved addresses for received addresses 1863 if (sm_address_resolution_idle()) { 1864 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1865 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1866 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1867 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1868 btstack_memory_sm_lookup_entry_free(entry); 1869 } 1870 } 1871 1872 // -- Continue with CSRK device lookup by public or resolvable private address 1873 if (!sm_address_resolution_idle()){ 1874 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1875 while (sm_address_resolution_test < le_device_db_count()){ 1876 int addr_type; 1877 bd_addr_t addr; 1878 sm_key_t irk; 1879 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1880 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1881 1882 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1883 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1884 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1885 break; 1886 } 1887 1888 if (sm_address_resolution_addr_type == 0){ 1889 sm_address_resolution_test++; 1890 continue; 1891 } 1892 1893 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1894 1895 log_info("LE Device Lookup: calculate AH"); 1896 log_info_key("IRK", irk); 1897 1898 sm_key_t r_prime; 1899 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1900 sm_address_resolution_ah_calculation_active = 1; 1901 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1902 return; 1903 } 1904 1905 if (sm_address_resolution_test >= le_device_db_count()){ 1906 log_info("LE Device Lookup: not found"); 1907 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1908 } 1909 } 1910 1911 // handle basic actions that don't requires the full context 1912 hci_connections_get_iterator(&it); 1913 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1914 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1915 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1916 switch(sm_connection->sm_engine_state){ 1917 // responder side 1918 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1919 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1920 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1921 return; 1922 default: 1923 break; 1924 } 1925 } 1926 1927 // 1928 // active connection handling 1929 // -- use loop to handle next connection if lock on setup context is released 1930 1931 while (1) { 1932 1933 // Find connections that requires setup context and make active if no other is locked 1934 hci_connections_get_iterator(&it); 1935 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1936 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1937 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1938 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1939 int done = 1; 1940 int err; 1941 switch (sm_connection->sm_engine_state) { 1942 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1943 // send packet if possible, 1944 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1945 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1946 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1947 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1948 } else { 1949 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1950 } 1951 // don't lock sxetup context yet 1952 done = 0; 1953 break; 1954 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1955 sm_reset_setup(); 1956 sm_init_setup(sm_connection); 1957 // recover pairing request 1958 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1959 err = sm_stk_generation_init(sm_connection); 1960 if (err){ 1961 setup->sm_pairing_failed_reason = err; 1962 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1963 break; 1964 } 1965 sm_timeout_start(sm_connection); 1966 // generate random number first, if we need to show passkey 1967 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1968 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1969 break; 1970 } 1971 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1972 break; 1973 case SM_INITIATOR_PH0_HAS_LTK: 1974 sm_reset_setup(); 1975 sm_load_security_info(sm_connection); 1976 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1977 break; 1978 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 1979 sm_reset_setup(); 1980 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 1981 break; 1982 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1983 sm_reset_setup(); 1984 sm_init_setup(sm_connection); 1985 sm_timeout_start(sm_connection); 1986 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1987 break; 1988 1989 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1990 case SM_SC_RECEIVED_LTK_REQUEST: 1991 switch (sm_connection->sm_irk_lookup_state){ 1992 case IRK_LOOKUP_SUCCEEDED: 1993 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 1994 // start using context by loading security info 1995 sm_reset_setup(); 1996 sm_load_security_info(sm_connection); 1997 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 1998 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 1999 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2000 break; 2001 } 2002 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2003 sm_connection->sm_engine_state = SM_SC_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2004 break; 2005 case IRK_LOOKUP_FAILED: 2006 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2007 sm_connection->sm_engine_state = SM_SC_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2008 break; 2009 default: 2010 // just wait until IRK lookup is completed 2011 // don't lock setup context yet 2012 done = 0; 2013 break; 2014 } 2015 break; 2016 #endif 2017 default: 2018 done = 0; 2019 break; 2020 } 2021 if (done){ 2022 sm_active_connection = sm_connection->sm_handle; 2023 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 2024 } 2025 } 2026 2027 // 2028 // active connection handling 2029 // 2030 2031 if (sm_active_connection == 0) return; 2032 2033 // assert that we could send a SM PDU - not needed for all of the following 2034 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2035 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2036 return; 2037 } 2038 2039 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2040 if (!connection) return; 2041 2042 // send keypress notifications 2043 if (setup->sm_keypress_notification != 0xff){ 2044 uint8_t buffer[2]; 2045 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2046 buffer[1] = setup->sm_keypress_notification; 2047 setup->sm_keypress_notification = 0xff; 2048 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2049 return; 2050 } 2051 2052 sm_key_t plaintext; 2053 int key_distribution_flags; 2054 2055 log_info("sm_run: state %u", connection->sm_engine_state); 2056 2057 switch (connection->sm_engine_state){ 2058 2059 // general 2060 case SM_GENERAL_SEND_PAIRING_FAILED: { 2061 uint8_t buffer[2]; 2062 buffer[0] = SM_CODE_PAIRING_FAILED; 2063 buffer[1] = setup->sm_pairing_failed_reason; 2064 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2065 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2066 sm_done_for_handle(connection->sm_handle); 2067 break; 2068 } 2069 2070 // responding state 2071 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2072 case SM_SC_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2073 connection->sm_engine_state = SM_RESPONDER_IDLE; 2074 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2075 sm_done_for_handle(connection->sm_handle); 2076 return; 2077 case SM_SC_W2_GET_RANDOM_A: 2078 sm_random_start(connection); 2079 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2080 break; 2081 case SM_SC_W2_GET_RANDOM_B: 2082 sm_random_start(connection); 2083 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2084 break; 2085 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2086 if (!sm_cmac_ready()) break; 2087 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2088 sm_sc_calculate_local_confirm(connection); 2089 break; 2090 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2091 if (!sm_cmac_ready()) break; 2092 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2093 sm_sc_calculate_remote_confirm(connection); 2094 break; 2095 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2096 if (!sm_cmac_ready()) break; 2097 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2098 sm_sc_calculate_f6_for_dhkey_check(connection); 2099 break; 2100 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2101 if (!sm_cmac_ready()) break; 2102 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2103 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2104 break; 2105 case SM_SC_W2_CALCULATE_F5_SALT: 2106 if (!sm_cmac_ready()) break; 2107 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2108 f5_calculate_salt(connection); 2109 break; 2110 case SM_SC_W2_CALCULATE_F5_MACKEY: 2111 if (!sm_cmac_ready()) break; 2112 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2113 f5_calculate_mackey(connection); 2114 break; 2115 case SM_SC_W2_CALCULATE_F5_LTK: 2116 if (!sm_cmac_ready()) break; 2117 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2118 f5_calculate_ltk(connection); 2119 break; 2120 case SM_SC_W2_CALCULATE_G2: 2121 if (!sm_cmac_ready()) break; 2122 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2123 g2_calculate(connection); 2124 break; 2125 case SM_SC_W2_CALCULATE_H6_ILK: 2126 if (!sm_cmac_ready()) break; 2127 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2128 h6_calculate_ilk(connection); 2129 break; 2130 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2131 if (!sm_cmac_ready()) break; 2132 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2133 h6_calculate_br_edr_link_key(connection); 2134 break; 2135 #endif 2136 2137 // initiator side 2138 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2139 sm_key_t peer_ltk_flipped; 2140 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2141 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2142 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2143 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2144 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2145 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2146 return; 2147 } 2148 2149 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2150 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2151 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2152 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2153 sm_timeout_reset(connection); 2154 break; 2155 2156 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2157 2158 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2159 uint8_t buffer[65]; 2160 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2161 // 2162 reverse_256(ec_qx, &buffer[1]); 2163 reverse_256(ec_qy, &buffer[33]); 2164 2165 // stk generation method 2166 // passkey entry: notify app to show passkey or to request passkey 2167 switch (setup->sm_stk_generation_method){ 2168 case JUST_WORKS: 2169 case NK_BOTH_INPUT: 2170 if (connection->sm_role){ 2171 // responder 2172 sm_sc_start_calculating_local_confirm(connection); 2173 } else { 2174 // initiator 2175 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2176 } 2177 break; 2178 case PK_INIT_INPUT: 2179 case PK_RESP_INPUT: 2180 case OK_BOTH_INPUT: 2181 // use random TK for display 2182 memcpy(setup->sm_ra, setup->sm_tk, 16); 2183 memcpy(setup->sm_rb, setup->sm_tk, 16); 2184 setup->sm_passkey_bit = 0; 2185 2186 if (connection->sm_role){ 2187 // responder 2188 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2189 } else { 2190 // initiator 2191 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2192 } 2193 sm_trigger_user_response(connection); 2194 break; 2195 case OOB: 2196 // TODO: implement SC OOB 2197 break; 2198 } 2199 2200 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2201 sm_timeout_reset(connection); 2202 break; 2203 } 2204 case SM_SC_SEND_CONFIRMATION: { 2205 uint8_t buffer[17]; 2206 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2207 reverse_128(setup->sm_local_confirm, &buffer[1]); 2208 if (connection->sm_role){ 2209 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2210 } else { 2211 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2212 } 2213 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2214 sm_timeout_reset(connection); 2215 break; 2216 } 2217 case SM_SC_SEND_PAIRING_RANDOM: { 2218 uint8_t buffer[17]; 2219 buffer[0] = SM_CODE_PAIRING_RANDOM; 2220 reverse_128(setup->sm_local_nonce, &buffer[1]); 2221 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2222 if (connection->sm_role){ 2223 // responder 2224 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2225 } else { 2226 // initiator 2227 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2228 } 2229 } else { 2230 if (connection->sm_role){ 2231 // responder 2232 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2233 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2234 } else { 2235 sm_sc_prepare_dhkey_check(connection); 2236 } 2237 } else { 2238 // initiator 2239 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2240 } 2241 } 2242 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2243 sm_timeout_reset(connection); 2244 break; 2245 } 2246 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2247 uint8_t buffer[17]; 2248 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2249 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2250 2251 if (connection->sm_role){ 2252 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2253 } else { 2254 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2255 } 2256 2257 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2258 sm_timeout_reset(connection); 2259 break; 2260 } 2261 2262 #endif 2263 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2264 // echo initiator for now 2265 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2266 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2267 2268 if (setup->sm_use_secure_connections){ 2269 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2270 // skip LTK/EDIV for SC 2271 log_info("sm: dropping encryption information flag"); 2272 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2273 } else { 2274 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2275 } 2276 2277 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); 2278 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); 2279 // update key distribution after ENC was dropped 2280 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2281 2282 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2283 sm_timeout_reset(connection); 2284 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2285 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2286 sm_trigger_user_response(connection); 2287 } 2288 return; 2289 2290 case SM_PH2_SEND_PAIRING_RANDOM: { 2291 uint8_t buffer[17]; 2292 buffer[0] = SM_CODE_PAIRING_RANDOM; 2293 reverse_128(setup->sm_local_random, &buffer[1]); 2294 if (connection->sm_role){ 2295 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2296 } else { 2297 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2298 } 2299 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2300 sm_timeout_reset(connection); 2301 break; 2302 } 2303 2304 case SM_PH2_GET_RANDOM_TK: 2305 case SM_PH2_C1_GET_RANDOM_A: 2306 case SM_PH2_C1_GET_RANDOM_B: 2307 case SM_PH3_GET_RANDOM: 2308 case SM_PH3_GET_DIV: 2309 sm_next_responding_state(connection); 2310 sm_random_start(connection); 2311 return; 2312 2313 case SM_PH2_C1_GET_ENC_B: 2314 case SM_PH2_C1_GET_ENC_D: 2315 // already busy? 2316 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2317 sm_next_responding_state(connection); 2318 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2319 return; 2320 2321 case SM_PH3_LTK_GET_ENC: 2322 case SM_RESPONDER_PH4_LTK_GET_ENC: 2323 // already busy? 2324 if (sm_aes128_state == SM_AES128_IDLE) { 2325 sm_key_t d_prime; 2326 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 2327 sm_next_responding_state(connection); 2328 sm_aes128_start(sm_persistent_er, d_prime, connection); 2329 return; 2330 } 2331 break; 2332 2333 case SM_PH3_CSRK_GET_ENC: 2334 // already busy? 2335 if (sm_aes128_state == SM_AES128_IDLE) { 2336 sm_key_t d_prime; 2337 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2338 sm_next_responding_state(connection); 2339 sm_aes128_start(sm_persistent_er, d_prime, connection); 2340 return; 2341 } 2342 break; 2343 2344 case SM_PH2_C1_GET_ENC_C: 2345 // already busy? 2346 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2347 // calculate m_confirm using aes128 engine - step 1 2348 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); 2349 sm_next_responding_state(connection); 2350 sm_aes128_start(setup->sm_tk, plaintext, connection); 2351 break; 2352 case SM_PH2_C1_GET_ENC_A: 2353 // already busy? 2354 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2355 // calculate confirm using aes128 engine - step 1 2356 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); 2357 sm_next_responding_state(connection); 2358 sm_aes128_start(setup->sm_tk, plaintext, connection); 2359 break; 2360 case SM_PH2_CALC_STK: 2361 // already busy? 2362 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2363 // calculate STK 2364 if (connection->sm_role){ 2365 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2366 } else { 2367 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2368 } 2369 sm_next_responding_state(connection); 2370 sm_aes128_start(setup->sm_tk, plaintext, connection); 2371 break; 2372 case SM_PH3_Y_GET_ENC: 2373 // already busy? 2374 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2375 // PH3B2 - calculate Y from - enc 2376 // Y = dm(DHK, Rand) 2377 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2378 sm_next_responding_state(connection); 2379 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2380 return; 2381 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2382 uint8_t buffer[17]; 2383 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2384 reverse_128(setup->sm_local_confirm, &buffer[1]); 2385 if (connection->sm_role){ 2386 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2387 } else { 2388 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2389 } 2390 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2391 sm_timeout_reset(connection); 2392 return; 2393 } 2394 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2395 sm_key_t stk_flipped; 2396 reverse_128(setup->sm_ltk, stk_flipped); 2397 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2398 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2399 return; 2400 } 2401 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2402 sm_key_t stk_flipped; 2403 reverse_128(setup->sm_ltk, stk_flipped); 2404 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2405 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2406 return; 2407 } 2408 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2409 sm_key_t ltk_flipped; 2410 reverse_128(setup->sm_ltk, ltk_flipped); 2411 connection->sm_engine_state = SM_RESPONDER_IDLE; 2412 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2413 return; 2414 } 2415 case SM_RESPONDER_PH4_Y_GET_ENC: 2416 // already busy? 2417 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2418 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2419 // Y = dm(DHK, Rand) 2420 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2421 sm_next_responding_state(connection); 2422 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2423 return; 2424 2425 case SM_PH3_DISTRIBUTE_KEYS: 2426 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2427 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2428 uint8_t buffer[17]; 2429 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2430 reverse_128(setup->sm_ltk, &buffer[1]); 2431 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2432 sm_timeout_reset(connection); 2433 return; 2434 } 2435 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2436 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2437 uint8_t buffer[11]; 2438 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2439 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2440 reverse_64(setup->sm_local_rand, &buffer[3]); 2441 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2442 sm_timeout_reset(connection); 2443 return; 2444 } 2445 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2446 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2447 uint8_t buffer[17]; 2448 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2449 reverse_128(sm_persistent_irk, &buffer[1]); 2450 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2451 sm_timeout_reset(connection); 2452 return; 2453 } 2454 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2455 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2456 bd_addr_t local_address; 2457 uint8_t buffer[8]; 2458 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2459 gap_advertisements_get_address(&buffer[1], local_address); 2460 reverse_bd_addr(local_address, &buffer[2]); 2461 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2462 sm_timeout_reset(connection); 2463 return; 2464 } 2465 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2466 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2467 2468 // hack to reproduce test runs 2469 if (test_use_fixed_local_csrk){ 2470 memset(setup->sm_local_csrk, 0xcc, 16); 2471 } 2472 2473 uint8_t buffer[17]; 2474 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2475 reverse_128(setup->sm_local_csrk, &buffer[1]); 2476 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2477 sm_timeout_reset(connection); 2478 return; 2479 } 2480 2481 // keys are sent 2482 if (connection->sm_role){ 2483 // slave -> receive master keys if any 2484 if (sm_key_distribution_all_received(connection)){ 2485 sm_key_distribution_handle_all_received(connection); 2486 connection->sm_engine_state = SM_RESPONDER_IDLE; 2487 sm_done_for_handle(connection->sm_handle); 2488 } else { 2489 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2490 } 2491 } else { 2492 // master -> all done 2493 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2494 sm_done_for_handle(connection->sm_handle); 2495 } 2496 break; 2497 2498 default: 2499 break; 2500 } 2501 2502 // check again if active connection was released 2503 if (sm_active_connection) break; 2504 } 2505 } 2506 2507 // note: aes engine is ready as we just got the aes result 2508 static void sm_handle_encryption_result(uint8_t * data){ 2509 2510 sm_aes128_state = SM_AES128_IDLE; 2511 2512 if (sm_address_resolution_ah_calculation_active){ 2513 sm_address_resolution_ah_calculation_active = 0; 2514 // compare calulated address against connecting device 2515 uint8_t hash[3]; 2516 reverse_24(data, hash); 2517 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2518 log_info("LE Device Lookup: matched resolvable private address"); 2519 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2520 return; 2521 } 2522 // no match, try next 2523 sm_address_resolution_test++; 2524 return; 2525 } 2526 2527 switch (dkg_state){ 2528 case DKG_W4_IRK: 2529 reverse_128(data, sm_persistent_irk); 2530 log_info_key("irk", sm_persistent_irk); 2531 dkg_next_state(); 2532 return; 2533 case DKG_W4_DHK: 2534 reverse_128(data, sm_persistent_dhk); 2535 log_info_key("dhk", sm_persistent_dhk); 2536 dkg_next_state(); 2537 // SM Init Finished 2538 return; 2539 default: 2540 break; 2541 } 2542 2543 switch (rau_state){ 2544 case RAU_W4_ENC: 2545 reverse_24(data, &sm_random_address[3]); 2546 rau_next_state(); 2547 return; 2548 default: 2549 break; 2550 } 2551 2552 switch (sm_cmac_state){ 2553 case CMAC_W4_SUBKEYS: 2554 case CMAC_W4_MI: 2555 case CMAC_W4_MLAST: 2556 { 2557 sm_key_t t; 2558 reverse_128(data, t); 2559 sm_cmac_handle_encryption_result(t); 2560 } 2561 return; 2562 default: 2563 break; 2564 } 2565 2566 // retrieve sm_connection provided to sm_aes128_start_encryption 2567 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2568 if (!connection) return; 2569 switch (connection->sm_engine_state){ 2570 case SM_PH2_C1_W4_ENC_A: 2571 case SM_PH2_C1_W4_ENC_C: 2572 { 2573 sm_key_t t2; 2574 reverse_128(data, t2); 2575 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2576 } 2577 sm_next_responding_state(connection); 2578 return; 2579 case SM_PH2_C1_W4_ENC_B: 2580 reverse_128(data, setup->sm_local_confirm); 2581 log_info_key("c1!", setup->sm_local_confirm); 2582 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2583 return; 2584 case SM_PH2_C1_W4_ENC_D: 2585 { 2586 sm_key_t peer_confirm_test; 2587 reverse_128(data, peer_confirm_test); 2588 log_info_key("c1!", peer_confirm_test); 2589 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2590 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2591 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2592 return; 2593 } 2594 if (connection->sm_role){ 2595 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2596 } else { 2597 connection->sm_engine_state = SM_PH2_CALC_STK; 2598 } 2599 } 2600 return; 2601 case SM_PH2_W4_STK: 2602 reverse_128(data, setup->sm_ltk); 2603 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2604 log_info_key("stk", setup->sm_ltk); 2605 if (connection->sm_role){ 2606 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2607 } else { 2608 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2609 } 2610 return; 2611 case SM_PH3_Y_W4_ENC:{ 2612 sm_key_t y128; 2613 reverse_128(data, y128); 2614 setup->sm_local_y = big_endian_read_16(y128, 14); 2615 log_info_hex16("y", setup->sm_local_y); 2616 // PH3B3 - calculate EDIV 2617 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2618 log_info_hex16("ediv", setup->sm_local_ediv); 2619 // PH3B4 - calculate LTK - enc 2620 // LTK = d1(ER, DIV, 0)) 2621 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2622 return; 2623 } 2624 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2625 sm_key_t y128; 2626 reverse_128(data, y128); 2627 setup->sm_local_y = big_endian_read_16(y128, 14); 2628 log_info_hex16("y", setup->sm_local_y); 2629 2630 // PH3B3 - calculate DIV 2631 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2632 log_info_hex16("ediv", setup->sm_local_ediv); 2633 // PH3B4 - calculate LTK - enc 2634 // LTK = d1(ER, DIV, 0)) 2635 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2636 return; 2637 } 2638 case SM_PH3_LTK_W4_ENC: 2639 reverse_128(data, setup->sm_ltk); 2640 log_info_key("ltk", setup->sm_ltk); 2641 // calc CSRK next 2642 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2643 return; 2644 case SM_PH3_CSRK_W4_ENC: 2645 reverse_128(data, setup->sm_local_csrk); 2646 log_info_key("csrk", setup->sm_local_csrk); 2647 if (setup->sm_key_distribution_send_set){ 2648 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2649 } else { 2650 // no keys to send, just continue 2651 if (connection->sm_role){ 2652 // slave -> receive master keys 2653 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2654 } else { 2655 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2656 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2657 } else { 2658 // master -> all done 2659 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2660 sm_done_for_handle(connection->sm_handle); 2661 } 2662 } 2663 } 2664 return; 2665 case SM_RESPONDER_PH4_LTK_W4_ENC: 2666 reverse_128(data, setup->sm_ltk); 2667 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2668 log_info_key("ltk", setup->sm_ltk); 2669 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2670 return; 2671 default: 2672 break; 2673 } 2674 } 2675 2676 #ifdef USE_MBEDTLS_FOR_ECDH 2677 2678 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2679 int offset = setup->sm_passkey_bit; 2680 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2681 while (size) { 2682 if (offset < 32){ 2683 *buffer++ = setup->sm_peer_qx[offset++]; 2684 } else { 2685 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2686 } 2687 size--; 2688 } 2689 setup->sm_passkey_bit = offset; 2690 return 0; 2691 } 2692 #endif 2693 2694 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2695 static void sm_handle_random_result(uint8_t * data){ 2696 2697 #ifdef USE_MBEDTLS_FOR_ECDH 2698 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2699 int num_bytes = setup->sm_passkey_bit; 2700 if (num_bytes < 32){ 2701 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2702 } else { 2703 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2704 } 2705 num_bytes += 8; 2706 setup->sm_passkey_bit = num_bytes; 2707 2708 if (num_bytes >= 64){ 2709 2710 // generate EC key 2711 setup->sm_passkey_bit = 0; 2712 mbedtls_mpi d; 2713 mbedtls_ecp_point P; 2714 mbedtls_mpi_init(&d); 2715 mbedtls_ecp_point_init(&P); 2716 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2717 log_info("gen keypair %x", res); 2718 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2719 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2720 mbedtls_mpi_write_binary(&d, ec_d, 32); 2721 mbedtls_ecp_point_free(&P); 2722 mbedtls_mpi_free(&d); 2723 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2724 sm_log_ec_keypair(); 2725 2726 #if 0 2727 int i; 2728 sm_key256_t dhkey; 2729 for (i=0;i<10;i++){ 2730 // printf("test dhkey check\n"); 2731 memcpy(setup->sm_peer_qx, ec_qx, 32); 2732 memcpy(setup->sm_peer_qy, ec_qy, 32); 2733 sm_sc_calculate_dhkey(dhkey); 2734 // printf("test dhkey check end\n"); 2735 } 2736 #endif 2737 2738 } 2739 } 2740 #endif 2741 2742 switch (rau_state){ 2743 case RAU_W4_RANDOM: 2744 // non-resolvable vs. resolvable 2745 switch (gap_random_adress_type){ 2746 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2747 // resolvable: use random as prand and calc address hash 2748 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2749 memcpy(sm_random_address, data, 3); 2750 sm_random_address[0] &= 0x3f; 2751 sm_random_address[0] |= 0x40; 2752 rau_state = RAU_GET_ENC; 2753 break; 2754 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2755 default: 2756 // "The two most significant bits of the address shall be equal to ‘0’"" 2757 memcpy(sm_random_address, data, 6); 2758 sm_random_address[0] &= 0x3f; 2759 rau_state = RAU_SET_ADDRESS; 2760 break; 2761 } 2762 return; 2763 default: 2764 break; 2765 } 2766 2767 // retrieve sm_connection provided to sm_random_start 2768 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2769 if (!connection) return; 2770 switch (connection->sm_engine_state){ 2771 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2772 case SM_SC_W4_GET_RANDOM_A: 2773 memcpy(&setup->sm_local_nonce[0], data, 8); 2774 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2775 break; 2776 case SM_SC_W4_GET_RANDOM_B: 2777 memcpy(&setup->sm_local_nonce[8], data, 8); 2778 // initiator & jw/nc -> send pairing random 2779 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2780 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2781 break; 2782 } else { 2783 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2784 } 2785 break; 2786 #endif 2787 2788 case SM_PH2_W4_RANDOM_TK: 2789 { 2790 // map random to 0-999999 without speding much cycles on a modulus operation 2791 uint32_t tk = little_endian_read_32(data,0); 2792 tk = tk & 0xfffff; // 1048575 2793 if (tk >= 999999){ 2794 tk = tk - 999999; 2795 } 2796 sm_reset_tk(); 2797 big_endian_store_32(setup->sm_tk, 12, tk); 2798 if (connection->sm_role){ 2799 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2800 } else { 2801 if (setup->sm_use_secure_connections){ 2802 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2803 } else { 2804 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2805 sm_trigger_user_response(connection); 2806 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2807 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2808 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2809 } 2810 } 2811 } 2812 return; 2813 } 2814 case SM_PH2_C1_W4_RANDOM_A: 2815 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2816 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2817 return; 2818 case SM_PH2_C1_W4_RANDOM_B: 2819 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2820 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2821 return; 2822 case SM_PH3_W4_RANDOM: 2823 reverse_64(data, setup->sm_local_rand); 2824 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2825 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2826 // no db for authenticated flag hack: store flag in bit 4 of LSB 2827 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2828 connection->sm_engine_state = SM_PH3_GET_DIV; 2829 return; 2830 case SM_PH3_W4_DIV: 2831 // use 16 bit from random value as div 2832 setup->sm_local_div = big_endian_read_16(data, 0); 2833 log_info_hex16("div", setup->sm_local_div); 2834 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2835 return; 2836 default: 2837 break; 2838 } 2839 } 2840 2841 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2842 2843 sm_connection_t * sm_conn; 2844 hci_con_handle_t con_handle; 2845 2846 switch (packet_type) { 2847 2848 case HCI_EVENT_PACKET: 2849 switch (hci_event_packet_get_type(packet)) { 2850 2851 case BTSTACK_EVENT_STATE: 2852 // bt stack activated, get started 2853 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2854 log_info("HCI Working!"); 2855 2856 // set local addr for le device db 2857 bd_addr_t local_bd_addr; 2858 gap_local_bd_addr(local_bd_addr); 2859 le_device_db_set_local_bd_addr(local_bd_addr); 2860 2861 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2862 rau_state = RAU_IDLE; 2863 #ifdef USE_MBEDTLS_FOR_ECDH 2864 if (!sm_have_ec_keypair){ 2865 setup->sm_passkey_bit = 0; 2866 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2867 } 2868 #endif 2869 sm_run(); 2870 } 2871 break; 2872 2873 case HCI_EVENT_LE_META: 2874 switch (packet[2]) { 2875 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2876 2877 log_info("sm: connected"); 2878 2879 if (packet[3]) return; // connection failed 2880 2881 con_handle = little_endian_read_16(packet, 4); 2882 sm_conn = sm_get_connection_for_handle(con_handle); 2883 if (!sm_conn) break; 2884 2885 sm_conn->sm_handle = con_handle; 2886 sm_conn->sm_role = packet[6]; 2887 sm_conn->sm_peer_addr_type = packet[7]; 2888 reverse_bd_addr(&packet[8], 2889 sm_conn->sm_peer_address); 2890 2891 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2892 2893 // reset security properties 2894 sm_conn->sm_connection_encrypted = 0; 2895 sm_conn->sm_connection_authenticated = 0; 2896 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2897 sm_conn->sm_le_db_index = -1; 2898 2899 // prepare CSRK lookup (does not involve setup) 2900 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2901 2902 // just connected -> everything else happens in sm_run() 2903 if (sm_conn->sm_role){ 2904 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2905 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2906 if (sm_slave_request_security) { 2907 // request security if requested by app 2908 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2909 } else { 2910 // otherwise, wait for pairing request 2911 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2912 } 2913 } 2914 break; 2915 } else { 2916 // master 2917 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2918 } 2919 break; 2920 2921 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2922 con_handle = little_endian_read_16(packet, 3); 2923 sm_conn = sm_get_connection_for_handle(con_handle); 2924 if (!sm_conn) break; 2925 2926 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2927 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2928 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2929 break; 2930 } 2931 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2932 // PH2 SEND LTK as we need to exchange keys in PH3 2933 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2934 break; 2935 } 2936 2937 // store rand and ediv 2938 reverse_64(&packet[5], sm_conn->sm_local_rand); 2939 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2940 2941 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 2942 // potentially stored LTK is from the master 2943 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 2944 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2945 break; 2946 } 2947 2948 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2949 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 2950 #else 2951 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 2952 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2953 #endif 2954 break; 2955 2956 default: 2957 break; 2958 } 2959 break; 2960 2961 case HCI_EVENT_ENCRYPTION_CHANGE: 2962 con_handle = little_endian_read_16(packet, 3); 2963 sm_conn = sm_get_connection_for_handle(con_handle); 2964 if (!sm_conn) break; 2965 2966 sm_conn->sm_connection_encrypted = packet[5]; 2967 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2968 sm_conn->sm_actual_encryption_key_size); 2969 log_info("event handler, state %u", sm_conn->sm_engine_state); 2970 if (!sm_conn->sm_connection_encrypted) break; 2971 // continue if part of initial pairing 2972 switch (sm_conn->sm_engine_state){ 2973 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2974 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2975 sm_done_for_handle(sm_conn->sm_handle); 2976 break; 2977 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2978 if (sm_conn->sm_role){ 2979 // slave 2980 if (setup->sm_use_secure_connections){ 2981 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2982 } else { 2983 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2984 } 2985 } else { 2986 // master 2987 if (sm_key_distribution_all_received(sm_conn)){ 2988 // skip receiving keys as there are none 2989 sm_key_distribution_handle_all_received(sm_conn); 2990 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2991 } else { 2992 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2993 } 2994 } 2995 break; 2996 default: 2997 break; 2998 } 2999 break; 3000 3001 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3002 con_handle = little_endian_read_16(packet, 3); 3003 sm_conn = sm_get_connection_for_handle(con_handle); 3004 if (!sm_conn) break; 3005 3006 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3007 log_info("event handler, state %u", sm_conn->sm_engine_state); 3008 // continue if part of initial pairing 3009 switch (sm_conn->sm_engine_state){ 3010 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3011 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3012 sm_done_for_handle(sm_conn->sm_handle); 3013 break; 3014 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3015 if (sm_conn->sm_role){ 3016 // slave 3017 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3018 } else { 3019 // master 3020 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3021 } 3022 break; 3023 default: 3024 break; 3025 } 3026 break; 3027 3028 3029 case HCI_EVENT_DISCONNECTION_COMPLETE: 3030 con_handle = little_endian_read_16(packet, 3); 3031 sm_done_for_handle(con_handle); 3032 sm_conn = sm_get_connection_for_handle(con_handle); 3033 if (!sm_conn) break; 3034 3035 // delete stored bonding on disconnect with authentication failure in ph0 3036 if (sm_conn->sm_role == 0 3037 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3038 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3039 le_device_db_remove(sm_conn->sm_le_db_index); 3040 } 3041 3042 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3043 sm_conn->sm_handle = 0; 3044 break; 3045 3046 case HCI_EVENT_COMMAND_COMPLETE: 3047 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3048 sm_handle_encryption_result(&packet[6]); 3049 break; 3050 } 3051 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3052 sm_handle_random_result(&packet[6]); 3053 break; 3054 } 3055 break; 3056 default: 3057 break; 3058 } 3059 break; 3060 default: 3061 break; 3062 } 3063 3064 sm_run(); 3065 } 3066 3067 static inline int sm_calc_actual_encryption_key_size(int other){ 3068 if (other < sm_min_encryption_key_size) return 0; 3069 if (other < sm_max_encryption_key_size) return other; 3070 return sm_max_encryption_key_size; 3071 } 3072 3073 3074 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3075 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3076 switch (method){ 3077 case JUST_WORKS: 3078 case NK_BOTH_INPUT: 3079 return 1; 3080 default: 3081 return 0; 3082 } 3083 } 3084 // responder 3085 3086 static int sm_passkey_used(stk_generation_method_t method){ 3087 switch (method){ 3088 case PK_RESP_INPUT: 3089 return 1; 3090 default: 3091 return 0; 3092 } 3093 } 3094 #endif 3095 3096 /** 3097 * @return ok 3098 */ 3099 static int sm_validate_stk_generation_method(void){ 3100 // check if STK generation method is acceptable by client 3101 switch (setup->sm_stk_generation_method){ 3102 case JUST_WORKS: 3103 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3104 case PK_RESP_INPUT: 3105 case PK_INIT_INPUT: 3106 case OK_BOTH_INPUT: 3107 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3108 case OOB: 3109 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3110 case NK_BOTH_INPUT: 3111 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3112 return 1; 3113 default: 3114 return 0; 3115 } 3116 } 3117 3118 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3119 3120 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3121 sm_run(); 3122 } 3123 3124 if (packet_type != SM_DATA_PACKET) return; 3125 3126 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3127 if (!sm_conn) return; 3128 3129 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3130 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3131 return; 3132 } 3133 3134 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3135 3136 int err; 3137 3138 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3139 uint8_t buffer[5]; 3140 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3141 buffer[1] = 3; 3142 little_endian_store_16(buffer, 2, con_handle); 3143 buffer[4] = packet[1]; 3144 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3145 return; 3146 } 3147 3148 switch (sm_conn->sm_engine_state){ 3149 3150 // a sm timeout requries a new physical connection 3151 case SM_GENERAL_TIMEOUT: 3152 return; 3153 3154 // Initiator 3155 case SM_INITIATOR_CONNECTED: 3156 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3157 sm_pdu_received_in_wrong_state(sm_conn); 3158 break; 3159 } 3160 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3161 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3162 break; 3163 } 3164 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3165 sm_key_t ltk; 3166 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3167 if (!sm_is_null_key(ltk)){ 3168 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3169 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3170 } else { 3171 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3172 } 3173 break; 3174 } 3175 // otherwise, store security request 3176 sm_conn->sm_security_request_received = 1; 3177 break; 3178 3179 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3180 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3181 sm_pdu_received_in_wrong_state(sm_conn); 3182 break; 3183 } 3184 // store pairing request 3185 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3186 err = sm_stk_generation_init(sm_conn); 3187 if (err){ 3188 setup->sm_pairing_failed_reason = err; 3189 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3190 break; 3191 } 3192 3193 // generate random number first, if we need to show passkey 3194 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3195 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3196 break; 3197 } 3198 3199 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3200 if (setup->sm_use_secure_connections){ 3201 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3202 if (setup->sm_stk_generation_method == JUST_WORKS){ 3203 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3204 sm_trigger_user_response(sm_conn); 3205 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3206 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3207 } 3208 } else { 3209 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3210 } 3211 break; 3212 } 3213 #endif 3214 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3215 sm_trigger_user_response(sm_conn); 3216 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3217 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3218 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3219 } 3220 break; 3221 3222 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3223 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3224 sm_pdu_received_in_wrong_state(sm_conn); 3225 break; 3226 } 3227 3228 // store s_confirm 3229 reverse_128(&packet[1], setup->sm_peer_confirm); 3230 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3231 break; 3232 3233 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3234 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3235 sm_pdu_received_in_wrong_state(sm_conn); 3236 break;; 3237 } 3238 3239 // received random value 3240 reverse_128(&packet[1], setup->sm_peer_random); 3241 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3242 break; 3243 3244 // Responder 3245 case SM_RESPONDER_IDLE: 3246 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3247 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3248 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3249 sm_pdu_received_in_wrong_state(sm_conn); 3250 break;; 3251 } 3252 3253 // store pairing request 3254 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3255 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3256 break; 3257 3258 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3259 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3260 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3261 sm_pdu_received_in_wrong_state(sm_conn); 3262 break; 3263 } 3264 3265 // store public key for DH Key calculation 3266 reverse_256(&packet[01], setup->sm_peer_qx); 3267 reverse_256(&packet[33], setup->sm_peer_qy); 3268 3269 #ifdef USE_MBEDTLS_FOR_ECDH 3270 // validate public key 3271 mbedtls_ecp_point Q; 3272 mbedtls_ecp_point_init( &Q ); 3273 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3274 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3275 mbedtls_mpi_lset(&Q.Z, 1); 3276 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3277 mbedtls_ecp_point_free( & Q); 3278 if (err){ 3279 log_error("sm: peer public key invalid %x", err); 3280 // uses "unspecified reason", there is no "public key invalid" error code 3281 sm_pdu_received_in_wrong_state(sm_conn); 3282 break; 3283 } 3284 3285 #endif 3286 if (sm_conn->sm_role){ 3287 // responder 3288 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3289 } else { 3290 // initiator 3291 // stk generation method 3292 // passkey entry: notify app to show passkey or to request passkey 3293 switch (setup->sm_stk_generation_method){ 3294 case JUST_WORKS: 3295 case NK_BOTH_INPUT: 3296 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3297 break; 3298 case PK_RESP_INPUT: 3299 sm_sc_start_calculating_local_confirm(sm_conn); 3300 break; 3301 case PK_INIT_INPUT: 3302 case OK_BOTH_INPUT: 3303 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3304 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3305 break; 3306 } 3307 sm_sc_start_calculating_local_confirm(sm_conn); 3308 break; 3309 case OOB: 3310 // TODO: implement SC OOB 3311 break; 3312 } 3313 } 3314 break; 3315 3316 case SM_SC_W4_CONFIRMATION: 3317 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3318 sm_pdu_received_in_wrong_state(sm_conn); 3319 break; 3320 } 3321 // received confirm value 3322 reverse_128(&packet[1], setup->sm_peer_confirm); 3323 3324 if (sm_conn->sm_role){ 3325 // responder 3326 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3327 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3328 // still waiting for passkey 3329 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3330 break; 3331 } 3332 } 3333 sm_sc_start_calculating_local_confirm(sm_conn); 3334 } else { 3335 // initiator 3336 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3337 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3338 } else { 3339 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3340 } 3341 } 3342 break; 3343 3344 case SM_SC_W4_PAIRING_RANDOM: 3345 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3346 sm_pdu_received_in_wrong_state(sm_conn); 3347 break; 3348 } 3349 3350 // received random value 3351 reverse_128(&packet[1], setup->sm_peer_nonce); 3352 3353 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3354 // only check for JUST WORK/NC in initiator role AND passkey entry 3355 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3356 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3357 } 3358 3359 sm_sc_state_after_receiving_random(sm_conn); 3360 break; 3361 3362 case SM_SC_W2_CALCULATE_G2: 3363 case SM_SC_W4_CALCULATE_G2: 3364 case SM_SC_W2_CALCULATE_F5_SALT: 3365 case SM_SC_W4_CALCULATE_F5_SALT: 3366 case SM_SC_W2_CALCULATE_F5_MACKEY: 3367 case SM_SC_W4_CALCULATE_F5_MACKEY: 3368 case SM_SC_W2_CALCULATE_F5_LTK: 3369 case SM_SC_W4_CALCULATE_F5_LTK: 3370 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3371 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3372 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3373 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3374 sm_pdu_received_in_wrong_state(sm_conn); 3375 break; 3376 } 3377 // store DHKey Check 3378 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3379 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3380 3381 // have we been only waiting for dhkey check command? 3382 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3383 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3384 } 3385 break; 3386 #endif 3387 3388 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3389 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3390 sm_pdu_received_in_wrong_state(sm_conn); 3391 break; 3392 } 3393 3394 // received confirm value 3395 reverse_128(&packet[1], setup->sm_peer_confirm); 3396 3397 // notify client to hide shown passkey 3398 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3399 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3400 } 3401 3402 // handle user cancel pairing? 3403 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3404 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3405 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3406 break; 3407 } 3408 3409 // wait for user action? 3410 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3411 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3412 break; 3413 } 3414 3415 // calculate and send local_confirm 3416 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3417 break; 3418 3419 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3420 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3421 sm_pdu_received_in_wrong_state(sm_conn); 3422 break;; 3423 } 3424 3425 // received random value 3426 reverse_128(&packet[1], setup->sm_peer_random); 3427 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3428 break; 3429 3430 case SM_PH3_RECEIVE_KEYS: 3431 switch(packet[0]){ 3432 case SM_CODE_ENCRYPTION_INFORMATION: 3433 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3434 reverse_128(&packet[1], setup->sm_peer_ltk); 3435 break; 3436 3437 case SM_CODE_MASTER_IDENTIFICATION: 3438 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3439 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3440 reverse_64(&packet[3], setup->sm_peer_rand); 3441 break; 3442 3443 case SM_CODE_IDENTITY_INFORMATION: 3444 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3445 reverse_128(&packet[1], setup->sm_peer_irk); 3446 break; 3447 3448 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3449 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3450 setup->sm_peer_addr_type = packet[1]; 3451 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3452 break; 3453 3454 case SM_CODE_SIGNING_INFORMATION: 3455 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3456 reverse_128(&packet[1], setup->sm_peer_csrk); 3457 break; 3458 default: 3459 // Unexpected PDU 3460 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3461 break; 3462 } 3463 // done with key distribution? 3464 if (sm_key_distribution_all_received(sm_conn)){ 3465 3466 sm_key_distribution_handle_all_received(sm_conn); 3467 3468 if (sm_conn->sm_role){ 3469 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3470 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3471 } else { 3472 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3473 sm_done_for_handle(sm_conn->sm_handle); 3474 } 3475 } else { 3476 if (setup->sm_use_secure_connections){ 3477 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3478 } else { 3479 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3480 } 3481 } 3482 } 3483 break; 3484 default: 3485 // Unexpected PDU 3486 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3487 break; 3488 } 3489 3490 // try to send preparared packet 3491 sm_run(); 3492 } 3493 3494 // Security Manager Client API 3495 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3496 sm_get_oob_data = get_oob_data_callback; 3497 } 3498 3499 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3500 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3501 } 3502 3503 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3504 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3505 } 3506 3507 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3508 sm_min_encryption_key_size = min_size; 3509 sm_max_encryption_key_size = max_size; 3510 } 3511 3512 void sm_set_authentication_requirements(uint8_t auth_req){ 3513 sm_auth_req = auth_req; 3514 } 3515 3516 void sm_set_io_capabilities(io_capability_t io_capability){ 3517 sm_io_capabilities = io_capability; 3518 } 3519 3520 void sm_set_request_security(int enable){ 3521 sm_slave_request_security = enable; 3522 } 3523 3524 void sm_set_er(sm_key_t er){ 3525 memcpy(sm_persistent_er, er, 16); 3526 } 3527 3528 void sm_set_ir(sm_key_t ir){ 3529 memcpy(sm_persistent_ir, ir, 16); 3530 } 3531 3532 // Testing support only 3533 void sm_test_set_irk(sm_key_t irk){ 3534 memcpy(sm_persistent_irk, irk, 16); 3535 sm_persistent_irk_ready = 1; 3536 } 3537 3538 void sm_test_use_fixed_local_csrk(void){ 3539 test_use_fixed_local_csrk = 1; 3540 } 3541 3542 void sm_init(void){ 3543 // set some (BTstack default) ER and IR 3544 int i; 3545 sm_key_t er; 3546 sm_key_t ir; 3547 for (i=0;i<16;i++){ 3548 er[i] = 0x30 + i; 3549 ir[i] = 0x90 + i; 3550 } 3551 sm_set_er(er); 3552 sm_set_ir(ir); 3553 // defaults 3554 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3555 | SM_STK_GENERATION_METHOD_OOB 3556 | SM_STK_GENERATION_METHOD_PASSKEY 3557 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3558 3559 sm_max_encryption_key_size = 16; 3560 sm_min_encryption_key_size = 7; 3561 3562 sm_cmac_state = CMAC_IDLE; 3563 dkg_state = DKG_W4_WORKING; 3564 rau_state = RAU_W4_WORKING; 3565 sm_aes128_state = SM_AES128_IDLE; 3566 sm_address_resolution_test = -1; // no private address to resolve yet 3567 sm_address_resolution_ah_calculation_active = 0; 3568 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3569 sm_address_resolution_general_queue = NULL; 3570 3571 gap_random_adress_update_period = 15 * 60 * 1000L; 3572 3573 sm_active_connection = 0; 3574 3575 test_use_fixed_local_csrk = 0; 3576 3577 // register for HCI Events from HCI 3578 hci_event_callback_registration.callback = &sm_event_packet_handler; 3579 hci_add_event_handler(&hci_event_callback_registration); 3580 3581 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3582 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3583 3584 #ifdef USE_MBEDTLS_FOR_ECDH 3585 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3586 3587 #ifndef HAVE_MALLOC 3588 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3589 #endif 3590 mbedtls_ecp_group_init(&mbedtls_ec_group); 3591 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3592 #if 0 3593 // test 3594 sm_test_use_fixed_ec_keypair(); 3595 if (sm_have_ec_keypair){ 3596 printf("test dhkey check\n"); 3597 sm_key256_t dhkey; 3598 memcpy(setup->sm_peer_qx, ec_qx, 32); 3599 memcpy(setup->sm_peer_qy, ec_qy, 32); 3600 sm_sc_calculate_dhkey(dhkey); 3601 } 3602 #endif 3603 #endif 3604 } 3605 3606 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3607 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3608 memcpy(ec_qx, qx, 32); 3609 memcpy(ec_qy, qy, 32); 3610 memcpy(ec_d, d, 32); 3611 sm_have_ec_keypair = 1; 3612 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3613 #endif 3614 } 3615 3616 void sm_test_use_fixed_ec_keypair(void){ 3617 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3618 #ifdef USE_MBEDTLS_FOR_ECDH 3619 // use test keypair from spec 3620 mbedtls_mpi x; 3621 mbedtls_mpi_init(&x); 3622 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3623 mbedtls_mpi_write_binary(&x, ec_d, 32); 3624 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3625 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3626 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3627 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3628 mbedtls_mpi_free(&x); 3629 #endif 3630 sm_have_ec_keypair = 1; 3631 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3632 #endif 3633 } 3634 3635 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3636 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3637 if (!hci_con) return NULL; 3638 return &hci_con->sm_connection; 3639 } 3640 3641 // @returns 0 if not encrypted, 7-16 otherwise 3642 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3643 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3644 if (!sm_conn) return 0; // wrong connection 3645 if (!sm_conn->sm_connection_encrypted) return 0; 3646 return sm_conn->sm_actual_encryption_key_size; 3647 } 3648 3649 int sm_authenticated(hci_con_handle_t con_handle){ 3650 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3651 if (!sm_conn) return 0; // wrong connection 3652 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3653 return sm_conn->sm_connection_authenticated; 3654 } 3655 3656 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3657 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3658 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3659 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3660 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3661 return sm_conn->sm_connection_authorization_state; 3662 } 3663 3664 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3665 switch (sm_conn->sm_engine_state){ 3666 case SM_GENERAL_IDLE: 3667 case SM_RESPONDER_IDLE: 3668 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3669 sm_run(); 3670 break; 3671 default: 3672 break; 3673 } 3674 } 3675 3676 /** 3677 * @brief Trigger Security Request 3678 */ 3679 void sm_send_security_request(hci_con_handle_t con_handle){ 3680 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3681 if (!sm_conn) return; 3682 sm_send_security_request_for_connection(sm_conn); 3683 } 3684 3685 // request pairing 3686 void sm_request_pairing(hci_con_handle_t con_handle){ 3687 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3688 if (!sm_conn) return; // wrong connection 3689 3690 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3691 if (sm_conn->sm_role){ 3692 sm_send_security_request_for_connection(sm_conn); 3693 } else { 3694 // used as a trigger to start central/master/initiator security procedures 3695 uint16_t ediv; 3696 sm_key_t ltk; 3697 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3698 switch (sm_conn->sm_irk_lookup_state){ 3699 case IRK_LOOKUP_FAILED: 3700 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3701 break; 3702 case IRK_LOOKUP_SUCCEEDED: 3703 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3704 if (!sm_is_null_key(ltk) || ediv){ 3705 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3706 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3707 } else { 3708 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3709 } 3710 break; 3711 default: 3712 sm_conn->sm_bonding_requested = 1; 3713 break; 3714 } 3715 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3716 sm_conn->sm_bonding_requested = 1; 3717 } 3718 } 3719 sm_run(); 3720 } 3721 3722 // called by client app on authorization request 3723 void sm_authorization_decline(hci_con_handle_t con_handle){ 3724 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3725 if (!sm_conn) return; // wrong connection 3726 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3727 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3728 } 3729 3730 void sm_authorization_grant(hci_con_handle_t con_handle){ 3731 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3732 if (!sm_conn) return; // wrong connection 3733 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3734 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3735 } 3736 3737 // GAP Bonding API 3738 3739 void sm_bonding_decline(hci_con_handle_t con_handle){ 3740 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3741 if (!sm_conn) return; // wrong connection 3742 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3743 3744 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3745 switch (setup->sm_stk_generation_method){ 3746 case PK_RESP_INPUT: 3747 case PK_INIT_INPUT: 3748 case OK_BOTH_INPUT: 3749 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3750 break; 3751 case NK_BOTH_INPUT: 3752 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3753 break; 3754 case JUST_WORKS: 3755 case OOB: 3756 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3757 break; 3758 } 3759 } 3760 sm_run(); 3761 } 3762 3763 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3764 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3765 if (!sm_conn) return; // wrong connection 3766 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3767 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3768 if (setup->sm_use_secure_connections){ 3769 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3770 } else { 3771 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3772 } 3773 } 3774 3775 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3776 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3777 sm_sc_prepare_dhkey_check(sm_conn); 3778 } 3779 #endif 3780 3781 sm_run(); 3782 } 3783 3784 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3785 // for now, it's the same 3786 sm_just_works_confirm(con_handle); 3787 } 3788 3789 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3790 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3791 if (!sm_conn) return; // wrong connection 3792 sm_reset_tk(); 3793 big_endian_store_32(setup->sm_tk, 12, passkey); 3794 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3795 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3796 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3797 } 3798 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3799 memcpy(setup->sm_ra, setup->sm_tk, 16); 3800 memcpy(setup->sm_rb, setup->sm_tk, 16); 3801 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3802 sm_sc_start_calculating_local_confirm(sm_conn); 3803 } 3804 #endif 3805 sm_run(); 3806 } 3807 3808 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3809 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3810 if (!sm_conn) return; // wrong connection 3811 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3812 setup->sm_keypress_notification = action; 3813 sm_run(); 3814 } 3815 3816 /** 3817 * @brief Identify device in LE Device DB 3818 * @param handle 3819 * @returns index from le_device_db or -1 if not found/identified 3820 */ 3821 int sm_le_device_index(hci_con_handle_t con_handle ){ 3822 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3823 if (!sm_conn) return -1; 3824 return sm_conn->sm_le_db_index; 3825 } 3826 3827 // GAP LE API 3828 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3829 gap_random_address_update_stop(); 3830 gap_random_adress_type = random_address_type; 3831 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3832 gap_random_address_update_start(); 3833 gap_random_address_trigger(); 3834 } 3835 3836 gap_random_address_type_t gap_random_address_get_mode(void){ 3837 return gap_random_adress_type; 3838 } 3839 3840 void gap_random_address_set_update_period(int period_ms){ 3841 gap_random_adress_update_period = period_ms; 3842 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3843 gap_random_address_update_stop(); 3844 gap_random_address_update_start(); 3845 } 3846 3847 void gap_random_address_set(bd_addr_t addr){ 3848 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3849 memcpy(sm_random_address, addr, 6); 3850 rau_state = RAU_SET_ADDRESS; 3851 sm_run(); 3852 } 3853 3854 /* 3855 * @brief Set Advertisement Paramters 3856 * @param adv_int_min 3857 * @param adv_int_max 3858 * @param adv_type 3859 * @param direct_address_type 3860 * @param direct_address 3861 * @param channel_map 3862 * @param filter_policy 3863 * 3864 * @note own_address_type is used from gap_random_address_set_mode 3865 */ 3866 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3867 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3868 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3869 direct_address_typ, direct_address, channel_map, filter_policy); 3870 } 3871 3872