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], uint8_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, uint8_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], uint8_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, uint8_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, uint8_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, uint8_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 #ifdef ENABLE_CLASSIC 1457 gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); 1458 #endif 1459 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1460 } else { 1461 #ifdef ENABLE_CLASSIC 1462 gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); 1463 #endif 1464 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1465 } 1466 sm_done_for_handle(sm_conn->sm_handle); 1467 break; 1468 default: 1469 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1470 break; 1471 } 1472 sm_run(); 1473 } 1474 1475 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){ 1476 const uint16_t message_len = 65; 1477 sm_cmac_connection = sm_conn; 1478 memcpy(sm_cmac_sc_buffer, u, 32); 1479 memcpy(sm_cmac_sc_buffer+32, v, 32); 1480 sm_cmac_sc_buffer[64] = z; 1481 log_info("f4 key"); 1482 log_info_hexdump(x, 16); 1483 log_info("f4 message"); 1484 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1485 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1486 } 1487 1488 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1489 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1490 static const uint8_t f5_length[] = { 0x01, 0x00}; 1491 1492 static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ 1493 #ifdef USE_MBEDTLS_FOR_ECDH 1494 // da * Pb 1495 mbedtls_mpi d; 1496 mbedtls_ecp_point Q; 1497 mbedtls_ecp_point DH; 1498 mbedtls_mpi_init(&d); 1499 mbedtls_ecp_point_init(&Q); 1500 mbedtls_ecp_point_init(&DH); 1501 mbedtls_mpi_read_binary(&d, ec_d, 32); 1502 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1503 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1504 mbedtls_mpi_lset(&Q.Z, 1); 1505 mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); 1506 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1507 mbedtls_ecp_point_free(&DH); 1508 mbedtls_mpi_free(&d); 1509 mbedtls_ecp_point_free(&Q); 1510 #endif 1511 log_info("dhkey"); 1512 log_info_hexdump(dhkey, 32); 1513 } 1514 1515 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1516 // calculate DHKEY 1517 sm_key256_t dhkey; 1518 sm_sc_calculate_dhkey(dhkey); 1519 1520 // calculate salt for f5 1521 const uint16_t message_len = 32; 1522 sm_cmac_connection = sm_conn; 1523 memcpy(sm_cmac_sc_buffer, dhkey, message_len); 1524 sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1525 } 1526 1527 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){ 1528 const uint16_t message_len = 53; 1529 sm_cmac_connection = sm_conn; 1530 1531 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1532 sm_cmac_sc_buffer[0] = 0; 1533 memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); 1534 memcpy(sm_cmac_sc_buffer+05, n1, 16); 1535 memcpy(sm_cmac_sc_buffer+21, n2, 16); 1536 memcpy(sm_cmac_sc_buffer+37, a1, 7); 1537 memcpy(sm_cmac_sc_buffer+44, a2, 7); 1538 memcpy(sm_cmac_sc_buffer+51, f5_length, 2); 1539 log_info("f5 key"); 1540 log_info_hexdump(t, 16); 1541 log_info("f5 message for MacKey"); 1542 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1543 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1544 } 1545 1546 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1547 sm_key56_t bd_addr_master, bd_addr_slave; 1548 bd_addr_master[0] = setup->sm_m_addr_type; 1549 bd_addr_slave[0] = setup->sm_s_addr_type; 1550 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1551 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1552 if (sm_conn->sm_role){ 1553 // responder 1554 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1555 } else { 1556 // initiator 1557 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1558 } 1559 } 1560 1561 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1562 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1563 const uint16_t message_len = 53; 1564 sm_cmac_connection = sm_conn; 1565 sm_cmac_sc_buffer[0] = 1; 1566 // 1..52 setup before 1567 log_info("f5 key"); 1568 log_info_hexdump(t, 16); 1569 log_info("f5 message for LTK"); 1570 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1571 sm_cmac_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1572 } 1573 1574 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1575 f5_ltk(sm_conn, setup->sm_t); 1576 } 1577 1578 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){ 1579 const uint16_t message_len = 65; 1580 sm_cmac_connection = sm_conn; 1581 memcpy(sm_cmac_sc_buffer, n1, 16); 1582 memcpy(sm_cmac_sc_buffer+16, n2, 16); 1583 memcpy(sm_cmac_sc_buffer+32, r, 16); 1584 memcpy(sm_cmac_sc_buffer+48, io_cap, 3); 1585 memcpy(sm_cmac_sc_buffer+51, a1, 7); 1586 memcpy(sm_cmac_sc_buffer+58, a2, 7); 1587 log_info("f6 key"); 1588 log_info_hexdump(w, 16); 1589 log_info("f6 message"); 1590 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1591 sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1592 } 1593 1594 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1595 // - U is 256 bits 1596 // - V is 256 bits 1597 // - X is 128 bits 1598 // - Y is 128 bits 1599 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){ 1600 const uint16_t message_len = 80; 1601 sm_cmac_connection = sm_conn; 1602 memcpy(sm_cmac_sc_buffer, u, 32); 1603 memcpy(sm_cmac_sc_buffer+32, v, 32); 1604 memcpy(sm_cmac_sc_buffer+64, y, 16); 1605 log_info("g2 key"); 1606 log_info_hexdump(x, 16); 1607 log_info("g2 message"); 1608 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1609 sm_cmac_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1610 } 1611 1612 static void g2_calculate(sm_connection_t * sm_conn) { 1613 // calc Va if numeric comparison 1614 if (sm_conn->sm_role){ 1615 // responder 1616 g2_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, setup->sm_local_nonce);; 1617 } else { 1618 // initiator 1619 g2_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce); 1620 } 1621 } 1622 1623 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1624 uint8_t z = 0; 1625 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1626 // some form of passkey 1627 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1628 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1629 setup->sm_passkey_bit++; 1630 } 1631 f4_engine(sm_conn, ec_qx, setup->sm_peer_qx, setup->sm_local_nonce, z); 1632 } 1633 1634 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1635 uint8_t z = 0; 1636 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1637 // some form of passkey 1638 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1639 // sm_passkey_bit was increased before sending confirm value 1640 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 1641 } 1642 f4_engine(sm_conn, setup->sm_peer_qx, ec_qx, setup->sm_peer_nonce, z); 1643 } 1644 1645 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1646 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1647 } 1648 1649 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1650 // calculate DHKCheck 1651 sm_key56_t bd_addr_master, bd_addr_slave; 1652 bd_addr_master[0] = setup->sm_m_addr_type; 1653 bd_addr_slave[0] = setup->sm_s_addr_type; 1654 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1655 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1656 uint8_t iocap_a[3]; 1657 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1658 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1659 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1660 uint8_t iocap_b[3]; 1661 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1662 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1663 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1664 if (sm_conn->sm_role){ 1665 // responder 1666 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); 1667 } else { 1668 // initiator 1669 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); 1670 } 1671 } 1672 1673 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1674 // validate E = f6() 1675 sm_key56_t bd_addr_master, bd_addr_slave; 1676 bd_addr_master[0] = setup->sm_m_addr_type; 1677 bd_addr_slave[0] = setup->sm_s_addr_type; 1678 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1679 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1680 1681 uint8_t iocap_a[3]; 1682 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1683 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1684 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1685 uint8_t iocap_b[3]; 1686 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1687 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1688 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1689 if (sm_conn->sm_role){ 1690 // responder 1691 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); 1692 } else { 1693 // initiator 1694 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); 1695 } 1696 } 1697 1698 1699 // 1700 // Link Key Conversion Function h6 1701 // 1702 // h6(W, keyID) = AES-CMACW(keyID) 1703 // - W is 128 bits 1704 // - keyID is 32 bits 1705 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1706 const uint16_t message_len = 4; 1707 sm_cmac_connection = sm_conn; 1708 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1709 log_info("h6 key"); 1710 log_info_hexdump(w, 16); 1711 log_info("h6 message"); 1712 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1713 sm_cmac_general_start(w, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1714 } 1715 1716 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1717 // Errata Service Release to the Bluetooth Specification: ESR09 1718 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1719 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1720 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1721 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1722 } 1723 1724 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1725 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1726 } 1727 1728 #endif 1729 1730 // key management legacy connections: 1731 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1732 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1733 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1734 // - responder reconnects: responder uses LTK receveived from master 1735 1736 // key management secure connections: 1737 // - both devices store same LTK from ECDH key exchange. 1738 1739 static void sm_load_security_info(sm_connection_t * sm_connection){ 1740 int encryption_key_size; 1741 int authenticated; 1742 int authorized; 1743 1744 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1745 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1746 &encryption_key_size, &authenticated, &authorized); 1747 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1748 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1749 sm_connection->sm_connection_authenticated = authenticated; 1750 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1751 } 1752 1753 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1754 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1755 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1756 // re-establish used key encryption size 1757 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1758 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1759 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1760 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1761 log_info("sm: received ltk request with key size %u, authenticated %u", 1762 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1763 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1764 } 1765 1766 static void sm_run(void){ 1767 1768 btstack_linked_list_iterator_t it; 1769 1770 // assert that we can send at least commands 1771 if (!hci_can_send_command_packet_now()) return; 1772 1773 // 1774 // non-connection related behaviour 1775 // 1776 1777 // distributed key generation 1778 switch (dkg_state){ 1779 case DKG_CALC_IRK: 1780 // already busy? 1781 if (sm_aes128_state == SM_AES128_IDLE) { 1782 // IRK = d1(IR, 1, 0) 1783 sm_key_t d1_prime; 1784 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1785 dkg_next_state(); 1786 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1787 return; 1788 } 1789 break; 1790 case DKG_CALC_DHK: 1791 // already busy? 1792 if (sm_aes128_state == SM_AES128_IDLE) { 1793 // DHK = d1(IR, 3, 0) 1794 sm_key_t d1_prime; 1795 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1796 dkg_next_state(); 1797 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1798 return; 1799 } 1800 break; 1801 default: 1802 break; 1803 } 1804 1805 #ifdef USE_MBEDTLS_FOR_ECDH 1806 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 1807 sm_random_start(NULL); 1808 return; 1809 } 1810 #endif 1811 1812 // random address updates 1813 switch (rau_state){ 1814 case RAU_GET_RANDOM: 1815 rau_next_state(); 1816 sm_random_start(NULL); 1817 return; 1818 case RAU_GET_ENC: 1819 // already busy? 1820 if (sm_aes128_state == SM_AES128_IDLE) { 1821 sm_key_t r_prime; 1822 sm_ah_r_prime(sm_random_address, r_prime); 1823 rau_next_state(); 1824 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1825 return; 1826 } 1827 break; 1828 case RAU_SET_ADDRESS: 1829 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1830 rau_state = RAU_IDLE; 1831 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1832 return; 1833 default: 1834 break; 1835 } 1836 1837 // CMAC 1838 switch (sm_cmac_state){ 1839 case CMAC_CALC_SUBKEYS: 1840 case CMAC_CALC_MI: 1841 case CMAC_CALC_MLAST: 1842 // already busy? 1843 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1844 sm_cmac_handle_aes_engine_ready(); 1845 return; 1846 default: 1847 break; 1848 } 1849 1850 // CSRK Lookup 1851 // -- if csrk lookup ready, find connection that require csrk lookup 1852 if (sm_address_resolution_idle()){ 1853 hci_connections_get_iterator(&it); 1854 while(btstack_linked_list_iterator_has_next(&it)){ 1855 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1856 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1857 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1858 // and start lookup 1859 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); 1860 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1861 break; 1862 } 1863 } 1864 } 1865 1866 // -- if csrk lookup ready, resolved addresses for received addresses 1867 if (sm_address_resolution_idle()) { 1868 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1869 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1870 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1871 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1872 btstack_memory_sm_lookup_entry_free(entry); 1873 } 1874 } 1875 1876 // -- Continue with CSRK device lookup by public or resolvable private address 1877 if (!sm_address_resolution_idle()){ 1878 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1879 while (sm_address_resolution_test < le_device_db_count()){ 1880 int addr_type; 1881 bd_addr_t addr; 1882 sm_key_t irk; 1883 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1884 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1885 1886 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1887 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1888 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1889 break; 1890 } 1891 1892 if (sm_address_resolution_addr_type == 0){ 1893 sm_address_resolution_test++; 1894 continue; 1895 } 1896 1897 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1898 1899 log_info("LE Device Lookup: calculate AH"); 1900 log_info_key("IRK", irk); 1901 1902 sm_key_t r_prime; 1903 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1904 sm_address_resolution_ah_calculation_active = 1; 1905 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1906 return; 1907 } 1908 1909 if (sm_address_resolution_test >= le_device_db_count()){ 1910 log_info("LE Device Lookup: not found"); 1911 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1912 } 1913 } 1914 1915 // handle basic actions that don't requires the full context 1916 hci_connections_get_iterator(&it); 1917 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1918 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1919 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1920 switch(sm_connection->sm_engine_state){ 1921 // responder side 1922 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1923 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1924 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1925 return; 1926 1927 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1928 case SM_SC_RECEIVED_LTK_REQUEST: 1929 switch (sm_connection->sm_irk_lookup_state){ 1930 case IRK_LOOKUP_FAILED: 1931 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 1932 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 1933 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 1934 return; 1935 default: 1936 break; 1937 } 1938 break; 1939 #endif 1940 default: 1941 break; 1942 } 1943 } 1944 1945 // 1946 // active connection handling 1947 // -- use loop to handle next connection if lock on setup context is released 1948 1949 while (1) { 1950 1951 // Find connections that requires setup context and make active if no other is locked 1952 hci_connections_get_iterator(&it); 1953 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1954 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1955 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1956 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1957 int done = 1; 1958 int err; 1959 switch (sm_connection->sm_engine_state) { 1960 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1961 // send packet if possible, 1962 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1963 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1964 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1965 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1966 } else { 1967 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1968 } 1969 // don't lock sxetup context yet 1970 done = 0; 1971 break; 1972 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1973 sm_reset_setup(); 1974 sm_init_setup(sm_connection); 1975 // recover pairing request 1976 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1977 err = sm_stk_generation_init(sm_connection); 1978 if (err){ 1979 setup->sm_pairing_failed_reason = err; 1980 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1981 break; 1982 } 1983 sm_timeout_start(sm_connection); 1984 // generate random number first, if we need to show passkey 1985 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1986 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1987 break; 1988 } 1989 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1990 break; 1991 case SM_INITIATOR_PH0_HAS_LTK: 1992 sm_reset_setup(); 1993 sm_load_security_info(sm_connection); 1994 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1995 break; 1996 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 1997 sm_reset_setup(); 1998 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 1999 break; 2000 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2001 sm_reset_setup(); 2002 sm_init_setup(sm_connection); 2003 sm_timeout_start(sm_connection); 2004 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2005 break; 2006 2007 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2008 case SM_SC_RECEIVED_LTK_REQUEST: 2009 switch (sm_connection->sm_irk_lookup_state){ 2010 case IRK_LOOKUP_SUCCEEDED: 2011 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2012 // start using context by loading security info 2013 sm_reset_setup(); 2014 sm_load_security_info(sm_connection); 2015 if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2016 memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2017 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2018 break; 2019 } 2020 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2021 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2022 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2023 // don't lock setup context yet 2024 return; 2025 default: 2026 // just wait until IRK lookup is completed 2027 // don't lock setup context yet 2028 done = 0; 2029 break; 2030 } 2031 break; 2032 #endif 2033 default: 2034 done = 0; 2035 break; 2036 } 2037 if (done){ 2038 sm_active_connection = sm_connection->sm_handle; 2039 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 2040 } 2041 } 2042 2043 // 2044 // active connection handling 2045 // 2046 2047 if (sm_active_connection == 0) return; 2048 2049 // assert that we could send a SM PDU - not needed for all of the following 2050 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2051 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2052 return; 2053 } 2054 2055 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 2056 if (!connection) return; 2057 2058 // send keypress notifications 2059 if (setup->sm_keypress_notification != 0xff){ 2060 uint8_t buffer[2]; 2061 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2062 buffer[1] = setup->sm_keypress_notification; 2063 setup->sm_keypress_notification = 0xff; 2064 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2065 return; 2066 } 2067 2068 sm_key_t plaintext; 2069 int key_distribution_flags; 2070 2071 log_info("sm_run: state %u", connection->sm_engine_state); 2072 2073 switch (connection->sm_engine_state){ 2074 2075 // general 2076 case SM_GENERAL_SEND_PAIRING_FAILED: { 2077 uint8_t buffer[2]; 2078 buffer[0] = SM_CODE_PAIRING_FAILED; 2079 buffer[1] = setup->sm_pairing_failed_reason; 2080 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2081 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2082 sm_done_for_handle(connection->sm_handle); 2083 break; 2084 } 2085 2086 // responding state 2087 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2088 case SM_SC_W2_GET_RANDOM_A: 2089 sm_random_start(connection); 2090 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; 2091 break; 2092 case SM_SC_W2_GET_RANDOM_B: 2093 sm_random_start(connection); 2094 connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; 2095 break; 2096 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2097 if (!sm_cmac_ready()) break; 2098 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2099 sm_sc_calculate_local_confirm(connection); 2100 break; 2101 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2102 if (!sm_cmac_ready()) break; 2103 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2104 sm_sc_calculate_remote_confirm(connection); 2105 break; 2106 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2107 if (!sm_cmac_ready()) break; 2108 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2109 sm_sc_calculate_f6_for_dhkey_check(connection); 2110 break; 2111 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2112 if (!sm_cmac_ready()) break; 2113 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2114 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2115 break; 2116 case SM_SC_W2_CALCULATE_F5_SALT: 2117 if (!sm_cmac_ready()) break; 2118 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2119 f5_calculate_salt(connection); 2120 break; 2121 case SM_SC_W2_CALCULATE_F5_MACKEY: 2122 if (!sm_cmac_ready()) break; 2123 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2124 f5_calculate_mackey(connection); 2125 break; 2126 case SM_SC_W2_CALCULATE_F5_LTK: 2127 if (!sm_cmac_ready()) break; 2128 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2129 f5_calculate_ltk(connection); 2130 break; 2131 case SM_SC_W2_CALCULATE_G2: 2132 if (!sm_cmac_ready()) break; 2133 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2134 g2_calculate(connection); 2135 break; 2136 case SM_SC_W2_CALCULATE_H6_ILK: 2137 if (!sm_cmac_ready()) break; 2138 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2139 h6_calculate_ilk(connection); 2140 break; 2141 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2142 if (!sm_cmac_ready()) break; 2143 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2144 h6_calculate_br_edr_link_key(connection); 2145 break; 2146 #endif 2147 2148 // initiator side 2149 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2150 sm_key_t peer_ltk_flipped; 2151 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2152 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2153 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2154 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2155 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2156 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2157 return; 2158 } 2159 2160 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2161 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2162 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2163 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2164 sm_timeout_reset(connection); 2165 break; 2166 2167 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2168 2169 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2170 uint8_t buffer[65]; 2171 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2172 // 2173 reverse_256(ec_qx, &buffer[1]); 2174 reverse_256(ec_qy, &buffer[33]); 2175 2176 // stk generation method 2177 // passkey entry: notify app to show passkey or to request passkey 2178 switch (setup->sm_stk_generation_method){ 2179 case JUST_WORKS: 2180 case NK_BOTH_INPUT: 2181 if (connection->sm_role){ 2182 // responder 2183 sm_sc_start_calculating_local_confirm(connection); 2184 } else { 2185 // initiator 2186 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2187 } 2188 break; 2189 case PK_INIT_INPUT: 2190 case PK_RESP_INPUT: 2191 case OK_BOTH_INPUT: 2192 // use random TK for display 2193 memcpy(setup->sm_ra, setup->sm_tk, 16); 2194 memcpy(setup->sm_rb, setup->sm_tk, 16); 2195 setup->sm_passkey_bit = 0; 2196 2197 if (connection->sm_role){ 2198 // responder 2199 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2200 } else { 2201 // initiator 2202 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2203 } 2204 sm_trigger_user_response(connection); 2205 break; 2206 case OOB: 2207 // TODO: implement SC OOB 2208 break; 2209 } 2210 2211 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2212 sm_timeout_reset(connection); 2213 break; 2214 } 2215 case SM_SC_SEND_CONFIRMATION: { 2216 uint8_t buffer[17]; 2217 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2218 reverse_128(setup->sm_local_confirm, &buffer[1]); 2219 if (connection->sm_role){ 2220 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2221 } else { 2222 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2223 } 2224 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2225 sm_timeout_reset(connection); 2226 break; 2227 } 2228 case SM_SC_SEND_PAIRING_RANDOM: { 2229 uint8_t buffer[17]; 2230 buffer[0] = SM_CODE_PAIRING_RANDOM; 2231 reverse_128(setup->sm_local_nonce, &buffer[1]); 2232 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 2233 if (connection->sm_role){ 2234 // responder 2235 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2236 } else { 2237 // initiator 2238 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2239 } 2240 } else { 2241 if (connection->sm_role){ 2242 // responder 2243 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 2244 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2245 } else { 2246 sm_sc_prepare_dhkey_check(connection); 2247 } 2248 } else { 2249 // initiator 2250 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2251 } 2252 } 2253 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2254 sm_timeout_reset(connection); 2255 break; 2256 } 2257 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2258 uint8_t buffer[17]; 2259 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2260 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2261 2262 if (connection->sm_role){ 2263 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2264 } else { 2265 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2266 } 2267 2268 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2269 sm_timeout_reset(connection); 2270 break; 2271 } 2272 2273 #endif 2274 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2275 // echo initiator for now 2276 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2277 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2278 2279 if (setup->sm_use_secure_connections){ 2280 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2281 // skip LTK/EDIV for SC 2282 log_info("sm: dropping encryption information flag"); 2283 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2284 } else { 2285 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2286 } 2287 2288 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); 2289 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); 2290 // update key distribution after ENC was dropped 2291 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2292 2293 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2294 sm_timeout_reset(connection); 2295 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2296 if (!setup->sm_use_secure_connections || setup->sm_stk_generation_method == JUST_WORKS){ 2297 sm_trigger_user_response(connection); 2298 } 2299 return; 2300 2301 case SM_PH2_SEND_PAIRING_RANDOM: { 2302 uint8_t buffer[17]; 2303 buffer[0] = SM_CODE_PAIRING_RANDOM; 2304 reverse_128(setup->sm_local_random, &buffer[1]); 2305 if (connection->sm_role){ 2306 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2307 } else { 2308 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2309 } 2310 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2311 sm_timeout_reset(connection); 2312 break; 2313 } 2314 2315 case SM_PH2_GET_RANDOM_TK: 2316 case SM_PH2_C1_GET_RANDOM_A: 2317 case SM_PH2_C1_GET_RANDOM_B: 2318 case SM_PH3_GET_RANDOM: 2319 case SM_PH3_GET_DIV: 2320 sm_next_responding_state(connection); 2321 sm_random_start(connection); 2322 return; 2323 2324 case SM_PH2_C1_GET_ENC_B: 2325 case SM_PH2_C1_GET_ENC_D: 2326 // already busy? 2327 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2328 sm_next_responding_state(connection); 2329 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 2330 return; 2331 2332 case SM_PH3_LTK_GET_ENC: 2333 case SM_RESPONDER_PH4_LTK_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, 0, 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_PH3_CSRK_GET_ENC: 2345 // already busy? 2346 if (sm_aes128_state == SM_AES128_IDLE) { 2347 sm_key_t d_prime; 2348 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 2349 sm_next_responding_state(connection); 2350 sm_aes128_start(sm_persistent_er, d_prime, connection); 2351 return; 2352 } 2353 break; 2354 2355 case SM_PH2_C1_GET_ENC_C: 2356 // already busy? 2357 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2358 // calculate m_confirm using aes128 engine - step 1 2359 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); 2360 sm_next_responding_state(connection); 2361 sm_aes128_start(setup->sm_tk, plaintext, connection); 2362 break; 2363 case SM_PH2_C1_GET_ENC_A: 2364 // already busy? 2365 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2366 // calculate confirm using aes128 engine - step 1 2367 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); 2368 sm_next_responding_state(connection); 2369 sm_aes128_start(setup->sm_tk, plaintext, connection); 2370 break; 2371 case SM_PH2_CALC_STK: 2372 // already busy? 2373 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2374 // calculate STK 2375 if (connection->sm_role){ 2376 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 2377 } else { 2378 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 2379 } 2380 sm_next_responding_state(connection); 2381 sm_aes128_start(setup->sm_tk, plaintext, connection); 2382 break; 2383 case SM_PH3_Y_GET_ENC: 2384 // already busy? 2385 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2386 // PH3B2 - calculate Y from - enc 2387 // Y = dm(DHK, Rand) 2388 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2389 sm_next_responding_state(connection); 2390 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2391 return; 2392 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2393 uint8_t buffer[17]; 2394 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2395 reverse_128(setup->sm_local_confirm, &buffer[1]); 2396 if (connection->sm_role){ 2397 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2398 } else { 2399 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2400 } 2401 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2402 sm_timeout_reset(connection); 2403 return; 2404 } 2405 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2406 sm_key_t stk_flipped; 2407 reverse_128(setup->sm_ltk, stk_flipped); 2408 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2409 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2410 return; 2411 } 2412 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2413 sm_key_t stk_flipped; 2414 reverse_128(setup->sm_ltk, stk_flipped); 2415 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2416 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2417 return; 2418 } 2419 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2420 sm_key_t ltk_flipped; 2421 reverse_128(setup->sm_ltk, ltk_flipped); 2422 connection->sm_engine_state = SM_RESPONDER_IDLE; 2423 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2424 return; 2425 } 2426 case SM_RESPONDER_PH4_Y_GET_ENC: 2427 // already busy? 2428 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2429 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2430 // Y = dm(DHK, Rand) 2431 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2432 sm_next_responding_state(connection); 2433 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2434 return; 2435 2436 case SM_PH3_DISTRIBUTE_KEYS: 2437 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2438 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2439 uint8_t buffer[17]; 2440 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2441 reverse_128(setup->sm_ltk, &buffer[1]); 2442 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2443 sm_timeout_reset(connection); 2444 return; 2445 } 2446 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2447 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2448 uint8_t buffer[11]; 2449 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2450 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2451 reverse_64(setup->sm_local_rand, &buffer[3]); 2452 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2453 sm_timeout_reset(connection); 2454 return; 2455 } 2456 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2457 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2458 uint8_t buffer[17]; 2459 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2460 reverse_128(sm_persistent_irk, &buffer[1]); 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_IDENTITY_ADDRESS_INFORMATION){ 2466 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2467 bd_addr_t local_address; 2468 uint8_t buffer[8]; 2469 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2470 gap_advertisements_get_address(&buffer[1], local_address); 2471 reverse_bd_addr(local_address, &buffer[2]); 2472 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2473 sm_timeout_reset(connection); 2474 return; 2475 } 2476 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2477 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2478 2479 // hack to reproduce test runs 2480 if (test_use_fixed_local_csrk){ 2481 memset(setup->sm_local_csrk, 0xcc, 16); 2482 } 2483 2484 uint8_t buffer[17]; 2485 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2486 reverse_128(setup->sm_local_csrk, &buffer[1]); 2487 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2488 sm_timeout_reset(connection); 2489 return; 2490 } 2491 2492 // keys are sent 2493 if (connection->sm_role){ 2494 // slave -> receive master keys if any 2495 if (sm_key_distribution_all_received(connection)){ 2496 sm_key_distribution_handle_all_received(connection); 2497 connection->sm_engine_state = SM_RESPONDER_IDLE; 2498 sm_done_for_handle(connection->sm_handle); 2499 } else { 2500 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2501 } 2502 } else { 2503 // master -> all done 2504 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2505 sm_done_for_handle(connection->sm_handle); 2506 } 2507 break; 2508 2509 default: 2510 break; 2511 } 2512 2513 // check again if active connection was released 2514 if (sm_active_connection) break; 2515 } 2516 } 2517 2518 // note: aes engine is ready as we just got the aes result 2519 static void sm_handle_encryption_result(uint8_t * data){ 2520 2521 sm_aes128_state = SM_AES128_IDLE; 2522 2523 if (sm_address_resolution_ah_calculation_active){ 2524 sm_address_resolution_ah_calculation_active = 0; 2525 // compare calulated address against connecting device 2526 uint8_t hash[3]; 2527 reverse_24(data, hash); 2528 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2529 log_info("LE Device Lookup: matched resolvable private address"); 2530 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2531 return; 2532 } 2533 // no match, try next 2534 sm_address_resolution_test++; 2535 return; 2536 } 2537 2538 switch (dkg_state){ 2539 case DKG_W4_IRK: 2540 reverse_128(data, sm_persistent_irk); 2541 log_info_key("irk", sm_persistent_irk); 2542 dkg_next_state(); 2543 return; 2544 case DKG_W4_DHK: 2545 reverse_128(data, sm_persistent_dhk); 2546 log_info_key("dhk", sm_persistent_dhk); 2547 dkg_next_state(); 2548 // SM Init Finished 2549 return; 2550 default: 2551 break; 2552 } 2553 2554 switch (rau_state){ 2555 case RAU_W4_ENC: 2556 reverse_24(data, &sm_random_address[3]); 2557 rau_next_state(); 2558 return; 2559 default: 2560 break; 2561 } 2562 2563 switch (sm_cmac_state){ 2564 case CMAC_W4_SUBKEYS: 2565 case CMAC_W4_MI: 2566 case CMAC_W4_MLAST: 2567 { 2568 sm_key_t t; 2569 reverse_128(data, t); 2570 sm_cmac_handle_encryption_result(t); 2571 } 2572 return; 2573 default: 2574 break; 2575 } 2576 2577 // retrieve sm_connection provided to sm_aes128_start_encryption 2578 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2579 if (!connection) return; 2580 switch (connection->sm_engine_state){ 2581 case SM_PH2_C1_W4_ENC_A: 2582 case SM_PH2_C1_W4_ENC_C: 2583 { 2584 sm_key_t t2; 2585 reverse_128(data, t2); 2586 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2587 } 2588 sm_next_responding_state(connection); 2589 return; 2590 case SM_PH2_C1_W4_ENC_B: 2591 reverse_128(data, setup->sm_local_confirm); 2592 log_info_key("c1!", setup->sm_local_confirm); 2593 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2594 return; 2595 case SM_PH2_C1_W4_ENC_D: 2596 { 2597 sm_key_t peer_confirm_test; 2598 reverse_128(data, peer_confirm_test); 2599 log_info_key("c1!", peer_confirm_test); 2600 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2601 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2602 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2603 return; 2604 } 2605 if (connection->sm_role){ 2606 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2607 } else { 2608 connection->sm_engine_state = SM_PH2_CALC_STK; 2609 } 2610 } 2611 return; 2612 case SM_PH2_W4_STK: 2613 reverse_128(data, setup->sm_ltk); 2614 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2615 log_info_key("stk", setup->sm_ltk); 2616 if (connection->sm_role){ 2617 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2618 } else { 2619 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2620 } 2621 return; 2622 case SM_PH3_Y_W4_ENC:{ 2623 sm_key_t y128; 2624 reverse_128(data, y128); 2625 setup->sm_local_y = big_endian_read_16(y128, 14); 2626 log_info_hex16("y", setup->sm_local_y); 2627 // PH3B3 - calculate EDIV 2628 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2629 log_info_hex16("ediv", setup->sm_local_ediv); 2630 // PH3B4 - calculate LTK - enc 2631 // LTK = d1(ER, DIV, 0)) 2632 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2633 return; 2634 } 2635 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2636 sm_key_t y128; 2637 reverse_128(data, y128); 2638 setup->sm_local_y = big_endian_read_16(y128, 14); 2639 log_info_hex16("y", setup->sm_local_y); 2640 2641 // PH3B3 - calculate DIV 2642 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2643 log_info_hex16("ediv", setup->sm_local_ediv); 2644 // PH3B4 - calculate LTK - enc 2645 // LTK = d1(ER, DIV, 0)) 2646 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2647 return; 2648 } 2649 case SM_PH3_LTK_W4_ENC: 2650 reverse_128(data, setup->sm_ltk); 2651 log_info_key("ltk", setup->sm_ltk); 2652 // calc CSRK next 2653 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2654 return; 2655 case SM_PH3_CSRK_W4_ENC: 2656 reverse_128(data, setup->sm_local_csrk); 2657 log_info_key("csrk", setup->sm_local_csrk); 2658 if (setup->sm_key_distribution_send_set){ 2659 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2660 } else { 2661 // no keys to send, just continue 2662 if (connection->sm_role){ 2663 // slave -> receive master keys 2664 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2665 } else { 2666 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 2667 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2668 } else { 2669 // master -> all done 2670 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2671 sm_done_for_handle(connection->sm_handle); 2672 } 2673 } 2674 } 2675 return; 2676 case SM_RESPONDER_PH4_LTK_W4_ENC: 2677 reverse_128(data, setup->sm_ltk); 2678 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2679 log_info_key("ltk", setup->sm_ltk); 2680 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2681 return; 2682 default: 2683 break; 2684 } 2685 } 2686 2687 #ifdef USE_MBEDTLS_FOR_ECDH 2688 2689 static int sm_generate_f_rng(void * context, unsigned char * buffer, size_t size){ 2690 int offset = setup->sm_passkey_bit; 2691 log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); 2692 while (size) { 2693 if (offset < 32){ 2694 *buffer++ = setup->sm_peer_qx[offset++]; 2695 } else { 2696 *buffer++ = setup->sm_peer_qx[offset++ - 32]; 2697 } 2698 size--; 2699 } 2700 setup->sm_passkey_bit = offset; 2701 return 0; 2702 } 2703 #endif 2704 2705 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2706 static void sm_handle_random_result(uint8_t * data){ 2707 2708 #ifdef USE_MBEDTLS_FOR_ECDH 2709 if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ 2710 int num_bytes = setup->sm_passkey_bit; 2711 if (num_bytes < 32){ 2712 memcpy(&setup->sm_peer_qx[num_bytes], data, 8); 2713 } else { 2714 memcpy(&setup->sm_peer_qx[num_bytes-32], data, 8); 2715 } 2716 num_bytes += 8; 2717 setup->sm_passkey_bit = num_bytes; 2718 2719 if (num_bytes >= 64){ 2720 2721 // generate EC key 2722 setup->sm_passkey_bit = 0; 2723 mbedtls_mpi d; 2724 mbedtls_ecp_point P; 2725 mbedtls_mpi_init(&d); 2726 mbedtls_ecp_point_init(&P); 2727 int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng, NULL); 2728 log_info("gen keypair %x", res); 2729 mbedtls_mpi_write_binary(&P.X, ec_qx, 32); 2730 mbedtls_mpi_write_binary(&P.Y, ec_qy, 32); 2731 mbedtls_mpi_write_binary(&d, ec_d, 32); 2732 mbedtls_ecp_point_free(&P); 2733 mbedtls_mpi_free(&d); 2734 ec_key_generation_state = EC_KEY_GENERATION_DONE; 2735 sm_log_ec_keypair(); 2736 2737 #if 0 2738 int i; 2739 sm_key256_t dhkey; 2740 for (i=0;i<10;i++){ 2741 // printf("test dhkey check\n"); 2742 memcpy(setup->sm_peer_qx, ec_qx, 32); 2743 memcpy(setup->sm_peer_qy, ec_qy, 32); 2744 sm_sc_calculate_dhkey(dhkey); 2745 // printf("test dhkey check end\n"); 2746 } 2747 #endif 2748 2749 } 2750 } 2751 #endif 2752 2753 switch (rau_state){ 2754 case RAU_W4_RANDOM: 2755 // non-resolvable vs. resolvable 2756 switch (gap_random_adress_type){ 2757 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2758 // resolvable: use random as prand and calc address hash 2759 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2760 memcpy(sm_random_address, data, 3); 2761 sm_random_address[0] &= 0x3f; 2762 sm_random_address[0] |= 0x40; 2763 rau_state = RAU_GET_ENC; 2764 break; 2765 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2766 default: 2767 // "The two most significant bits of the address shall be equal to ‘0’"" 2768 memcpy(sm_random_address, data, 6); 2769 sm_random_address[0] &= 0x3f; 2770 rau_state = RAU_SET_ADDRESS; 2771 break; 2772 } 2773 return; 2774 default: 2775 break; 2776 } 2777 2778 // retrieve sm_connection provided to sm_random_start 2779 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2780 if (!connection) return; 2781 switch (connection->sm_engine_state){ 2782 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2783 case SM_SC_W4_GET_RANDOM_A: 2784 memcpy(&setup->sm_local_nonce[0], data, 8); 2785 connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; 2786 break; 2787 case SM_SC_W4_GET_RANDOM_B: 2788 memcpy(&setup->sm_local_nonce[8], data, 8); 2789 // initiator & jw/nc -> send pairing random 2790 if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 2791 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2792 break; 2793 } else { 2794 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2795 } 2796 break; 2797 #endif 2798 2799 case SM_PH2_W4_RANDOM_TK: 2800 { 2801 // map random to 0-999999 without speding much cycles on a modulus operation 2802 uint32_t tk = little_endian_read_32(data,0); 2803 tk = tk & 0xfffff; // 1048575 2804 if (tk >= 999999){ 2805 tk = tk - 999999; 2806 } 2807 sm_reset_tk(); 2808 big_endian_store_32(setup->sm_tk, 12, tk); 2809 if (connection->sm_role){ 2810 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2811 } else { 2812 if (setup->sm_use_secure_connections){ 2813 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2814 } else { 2815 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2816 sm_trigger_user_response(connection); 2817 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2818 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2819 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2820 } 2821 } 2822 } 2823 return; 2824 } 2825 case SM_PH2_C1_W4_RANDOM_A: 2826 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2827 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2828 return; 2829 case SM_PH2_C1_W4_RANDOM_B: 2830 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2831 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2832 return; 2833 case SM_PH3_W4_RANDOM: 2834 reverse_64(data, setup->sm_local_rand); 2835 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2836 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2837 // no db for authenticated flag hack: store flag in bit 4 of LSB 2838 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2839 connection->sm_engine_state = SM_PH3_GET_DIV; 2840 return; 2841 case SM_PH3_W4_DIV: 2842 // use 16 bit from random value as div 2843 setup->sm_local_div = big_endian_read_16(data, 0); 2844 log_info_hex16("div", setup->sm_local_div); 2845 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2846 return; 2847 default: 2848 break; 2849 } 2850 } 2851 2852 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2853 2854 sm_connection_t * sm_conn; 2855 hci_con_handle_t con_handle; 2856 2857 switch (packet_type) { 2858 2859 case HCI_EVENT_PACKET: 2860 switch (hci_event_packet_get_type(packet)) { 2861 2862 case BTSTACK_EVENT_STATE: 2863 // bt stack activated, get started 2864 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2865 log_info("HCI Working!"); 2866 2867 // set local addr for le device db 2868 bd_addr_t local_bd_addr; 2869 gap_local_bd_addr(local_bd_addr); 2870 le_device_db_set_local_bd_addr(local_bd_addr); 2871 2872 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2873 rau_state = RAU_IDLE; 2874 #ifdef USE_MBEDTLS_FOR_ECDH 2875 if (!sm_have_ec_keypair){ 2876 setup->sm_passkey_bit = 0; 2877 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 2878 } 2879 #endif 2880 sm_run(); 2881 } 2882 break; 2883 2884 case HCI_EVENT_LE_META: 2885 switch (packet[2]) { 2886 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2887 2888 log_info("sm: connected"); 2889 2890 if (packet[3]) return; // connection failed 2891 2892 con_handle = little_endian_read_16(packet, 4); 2893 sm_conn = sm_get_connection_for_handle(con_handle); 2894 if (!sm_conn) break; 2895 2896 sm_conn->sm_handle = con_handle; 2897 sm_conn->sm_role = packet[6]; 2898 sm_conn->sm_peer_addr_type = packet[7]; 2899 reverse_bd_addr(&packet[8], 2900 sm_conn->sm_peer_address); 2901 2902 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2903 2904 // reset security properties 2905 sm_conn->sm_connection_encrypted = 0; 2906 sm_conn->sm_connection_authenticated = 0; 2907 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2908 sm_conn->sm_le_db_index = -1; 2909 2910 // prepare CSRK lookup (does not involve setup) 2911 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2912 2913 // just connected -> everything else happens in sm_run() 2914 if (sm_conn->sm_role){ 2915 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2916 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2917 if (sm_slave_request_security) { 2918 // request security if requested by app 2919 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2920 } else { 2921 // otherwise, wait for pairing request 2922 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2923 } 2924 } 2925 break; 2926 } else { 2927 // master 2928 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2929 } 2930 break; 2931 2932 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2933 con_handle = little_endian_read_16(packet, 3); 2934 sm_conn = sm_get_connection_for_handle(con_handle); 2935 if (!sm_conn) break; 2936 2937 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2938 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2939 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2940 break; 2941 } 2942 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2943 // PH2 SEND LTK as we need to exchange keys in PH3 2944 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2945 break; 2946 } 2947 2948 // store rand and ediv 2949 reverse_64(&packet[5], sm_conn->sm_local_rand); 2950 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2951 2952 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 2953 // potentially stored LTK is from the master 2954 if (sm_conn->sm_local_ediv != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ 2955 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 2956 break; 2957 } 2958 2959 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2960 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 2961 #else 2962 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 2963 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2964 #endif 2965 break; 2966 2967 default: 2968 break; 2969 } 2970 break; 2971 2972 case HCI_EVENT_ENCRYPTION_CHANGE: 2973 con_handle = little_endian_read_16(packet, 3); 2974 sm_conn = sm_get_connection_for_handle(con_handle); 2975 if (!sm_conn) break; 2976 2977 sm_conn->sm_connection_encrypted = packet[5]; 2978 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2979 sm_conn->sm_actual_encryption_key_size); 2980 log_info("event handler, state %u", sm_conn->sm_engine_state); 2981 if (!sm_conn->sm_connection_encrypted) break; 2982 // continue if part of initial pairing 2983 switch (sm_conn->sm_engine_state){ 2984 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2985 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2986 sm_done_for_handle(sm_conn->sm_handle); 2987 break; 2988 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2989 if (sm_conn->sm_role){ 2990 // slave 2991 if (setup->sm_use_secure_connections){ 2992 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2993 } else { 2994 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2995 } 2996 } else { 2997 // master 2998 if (sm_key_distribution_all_received(sm_conn)){ 2999 // skip receiving keys as there are none 3000 sm_key_distribution_handle_all_received(sm_conn); 3001 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3002 } else { 3003 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3004 } 3005 } 3006 break; 3007 default: 3008 break; 3009 } 3010 break; 3011 3012 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3013 con_handle = little_endian_read_16(packet, 3); 3014 sm_conn = sm_get_connection_for_handle(con_handle); 3015 if (!sm_conn) break; 3016 3017 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3018 log_info("event handler, state %u", sm_conn->sm_engine_state); 3019 // continue if part of initial pairing 3020 switch (sm_conn->sm_engine_state){ 3021 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3022 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3023 sm_done_for_handle(sm_conn->sm_handle); 3024 break; 3025 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3026 if (sm_conn->sm_role){ 3027 // slave 3028 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3029 } else { 3030 // master 3031 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3032 } 3033 break; 3034 default: 3035 break; 3036 } 3037 break; 3038 3039 3040 case HCI_EVENT_DISCONNECTION_COMPLETE: 3041 con_handle = little_endian_read_16(packet, 3); 3042 sm_done_for_handle(con_handle); 3043 sm_conn = sm_get_connection_for_handle(con_handle); 3044 if (!sm_conn) break; 3045 3046 // delete stored bonding on disconnect with authentication failure in ph0 3047 if (sm_conn->sm_role == 0 3048 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 3049 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 3050 le_device_db_remove(sm_conn->sm_le_db_index); 3051 } 3052 3053 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3054 sm_conn->sm_handle = 0; 3055 break; 3056 3057 case HCI_EVENT_COMMAND_COMPLETE: 3058 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 3059 sm_handle_encryption_result(&packet[6]); 3060 break; 3061 } 3062 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 3063 sm_handle_random_result(&packet[6]); 3064 break; 3065 } 3066 break; 3067 default: 3068 break; 3069 } 3070 break; 3071 default: 3072 break; 3073 } 3074 3075 sm_run(); 3076 } 3077 3078 static inline int sm_calc_actual_encryption_key_size(int other){ 3079 if (other < sm_min_encryption_key_size) return 0; 3080 if (other < sm_max_encryption_key_size) return other; 3081 return sm_max_encryption_key_size; 3082 } 3083 3084 3085 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3086 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3087 switch (method){ 3088 case JUST_WORKS: 3089 case NK_BOTH_INPUT: 3090 return 1; 3091 default: 3092 return 0; 3093 } 3094 } 3095 // responder 3096 3097 static int sm_passkey_used(stk_generation_method_t method){ 3098 switch (method){ 3099 case PK_RESP_INPUT: 3100 return 1; 3101 default: 3102 return 0; 3103 } 3104 } 3105 #endif 3106 3107 /** 3108 * @return ok 3109 */ 3110 static int sm_validate_stk_generation_method(void){ 3111 // check if STK generation method is acceptable by client 3112 switch (setup->sm_stk_generation_method){ 3113 case JUST_WORKS: 3114 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 3115 case PK_RESP_INPUT: 3116 case PK_INIT_INPUT: 3117 case OK_BOTH_INPUT: 3118 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 3119 case OOB: 3120 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 3121 case NK_BOTH_INPUT: 3122 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 3123 return 1; 3124 default: 3125 return 0; 3126 } 3127 } 3128 3129 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3130 3131 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 3132 sm_run(); 3133 } 3134 3135 if (packet_type != SM_DATA_PACKET) return; 3136 3137 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3138 if (!sm_conn) return; 3139 3140 if (packet[0] == SM_CODE_PAIRING_FAILED){ 3141 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3142 return; 3143 } 3144 3145 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 3146 3147 int err; 3148 3149 if (packet[0] == SM_CODE_KEYPRESS_NOTIFICATION){ 3150 uint8_t buffer[5]; 3151 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3152 buffer[1] = 3; 3153 little_endian_store_16(buffer, 2, con_handle); 3154 buffer[4] = packet[1]; 3155 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3156 return; 3157 } 3158 3159 switch (sm_conn->sm_engine_state){ 3160 3161 // a sm timeout requries a new physical connection 3162 case SM_GENERAL_TIMEOUT: 3163 return; 3164 3165 // Initiator 3166 case SM_INITIATOR_CONNECTED: 3167 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3168 sm_pdu_received_in_wrong_state(sm_conn); 3169 break; 3170 } 3171 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 3172 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3173 break; 3174 } 3175 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 3176 sm_key_t ltk; 3177 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); 3178 if (!sm_is_null_key(ltk)){ 3179 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3180 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3181 } else { 3182 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3183 } 3184 break; 3185 } 3186 // otherwise, store security request 3187 sm_conn->sm_security_request_received = 1; 3188 break; 3189 3190 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3191 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 3192 sm_pdu_received_in_wrong_state(sm_conn); 3193 break; 3194 } 3195 // store pairing request 3196 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 3197 err = sm_stk_generation_init(sm_conn); 3198 if (err){ 3199 setup->sm_pairing_failed_reason = err; 3200 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3201 break; 3202 } 3203 3204 // generate random number first, if we need to show passkey 3205 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3206 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 3207 break; 3208 } 3209 3210 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3211 if (setup->sm_use_secure_connections){ 3212 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3213 if (setup->sm_stk_generation_method == JUST_WORKS){ 3214 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3215 sm_trigger_user_response(sm_conn); 3216 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3217 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3218 } 3219 } else { 3220 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3221 } 3222 break; 3223 } 3224 #endif 3225 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3226 sm_trigger_user_response(sm_conn); 3227 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3228 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3229 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3230 } 3231 break; 3232 3233 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3234 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3235 sm_pdu_received_in_wrong_state(sm_conn); 3236 break; 3237 } 3238 3239 // store s_confirm 3240 reverse_128(&packet[1], setup->sm_peer_confirm); 3241 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3242 break; 3243 3244 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3245 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3246 sm_pdu_received_in_wrong_state(sm_conn); 3247 break;; 3248 } 3249 3250 // received random value 3251 reverse_128(&packet[1], setup->sm_peer_random); 3252 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3253 break; 3254 3255 // Responder 3256 case SM_RESPONDER_IDLE: 3257 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3258 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3259 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 3260 sm_pdu_received_in_wrong_state(sm_conn); 3261 break;; 3262 } 3263 3264 // store pairing request 3265 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 3266 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3267 break; 3268 3269 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3270 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3271 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 3272 sm_pdu_received_in_wrong_state(sm_conn); 3273 break; 3274 } 3275 3276 // store public key for DH Key calculation 3277 reverse_256(&packet[01], setup->sm_peer_qx); 3278 reverse_256(&packet[33], setup->sm_peer_qy); 3279 3280 #ifdef USE_MBEDTLS_FOR_ECDH 3281 // validate public key 3282 mbedtls_ecp_point Q; 3283 mbedtls_ecp_point_init( &Q ); 3284 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 3285 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 3286 mbedtls_mpi_lset(&Q.Z, 1); 3287 err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); 3288 mbedtls_ecp_point_free( & Q); 3289 if (err){ 3290 log_error("sm: peer public key invalid %x", err); 3291 // uses "unspecified reason", there is no "public key invalid" error code 3292 sm_pdu_received_in_wrong_state(sm_conn); 3293 break; 3294 } 3295 3296 #endif 3297 if (sm_conn->sm_role){ 3298 // responder 3299 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3300 } else { 3301 // initiator 3302 // stk generation method 3303 // passkey entry: notify app to show passkey or to request passkey 3304 switch (setup->sm_stk_generation_method){ 3305 case JUST_WORKS: 3306 case NK_BOTH_INPUT: 3307 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3308 break; 3309 case PK_RESP_INPUT: 3310 sm_sc_start_calculating_local_confirm(sm_conn); 3311 break; 3312 case PK_INIT_INPUT: 3313 case OK_BOTH_INPUT: 3314 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3315 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3316 break; 3317 } 3318 sm_sc_start_calculating_local_confirm(sm_conn); 3319 break; 3320 case OOB: 3321 // TODO: implement SC OOB 3322 break; 3323 } 3324 } 3325 break; 3326 3327 case SM_SC_W4_CONFIRMATION: 3328 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3329 sm_pdu_received_in_wrong_state(sm_conn); 3330 break; 3331 } 3332 // received confirm value 3333 reverse_128(&packet[1], setup->sm_peer_confirm); 3334 3335 if (sm_conn->sm_role){ 3336 // responder 3337 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3338 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3339 // still waiting for passkey 3340 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3341 break; 3342 } 3343 } 3344 sm_sc_start_calculating_local_confirm(sm_conn); 3345 } else { 3346 // initiator 3347 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3348 sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; 3349 } else { 3350 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3351 } 3352 } 3353 break; 3354 3355 case SM_SC_W4_PAIRING_RANDOM: 3356 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3357 sm_pdu_received_in_wrong_state(sm_conn); 3358 break; 3359 } 3360 3361 // received random value 3362 reverse_128(&packet[1], setup->sm_peer_nonce); 3363 3364 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3365 // only check for JUST WORK/NC in initiator role AND passkey entry 3366 if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { 3367 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3368 } 3369 3370 sm_sc_state_after_receiving_random(sm_conn); 3371 break; 3372 3373 case SM_SC_W2_CALCULATE_G2: 3374 case SM_SC_W4_CALCULATE_G2: 3375 case SM_SC_W2_CALCULATE_F5_SALT: 3376 case SM_SC_W4_CALCULATE_F5_SALT: 3377 case SM_SC_W2_CALCULATE_F5_MACKEY: 3378 case SM_SC_W4_CALCULATE_F5_MACKEY: 3379 case SM_SC_W2_CALCULATE_F5_LTK: 3380 case SM_SC_W4_CALCULATE_F5_LTK: 3381 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3382 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3383 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3384 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 3385 sm_pdu_received_in_wrong_state(sm_conn); 3386 break; 3387 } 3388 // store DHKey Check 3389 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3390 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3391 3392 // have we been only waiting for dhkey check command? 3393 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3394 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3395 } 3396 break; 3397 #endif 3398 3399 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3400 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 3401 sm_pdu_received_in_wrong_state(sm_conn); 3402 break; 3403 } 3404 3405 // received confirm value 3406 reverse_128(&packet[1], setup->sm_peer_confirm); 3407 3408 // notify client to hide shown passkey 3409 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3410 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3411 } 3412 3413 // handle user cancel pairing? 3414 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3415 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 3416 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3417 break; 3418 } 3419 3420 // wait for user action? 3421 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3422 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3423 break; 3424 } 3425 3426 // calculate and send local_confirm 3427 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3428 break; 3429 3430 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3431 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 3432 sm_pdu_received_in_wrong_state(sm_conn); 3433 break;; 3434 } 3435 3436 // received random value 3437 reverse_128(&packet[1], setup->sm_peer_random); 3438 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3439 break; 3440 3441 case SM_PH3_RECEIVE_KEYS: 3442 switch(packet[0]){ 3443 case SM_CODE_ENCRYPTION_INFORMATION: 3444 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3445 reverse_128(&packet[1], setup->sm_peer_ltk); 3446 break; 3447 3448 case SM_CODE_MASTER_IDENTIFICATION: 3449 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3450 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3451 reverse_64(&packet[3], setup->sm_peer_rand); 3452 break; 3453 3454 case SM_CODE_IDENTITY_INFORMATION: 3455 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 3456 reverse_128(&packet[1], setup->sm_peer_irk); 3457 break; 3458 3459 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 3460 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 3461 setup->sm_peer_addr_type = packet[1]; 3462 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3463 break; 3464 3465 case SM_CODE_SIGNING_INFORMATION: 3466 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3467 reverse_128(&packet[1], setup->sm_peer_csrk); 3468 break; 3469 default: 3470 // Unexpected PDU 3471 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3472 break; 3473 } 3474 // done with key distribution? 3475 if (sm_key_distribution_all_received(sm_conn)){ 3476 3477 sm_key_distribution_handle_all_received(sm_conn); 3478 3479 if (sm_conn->sm_role){ 3480 if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ 3481 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 3482 } else { 3483 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3484 sm_done_for_handle(sm_conn->sm_handle); 3485 } 3486 } else { 3487 if (setup->sm_use_secure_connections){ 3488 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3489 } else { 3490 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3491 } 3492 } 3493 } 3494 break; 3495 default: 3496 // Unexpected PDU 3497 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3498 break; 3499 } 3500 3501 // try to send preparared packet 3502 sm_run(); 3503 } 3504 3505 // Security Manager Client API 3506 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3507 sm_get_oob_data = get_oob_data_callback; 3508 } 3509 3510 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3511 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3512 } 3513 3514 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3515 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3516 } 3517 3518 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3519 sm_min_encryption_key_size = min_size; 3520 sm_max_encryption_key_size = max_size; 3521 } 3522 3523 void sm_set_authentication_requirements(uint8_t auth_req){ 3524 sm_auth_req = auth_req; 3525 } 3526 3527 void sm_set_io_capabilities(io_capability_t io_capability){ 3528 sm_io_capabilities = io_capability; 3529 } 3530 3531 void sm_set_request_security(int enable){ 3532 sm_slave_request_security = enable; 3533 } 3534 3535 void sm_set_er(sm_key_t er){ 3536 memcpy(sm_persistent_er, er, 16); 3537 } 3538 3539 void sm_set_ir(sm_key_t ir){ 3540 memcpy(sm_persistent_ir, ir, 16); 3541 } 3542 3543 // Testing support only 3544 void sm_test_set_irk(sm_key_t irk){ 3545 memcpy(sm_persistent_irk, irk, 16); 3546 sm_persistent_irk_ready = 1; 3547 } 3548 3549 void sm_test_use_fixed_local_csrk(void){ 3550 test_use_fixed_local_csrk = 1; 3551 } 3552 3553 void sm_init(void){ 3554 // set some (BTstack default) ER and IR 3555 int i; 3556 sm_key_t er; 3557 sm_key_t ir; 3558 for (i=0;i<16;i++){ 3559 er[i] = 0x30 + i; 3560 ir[i] = 0x90 + i; 3561 } 3562 sm_set_er(er); 3563 sm_set_ir(ir); 3564 // defaults 3565 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3566 | SM_STK_GENERATION_METHOD_OOB 3567 | SM_STK_GENERATION_METHOD_PASSKEY 3568 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3569 3570 sm_max_encryption_key_size = 16; 3571 sm_min_encryption_key_size = 7; 3572 3573 sm_cmac_state = CMAC_IDLE; 3574 dkg_state = DKG_W4_WORKING; 3575 rau_state = RAU_W4_WORKING; 3576 sm_aes128_state = SM_AES128_IDLE; 3577 sm_address_resolution_test = -1; // no private address to resolve yet 3578 sm_address_resolution_ah_calculation_active = 0; 3579 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3580 sm_address_resolution_general_queue = NULL; 3581 3582 gap_random_adress_update_period = 15 * 60 * 1000L; 3583 3584 sm_active_connection = 0; 3585 3586 test_use_fixed_local_csrk = 0; 3587 3588 // register for HCI Events from HCI 3589 hci_event_callback_registration.callback = &sm_event_packet_handler; 3590 hci_add_event_handler(&hci_event_callback_registration); 3591 3592 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3593 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3594 3595 #ifdef USE_MBEDTLS_FOR_ECDH 3596 ec_key_generation_state = EC_KEY_GENERATION_IDLE; 3597 3598 #ifndef HAVE_MALLOC 3599 sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); 3600 #endif 3601 mbedtls_ecp_group_init(&mbedtls_ec_group); 3602 mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); 3603 #if 0 3604 // test 3605 sm_test_use_fixed_ec_keypair(); 3606 if (sm_have_ec_keypair){ 3607 printf("test dhkey check\n"); 3608 sm_key256_t dhkey; 3609 memcpy(setup->sm_peer_qx, ec_qx, 32); 3610 memcpy(setup->sm_peer_qy, ec_qy, 32); 3611 sm_sc_calculate_dhkey(dhkey); 3612 } 3613 #endif 3614 #endif 3615 } 3616 3617 void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ 3618 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3619 memcpy(ec_qx, qx, 32); 3620 memcpy(ec_qy, qy, 32); 3621 memcpy(ec_d, d, 32); 3622 sm_have_ec_keypair = 1; 3623 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3624 #endif 3625 } 3626 3627 void sm_test_use_fixed_ec_keypair(void){ 3628 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3629 #ifdef USE_MBEDTLS_FOR_ECDH 3630 // use test keypair from spec 3631 mbedtls_mpi x; 3632 mbedtls_mpi_init(&x); 3633 mbedtls_mpi_read_string( &x, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3634 mbedtls_mpi_write_binary(&x, ec_d, 32); 3635 mbedtls_mpi_read_string( &x, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3636 mbedtls_mpi_write_binary(&x, ec_qx, 32); 3637 mbedtls_mpi_read_string( &x, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3638 mbedtls_mpi_write_binary(&x, ec_qy, 32); 3639 mbedtls_mpi_free(&x); 3640 #endif 3641 sm_have_ec_keypair = 1; 3642 ec_key_generation_state = EC_KEY_GENERATION_DONE; 3643 #endif 3644 } 3645 3646 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3647 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3648 if (!hci_con) return NULL; 3649 return &hci_con->sm_connection; 3650 } 3651 3652 // @returns 0 if not encrypted, 7-16 otherwise 3653 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3654 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3655 if (!sm_conn) return 0; // wrong connection 3656 if (!sm_conn->sm_connection_encrypted) return 0; 3657 return sm_conn->sm_actual_encryption_key_size; 3658 } 3659 3660 int sm_authenticated(hci_con_handle_t con_handle){ 3661 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3662 if (!sm_conn) return 0; // wrong connection 3663 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3664 return sm_conn->sm_connection_authenticated; 3665 } 3666 3667 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3668 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3669 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3670 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3671 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3672 return sm_conn->sm_connection_authorization_state; 3673 } 3674 3675 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3676 switch (sm_conn->sm_engine_state){ 3677 case SM_GENERAL_IDLE: 3678 case SM_RESPONDER_IDLE: 3679 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3680 sm_run(); 3681 break; 3682 default: 3683 break; 3684 } 3685 } 3686 3687 /** 3688 * @brief Trigger Security Request 3689 */ 3690 void sm_send_security_request(hci_con_handle_t con_handle){ 3691 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3692 if (!sm_conn) return; 3693 sm_send_security_request_for_connection(sm_conn); 3694 } 3695 3696 // request pairing 3697 void sm_request_pairing(hci_con_handle_t con_handle){ 3698 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3699 if (!sm_conn) return; // wrong connection 3700 3701 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3702 if (sm_conn->sm_role){ 3703 sm_send_security_request_for_connection(sm_conn); 3704 } else { 3705 // used as a trigger to start central/master/initiator security procedures 3706 uint16_t ediv; 3707 sm_key_t ltk; 3708 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3709 switch (sm_conn->sm_irk_lookup_state){ 3710 case IRK_LOOKUP_FAILED: 3711 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3712 break; 3713 case IRK_LOOKUP_SUCCEEDED: 3714 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, ltk, NULL, NULL, NULL); 3715 if (!sm_is_null_key(ltk) || ediv){ 3716 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3717 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3718 } else { 3719 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3720 } 3721 break; 3722 default: 3723 sm_conn->sm_bonding_requested = 1; 3724 break; 3725 } 3726 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3727 sm_conn->sm_bonding_requested = 1; 3728 } 3729 } 3730 sm_run(); 3731 } 3732 3733 // called by client app on authorization request 3734 void sm_authorization_decline(hci_con_handle_t con_handle){ 3735 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3736 if (!sm_conn) return; // wrong connection 3737 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3738 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3739 } 3740 3741 void sm_authorization_grant(hci_con_handle_t con_handle){ 3742 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3743 if (!sm_conn) return; // wrong connection 3744 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3745 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3746 } 3747 3748 // GAP Bonding API 3749 3750 void sm_bonding_decline(hci_con_handle_t con_handle){ 3751 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3752 if (!sm_conn) return; // wrong connection 3753 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3754 3755 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3756 switch (setup->sm_stk_generation_method){ 3757 case PK_RESP_INPUT: 3758 case PK_INIT_INPUT: 3759 case OK_BOTH_INPUT: 3760 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3761 break; 3762 case NK_BOTH_INPUT: 3763 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3764 break; 3765 case JUST_WORKS: 3766 case OOB: 3767 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3768 break; 3769 } 3770 } 3771 sm_run(); 3772 } 3773 3774 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3775 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3776 if (!sm_conn) return; // wrong connection 3777 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3778 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3779 if (setup->sm_use_secure_connections){ 3780 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3781 } else { 3782 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3783 } 3784 } 3785 3786 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3787 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3788 sm_sc_prepare_dhkey_check(sm_conn); 3789 } 3790 #endif 3791 3792 sm_run(); 3793 } 3794 3795 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3796 // for now, it's the same 3797 sm_just_works_confirm(con_handle); 3798 } 3799 3800 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3801 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3802 if (!sm_conn) return; // wrong connection 3803 sm_reset_tk(); 3804 big_endian_store_32(setup->sm_tk, 12, passkey); 3805 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3806 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3807 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3808 } 3809 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3810 memcpy(setup->sm_ra, setup->sm_tk, 16); 3811 memcpy(setup->sm_rb, setup->sm_tk, 16); 3812 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3813 sm_sc_start_calculating_local_confirm(sm_conn); 3814 } 3815 #endif 3816 sm_run(); 3817 } 3818 3819 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 3820 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3821 if (!sm_conn) return; // wrong connection 3822 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 3823 setup->sm_keypress_notification = action; 3824 sm_run(); 3825 } 3826 3827 /** 3828 * @brief Identify device in LE Device DB 3829 * @param handle 3830 * @returns index from le_device_db or -1 if not found/identified 3831 */ 3832 int sm_le_device_index(hci_con_handle_t con_handle ){ 3833 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3834 if (!sm_conn) return -1; 3835 return sm_conn->sm_le_db_index; 3836 } 3837 3838 // GAP LE API 3839 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3840 gap_random_address_update_stop(); 3841 gap_random_adress_type = random_address_type; 3842 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3843 gap_random_address_update_start(); 3844 gap_random_address_trigger(); 3845 } 3846 3847 gap_random_address_type_t gap_random_address_get_mode(void){ 3848 return gap_random_adress_type; 3849 } 3850 3851 void gap_random_address_set_update_period(int period_ms){ 3852 gap_random_adress_update_period = period_ms; 3853 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3854 gap_random_address_update_stop(); 3855 gap_random_address_update_start(); 3856 } 3857 3858 void gap_random_address_set(bd_addr_t addr){ 3859 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3860 memcpy(sm_random_address, addr, 6); 3861 rau_state = RAU_SET_ADDRESS; 3862 sm_run(); 3863 } 3864 3865 /* 3866 * @brief Set Advertisement Paramters 3867 * @param adv_int_min 3868 * @param adv_int_max 3869 * @param adv_type 3870 * @param direct_address_type 3871 * @param direct_address 3872 * @param channel_map 3873 * @param filter_policy 3874 * 3875 * @note own_address_type is used from gap_random_address_set_mode 3876 */ 3877 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3878 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3879 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3880 direct_address_typ, direct_address, channel_map, filter_policy); 3881 } 3882 3883