1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "ble/le_device_db.h" 43 #include "ble/core.h" 44 #include "ble/sm.h" 45 #include "btstack_debug.h" 46 #include "btstack_event.h" 47 #include "btstack_linked_list.h" 48 #include "btstack_memory.h" 49 #include "gap.h" 50 #include "hci.h" 51 #include "l2cap.h" 52 53 #ifdef ENABLE_LE_SECURE_CONNECTIONS 54 // TODO: remove software AES 55 #include "rijndael.h" 56 #endif 57 58 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(HAVE_HCI_CONTROLLER_DHKEY_SUPPORT) 59 #define USE_MBEDTLS_FOR_ECDH 60 #endif 61 62 // Software ECDH implementation provided by mbedtls 63 #ifdef USE_MBEDTLS_FOR_ECDH 64 #if !defined(MBEDTLS_CONFIG_FILE) 65 #include "mbedtls/config.h" 66 #else 67 #include MBEDTLS_CONFIG_FILE 68 #endif 69 #if defined(MBEDTLS_PLATFORM_C) 70 #include "mbedtls/platform.h" 71 #else 72 #include <stdio.h> 73 #define mbedtls_printf printf 74 #endif 75 #include "mbedtls/ecp.h" 76 #endif 77 78 // 79 // SM internal types and globals 80 // 81 82 typedef enum { 83 DKG_W4_WORKING, 84 DKG_CALC_IRK, 85 DKG_W4_IRK, 86 DKG_CALC_DHK, 87 DKG_W4_DHK, 88 DKG_READY 89 } derived_key_generation_t; 90 91 typedef enum { 92 RAU_W4_WORKING, 93 RAU_IDLE, 94 RAU_GET_RANDOM, 95 RAU_W4_RANDOM, 96 RAU_GET_ENC, 97 RAU_W4_ENC, 98 RAU_SET_ADDRESS, 99 } random_address_update_t; 100 101 typedef enum { 102 CMAC_IDLE, 103 CMAC_CALC_SUBKEYS, 104 CMAC_W4_SUBKEYS, 105 CMAC_CALC_MI, 106 CMAC_W4_MI, 107 CMAC_CALC_MLAST, 108 CMAC_W4_MLAST 109 } cmac_state_t; 110 111 typedef enum { 112 JUST_WORKS, 113 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 114 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 115 OK_BOTH_INPUT, // Only input on both, both input PK 116 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 117 OOB // OOB available on both sides 118 } stk_generation_method_t; 119 120 typedef enum { 121 SM_USER_RESPONSE_IDLE, 122 SM_USER_RESPONSE_PENDING, 123 SM_USER_RESPONSE_CONFIRM, 124 SM_USER_RESPONSE_PASSKEY, 125 SM_USER_RESPONSE_DECLINE 126 } sm_user_response_t; 127 128 typedef enum { 129 SM_AES128_IDLE, 130 SM_AES128_ACTIVE 131 } sm_aes128_state_t; 132 133 typedef enum { 134 ADDRESS_RESOLUTION_IDLE, 135 ADDRESS_RESOLUTION_GENERAL, 136 ADDRESS_RESOLUTION_FOR_CONNECTION, 137 } address_resolution_mode_t; 138 139 typedef enum { 140 ADDRESS_RESOLUTION_SUCEEDED, 141 ADDRESS_RESOLUTION_FAILED, 142 } address_resolution_event_t; 143 // 144 // GLOBAL DATA 145 // 146 147 static uint8_t test_use_fixed_local_csrk; 148 149 // configuration 150 static uint8_t sm_accepted_stk_generation_methods; 151 static uint8_t sm_max_encryption_key_size; 152 static uint8_t sm_min_encryption_key_size; 153 static uint8_t sm_auth_req = 0; 154 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 155 static uint8_t sm_slave_request_security; 156 157 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 158 static sm_key_t sm_persistent_er; 159 static sm_key_t sm_persistent_ir; 160 161 // derived from sm_persistent_ir 162 static sm_key_t sm_persistent_dhk; 163 static sm_key_t sm_persistent_irk; 164 static uint8_t sm_persistent_irk_ready = 0; // used for testing 165 static derived_key_generation_t dkg_state; 166 167 // derived from sm_persistent_er 168 // .. 169 170 // random address update 171 static random_address_update_t rau_state; 172 static bd_addr_t sm_random_address; 173 174 // CMAC Calculation: General 175 static cmac_state_t sm_cmac_state; 176 static uint16_t sm_cmac_message_len; 177 static sm_key_t sm_cmac_k; 178 static sm_key_t sm_cmac_x; 179 static sm_key_t sm_cmac_m_last; 180 static uint8_t sm_cmac_block_current; 181 static uint8_t sm_cmac_block_count; 182 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 183 static void (*sm_cmac_done_handler)(uint8_t * hash); 184 185 // CMAC for ATT Signed Writes 186 static uint8_t sm_cmac_header[3]; 187 static uint8_t * sm_cmac_message; 188 static uint8_t sm_cmac_sign_counter[4]; 189 190 // CMAC for Secure Connection functions 191 #ifdef ENABLE_LE_SECURE_CONNECTIONS 192 static uint8_t sm_cmac_sc_buffer[80]; 193 #endif 194 195 // resolvable private address lookup / CSRK calculation 196 static int sm_address_resolution_test; 197 static int sm_address_resolution_ah_calculation_active; 198 static uint8_t sm_address_resolution_addr_type; 199 static bd_addr_t sm_address_resolution_address; 200 static void * sm_address_resolution_context; 201 static address_resolution_mode_t sm_address_resolution_mode; 202 static btstack_linked_list_t sm_address_resolution_general_queue; 203 204 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 205 static sm_aes128_state_t sm_aes128_state; 206 static void * sm_aes128_context; 207 208 // random engine. store context (ususally sm_connection_t) 209 static void * sm_random_context; 210 211 // to receive hci events 212 static btstack_packet_callback_registration_t hci_event_callback_registration; 213 214 /* to dispatch sm event */ 215 static btstack_linked_list_t sm_event_handlers; 216 217 // Software ECDH implementation provided by mbedtls 218 #ifdef USE_MBEDTLS_FOR_ECDH 219 mbedtls_ecp_keypair le_keypair; 220 #endif 221 222 // 223 // Volume 3, Part H, Chapter 24 224 // "Security shall be initiated by the Security Manager in the device in the master role. 225 // The device in the slave role shall be the responding device." 226 // -> master := initiator, slave := responder 227 // 228 229 // data needed for security setup 230 typedef struct sm_setup_context { 231 232 btstack_timer_source_t sm_timeout; 233 234 // used in all phases 235 uint8_t sm_pairing_failed_reason; 236 237 // user response, (Phase 1 and/or 2) 238 uint8_t sm_user_response; 239 240 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 241 int sm_key_distribution_send_set; 242 int sm_key_distribution_received_set; 243 244 // Phase 2 (Pairing over SMP) 245 stk_generation_method_t sm_stk_generation_method; 246 sm_key_t sm_tk; 247 uint8_t sm_use_secure_connections; 248 249 sm_key_t sm_c1_t3_value; // c1 calculation 250 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 251 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 252 sm_key_t sm_local_random; 253 sm_key_t sm_local_confirm; 254 sm_key_t sm_peer_random; 255 sm_key_t sm_peer_confirm; 256 uint8_t sm_m_addr_type; // address and type can be removed 257 uint8_t sm_s_addr_type; // '' 258 bd_addr_t sm_m_address; // '' 259 bd_addr_t sm_s_address; // '' 260 sm_key_t sm_ltk; 261 262 #ifdef ENABLE_LE_SECURE_CONNECTIONS 263 uint8_t sm_peer_qx[32]; 264 uint8_t sm_peer_qy[32]; 265 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 266 sm_key_t sm_local_nonce; // might be combined with sm_local_random 267 sm_key_t sm_peer_dhkey_check; 268 sm_key_t sm_local_dhkey_check; 269 sm_key_t sm_ra; 270 sm_key_t sm_rb; 271 sm_key_t sm_mackey; 272 uint8_t sm_passkey_bit; 273 #endif 274 275 // Phase 3 276 277 // key distribution, we generate 278 uint16_t sm_local_y; 279 uint16_t sm_local_div; 280 uint16_t sm_local_ediv; 281 uint8_t sm_local_rand[8]; 282 sm_key_t sm_local_ltk; 283 sm_key_t sm_local_csrk; 284 sm_key_t sm_local_irk; 285 // sm_local_address/addr_type not needed 286 287 // key distribution, received from peer 288 uint16_t sm_peer_y; 289 uint16_t sm_peer_div; 290 uint16_t sm_peer_ediv; 291 uint8_t sm_peer_rand[8]; 292 sm_key_t sm_peer_ltk; 293 sm_key_t sm_peer_irk; 294 sm_key_t sm_peer_csrk; 295 uint8_t sm_peer_addr_type; 296 bd_addr_t sm_peer_address; 297 298 } sm_setup_context_t; 299 300 // 301 static sm_setup_context_t the_setup; 302 static sm_setup_context_t * setup = &the_setup; 303 304 // active connection - the one for which the_setup is used for 305 static uint16_t sm_active_connection = 0; 306 307 // @returns 1 if oob data is available 308 // stores oob data in provided 16 byte buffer if not null 309 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 310 311 // used to notify applicationss that user interaction is neccessary, see sm_notify_t below 312 static btstack_packet_handler_t sm_client_packet_handler = NULL; 313 314 // horizontal: initiator capabilities 315 // vertial: responder capabilities 316 static const stk_generation_method_t stk_generation_method [5] [5] = { 317 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 318 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 319 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 320 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 321 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 322 }; 323 324 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 325 #ifdef ENABLE_LE_SECURE_CONNECTIONS 326 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 327 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 328 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 329 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 330 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 331 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 332 }; 333 #endif 334 335 static void sm_run(void); 336 static void sm_done_for_handle(hci_con_handle_t con_handle); 337 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 338 static inline int sm_calc_actual_encryption_key_size(int other); 339 static int sm_validate_stk_generation_method(void); 340 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 341 342 static void log_info_hex16(const char * name, uint16_t value){ 343 log_info("%-6s 0x%04x", name, value); 344 } 345 346 // @returns 1 if all bytes are 0 347 static int sm_is_null_random(uint8_t random[8]){ 348 int i; 349 for (i=0; i < 8 ; i++){ 350 if (random[i]) return 0; 351 } 352 return 1; 353 } 354 355 // Key utils 356 static void sm_reset_tk(void){ 357 int i; 358 for (i=0;i<16;i++){ 359 setup->sm_tk[i] = 0; 360 } 361 } 362 363 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 364 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 365 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 366 int i; 367 for (i = max_encryption_size ; i < 16 ; i++){ 368 key[15-i] = 0; 369 } 370 } 371 372 // SMP Timeout implementation 373 374 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 375 // the Security Manager Timer shall be reset and started. 376 // 377 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 378 // 379 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 380 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 381 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 382 // established. 383 384 static void sm_timeout_handler(btstack_timer_source_t * timer){ 385 log_info("SM timeout"); 386 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 387 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 388 sm_done_for_handle(sm_conn->sm_handle); 389 390 // trigger handling of next ready connection 391 sm_run(); 392 } 393 static void sm_timeout_start(sm_connection_t * sm_conn){ 394 btstack_run_loop_remove_timer(&setup->sm_timeout); 395 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 396 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 397 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 398 btstack_run_loop_add_timer(&setup->sm_timeout); 399 } 400 static void sm_timeout_stop(void){ 401 btstack_run_loop_remove_timer(&setup->sm_timeout); 402 } 403 static void sm_timeout_reset(sm_connection_t * sm_conn){ 404 sm_timeout_stop(); 405 sm_timeout_start(sm_conn); 406 } 407 408 // end of sm timeout 409 410 // GAP Random Address updates 411 static gap_random_address_type_t gap_random_adress_type; 412 static btstack_timer_source_t gap_random_address_update_timer; 413 static uint32_t gap_random_adress_update_period; 414 415 static void gap_random_address_trigger(void){ 416 if (rau_state != RAU_IDLE) return; 417 log_info("gap_random_address_trigger"); 418 rau_state = RAU_GET_RANDOM; 419 sm_run(); 420 } 421 422 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 423 log_info("GAP Random Address Update due"); 424 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 425 btstack_run_loop_add_timer(&gap_random_address_update_timer); 426 gap_random_address_trigger(); 427 } 428 429 static void gap_random_address_update_start(void){ 430 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 431 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 432 btstack_run_loop_add_timer(&gap_random_address_update_timer); 433 } 434 435 static void gap_random_address_update_stop(void){ 436 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 437 } 438 439 440 static void sm_random_start(void * context){ 441 sm_random_context = context; 442 hci_send_cmd(&hci_le_rand); 443 } 444 445 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 446 // context is made availabe to aes128 result handler by this 447 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 448 sm_aes128_state = SM_AES128_ACTIVE; 449 sm_key_t key_flipped, plaintext_flipped; 450 reverse_128(key, key_flipped); 451 reverse_128(plaintext, plaintext_flipped); 452 sm_aes128_context = context; 453 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 454 } 455 456 // ah(k,r) helper 457 // r = padding || r 458 // r - 24 bit value 459 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 460 // r'= padding || r 461 memset(r_prime, 0, 16); 462 memcpy(&r_prime[13], r, 3); 463 } 464 465 // d1 helper 466 // d' = padding || r || d 467 // d,r - 16 bit values 468 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 469 // d'= padding || r || d 470 memset(d1_prime, 0, 16); 471 big_endian_store_16(d1_prime, 12, r); 472 big_endian_store_16(d1_prime, 14, d); 473 } 474 475 // dm helper 476 // r’ = padding || r 477 // r - 64 bit value 478 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 479 memset(r_prime, 0, 16); 480 memcpy(&r_prime[8], r, 8); 481 } 482 483 // calculate arguments for first AES128 operation in C1 function 484 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, sm_key_t t1){ 485 486 // p1 = pres || preq || rat’ || iat’ 487 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 488 // cant octet of pres becomes the most significant octet of p1. 489 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 490 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 491 // p1 is 0x05000800000302070710000001010001." 492 493 sm_key_t p1; 494 reverse_56(pres, &p1[0]); 495 reverse_56(preq, &p1[7]); 496 p1[14] = rat; 497 p1[15] = iat; 498 log_info_key("p1", p1); 499 log_info_key("r", r); 500 501 // t1 = r xor p1 502 int i; 503 for (i=0;i<16;i++){ 504 t1[i] = r[i] ^ p1[i]; 505 } 506 log_info_key("t1", t1); 507 } 508 509 // calculate arguments for second AES128 operation in C1 function 510 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 511 // p2 = padding || ia || ra 512 // "The least significant octet of ra becomes the least significant octet of p2 and 513 // the most significant octet of padding becomes the most significant octet of p2. 514 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 515 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 516 517 sm_key_t p2; 518 memset(p2, 0, 16); 519 memcpy(&p2[4], ia, 6); 520 memcpy(&p2[10], ra, 6); 521 log_info_key("p2", p2); 522 523 // c1 = e(k, t2_xor_p2) 524 int i; 525 for (i=0;i<16;i++){ 526 t3[i] = t2[i] ^ p2[i]; 527 } 528 log_info_key("t3", t3); 529 } 530 531 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 532 log_info_key("r1", r1); 533 log_info_key("r2", r2); 534 memcpy(&r_prime[8], &r2[8], 8); 535 memcpy(&r_prime[0], &r1[8], 8); 536 } 537 538 #ifdef ENABLE_LE_SECURE_CONNECTIONS 539 // Software implementations of crypto toolbox for LE Secure Connection 540 // TODO: replace with code to use AES Engine of HCI Controller 541 typedef uint8_t sm_key24_t[3]; 542 typedef uint8_t sm_key56_t[7]; 543 typedef uint8_t sm_key256_t[32]; 544 545 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 546 uint32_t rk[RKLENGTH(KEYBITS)]; 547 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 548 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 549 } 550 551 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 552 memcpy(k1, k0, 16); 553 sm_shift_left_by_one_bit_inplace(16, k1); 554 if (k0[0] & 0x80){ 555 k1[15] ^= 0x87; 556 } 557 memcpy(k2, k1, 16); 558 sm_shift_left_by_one_bit_inplace(16, k2); 559 if (k1[0] & 0x80){ 560 k2[15] ^= 0x87; 561 } 562 } 563 564 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 565 sm_key_t k0, k1, k2, zero; 566 memset(zero, 0, 16); 567 568 aes128_calc_cyphertext(key, zero, k0); 569 calc_subkeys(k0, k1, k2); 570 571 int cmac_block_count = (cmac_message_len + 15) / 16; 572 573 // step 3: .. 574 if (cmac_block_count==0){ 575 cmac_block_count = 1; 576 } 577 578 // step 4: set m_last 579 sm_key_t cmac_m_last; 580 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 581 int i; 582 if (sm_cmac_last_block_complete){ 583 for (i=0;i<16;i++){ 584 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 585 } 586 } else { 587 int valid_octets_in_last_block = cmac_message_len & 0x0f; 588 for (i=0;i<16;i++){ 589 if (i < valid_octets_in_last_block){ 590 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 591 continue; 592 } 593 if (i == valid_octets_in_last_block){ 594 cmac_m_last[i] = 0x80 ^ k2[i]; 595 continue; 596 } 597 cmac_m_last[i] = k2[i]; 598 } 599 } 600 601 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 602 // LOG_KEY(cmac_m_last); 603 604 // Step 5 605 sm_key_t cmac_x; 606 memset(cmac_x, 0, 16); 607 608 // Step 6 609 sm_key_t sm_cmac_y; 610 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 611 for (i=0;i<16;i++){ 612 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 613 } 614 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 615 } 616 for (i=0;i<16;i++){ 617 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 618 } 619 620 // Step 7 621 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 622 } 623 624 static void f4(sm_key_t res, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, uint8_t z){ 625 uint8_t buffer[65]; 626 memcpy(buffer, u, 32); 627 memcpy(buffer+32, v, 32); 628 buffer[64] = z; 629 log_info("f4 key"); 630 log_info_hexdump(x, 16); 631 log_info("f4 message"); 632 log_info_hexdump(buffer, sizeof(buffer)); 633 aes_cmac(res, x, buffer, sizeof(buffer)); 634 log_info("f4 result"); 635 log_info_hexdump(res, sizeof(sm_key_t)); 636 } 637 638 const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 639 const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 640 const uint8_t f5_length[] = { 0x01, 0x00}; 641 static void f5(sm_key256_t res, const sm_key256_t w, const sm_key_t n1, const sm_key_t n2, const sm_key56_t a1, const sm_key56_t a2){ 642 // T = AES-CMACSAL_T(W) 643 sm_key_t t; 644 aes_cmac(t, f5_salt, w, 32); 645 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 646 uint8_t buffer[53]; 647 buffer[0] = 0; 648 memcpy(buffer+01, f5_key_id, 4); 649 memcpy(buffer+05, n1, 16); 650 memcpy(buffer+21, n2, 16); 651 memcpy(buffer+37, a1, 7); 652 memcpy(buffer+44, a2, 7); 653 memcpy(buffer+51, f5_length, 2); 654 log_info("f5 DHKEY"); 655 log_info_hexdump(w, 32); 656 log_info("f5 key"); 657 log_info_hexdump(t, 16); 658 log_info("f5 message for MacKey"); 659 log_info_hexdump(buffer, sizeof(buffer)); 660 aes_cmac(res, t, buffer, sizeof(buffer)); 661 // hexdump2(res, 16); 662 // || AES-CMACT (Counter = 1 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the LTK 663 buffer[0] = 1; 664 // hexdump2(buffer, sizeof(buffer)); 665 log_info("f5 message for LTK"); 666 log_info_hexdump(buffer, sizeof(buffer)); 667 aes_cmac(res+16, t, buffer, sizeof(buffer)); 668 // hexdump2(res+16, 16); 669 } 670 671 // f6(W, N1, N2, R, IOcap, A1, A2) = AES-CMACW (N1 || N2 || R || IOcap || A1 || A2 672 // - W is 128 bits 673 // - N1 is 128 bits 674 // - N2 is 128 bits 675 // - R is 128 bits 676 // - IOcap is 24 bits 677 // - A1 is 56 bits 678 // - A2 is 56 bits 679 static void f6(sm_key_t res, const sm_key_t w, const sm_key_t n1, const sm_key_t n2, const sm_key_t r, const sm_key24_t io_cap, const sm_key56_t a1, const sm_key56_t a2){ 680 uint8_t buffer[65]; 681 memcpy(buffer, n1, 16); 682 memcpy(buffer+16, n2, 16); 683 memcpy(buffer+32, r, 16); 684 memcpy(buffer+48, io_cap, 3); 685 memcpy(buffer+51, a1, 7); 686 memcpy(buffer+58, a2, 7); 687 log_info("f6 key"); 688 log_info_hexdump(w, 16); 689 log_info("f6 message"); 690 log_info_hexdump(buffer, sizeof(buffer)); 691 aes_cmac(res, w, buffer,sizeof(buffer)); 692 log_info("f6 result"); 693 log_info_hexdump(res, 16); 694 } 695 696 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 697 // - U is 256 bits 698 // - V is 256 bits 699 // - X is 128 bits 700 // - Y is 128 bits 701 static uint32_t g2(const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 702 uint8_t buffer[80]; 703 memcpy(buffer, u, 32); 704 memcpy(buffer+32, v, 32); 705 memcpy(buffer+64, y, 16); 706 sm_key_t cmac; 707 log_info("g2 key"); 708 log_info_hexdump(x, 16); 709 log_info("g2 message"); 710 log_info_hexdump(buffer, sizeof(buffer)); 711 aes_cmac(cmac, x, buffer, sizeof(buffer)); 712 log_info("g2 result"); 713 log_info_hexdump(x, 16); 714 return big_endian_read_32(cmac, 12); 715 } 716 717 #if 0 718 // h6(W, keyID) = AES-CMACW(keyID) 719 // - W is 128 bits 720 // - keyID is 32 bits 721 static void h6(sm_key_t res, const sm_key_t w, const uint32_t key_id){ 722 uint8_t key_id_buffer[4]; 723 big_endian_store_32(key_id_buffer, 0, key_id); 724 aes_cmac(res, w, key_id_buffer, 4); 725 } 726 #endif 727 #endif 728 729 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){ 730 event[0] = type; 731 event[1] = event_size - 2; 732 little_endian_store_16(event, 2, con_handle); 733 event[4] = addr_type; 734 reverse_bd_addr(address, &event[5]); 735 } 736 737 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 738 if (sm_client_packet_handler) { 739 sm_client_packet_handler(HCI_EVENT_PACKET, 0, packet, size); 740 } 741 // dispatch to all event handlers 742 btstack_linked_list_iterator_t it; 743 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 744 while (btstack_linked_list_iterator_has_next(&it)){ 745 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 746 entry->callback(packet_type, 0, packet, size); 747 } 748 } 749 750 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 751 uint8_t event[11]; 752 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 753 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 754 } 755 756 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){ 757 uint8_t event[15]; 758 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 759 little_endian_store_32(event, 11, passkey); 760 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 761 } 762 763 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){ 764 uint8_t event[13]; 765 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 766 little_endian_store_16(event, 11, index); 767 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 768 } 769 770 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){ 771 772 uint8_t event[18]; 773 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 774 event[11] = result; 775 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 776 } 777 778 // decide on stk generation based on 779 // - pairing request 780 // - io capabilities 781 // - OOB data availability 782 static void sm_setup_tk(void){ 783 784 // default: just works 785 setup->sm_stk_generation_method = JUST_WORKS; 786 787 #ifdef ENABLE_LE_SECURE_CONNECTIONS 788 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 789 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 790 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 791 memset(setup->sm_ra, 0, 16); 792 memset(setup->sm_rb, 0, 16); 793 #else 794 setup->sm_use_secure_connections = 0; 795 #endif 796 797 // If both devices have not set the MITM option in the Authentication Requirements 798 // Flags, then the IO capabilities shall be ignored and the Just Works association 799 // model shall be used. 800 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 801 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 802 log_info("SM: MITM not required by both -> JUST WORKS"); 803 return; 804 } 805 806 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 807 808 // If both devices have out of band authentication data, then the Authentication 809 // Requirements Flags shall be ignored when selecting the pairing method and the 810 // Out of Band pairing method shall be used. 811 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 812 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 813 log_info("SM: have OOB data"); 814 log_info_key("OOB", setup->sm_tk); 815 setup->sm_stk_generation_method = OOB; 816 return; 817 } 818 819 // Reset TK as it has been setup in sm_init_setup 820 sm_reset_tk(); 821 822 // Also use just works if unknown io capabilites 823 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)){ 824 return; 825 } 826 827 // Otherwise the IO capabilities of the devices shall be used to determine the 828 // pairing method as defined in Table 2.4. 829 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 830 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 831 832 #ifdef ENABLE_LE_SECURE_CONNECTIONS 833 // table not define by default 834 if (setup->sm_use_secure_connections){ 835 generation_method = stk_generation_method_with_secure_connection; 836 } 837 #endif 838 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)]; 839 840 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 841 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); 842 } 843 844 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 845 int flags = 0; 846 if (key_set & SM_KEYDIST_ENC_KEY){ 847 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 848 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 849 } 850 if (key_set & SM_KEYDIST_ID_KEY){ 851 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 852 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 853 } 854 if (key_set & SM_KEYDIST_SIGN){ 855 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 856 } 857 return flags; 858 } 859 860 static void sm_setup_key_distribution(uint8_t key_set){ 861 setup->sm_key_distribution_received_set = 0; 862 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 863 } 864 865 // CSRK Key Lookup 866 867 868 static int sm_address_resolution_idle(void){ 869 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 870 } 871 872 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){ 873 memcpy(sm_address_resolution_address, addr, 6); 874 sm_address_resolution_addr_type = addr_type; 875 sm_address_resolution_test = 0; 876 sm_address_resolution_mode = mode; 877 sm_address_resolution_context = context; 878 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 879 } 880 881 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 882 // check if already in list 883 btstack_linked_list_iterator_t it; 884 sm_lookup_entry_t * entry; 885 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 886 while(btstack_linked_list_iterator_has_next(&it)){ 887 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 888 if (entry->address_type != address_type) continue; 889 if (memcmp(entry->address, address, 6)) continue; 890 // already in list 891 return BTSTACK_BUSY; 892 } 893 entry = btstack_memory_sm_lookup_entry_get(); 894 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 895 entry->address_type = (bd_addr_type_t) address_type; 896 memcpy(entry->address, address, 6); 897 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 898 sm_run(); 899 return 0; 900 } 901 902 // CMAC Implementation using AES128 engine 903 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 904 int i; 905 int carry = 0; 906 for (i=len-1; i >= 0 ; i--){ 907 int new_carry = data[i] >> 7; 908 data[i] = data[i] << 1 | carry; 909 carry = new_carry; 910 } 911 } 912 913 // 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 914 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 915 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 916 } 917 static inline void dkg_next_state(void){ 918 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 919 } 920 static inline void rau_next_state(void){ 921 rau_state = (random_address_update_t) (((int)rau_state) + 1); 922 } 923 924 // CMAC calculation using AES Engine 925 926 static inline void sm_cmac_next_state(void){ 927 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 928 } 929 930 static int sm_cmac_last_block_complete(void){ 931 if (sm_cmac_message_len == 0) return 0; 932 return (sm_cmac_message_len & 0x0f) == 0; 933 } 934 935 static inline uint8_t sm_cmac_message_get_byte(uint16_t offset){ 936 if (offset >= sm_cmac_message_len) { 937 log_error("sm_cmac_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 938 return 0; 939 } 940 941 offset = sm_cmac_message_len - 1 - offset; 942 943 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 944 if (offset < 3){ 945 return sm_cmac_header[offset]; 946 } 947 int actual_message_len_incl_header = sm_cmac_message_len - 4; 948 if (offset < actual_message_len_incl_header){ 949 return sm_cmac_message[offset - 3]; 950 } 951 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 952 } 953 954 // generic cmac calculation 955 void sm_cmac_general_start(sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t hash[8])){ 956 // Generalized CMAC 957 memcpy(sm_cmac_k, key, 16); 958 memset(sm_cmac_x, 0, 16); 959 sm_cmac_block_current = 0; 960 sm_cmac_message_len = message_len; 961 sm_cmac_done_handler = done_callback; 962 sm_cmac_get_byte = get_byte_callback; 963 964 // step 2: n := ceil(len/const_Bsize); 965 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 966 967 // step 3: .. 968 if (sm_cmac_block_count==0){ 969 sm_cmac_block_count = 1; 970 } 971 972 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 973 974 // first, we need to compute l for k1, k2, and m_last 975 sm_cmac_state = CMAC_CALC_SUBKEYS; 976 977 // let's go 978 sm_run(); 979 } 980 981 // cmac for ATT Message signing 982 void sm_cmac_start(sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 983 // ATT Message Signing 984 sm_cmac_header[0] = opcode; 985 little_endian_store_16(sm_cmac_header, 1, con_handle); 986 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 987 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 988 sm_cmac_message = message; 989 sm_cmac_general_start(k, total_message_len, &sm_cmac_message_get_byte, done_handler); 990 } 991 992 int sm_cmac_ready(void){ 993 return sm_cmac_state == CMAC_IDLE; 994 } 995 996 static void sm_cmac_handle_aes_engine_ready(void){ 997 switch (sm_cmac_state){ 998 case CMAC_CALC_SUBKEYS: { 999 sm_key_t const_zero; 1000 memset(const_zero, 0, 16); 1001 sm_cmac_next_state(); 1002 sm_aes128_start(sm_cmac_k, const_zero, NULL); 1003 break; 1004 } 1005 case CMAC_CALC_MI: { 1006 int j; 1007 sm_key_t y; 1008 for (j=0;j<16;j++){ 1009 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 1010 } 1011 sm_cmac_block_current++; 1012 sm_cmac_next_state(); 1013 sm_aes128_start(sm_cmac_k, y, NULL); 1014 break; 1015 } 1016 case CMAC_CALC_MLAST: { 1017 int i; 1018 sm_key_t y; 1019 for (i=0;i<16;i++){ 1020 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 1021 } 1022 log_info_key("Y", y); 1023 sm_cmac_block_current++; 1024 sm_cmac_next_state(); 1025 sm_aes128_start(sm_cmac_k, y, NULL); 1026 break; 1027 } 1028 default: 1029 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 1030 break; 1031 } 1032 } 1033 1034 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1035 switch (sm_cmac_state){ 1036 case CMAC_W4_SUBKEYS: { 1037 sm_key_t k1; 1038 memcpy(k1, data, 16); 1039 sm_shift_left_by_one_bit_inplace(16, k1); 1040 if (data[0] & 0x80){ 1041 k1[15] ^= 0x87; 1042 } 1043 sm_key_t k2; 1044 memcpy(k2, k1, 16); 1045 sm_shift_left_by_one_bit_inplace(16, k2); 1046 if (k1[0] & 0x80){ 1047 k2[15] ^= 0x87; 1048 } 1049 1050 log_info_key("k", sm_cmac_k); 1051 log_info_key("k1", k1); 1052 log_info_key("k2", k2); 1053 1054 // step 4: set m_last 1055 int i; 1056 if (sm_cmac_last_block_complete()){ 1057 for (i=0;i<16;i++){ 1058 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1059 } 1060 } else { 1061 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1062 for (i=0;i<16;i++){ 1063 if (i < valid_octets_in_last_block){ 1064 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1065 continue; 1066 } 1067 if (i == valid_octets_in_last_block){ 1068 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1069 continue; 1070 } 1071 sm_cmac_m_last[i] = k2[i]; 1072 } 1073 } 1074 1075 // next 1076 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1077 break; 1078 } 1079 case CMAC_W4_MI: 1080 memcpy(sm_cmac_x, data, 16); 1081 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1082 break; 1083 case CMAC_W4_MLAST: 1084 // done 1085 log_info_key("CMAC", data); 1086 sm_cmac_done_handler(data); 1087 sm_cmac_state = CMAC_IDLE; 1088 break; 1089 default: 1090 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1091 break; 1092 } 1093 } 1094 1095 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1096 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1097 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1098 switch (setup->sm_stk_generation_method){ 1099 case PK_RESP_INPUT: 1100 if (sm_conn->sm_role){ 1101 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1102 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1103 } else { 1104 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)); 1105 } 1106 break; 1107 case PK_INIT_INPUT: 1108 if (sm_conn->sm_role){ 1109 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)); 1110 } else { 1111 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1112 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1113 } 1114 break; 1115 case OK_BOTH_INPUT: 1116 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1117 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1118 break; 1119 case NK_BOTH_INPUT: 1120 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1121 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)); 1122 break; 1123 case JUST_WORKS: 1124 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1125 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1126 break; 1127 case OOB: 1128 // client already provided OOB data, let's skip notification. 1129 break; 1130 } 1131 } 1132 1133 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1134 int recv_flags; 1135 if (sm_conn->sm_role){ 1136 // slave / responder 1137 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1138 } else { 1139 // master / initiator 1140 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1141 } 1142 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1143 return recv_flags == setup->sm_key_distribution_received_set; 1144 } 1145 1146 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1147 if (sm_active_connection == con_handle){ 1148 sm_timeout_stop(); 1149 sm_active_connection = 0; 1150 log_info("sm: connection 0x%x released setup context", con_handle); 1151 } 1152 } 1153 1154 static int sm_key_distribution_flags_for_auth_req(void){ 1155 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1156 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1157 // encryption information only if bonding requested 1158 flags |= SM_KEYDIST_ENC_KEY; 1159 } 1160 return flags; 1161 } 1162 1163 static void sm_init_setup(sm_connection_t * sm_conn){ 1164 1165 // fill in sm setup 1166 sm_reset_tk(); 1167 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1168 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1169 1170 // query client for OOB data 1171 int have_oob_data = 0; 1172 if (sm_get_oob_data) { 1173 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1174 } 1175 1176 sm_pairing_packet_t * local_packet; 1177 if (sm_conn->sm_role){ 1178 // slave 1179 local_packet = &setup->sm_s_pres; 1180 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1181 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1182 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1183 } else { 1184 // master 1185 local_packet = &setup->sm_m_preq; 1186 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1187 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1188 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1189 1190 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1191 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1192 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1193 } 1194 1195 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1196 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1197 sm_pairing_packet_set_auth_req(*local_packet, sm_auth_req); 1198 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1199 } 1200 1201 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1202 1203 sm_pairing_packet_t * remote_packet; 1204 int remote_key_request; 1205 if (sm_conn->sm_role){ 1206 // slave / responder 1207 remote_packet = &setup->sm_m_preq; 1208 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1209 } else { 1210 // master / initiator 1211 remote_packet = &setup->sm_s_pres; 1212 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1213 } 1214 1215 // check key size 1216 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1217 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1218 1219 // decide on STK generation method 1220 sm_setup_tk(); 1221 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1222 1223 // check if STK generation method is acceptable by client 1224 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1225 1226 // identical to responder 1227 sm_setup_key_distribution(remote_key_request); 1228 1229 // JUST WORKS doens't provide authentication 1230 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1231 1232 return 0; 1233 } 1234 1235 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1236 1237 // cache and reset context 1238 int matched_device_id = sm_address_resolution_test; 1239 address_resolution_mode_t mode = sm_address_resolution_mode; 1240 void * context = sm_address_resolution_context; 1241 1242 // reset context 1243 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1244 sm_address_resolution_context = NULL; 1245 sm_address_resolution_test = -1; 1246 hci_con_handle_t con_handle = 0; 1247 1248 sm_connection_t * sm_connection; 1249 uint16_t ediv; 1250 switch (mode){ 1251 case ADDRESS_RESOLUTION_GENERAL: 1252 break; 1253 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1254 sm_connection = (sm_connection_t *) context; 1255 con_handle = sm_connection->sm_handle; 1256 switch (event){ 1257 case ADDRESS_RESOLUTION_SUCEEDED: 1258 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1259 sm_connection->sm_le_db_index = matched_device_id; 1260 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1261 if (sm_connection->sm_role) break; 1262 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1263 sm_connection->sm_security_request_received = 0; 1264 sm_connection->sm_bonding_requested = 0; 1265 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 1266 if (ediv){ 1267 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1268 } else { 1269 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1270 } 1271 break; 1272 case ADDRESS_RESOLUTION_FAILED: 1273 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1274 if (sm_connection->sm_role) break; 1275 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1276 sm_connection->sm_security_request_received = 0; 1277 sm_connection->sm_bonding_requested = 0; 1278 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1279 break; 1280 } 1281 break; 1282 default: 1283 break; 1284 } 1285 1286 switch (event){ 1287 case ADDRESS_RESOLUTION_SUCEEDED: 1288 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1289 break; 1290 case ADDRESS_RESOLUTION_FAILED: 1291 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1292 break; 1293 } 1294 } 1295 1296 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1297 1298 int le_db_index = -1; 1299 1300 // lookup device based on IRK 1301 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1302 int i; 1303 for (i=0; i < le_device_db_count(); i++){ 1304 sm_key_t irk; 1305 bd_addr_t address; 1306 int address_type; 1307 le_device_db_info(i, &address_type, address, irk); 1308 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1309 log_info("sm: device found for IRK, updating"); 1310 le_db_index = i; 1311 break; 1312 } 1313 } 1314 } 1315 1316 // if not found, lookup via public address if possible 1317 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1318 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1319 int i; 1320 for (i=0; i < le_device_db_count(); i++){ 1321 bd_addr_t address; 1322 int address_type; 1323 le_device_db_info(i, &address_type, address, NULL); 1324 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1325 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1326 log_info("sm: device found for public address, updating"); 1327 le_db_index = i; 1328 break; 1329 } 1330 } 1331 } 1332 1333 // if not found, add to db 1334 if (le_db_index < 0) { 1335 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1336 } 1337 1338 if (le_db_index >= 0){ 1339 le_device_db_local_counter_set(le_db_index, 0); 1340 1341 // store local CSRK 1342 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1343 log_info("sm: store local CSRK"); 1344 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1345 le_device_db_local_counter_set(le_db_index, 0); 1346 } 1347 1348 // store remote CSRK 1349 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1350 log_info("sm: store remote CSRK"); 1351 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1352 le_device_db_remote_counter_set(le_db_index, 0); 1353 } 1354 1355 // store encryption information 1356 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION 1357 && setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1358 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1359 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1360 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1361 } 1362 } 1363 1364 // keep le_db_index 1365 sm_conn->sm_le_db_index = le_db_index; 1366 } 1367 1368 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1369 void sm_sc_calculate_local_confirm(void){ 1370 uint8_t z = 0; 1371 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1372 // some form of passkey 1373 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1374 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1375 setup->sm_passkey_bit++; 1376 } 1377 #ifdef USE_MBEDTLS_FOR_ECDH 1378 uint8_t value[32]; 1379 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1380 #endif 1381 // TODO: use AES Engine to calculate commitment value using f4 1382 f4(setup->sm_local_confirm, value, setup->sm_peer_qx, setup->sm_local_nonce, z); 1383 } 1384 #endif 1385 1386 static void sm_run(void){ 1387 1388 btstack_linked_list_iterator_t it; 1389 1390 // assert that we can send at least commands 1391 if (!hci_can_send_command_packet_now()) return; 1392 1393 // 1394 // non-connection related behaviour 1395 // 1396 1397 // distributed key generation 1398 switch (dkg_state){ 1399 case DKG_CALC_IRK: 1400 // already busy? 1401 if (sm_aes128_state == SM_AES128_IDLE) { 1402 // IRK = d1(IR, 1, 0) 1403 sm_key_t d1_prime; 1404 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1405 dkg_next_state(); 1406 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1407 return; 1408 } 1409 break; 1410 case DKG_CALC_DHK: 1411 // already busy? 1412 if (sm_aes128_state == SM_AES128_IDLE) { 1413 // DHK = d1(IR, 3, 0) 1414 sm_key_t d1_prime; 1415 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1416 dkg_next_state(); 1417 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1418 return; 1419 } 1420 break; 1421 default: 1422 break; 1423 } 1424 1425 // random address updates 1426 switch (rau_state){ 1427 case RAU_GET_RANDOM: 1428 rau_next_state(); 1429 sm_random_start(NULL); 1430 return; 1431 case RAU_GET_ENC: 1432 // already busy? 1433 if (sm_aes128_state == SM_AES128_IDLE) { 1434 sm_key_t r_prime; 1435 sm_ah_r_prime(sm_random_address, r_prime); 1436 rau_next_state(); 1437 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1438 return; 1439 } 1440 break; 1441 case RAU_SET_ADDRESS: 1442 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1443 rau_state = RAU_IDLE; 1444 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1445 return; 1446 default: 1447 break; 1448 } 1449 1450 // CMAC 1451 switch (sm_cmac_state){ 1452 case CMAC_CALC_SUBKEYS: 1453 case CMAC_CALC_MI: 1454 case CMAC_CALC_MLAST: 1455 // already busy? 1456 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1457 sm_cmac_handle_aes_engine_ready(); 1458 return; 1459 default: 1460 break; 1461 } 1462 1463 // CSRK Lookup 1464 // -- if csrk lookup ready, find connection that require csrk lookup 1465 if (sm_address_resolution_idle()){ 1466 hci_connections_get_iterator(&it); 1467 while(btstack_linked_list_iterator_has_next(&it)){ 1468 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1469 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1470 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1471 // and start lookup 1472 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); 1473 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1474 break; 1475 } 1476 } 1477 } 1478 1479 // -- if csrk lookup ready, resolved addresses for received addresses 1480 if (sm_address_resolution_idle()) { 1481 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1482 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1483 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1484 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1485 btstack_memory_sm_lookup_entry_free(entry); 1486 } 1487 } 1488 1489 // -- Continue with CSRK device lookup by public or resolvable private address 1490 if (!sm_address_resolution_idle()){ 1491 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1492 while (sm_address_resolution_test < le_device_db_count()){ 1493 int addr_type; 1494 bd_addr_t addr; 1495 sm_key_t irk; 1496 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1497 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1498 1499 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1500 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1501 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1502 break; 1503 } 1504 1505 if (sm_address_resolution_addr_type == 0){ 1506 sm_address_resolution_test++; 1507 continue; 1508 } 1509 1510 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1511 1512 log_info("LE Device Lookup: calculate AH"); 1513 log_info_key("IRK", irk); 1514 1515 sm_key_t r_prime; 1516 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1517 sm_address_resolution_ah_calculation_active = 1; 1518 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1519 return; 1520 } 1521 1522 if (sm_address_resolution_test >= le_device_db_count()){ 1523 log_info("LE Device Lookup: not found"); 1524 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1525 } 1526 } 1527 1528 1529 // 1530 // active connection handling 1531 // -- use loop to handle next connection if lock on setup context is released 1532 1533 while (1) { 1534 1535 // Find connections that requires setup context and make active if no other is locked 1536 hci_connections_get_iterator(&it); 1537 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1538 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1539 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1540 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1541 int done = 1; 1542 int err; 1543 int encryption_key_size; 1544 int authenticated; 1545 int authorized; 1546 switch (sm_connection->sm_engine_state) { 1547 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1548 // send packet if possible, 1549 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1550 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1551 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1552 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1553 } else { 1554 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1555 } 1556 // don't lock setup context yet 1557 done = 0; 1558 break; 1559 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1560 sm_init_setup(sm_connection); 1561 // recover pairing request 1562 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1563 err = sm_stk_generation_init(sm_connection); 1564 if (err){ 1565 setup->sm_pairing_failed_reason = err; 1566 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1567 break; 1568 } 1569 sm_timeout_start(sm_connection); 1570 // generate random number first, if we need to show passkey 1571 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1572 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1573 break; 1574 } 1575 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1576 break; 1577 case SM_INITIATOR_PH0_HAS_LTK: 1578 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1579 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1580 &encryption_key_size, &authenticated, &authorized); 1581 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1582 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1583 sm_connection->sm_connection_authenticated = authenticated; 1584 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1585 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1586 break; 1587 case SM_RESPONDER_PH0_RECEIVED_LTK: 1588 // re-establish previously used LTK using Rand and EDIV 1589 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1590 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1591 // re-establish used key encryption size 1592 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1593 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1594 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1595 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1596 log_info("sm: received ltk request with key size %u, authenticated %u", 1597 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1598 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1599 break; 1600 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1601 sm_init_setup(sm_connection); 1602 sm_timeout_start(sm_connection); 1603 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1604 break; 1605 default: 1606 done = 0; 1607 break; 1608 } 1609 if (done){ 1610 sm_active_connection = sm_connection->sm_handle; 1611 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1612 } 1613 } 1614 1615 // 1616 // active connection handling 1617 // 1618 1619 if (sm_active_connection == 0) return; 1620 1621 // assert that we could send a SM PDU - not needed for all of the following 1622 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1623 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1624 return; 1625 } 1626 1627 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1628 if (!connection) return; 1629 1630 sm_key_t plaintext; 1631 int key_distribution_flags; 1632 1633 log_info("sm_run: state %u", connection->sm_engine_state); 1634 1635 // responding state 1636 switch (connection->sm_engine_state){ 1637 1638 // general 1639 case SM_GENERAL_SEND_PAIRING_FAILED: { 1640 uint8_t buffer[2]; 1641 buffer[0] = SM_CODE_PAIRING_FAILED; 1642 buffer[1] = setup->sm_pairing_failed_reason; 1643 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1644 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1645 sm_done_for_handle(connection->sm_handle); 1646 break; 1647 } 1648 1649 // initiator side 1650 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1651 sm_key_t peer_ltk_flipped; 1652 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1653 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1654 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1655 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1656 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1657 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1658 return; 1659 } 1660 1661 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1662 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 1663 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1664 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1665 sm_timeout_reset(connection); 1666 break; 1667 1668 // responder side 1669 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1670 connection->sm_engine_state = SM_RESPONDER_IDLE; 1671 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1672 return; 1673 1674 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1675 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 1676 uint8_t buffer[65]; 1677 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 1678 // 1679 #ifdef USE_MBEDTLS_FOR_ECDH 1680 uint8_t value[32]; 1681 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1682 reverse_256(value, &buffer[1]); 1683 mbedtls_mpi_write_binary(&le_keypair.Q.Y, value, sizeof(value)); 1684 reverse_256(value, &buffer[33]); 1685 #endif 1686 // TODO: use random generator to generate nonce 1687 1688 // generate 128-bit nonce 1689 int i; 1690 for (i=0;i<16;i++){ 1691 setup->sm_local_nonce[i] = rand() & 0xff; 1692 } 1693 1694 // stk generation method 1695 // passkey entry: notify app to show passkey or to request passkey 1696 switch (setup->sm_stk_generation_method){ 1697 case JUST_WORKS: 1698 case NK_BOTH_INPUT: 1699 if (connection->sm_role){ 1700 sm_sc_calculate_local_confirm(); 1701 connection->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1702 } else { 1703 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1704 } 1705 break; 1706 case PK_INIT_INPUT: 1707 case PK_RESP_INPUT: 1708 case OK_BOTH_INPUT: 1709 // hack for testing: assume user entered '000000' 1710 // memset(setup->sm_tk, 0, 16); 1711 memcpy(setup->sm_ra, setup->sm_tk, 16); 1712 memcpy(setup->sm_rb, setup->sm_tk, 16); 1713 setup->sm_passkey_bit = 0; 1714 if (connection->sm_role){ 1715 // responder 1716 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1717 } else { 1718 // initiator 1719 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1720 } 1721 sm_trigger_user_response(connection); 1722 break; 1723 case OOB: 1724 // TODO: implement SC OOB 1725 break; 1726 } 1727 1728 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1729 sm_timeout_reset(connection); 1730 break; 1731 } 1732 case SM_SC_SEND_CONFIRMATION: { 1733 uint8_t buffer[17]; 1734 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1735 reverse_128(setup->sm_local_confirm, &buffer[1]); 1736 if (connection->sm_role){ 1737 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1738 } else { 1739 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1740 } 1741 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1742 sm_timeout_reset(connection); 1743 break; 1744 } 1745 case SM_SC_SEND_PAIRING_RANDOM: { 1746 uint8_t buffer[17]; 1747 buffer[0] = SM_CODE_PAIRING_RANDOM; 1748 reverse_128(setup->sm_local_nonce, &buffer[1]); 1749 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 1750 if (connection->sm_role){ 1751 // responder 1752 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1753 } else { 1754 // initiator 1755 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1756 } 1757 } else { 1758 if (connection->sm_role){ 1759 // responder 1760 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1761 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 1762 // calc Vb if numeric comparison 1763 // TODO: use AES Engine to calculate g2 1764 uint8_t value[32]; 1765 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1766 uint32_t vb = g2(setup->sm_peer_qx, value, setup->sm_peer_nonce, setup->sm_local_nonce) % 1000000; 1767 big_endian_store_32(setup->sm_tk, 12, vb); 1768 sm_trigger_user_response(connection); 1769 } 1770 } else { 1771 // initiator 1772 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1773 } 1774 } 1775 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1776 sm_timeout_reset(connection); 1777 break; 1778 } 1779 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 1780 1781 uint8_t buffer[17]; 1782 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 1783 #ifdef USE_MBEDTLS_FOR_ECDH 1784 // calculate DHKEY 1785 mbedtls_ecp_group grp; 1786 mbedtls_ecp_group_init( &grp ); 1787 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 1788 mbedtls_ecp_point Q; 1789 mbedtls_ecp_point_init( &Q ); 1790 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1791 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1792 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1793 1794 // da * Pb 1795 mbedtls_ecp_point DH; 1796 mbedtls_ecp_point_init( &DH ); 1797 mbedtls_ecp_mul(&grp, &DH, &le_keypair.d, &Q, NULL, NULL); 1798 sm_key256_t dhkey; 1799 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1800 log_info("dhkey"); 1801 log_info_hexdump(dhkey, 32); 1802 1803 // calculate LTK + MacKey 1804 sm_key256_t ltk_mackey; 1805 sm_key56_t bd_addr_master, bd_addr_slave; 1806 bd_addr_master[0] = setup->sm_m_addr_type; 1807 bd_addr_slave[0] = setup->sm_s_addr_type; 1808 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1809 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1810 if (connection->sm_role){ 1811 // responder 1812 f5(ltk_mackey, dhkey, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1813 } else { 1814 // initiator 1815 f5(ltk_mackey, dhkey, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1816 } 1817 // store LTK 1818 memcpy(setup->sm_ltk, <k_mackey[16], 16); 1819 1820 // calc DHKCheck 1821 memcpy(setup->sm_mackey, <k_mackey[0], 16); 1822 1823 // TODO: checks 1824 1825 uint8_t iocap_a[3]; 1826 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1827 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1828 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1829 uint8_t iocap_b[3]; 1830 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1831 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1832 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1833 if (connection->sm_role){ 1834 // responder 1835 f6(setup->sm_local_dhkey_check, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1836 } else { 1837 // initiator 1838 f6(setup->sm_local_dhkey_check, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1839 } 1840 #endif 1841 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 1842 if (connection->sm_role){ 1843 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 1844 } else { 1845 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1846 } 1847 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1848 sm_timeout_reset(connection); 1849 break; 1850 } 1851 1852 #endif 1853 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 1854 // echo initiator for now 1855 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 1856 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1857 1858 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 1859 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1860 if (setup->sm_use_secure_connections){ 1861 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1862 // skip LTK/EDIV for SC 1863 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 1864 } 1865 #endif 1866 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); 1867 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); 1868 1869 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 1870 sm_timeout_reset(connection); 1871 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 1872 if (setup->sm_stk_generation_method == JUST_WORKS){ 1873 sm_trigger_user_response(connection); 1874 } 1875 return; 1876 1877 case SM_PH2_SEND_PAIRING_RANDOM: { 1878 uint8_t buffer[17]; 1879 buffer[0] = SM_CODE_PAIRING_RANDOM; 1880 reverse_128(setup->sm_local_random, &buffer[1]); 1881 if (connection->sm_role){ 1882 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 1883 } else { 1884 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 1885 } 1886 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1887 sm_timeout_reset(connection); 1888 break; 1889 } 1890 1891 case SM_PH2_GET_RANDOM_TK: 1892 case SM_PH2_C1_GET_RANDOM_A: 1893 case SM_PH2_C1_GET_RANDOM_B: 1894 case SM_PH3_GET_RANDOM: 1895 case SM_PH3_GET_DIV: 1896 sm_next_responding_state(connection); 1897 sm_random_start(connection); 1898 return; 1899 1900 case SM_PH2_C1_GET_ENC_B: 1901 case SM_PH2_C1_GET_ENC_D: 1902 // already busy? 1903 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1904 sm_next_responding_state(connection); 1905 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 1906 return; 1907 1908 case SM_PH3_LTK_GET_ENC: 1909 case SM_RESPONDER_PH4_LTK_GET_ENC: 1910 // already busy? 1911 if (sm_aes128_state == SM_AES128_IDLE) { 1912 sm_key_t d_prime; 1913 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 1914 sm_next_responding_state(connection); 1915 sm_aes128_start(sm_persistent_er, d_prime, connection); 1916 return; 1917 } 1918 break; 1919 1920 case SM_PH3_CSRK_GET_ENC: 1921 // already busy? 1922 if (sm_aes128_state == SM_AES128_IDLE) { 1923 sm_key_t d_prime; 1924 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 1925 sm_next_responding_state(connection); 1926 sm_aes128_start(sm_persistent_er, d_prime, connection); 1927 return; 1928 } 1929 break; 1930 1931 case SM_PH2_C1_GET_ENC_C: 1932 // already busy? 1933 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1934 // calculate m_confirm using aes128 engine - step 1 1935 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); 1936 sm_next_responding_state(connection); 1937 sm_aes128_start(setup->sm_tk, plaintext, connection); 1938 break; 1939 case SM_PH2_C1_GET_ENC_A: 1940 // already busy? 1941 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1942 // calculate confirm using aes128 engine - step 1 1943 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); 1944 sm_next_responding_state(connection); 1945 sm_aes128_start(setup->sm_tk, plaintext, connection); 1946 break; 1947 case SM_PH2_CALC_STK: 1948 // already busy? 1949 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1950 // calculate STK 1951 if (connection->sm_role){ 1952 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 1953 } else { 1954 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 1955 } 1956 sm_next_responding_state(connection); 1957 sm_aes128_start(setup->sm_tk, plaintext, connection); 1958 break; 1959 case SM_PH3_Y_GET_ENC: 1960 // already busy? 1961 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1962 // PH3B2 - calculate Y from - enc 1963 // Y = dm(DHK, Rand) 1964 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1965 sm_next_responding_state(connection); 1966 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1967 return; 1968 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 1969 uint8_t buffer[17]; 1970 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1971 reverse_128(setup->sm_local_confirm, &buffer[1]); 1972 if (connection->sm_role){ 1973 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 1974 } else { 1975 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 1976 } 1977 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1978 sm_timeout_reset(connection); 1979 return; 1980 } 1981 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 1982 sm_key_t stk_flipped; 1983 reverse_128(setup->sm_ltk, stk_flipped); 1984 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1985 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 1986 return; 1987 } 1988 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 1989 sm_key_t stk_flipped; 1990 reverse_128(setup->sm_ltk, stk_flipped); 1991 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1992 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 1993 return; 1994 } 1995 case SM_RESPONDER_PH4_SEND_LTK: { 1996 sm_key_t ltk_flipped; 1997 reverse_128(setup->sm_ltk, ltk_flipped); 1998 connection->sm_engine_state = SM_RESPONDER_IDLE; 1999 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2000 return; 2001 } 2002 case SM_RESPONDER_PH4_Y_GET_ENC: 2003 // already busy? 2004 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2005 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2006 // Y = dm(DHK, Rand) 2007 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2008 sm_next_responding_state(connection); 2009 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2010 return; 2011 2012 case SM_PH3_DISTRIBUTE_KEYS: 2013 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2014 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2015 uint8_t buffer[17]; 2016 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2017 reverse_128(setup->sm_ltk, &buffer[1]); 2018 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2019 sm_timeout_reset(connection); 2020 return; 2021 } 2022 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2023 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2024 uint8_t buffer[11]; 2025 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2026 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2027 reverse_64(setup->sm_local_rand, &buffer[3]); 2028 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2029 sm_timeout_reset(connection); 2030 return; 2031 } 2032 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2033 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2034 uint8_t buffer[17]; 2035 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2036 reverse_128(sm_persistent_irk, &buffer[1]); 2037 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2038 sm_timeout_reset(connection); 2039 return; 2040 } 2041 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2042 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2043 bd_addr_t local_address; 2044 uint8_t buffer[8]; 2045 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2046 gap_advertisements_get_address(&buffer[1], local_address); 2047 reverse_bd_addr(local_address, &buffer[2]); 2048 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2049 sm_timeout_reset(connection); 2050 return; 2051 } 2052 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2053 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2054 2055 // hack to reproduce test runs 2056 if (test_use_fixed_local_csrk){ 2057 memset(setup->sm_local_csrk, 0xcc, 16); 2058 } 2059 2060 uint8_t buffer[17]; 2061 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2062 reverse_128(setup->sm_local_csrk, &buffer[1]); 2063 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2064 sm_timeout_reset(connection); 2065 return; 2066 } 2067 2068 // keys are sent 2069 if (connection->sm_role){ 2070 // slave -> receive master keys if any 2071 if (sm_key_distribution_all_received(connection)){ 2072 sm_key_distribution_handle_all_received(connection); 2073 connection->sm_engine_state = SM_RESPONDER_IDLE; 2074 sm_done_for_handle(connection->sm_handle); 2075 } else { 2076 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2077 } 2078 } else { 2079 // master -> all done 2080 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2081 sm_done_for_handle(connection->sm_handle); 2082 } 2083 break; 2084 2085 default: 2086 break; 2087 } 2088 2089 // check again if active connection was released 2090 if (sm_active_connection) break; 2091 } 2092 } 2093 2094 // note: aes engine is ready as we just got the aes result 2095 static void sm_handle_encryption_result(uint8_t * data){ 2096 2097 sm_aes128_state = SM_AES128_IDLE; 2098 2099 if (sm_address_resolution_ah_calculation_active){ 2100 sm_address_resolution_ah_calculation_active = 0; 2101 // compare calulated address against connecting device 2102 uint8_t hash[3]; 2103 reverse_24(data, hash); 2104 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2105 log_info("LE Device Lookup: matched resolvable private address"); 2106 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2107 return; 2108 } 2109 // no match, try next 2110 sm_address_resolution_test++; 2111 return; 2112 } 2113 2114 switch (dkg_state){ 2115 case DKG_W4_IRK: 2116 reverse_128(data, sm_persistent_irk); 2117 log_info_key("irk", sm_persistent_irk); 2118 dkg_next_state(); 2119 return; 2120 case DKG_W4_DHK: 2121 reverse_128(data, sm_persistent_dhk); 2122 log_info_key("dhk", sm_persistent_dhk); 2123 dkg_next_state(); 2124 // SM Init Finished 2125 return; 2126 default: 2127 break; 2128 } 2129 2130 switch (rau_state){ 2131 case RAU_W4_ENC: 2132 reverse_24(data, &sm_random_address[3]); 2133 rau_next_state(); 2134 return; 2135 default: 2136 break; 2137 } 2138 2139 switch (sm_cmac_state){ 2140 case CMAC_W4_SUBKEYS: 2141 case CMAC_W4_MI: 2142 case CMAC_W4_MLAST: 2143 { 2144 sm_key_t t; 2145 reverse_128(data, t); 2146 sm_cmac_handle_encryption_result(t); 2147 } 2148 return; 2149 default: 2150 break; 2151 } 2152 2153 // retrieve sm_connection provided to sm_aes128_start_encryption 2154 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2155 if (!connection) return; 2156 switch (connection->sm_engine_state){ 2157 case SM_PH2_C1_W4_ENC_A: 2158 case SM_PH2_C1_W4_ENC_C: 2159 { 2160 sm_key_t t2; 2161 reverse_128(data, t2); 2162 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2163 } 2164 sm_next_responding_state(connection); 2165 return; 2166 case SM_PH2_C1_W4_ENC_B: 2167 reverse_128(data, setup->sm_local_confirm); 2168 log_info_key("c1!", setup->sm_local_confirm); 2169 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2170 return; 2171 case SM_PH2_C1_W4_ENC_D: 2172 { 2173 sm_key_t peer_confirm_test; 2174 reverse_128(data, peer_confirm_test); 2175 log_info_key("c1!", peer_confirm_test); 2176 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2177 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2178 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2179 return; 2180 } 2181 if (connection->sm_role){ 2182 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2183 } else { 2184 connection->sm_engine_state = SM_PH2_CALC_STK; 2185 } 2186 } 2187 return; 2188 case SM_PH2_W4_STK: 2189 reverse_128(data, setup->sm_ltk); 2190 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2191 log_info_key("stk", setup->sm_ltk); 2192 if (connection->sm_role){ 2193 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2194 } else { 2195 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2196 } 2197 return; 2198 case SM_PH3_Y_W4_ENC:{ 2199 sm_key_t y128; 2200 reverse_128(data, y128); 2201 setup->sm_local_y = big_endian_read_16(y128, 14); 2202 log_info_hex16("y", setup->sm_local_y); 2203 // PH3B3 - calculate EDIV 2204 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2205 log_info_hex16("ediv", setup->sm_local_ediv); 2206 // PH3B4 - calculate LTK - enc 2207 // LTK = d1(ER, DIV, 0)) 2208 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2209 return; 2210 } 2211 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2212 sm_key_t y128; 2213 reverse_128(data, y128); 2214 setup->sm_local_y = big_endian_read_16(y128, 14); 2215 log_info_hex16("y", setup->sm_local_y); 2216 2217 // PH3B3 - calculate DIV 2218 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2219 log_info_hex16("ediv", setup->sm_local_ediv); 2220 // PH3B4 - calculate LTK - enc 2221 // LTK = d1(ER, DIV, 0)) 2222 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2223 return; 2224 } 2225 case SM_PH3_LTK_W4_ENC: 2226 reverse_128(data, setup->sm_ltk); 2227 log_info_key("ltk", setup->sm_ltk); 2228 // calc CSRK next 2229 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2230 return; 2231 case SM_PH3_CSRK_W4_ENC: 2232 reverse_128(data, setup->sm_local_csrk); 2233 log_info_key("csrk", setup->sm_local_csrk); 2234 if (setup->sm_key_distribution_send_set){ 2235 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2236 } else { 2237 // no keys to send, just continue 2238 if (connection->sm_role){ 2239 // slave -> receive master keys 2240 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2241 } else { 2242 // master -> all done 2243 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2244 sm_done_for_handle(connection->sm_handle); 2245 } 2246 } 2247 return; 2248 case SM_RESPONDER_PH4_LTK_W4_ENC: 2249 reverse_128(data, setup->sm_ltk); 2250 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2251 log_info_key("ltk", setup->sm_ltk); 2252 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 2253 return; 2254 default: 2255 break; 2256 } 2257 } 2258 2259 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2260 static void sm_handle_random_result(uint8_t * data){ 2261 2262 switch (rau_state){ 2263 case RAU_W4_RANDOM: 2264 // non-resolvable vs. resolvable 2265 switch (gap_random_adress_type){ 2266 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2267 // resolvable: use random as prand and calc address hash 2268 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2269 memcpy(sm_random_address, data, 3); 2270 sm_random_address[0] &= 0x3f; 2271 sm_random_address[0] |= 0x40; 2272 rau_state = RAU_GET_ENC; 2273 break; 2274 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2275 default: 2276 // "The two most significant bits of the address shall be equal to ‘0’"" 2277 memcpy(sm_random_address, data, 6); 2278 sm_random_address[0] &= 0x3f; 2279 rau_state = RAU_SET_ADDRESS; 2280 break; 2281 } 2282 return; 2283 default: 2284 break; 2285 } 2286 2287 // retrieve sm_connection provided to sm_random_start 2288 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2289 if (!connection) return; 2290 switch (connection->sm_engine_state){ 2291 case SM_PH2_W4_RANDOM_TK: 2292 { 2293 // map random to 0-999999 without speding much cycles on a modulus operation 2294 uint32_t tk = little_endian_read_32(data,0); 2295 tk = tk & 0xfffff; // 1048575 2296 if (tk >= 999999){ 2297 tk = tk - 999999; 2298 } 2299 sm_reset_tk(); 2300 big_endian_store_32(setup->sm_tk, 12, tk); 2301 if (connection->sm_role){ 2302 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2303 } else { 2304 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2305 sm_trigger_user_response(connection); 2306 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2307 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2308 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2309 } 2310 } 2311 return; 2312 } 2313 case SM_PH2_C1_W4_RANDOM_A: 2314 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2315 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2316 return; 2317 case SM_PH2_C1_W4_RANDOM_B: 2318 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2319 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2320 return; 2321 case SM_PH3_W4_RANDOM: 2322 reverse_64(data, setup->sm_local_rand); 2323 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2324 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2325 // no db for authenticated flag hack: store flag in bit 4 of LSB 2326 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2327 connection->sm_engine_state = SM_PH3_GET_DIV; 2328 return; 2329 case SM_PH3_W4_DIV: 2330 // use 16 bit from random value as div 2331 setup->sm_local_div = big_endian_read_16(data, 0); 2332 log_info_hex16("div", setup->sm_local_div); 2333 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2334 return; 2335 default: 2336 break; 2337 } 2338 } 2339 2340 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2341 2342 sm_connection_t * sm_conn; 2343 hci_con_handle_t con_handle; 2344 2345 switch (packet_type) { 2346 2347 case HCI_EVENT_PACKET: 2348 switch (hci_event_packet_get_type(packet)) { 2349 2350 case BTSTACK_EVENT_STATE: 2351 // bt stack activated, get started 2352 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2353 log_info("HCI Working!"); 2354 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2355 rau_state = RAU_IDLE; 2356 sm_run(); 2357 } 2358 break; 2359 2360 case HCI_EVENT_LE_META: 2361 switch (packet[2]) { 2362 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2363 2364 log_info("sm: connected"); 2365 2366 if (packet[3]) return; // connection failed 2367 2368 con_handle = little_endian_read_16(packet, 4); 2369 sm_conn = sm_get_connection_for_handle(con_handle); 2370 if (!sm_conn) break; 2371 2372 sm_conn->sm_handle = con_handle; 2373 sm_conn->sm_role = packet[6]; 2374 sm_conn->sm_peer_addr_type = packet[7]; 2375 reverse_bd_addr(&packet[8], 2376 sm_conn->sm_peer_address); 2377 2378 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2379 2380 // reset security properties 2381 sm_conn->sm_connection_encrypted = 0; 2382 sm_conn->sm_connection_authenticated = 0; 2383 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2384 sm_conn->sm_le_db_index = -1; 2385 2386 // prepare CSRK lookup (does not involve setup) 2387 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2388 2389 // just connected -> everything else happens in sm_run() 2390 if (sm_conn->sm_role){ 2391 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2392 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2393 if (sm_slave_request_security) { 2394 // request security if requested by app 2395 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2396 } else { 2397 // otherwise, wait for pairing request 2398 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2399 } 2400 } 2401 break; 2402 } else { 2403 // master 2404 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2405 } 2406 break; 2407 2408 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2409 con_handle = little_endian_read_16(packet, 3); 2410 sm_conn = sm_get_connection_for_handle(con_handle); 2411 if (!sm_conn) break; 2412 2413 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2414 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2415 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2416 break; 2417 } 2418 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2419 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2420 break; 2421 } 2422 2423 // assume that we don't have a LTK for ediv == 0 and random == null 2424 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 2425 log_info("LTK Request: ediv & random are empty"); 2426 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2427 break; 2428 } 2429 2430 // store rand and ediv 2431 reverse_64(&packet[5], sm_conn->sm_local_rand); 2432 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2433 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 2434 break; 2435 2436 default: 2437 break; 2438 } 2439 break; 2440 2441 case HCI_EVENT_ENCRYPTION_CHANGE: 2442 con_handle = little_endian_read_16(packet, 3); 2443 sm_conn = sm_get_connection_for_handle(con_handle); 2444 if (!sm_conn) break; 2445 2446 sm_conn->sm_connection_encrypted = packet[5]; 2447 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2448 sm_conn->sm_actual_encryption_key_size); 2449 log_info("event handler, state %u", sm_conn->sm_engine_state); 2450 if (!sm_conn->sm_connection_encrypted) break; 2451 // continue if part of initial pairing 2452 switch (sm_conn->sm_engine_state){ 2453 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2454 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2455 sm_done_for_handle(sm_conn->sm_handle); 2456 break; 2457 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2458 if (sm_conn->sm_role){ 2459 // slave 2460 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2461 } else { 2462 // master 2463 if (sm_key_distribution_all_received(sm_conn)){ 2464 // skip receiving keys as there are none 2465 sm_key_distribution_handle_all_received(sm_conn); 2466 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2467 } else { 2468 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2469 } 2470 } 2471 break; 2472 default: 2473 break; 2474 } 2475 break; 2476 2477 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2478 con_handle = little_endian_read_16(packet, 3); 2479 sm_conn = sm_get_connection_for_handle(con_handle); 2480 if (!sm_conn) break; 2481 2482 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2483 log_info("event handler, state %u", sm_conn->sm_engine_state); 2484 // continue if part of initial pairing 2485 switch (sm_conn->sm_engine_state){ 2486 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2487 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2488 sm_done_for_handle(sm_conn->sm_handle); 2489 break; 2490 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2491 if (sm_conn->sm_role){ 2492 // slave 2493 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2494 } else { 2495 // master 2496 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2497 } 2498 break; 2499 default: 2500 break; 2501 } 2502 break; 2503 2504 2505 case HCI_EVENT_DISCONNECTION_COMPLETE: 2506 con_handle = little_endian_read_16(packet, 3); 2507 sm_done_for_handle(con_handle); 2508 sm_conn = sm_get_connection_for_handle(con_handle); 2509 if (!sm_conn) break; 2510 2511 // delete stored bonding on disconnect with authentication failure in ph0 2512 if (sm_conn->sm_role == 0 2513 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2514 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2515 le_device_db_remove(sm_conn->sm_le_db_index); 2516 } 2517 2518 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2519 sm_conn->sm_handle = 0; 2520 break; 2521 2522 case HCI_EVENT_COMMAND_COMPLETE: 2523 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2524 sm_handle_encryption_result(&packet[6]); 2525 break; 2526 } 2527 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2528 sm_handle_random_result(&packet[6]); 2529 break; 2530 } 2531 break; 2532 default: 2533 break; 2534 } 2535 break; 2536 default: 2537 break; 2538 } 2539 2540 sm_run(); 2541 } 2542 2543 static inline int sm_calc_actual_encryption_key_size(int other){ 2544 if (other < sm_min_encryption_key_size) return 0; 2545 if (other < sm_max_encryption_key_size) return other; 2546 return sm_max_encryption_key_size; 2547 } 2548 2549 /** 2550 * @return ok 2551 */ 2552 static int sm_validate_stk_generation_method(void){ 2553 // check if STK generation method is acceptable by client 2554 switch (setup->sm_stk_generation_method){ 2555 case JUST_WORKS: 2556 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2557 case PK_RESP_INPUT: 2558 case PK_INIT_INPUT: 2559 case OK_BOTH_INPUT: 2560 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2561 case OOB: 2562 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2563 case NK_BOTH_INPUT: 2564 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 2565 return 1; 2566 default: 2567 return 0; 2568 } 2569 } 2570 2571 // helper for sm_pdu_handler, calls sm_run on exit 2572 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 2573 setup->sm_pairing_failed_reason = reason; 2574 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2575 } 2576 2577 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 2578 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 2579 } 2580 2581 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2582 2583 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 2584 sm_run(); 2585 } 2586 2587 if (packet_type != SM_DATA_PACKET) return; 2588 2589 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2590 if (!sm_conn) return; 2591 2592 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2593 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2594 return; 2595 } 2596 2597 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2598 2599 int err; 2600 2601 switch (sm_conn->sm_engine_state){ 2602 2603 // a sm timeout requries a new physical connection 2604 case SM_GENERAL_TIMEOUT: 2605 return; 2606 2607 // Initiator 2608 case SM_INITIATOR_CONNECTED: 2609 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2610 sm_pdu_received_in_wrong_state(sm_conn); 2611 break; 2612 } 2613 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2614 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2615 break; 2616 } 2617 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2618 uint16_t ediv; 2619 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2620 if (ediv){ 2621 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2622 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2623 } else { 2624 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2625 } 2626 break; 2627 } 2628 // otherwise, store security request 2629 sm_conn->sm_security_request_received = 1; 2630 break; 2631 2632 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2633 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2634 sm_pdu_received_in_wrong_state(sm_conn); 2635 break; 2636 } 2637 // store pairing request 2638 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2639 err = sm_stk_generation_init(sm_conn); 2640 if (err){ 2641 setup->sm_pairing_failed_reason = err; 2642 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2643 break; 2644 } 2645 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2646 if (setup->sm_use_secure_connections){ 2647 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2648 if (setup->sm_stk_generation_method == JUST_WORKS){ 2649 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2650 sm_trigger_user_response(sm_conn); 2651 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2652 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2653 } 2654 } else { 2655 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2656 } 2657 break; 2658 } 2659 #endif 2660 // generate random number first, if we need to show passkey 2661 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2662 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2663 break; 2664 } 2665 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2666 sm_trigger_user_response(sm_conn); 2667 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2668 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2669 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2670 } 2671 break; 2672 2673 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2674 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2675 sm_pdu_received_in_wrong_state(sm_conn); 2676 break; 2677 } 2678 2679 // store s_confirm 2680 reverse_128(&packet[1], setup->sm_peer_confirm); 2681 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2682 break; 2683 2684 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2685 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2686 sm_pdu_received_in_wrong_state(sm_conn); 2687 break;; 2688 } 2689 2690 // received random value 2691 reverse_128(&packet[1], setup->sm_peer_random); 2692 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2693 break; 2694 2695 // Responder 2696 case SM_RESPONDER_IDLE: 2697 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2698 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2699 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2700 sm_pdu_received_in_wrong_state(sm_conn); 2701 break;; 2702 } 2703 2704 // store pairing request 2705 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2706 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2707 break; 2708 2709 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2710 case SM_SC_W4_PUBLIC_KEY_COMMAND: 2711 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 2712 sm_pdu_received_in_wrong_state(sm_conn); 2713 break; 2714 } 2715 2716 // store public key for DH Key calculation 2717 reverse_256(&packet[01], setup->sm_peer_qx); 2718 reverse_256(&packet[33], setup->sm_peer_qy); 2719 2720 #ifdef USE_MBEDTLS_FOR_ECDH 2721 // validate public key 2722 mbedtls_ecp_group grp; 2723 mbedtls_ecp_group_init( &grp ); 2724 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 2725 2726 mbedtls_ecp_point Q; 2727 mbedtls_ecp_point_init( &Q ); 2728 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 2729 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 2730 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 2731 err = mbedtls_ecp_check_pubkey(&grp, &Q); 2732 if (err){ 2733 log_error("sm: peer public key invalid %x", err); 2734 // uses "unspecified reason", there is no "public key invalid" error code 2735 sm_pdu_received_in_wrong_state(sm_conn); 2736 break; 2737 } 2738 #endif 2739 if (sm_conn->sm_role){ 2740 // responder 2741 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2742 } else { 2743 // initiator 2744 // stk generation method 2745 // passkey entry: notify app to show passkey or to request passkey 2746 switch (setup->sm_stk_generation_method){ 2747 case JUST_WORKS: 2748 case NK_BOTH_INPUT: 2749 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 2750 break; 2751 case PK_INIT_INPUT: 2752 case PK_RESP_INPUT: 2753 case OK_BOTH_INPUT: 2754 sm_sc_calculate_local_confirm(); 2755 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 2756 break; 2757 case OOB: 2758 // TODO: implement SC OOB 2759 break; 2760 } 2761 } 2762 break; 2763 2764 case SM_SC_W4_CONFIRMATION: 2765 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2766 sm_pdu_received_in_wrong_state(sm_conn); 2767 break; 2768 } 2769 // received confirm value 2770 reverse_128(&packet[1], setup->sm_peer_confirm); 2771 2772 if (sm_conn->sm_role){ 2773 // responder 2774 sm_sc_calculate_local_confirm(); 2775 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 2776 } else { 2777 // initiator 2778 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2779 } 2780 break; 2781 2782 case SM_SC_W4_PAIRING_RANDOM: 2783 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2784 sm_pdu_received_in_wrong_state(sm_conn); 2785 break; 2786 } 2787 2788 // received random value 2789 reverse_128(&packet[1], setup->sm_peer_nonce); 2790 2791 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 2792 uint8_t z = 0; 2793 int passkey_entry = 0; 2794 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 2795 // some form of passkey 2796 passkey_entry = 1; 2797 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 2798 // sm_passkey_bit was increased before sending confirm value 2799 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 2800 } 2801 // only check for JUST WORK/NC in initiator role AND passkey entry 2802 if (sm_conn->sm_role || passkey_entry) { 2803 sm_key_t confirm_value; 2804 2805 #ifdef USE_MBEDTLS_FOR_ECDH 2806 uint8_t local_qx[32]; 2807 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 2808 f4(confirm_value, setup->sm_peer_qx, local_qx, setup->sm_peer_nonce, z); 2809 #endif 2810 if (0 != memcmp(confirm_value, setup->sm_peer_confirm, 16)){ 2811 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 2812 break; 2813 } 2814 } 2815 2816 if (sm_conn->sm_role){ 2817 // Responder 2818 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2819 } else { 2820 // Initiator role 2821 switch (setup->sm_stk_generation_method){ 2822 case JUST_WORKS: 2823 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 2824 break; 2825 2826 case NK_BOTH_INPUT: { 2827 // calc Va if numeric comparison 2828 // TODO: use AES Engine to calculate g2 2829 uint8_t value[32]; 2830 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 2831 uint32_t va = g2(value, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce) % 1000000; 2832 big_endian_store_32(setup->sm_tk, 12, va); 2833 sm_trigger_user_response(sm_conn); 2834 break; 2835 } 2836 case PK_INIT_INPUT: 2837 case PK_RESP_INPUT: 2838 case OK_BOTH_INPUT: 2839 if (setup->sm_passkey_bit < 20) { 2840 sm_sc_calculate_local_confirm(); 2841 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 2842 } else { 2843 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 2844 } 2845 break; 2846 case OOB: 2847 // TODO: implement SC OOB 2848 break; 2849 } 2850 } 2851 break; 2852 2853 case SM_SC_W4_DHKEY_CHECK_COMMAND: 2854 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 2855 sm_pdu_received_in_wrong_state(sm_conn); 2856 break; 2857 } 2858 // store DHKey Check 2859 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 2860 2861 // validate E = f6() 2862 sm_key56_t bd_addr_master, bd_addr_slave; 2863 bd_addr_master[0] = setup->sm_m_addr_type; 2864 bd_addr_slave[0] = setup->sm_s_addr_type; 2865 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 2866 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 2867 2868 uint8_t iocap_a[3]; 2869 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 2870 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 2871 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 2872 uint8_t iocap_b[3]; 2873 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 2874 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 2875 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 2876 sm_key_t peer_dhkey_check; 2877 if (sm_conn->sm_role){ 2878 // responder 2879 f6(peer_dhkey_check, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 2880 } else { 2881 // initiator 2882 f6(peer_dhkey_check, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 2883 } 2884 2885 if (0 != memcmp(setup->sm_peer_dhkey_check, peer_dhkey_check, 16) ){ 2886 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 2887 break; 2888 } 2889 2890 if (sm_conn->sm_role){ 2891 // responder 2892 // for numeric comparison, we need to wait for user confirm 2893 if (setup->sm_stk_generation_method == NK_BOTH_INPUT && setup->sm_user_response != SM_USER_RESPONSE_CONFIRM){ 2894 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 2895 } else { 2896 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 2897 } 2898 } else { 2899 // initiator 2900 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2901 } 2902 break; 2903 #endif 2904 2905 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 2906 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2907 sm_pdu_received_in_wrong_state(sm_conn); 2908 break; 2909 } 2910 2911 // received confirm value 2912 reverse_128(&packet[1], setup->sm_peer_confirm); 2913 2914 // notify client to hide shown passkey 2915 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2916 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 2917 } 2918 2919 // handle user cancel pairing? 2920 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 2921 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2922 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2923 break; 2924 } 2925 2926 // wait for user action? 2927 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 2928 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2929 break; 2930 } 2931 2932 // calculate and send local_confirm 2933 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2934 break; 2935 2936 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 2937 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2938 sm_pdu_received_in_wrong_state(sm_conn); 2939 break;; 2940 } 2941 2942 // received random value 2943 reverse_128(&packet[1], setup->sm_peer_random); 2944 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2945 break; 2946 2947 case SM_PH3_RECEIVE_KEYS: 2948 switch(packet[0]){ 2949 case SM_CODE_ENCRYPTION_INFORMATION: 2950 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2951 reverse_128(&packet[1], setup->sm_peer_ltk); 2952 break; 2953 2954 case SM_CODE_MASTER_IDENTIFICATION: 2955 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2956 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 2957 reverse_64(&packet[3], setup->sm_peer_rand); 2958 break; 2959 2960 case SM_CODE_IDENTITY_INFORMATION: 2961 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2962 reverse_128(&packet[1], setup->sm_peer_irk); 2963 break; 2964 2965 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 2966 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2967 setup->sm_peer_addr_type = packet[1]; 2968 reverse_bd_addr(&packet[2], setup->sm_peer_address); 2969 break; 2970 2971 case SM_CODE_SIGNING_INFORMATION: 2972 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2973 reverse_128(&packet[1], setup->sm_peer_csrk); 2974 break; 2975 default: 2976 // Unexpected PDU 2977 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 2978 break; 2979 } 2980 // done with key distribution? 2981 if (sm_key_distribution_all_received(sm_conn)){ 2982 2983 sm_key_distribution_handle_all_received(sm_conn); 2984 2985 if (sm_conn->sm_role){ 2986 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2987 sm_done_for_handle(sm_conn->sm_handle); 2988 } else { 2989 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2990 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2991 if (setup->sm_use_secure_connections){ 2992 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2993 } 2994 #endif 2995 } 2996 } 2997 break; 2998 default: 2999 // Unexpected PDU 3000 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3001 break; 3002 } 3003 3004 // try to send preparared packet 3005 sm_run(); 3006 } 3007 3008 // Security Manager Client API 3009 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3010 sm_get_oob_data = get_oob_data_callback; 3011 } 3012 3013 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3014 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3015 } 3016 3017 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3018 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3019 } 3020 3021 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3022 sm_min_encryption_key_size = min_size; 3023 sm_max_encryption_key_size = max_size; 3024 } 3025 3026 void sm_set_authentication_requirements(uint8_t auth_req){ 3027 sm_auth_req = auth_req; 3028 } 3029 3030 void sm_set_io_capabilities(io_capability_t io_capability){ 3031 sm_io_capabilities = io_capability; 3032 } 3033 3034 void sm_set_request_security(int enable){ 3035 sm_slave_request_security = enable; 3036 } 3037 3038 void sm_set_er(sm_key_t er){ 3039 memcpy(sm_persistent_er, er, 16); 3040 } 3041 3042 void sm_set_ir(sm_key_t ir){ 3043 memcpy(sm_persistent_ir, ir, 16); 3044 } 3045 3046 // Testing support only 3047 void sm_test_set_irk(sm_key_t irk){ 3048 memcpy(sm_persistent_irk, irk, 16); 3049 sm_persistent_irk_ready = 1; 3050 } 3051 3052 void sm_test_use_fixed_local_csrk(void){ 3053 test_use_fixed_local_csrk = 1; 3054 } 3055 3056 void sm_init(void){ 3057 // set some (BTstack default) ER and IR 3058 int i; 3059 sm_key_t er; 3060 sm_key_t ir; 3061 for (i=0;i<16;i++){ 3062 er[i] = 0x30 + i; 3063 ir[i] = 0x90 + i; 3064 } 3065 sm_set_er(er); 3066 sm_set_ir(ir); 3067 // defaults 3068 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3069 | SM_STK_GENERATION_METHOD_OOB 3070 | SM_STK_GENERATION_METHOD_PASSKEY 3071 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3072 3073 sm_max_encryption_key_size = 16; 3074 sm_min_encryption_key_size = 7; 3075 3076 sm_cmac_state = CMAC_IDLE; 3077 dkg_state = DKG_W4_WORKING; 3078 rau_state = RAU_W4_WORKING; 3079 sm_aes128_state = SM_AES128_IDLE; 3080 sm_address_resolution_test = -1; // no private address to resolve yet 3081 sm_address_resolution_ah_calculation_active = 0; 3082 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3083 sm_address_resolution_general_queue = NULL; 3084 3085 gap_random_adress_update_period = 15 * 60 * 1000L; 3086 3087 sm_active_connection = 0; 3088 3089 test_use_fixed_local_csrk = 0; 3090 3091 // register for HCI Events from HCI 3092 hci_event_callback_registration.callback = &sm_event_packet_handler; 3093 hci_add_event_handler(&hci_event_callback_registration); 3094 3095 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3096 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3097 3098 #ifdef USE_MBEDTLS_FOR_ECDH 3099 // TODO: calculate keypair using LE Random Number Generator 3100 // use test keypair from spec initially 3101 mbedtls_ecp_keypair_init(&le_keypair); 3102 mbedtls_ecp_group_load(&le_keypair.grp, MBEDTLS_ECP_DP_SECP256R1); 3103 mbedtls_mpi_read_string( &le_keypair.d, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3104 mbedtls_mpi_read_string( &le_keypair.Q.X, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3105 mbedtls_mpi_read_string( &le_keypair.Q.Y, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3106 mbedtls_mpi_read_string( &le_keypair.Q.Z, 16, "1"); 3107 // print keypair 3108 char buffer[100]; 3109 size_t len; 3110 mbedtls_mpi_write_string( &le_keypair.d, 16, buffer, sizeof(buffer), &len); 3111 log_info("d: %s", buffer); 3112 mbedtls_mpi_write_string( &le_keypair.Q.X, 16, buffer, sizeof(buffer), &len); 3113 log_info("X: %s", buffer); 3114 mbedtls_mpi_write_string( &le_keypair.Q.Y, 16, buffer, sizeof(buffer), &len); 3115 log_info("Y: %s", buffer); 3116 #endif 3117 } 3118 3119 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3120 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3121 if (!hci_con) return NULL; 3122 return &hci_con->sm_connection; 3123 } 3124 3125 // @returns 0 if not encrypted, 7-16 otherwise 3126 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3127 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3128 if (!sm_conn) return 0; // wrong connection 3129 if (!sm_conn->sm_connection_encrypted) return 0; 3130 return sm_conn->sm_actual_encryption_key_size; 3131 } 3132 3133 int sm_authenticated(hci_con_handle_t con_handle){ 3134 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3135 if (!sm_conn) return 0; // wrong connection 3136 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3137 return sm_conn->sm_connection_authenticated; 3138 } 3139 3140 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3141 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3142 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3143 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3144 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3145 return sm_conn->sm_connection_authorization_state; 3146 } 3147 3148 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3149 switch (sm_conn->sm_engine_state){ 3150 case SM_GENERAL_IDLE: 3151 case SM_RESPONDER_IDLE: 3152 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3153 sm_run(); 3154 break; 3155 default: 3156 break; 3157 } 3158 } 3159 3160 /** 3161 * @brief Trigger Security Request 3162 */ 3163 void sm_send_security_request(hci_con_handle_t con_handle){ 3164 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3165 if (!sm_conn) return; 3166 sm_send_security_request_for_connection(sm_conn); 3167 } 3168 3169 // request pairing 3170 void sm_request_pairing(hci_con_handle_t con_handle){ 3171 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3172 if (!sm_conn) return; // wrong connection 3173 3174 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3175 if (sm_conn->sm_role){ 3176 sm_send_security_request_for_connection(sm_conn); 3177 } else { 3178 // used as a trigger to start central/master/initiator security procedures 3179 uint16_t ediv; 3180 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3181 switch (sm_conn->sm_irk_lookup_state){ 3182 case IRK_LOOKUP_FAILED: 3183 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3184 break; 3185 case IRK_LOOKUP_SUCCEEDED: 3186 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 3187 if (ediv){ 3188 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3189 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3190 } else { 3191 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3192 } 3193 break; 3194 default: 3195 sm_conn->sm_bonding_requested = 1; 3196 break; 3197 } 3198 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3199 sm_conn->sm_bonding_requested = 1; 3200 } 3201 } 3202 sm_run(); 3203 } 3204 3205 // called by client app on authorization request 3206 void sm_authorization_decline(hci_con_handle_t con_handle){ 3207 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3208 if (!sm_conn) return; // wrong connection 3209 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3210 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3211 } 3212 3213 void sm_authorization_grant(hci_con_handle_t con_handle){ 3214 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3215 if (!sm_conn) return; // wrong connection 3216 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3217 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3218 } 3219 3220 // GAP Bonding API 3221 3222 void sm_bonding_decline(hci_con_handle_t con_handle){ 3223 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3224 if (!sm_conn) return; // wrong connection 3225 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3226 3227 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3228 switch (setup->sm_stk_generation_method){ 3229 case PK_RESP_INPUT: 3230 case PK_INIT_INPUT: 3231 case OK_BOTH_INPUT: 3232 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3233 break; 3234 case NK_BOTH_INPUT: 3235 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3236 break; 3237 case JUST_WORKS: 3238 case OOB: 3239 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3240 break; 3241 } 3242 } 3243 sm_run(); 3244 } 3245 3246 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3247 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3248 if (!sm_conn) return; // wrong connection 3249 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3250 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3251 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3252 3253 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3254 if (setup->sm_use_secure_connections){ 3255 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3256 } 3257 #endif 3258 } 3259 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3260 if (sm_conn->sm_role){ 3261 // responder 3262 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 3263 } else { 3264 // initiator 3265 // TODO handle intiator role 3266 } 3267 } 3268 sm_run(); 3269 } 3270 3271 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3272 // for now, it's the same 3273 sm_just_works_confirm(con_handle); 3274 } 3275 3276 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3277 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3278 if (!sm_conn) return; // wrong connection 3279 sm_reset_tk(); 3280 big_endian_store_32(setup->sm_tk, 12, passkey); 3281 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3282 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3283 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3284 } 3285 sm_run(); 3286 } 3287 3288 /** 3289 * @brief Identify device in LE Device DB 3290 * @param handle 3291 * @returns index from le_device_db or -1 if not found/identified 3292 */ 3293 int sm_le_device_index(hci_con_handle_t con_handle ){ 3294 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3295 if (!sm_conn) return -1; 3296 return sm_conn->sm_le_db_index; 3297 } 3298 3299 // GAP LE API 3300 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3301 gap_random_address_update_stop(); 3302 gap_random_adress_type = random_address_type; 3303 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3304 gap_random_address_update_start(); 3305 gap_random_address_trigger(); 3306 } 3307 3308 gap_random_address_type_t gap_random_address_get_mode(void){ 3309 return gap_random_adress_type; 3310 } 3311 3312 void gap_random_address_set_update_period(int period_ms){ 3313 gap_random_adress_update_period = period_ms; 3314 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3315 gap_random_address_update_stop(); 3316 gap_random_address_update_start(); 3317 } 3318 3319 void gap_random_address_set(bd_addr_t addr){ 3320 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3321 memcpy(sm_random_address, addr, 6); 3322 rau_state = RAU_SET_ADDRESS; 3323 sm_run(); 3324 } 3325 3326 /* 3327 * @brief Set Advertisement Paramters 3328 * @param adv_int_min 3329 * @param adv_int_max 3330 * @param adv_type 3331 * @param direct_address_type 3332 * @param direct_address 3333 * @param channel_map 3334 * @param filter_policy 3335 * 3336 * @note own_address_type is used from gap_random_address_set_mode 3337 */ 3338 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3339 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3340 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3341 direct_address_typ, direct_address, channel_map, filter_policy); 3342 } 3343 3344