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 static void sm_run(void){ 1369 1370 btstack_linked_list_iterator_t it; 1371 1372 // assert that we can send at least commands 1373 if (!hci_can_send_command_packet_now()) return; 1374 1375 // 1376 // non-connection related behaviour 1377 // 1378 1379 // distributed key generation 1380 switch (dkg_state){ 1381 case DKG_CALC_IRK: 1382 // already busy? 1383 if (sm_aes128_state == SM_AES128_IDLE) { 1384 // IRK = d1(IR, 1, 0) 1385 sm_key_t d1_prime; 1386 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1387 dkg_next_state(); 1388 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1389 return; 1390 } 1391 break; 1392 case DKG_CALC_DHK: 1393 // already busy? 1394 if (sm_aes128_state == SM_AES128_IDLE) { 1395 // DHK = d1(IR, 3, 0) 1396 sm_key_t d1_prime; 1397 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1398 dkg_next_state(); 1399 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1400 return; 1401 } 1402 break; 1403 default: 1404 break; 1405 } 1406 1407 // random address updates 1408 switch (rau_state){ 1409 case RAU_GET_RANDOM: 1410 rau_next_state(); 1411 sm_random_start(NULL); 1412 return; 1413 case RAU_GET_ENC: 1414 // already busy? 1415 if (sm_aes128_state == SM_AES128_IDLE) { 1416 sm_key_t r_prime; 1417 sm_ah_r_prime(sm_random_address, r_prime); 1418 rau_next_state(); 1419 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1420 return; 1421 } 1422 break; 1423 case RAU_SET_ADDRESS: 1424 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1425 rau_state = RAU_IDLE; 1426 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1427 return; 1428 default: 1429 break; 1430 } 1431 1432 // CMAC 1433 switch (sm_cmac_state){ 1434 case CMAC_CALC_SUBKEYS: 1435 case CMAC_CALC_MI: 1436 case CMAC_CALC_MLAST: 1437 // already busy? 1438 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1439 sm_cmac_handle_aes_engine_ready(); 1440 return; 1441 default: 1442 break; 1443 } 1444 1445 // CSRK Lookup 1446 // -- if csrk lookup ready, find connection that require csrk lookup 1447 if (sm_address_resolution_idle()){ 1448 hci_connections_get_iterator(&it); 1449 while(btstack_linked_list_iterator_has_next(&it)){ 1450 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1451 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1452 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1453 // and start lookup 1454 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); 1455 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1456 break; 1457 } 1458 } 1459 } 1460 1461 // -- if csrk lookup ready, resolved addresses for received addresses 1462 if (sm_address_resolution_idle()) { 1463 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1464 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1465 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1466 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1467 btstack_memory_sm_lookup_entry_free(entry); 1468 } 1469 } 1470 1471 // -- Continue with CSRK device lookup by public or resolvable private address 1472 if (!sm_address_resolution_idle()){ 1473 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1474 while (sm_address_resolution_test < le_device_db_count()){ 1475 int addr_type; 1476 bd_addr_t addr; 1477 sm_key_t irk; 1478 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1479 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1480 1481 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1482 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1483 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1484 break; 1485 } 1486 1487 if (sm_address_resolution_addr_type == 0){ 1488 sm_address_resolution_test++; 1489 continue; 1490 } 1491 1492 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1493 1494 log_info("LE Device Lookup: calculate AH"); 1495 log_info_key("IRK", irk); 1496 1497 sm_key_t r_prime; 1498 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1499 sm_address_resolution_ah_calculation_active = 1; 1500 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1501 return; 1502 } 1503 1504 if (sm_address_resolution_test >= le_device_db_count()){ 1505 log_info("LE Device Lookup: not found"); 1506 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1507 } 1508 } 1509 1510 1511 // 1512 // active connection handling 1513 // -- use loop to handle next connection if lock on setup context is released 1514 1515 while (1) { 1516 1517 // Find connections that requires setup context and make active if no other is locked 1518 hci_connections_get_iterator(&it); 1519 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1520 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1521 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1522 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1523 int done = 1; 1524 int err; 1525 int encryption_key_size; 1526 int authenticated; 1527 int authorized; 1528 switch (sm_connection->sm_engine_state) { 1529 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1530 // send packet if possible, 1531 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1532 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1533 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1534 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1535 } else { 1536 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1537 } 1538 // don't lock setup context yet 1539 done = 0; 1540 break; 1541 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1542 sm_init_setup(sm_connection); 1543 // recover pairing request 1544 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1545 err = sm_stk_generation_init(sm_connection); 1546 if (err){ 1547 setup->sm_pairing_failed_reason = err; 1548 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1549 break; 1550 } 1551 sm_timeout_start(sm_connection); 1552 // generate random number first, if we need to show passkey 1553 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1554 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1555 break; 1556 } 1557 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1558 break; 1559 case SM_INITIATOR_PH0_HAS_LTK: 1560 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1561 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1562 &encryption_key_size, &authenticated, &authorized); 1563 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1564 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1565 sm_connection->sm_connection_authenticated = authenticated; 1566 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1567 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1568 break; 1569 case SM_RESPONDER_PH0_RECEIVED_LTK: 1570 // re-establish previously used LTK using Rand and EDIV 1571 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1572 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1573 // re-establish used key encryption size 1574 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1575 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1576 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1577 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1578 log_info("sm: received ltk request with key size %u, authenticated %u", 1579 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1580 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1581 break; 1582 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1583 sm_init_setup(sm_connection); 1584 sm_timeout_start(sm_connection); 1585 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1586 break; 1587 default: 1588 done = 0; 1589 break; 1590 } 1591 if (done){ 1592 sm_active_connection = sm_connection->sm_handle; 1593 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1594 } 1595 } 1596 1597 // 1598 // active connection handling 1599 // 1600 1601 if (sm_active_connection == 0) return; 1602 1603 // assert that we could send a SM PDU - not needed for all of the following 1604 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1605 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1606 return; 1607 } 1608 1609 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1610 if (!connection) return; 1611 1612 sm_key_t plaintext; 1613 int key_distribution_flags; 1614 1615 log_info("sm_run: state %u", connection->sm_engine_state); 1616 1617 // responding state 1618 switch (connection->sm_engine_state){ 1619 1620 // general 1621 case SM_GENERAL_SEND_PAIRING_FAILED: { 1622 uint8_t buffer[2]; 1623 buffer[0] = SM_CODE_PAIRING_FAILED; 1624 buffer[1] = setup->sm_pairing_failed_reason; 1625 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1626 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1627 sm_done_for_handle(connection->sm_handle); 1628 break; 1629 } 1630 1631 // initiator side 1632 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1633 sm_key_t peer_ltk_flipped; 1634 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1635 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1636 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1637 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1638 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1639 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1640 return; 1641 } 1642 1643 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1644 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 1645 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1646 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1647 sm_timeout_reset(connection); 1648 break; 1649 1650 // responder side 1651 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1652 connection->sm_engine_state = SM_RESPONDER_IDLE; 1653 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1654 return; 1655 1656 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1657 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 1658 uint8_t buffer[65]; 1659 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 1660 // 1661 #ifdef USE_MBEDTLS_FOR_ECDH 1662 uint8_t value[32]; 1663 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1664 reverse_256(value, &buffer[1]); 1665 mbedtls_mpi_write_binary(&le_keypair.Q.Y, value, sizeof(value)); 1666 reverse_256(value, &buffer[33]); 1667 #endif 1668 // TODO: use random generator to generate nonce 1669 1670 // generate 128-bit nonce 1671 int i; 1672 for (i=0;i<16;i++){ 1673 setup->sm_local_nonce[i] = rand() & 0xff; 1674 } 1675 1676 // stk generation method 1677 // passkey entry: notify app to show passkey or to request passkey 1678 switch (setup->sm_stk_generation_method){ 1679 case JUST_WORKS: 1680 case NK_BOTH_INPUT: 1681 if (connection->sm_role){ 1682 connection->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1683 } else { 1684 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1685 } 1686 break; 1687 case PK_INIT_INPUT: 1688 case PK_RESP_INPUT: 1689 case OK_BOTH_INPUT: 1690 // hack for testing: assume user entered '000000' 1691 // memset(setup->sm_tk, 0, 16); 1692 memcpy(setup->sm_ra, setup->sm_tk, 16); 1693 memcpy(setup->sm_rb, setup->sm_tk, 16); 1694 setup->sm_passkey_bit = 0; 1695 if (connection->sm_role){ 1696 // responder 1697 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1698 } else { 1699 // initiator 1700 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1701 } 1702 sm_trigger_user_response(connection); 1703 break; 1704 case OOB: 1705 // TODO: implement SC OOB 1706 break; 1707 } 1708 1709 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1710 sm_timeout_reset(connection); 1711 break; 1712 } 1713 case SM_SC_SEND_CONFIRMATION: { 1714 uint8_t buffer[17]; 1715 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1716 #ifdef USE_MBEDTLS_FOR_ECDH 1717 uint8_t z = 0; 1718 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1719 // some form of passkey 1720 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1721 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1722 setup->sm_passkey_bit++; 1723 } 1724 1725 // TODO: use AES Engine to calculate commitment value using f4 1726 uint8_t value[32]; 1727 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1728 sm_key_t confirm_value; 1729 f4(confirm_value, value, setup->sm_peer_qx, setup->sm_local_nonce, z); 1730 reverse_128(confirm_value, &buffer[1]); 1731 #endif 1732 if (connection->sm_role){ 1733 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1734 } else { 1735 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1736 } 1737 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1738 sm_timeout_reset(connection); 1739 break; 1740 } 1741 case SM_SC_SEND_PAIRING_RANDOM: { 1742 uint8_t buffer[17]; 1743 buffer[0] = SM_CODE_PAIRING_RANDOM; 1744 reverse_128(setup->sm_local_nonce, &buffer[1]); 1745 1746 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 1747 if (connection->sm_role){ 1748 // responder 1749 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1750 } else { 1751 // initiator 1752 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1753 } 1754 } else { 1755 if (connection->sm_role){ 1756 // responder 1757 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1758 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 1759 // calc Vb if numeric comparison 1760 // TODO: use AES Engine to calculate g2 1761 uint8_t value[32]; 1762 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1763 uint32_t vb = g2(setup->sm_peer_qx, value, setup->sm_peer_nonce, setup->sm_local_nonce) % 1000000; 1764 big_endian_store_32(setup->sm_tk, 12, vb); 1765 sm_trigger_user_response(connection); 1766 } 1767 } else { 1768 // initiator 1769 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1770 } 1771 } 1772 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1773 sm_timeout_reset(connection); 1774 break; 1775 } 1776 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 1777 1778 uint8_t buffer[17]; 1779 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 1780 #ifdef USE_MBEDTLS_FOR_ECDH 1781 // calculate DHKEY 1782 mbedtls_ecp_group grp; 1783 mbedtls_ecp_group_init( &grp ); 1784 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 1785 mbedtls_ecp_point Q; 1786 mbedtls_ecp_point_init( &Q ); 1787 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1788 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1789 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1790 1791 // da * Pb 1792 mbedtls_ecp_point DH; 1793 mbedtls_ecp_point_init( &DH ); 1794 mbedtls_ecp_mul(&grp, &DH, &le_keypair.d, &Q, NULL, NULL); 1795 sm_key256_t dhkey; 1796 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1797 log_info("dhkey"); 1798 log_info_hexdump(dhkey, 32); 1799 1800 // calculate LTK + MacKey 1801 sm_key256_t ltk_mackey; 1802 sm_key56_t bd_addr_master, bd_addr_slave; 1803 bd_addr_master[0] = setup->sm_m_addr_type; 1804 bd_addr_slave[0] = setup->sm_s_addr_type; 1805 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1806 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1807 if (connection->sm_role){ 1808 // responder 1809 f5(ltk_mackey, dhkey, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1810 } else { 1811 // initiator 1812 f5(ltk_mackey, dhkey, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1813 } 1814 // store LTK 1815 memcpy(setup->sm_ltk, <k_mackey[16], 16); 1816 1817 // calc DHKCheck 1818 memcpy(setup->sm_mackey, <k_mackey[0], 16); 1819 1820 // TODO: checks 1821 1822 uint8_t iocap_a[3]; 1823 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1824 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1825 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1826 uint8_t iocap_b[3]; 1827 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1828 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1829 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1830 if (connection->sm_role){ 1831 // responder 1832 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); 1833 } else { 1834 // initiator 1835 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); 1836 } 1837 #endif 1838 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 1839 if (connection->sm_role){ 1840 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 1841 } else { 1842 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1843 } 1844 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1845 sm_timeout_reset(connection); 1846 break; 1847 } 1848 1849 #endif 1850 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 1851 // echo initiator for now 1852 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 1853 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1854 1855 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 1856 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1857 if (setup->sm_use_secure_connections){ 1858 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1859 // skip LTK/EDIV for SC 1860 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 1861 } 1862 #endif 1863 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); 1864 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); 1865 1866 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 1867 sm_timeout_reset(connection); 1868 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 1869 if (setup->sm_stk_generation_method == JUST_WORKS){ 1870 sm_trigger_user_response(connection); 1871 } 1872 return; 1873 1874 case SM_PH2_SEND_PAIRING_RANDOM: { 1875 uint8_t buffer[17]; 1876 buffer[0] = SM_CODE_PAIRING_RANDOM; 1877 reverse_128(setup->sm_local_random, &buffer[1]); 1878 if (connection->sm_role){ 1879 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 1880 } else { 1881 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 1882 } 1883 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1884 sm_timeout_reset(connection); 1885 break; 1886 } 1887 1888 case SM_PH2_GET_RANDOM_TK: 1889 case SM_PH2_C1_GET_RANDOM_A: 1890 case SM_PH2_C1_GET_RANDOM_B: 1891 case SM_PH3_GET_RANDOM: 1892 case SM_PH3_GET_DIV: 1893 sm_next_responding_state(connection); 1894 sm_random_start(connection); 1895 return; 1896 1897 case SM_PH2_C1_GET_ENC_B: 1898 case SM_PH2_C1_GET_ENC_D: 1899 // already busy? 1900 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1901 sm_next_responding_state(connection); 1902 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 1903 return; 1904 1905 case SM_PH3_LTK_GET_ENC: 1906 case SM_RESPONDER_PH4_LTK_GET_ENC: 1907 // already busy? 1908 if (sm_aes128_state == SM_AES128_IDLE) { 1909 sm_key_t d_prime; 1910 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 1911 sm_next_responding_state(connection); 1912 sm_aes128_start(sm_persistent_er, d_prime, connection); 1913 return; 1914 } 1915 break; 1916 1917 case SM_PH3_CSRK_GET_ENC: 1918 // already busy? 1919 if (sm_aes128_state == SM_AES128_IDLE) { 1920 sm_key_t d_prime; 1921 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 1922 sm_next_responding_state(connection); 1923 sm_aes128_start(sm_persistent_er, d_prime, connection); 1924 return; 1925 } 1926 break; 1927 1928 case SM_PH2_C1_GET_ENC_C: 1929 // already busy? 1930 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1931 // calculate m_confirm using aes128 engine - step 1 1932 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); 1933 sm_next_responding_state(connection); 1934 sm_aes128_start(setup->sm_tk, plaintext, connection); 1935 break; 1936 case SM_PH2_C1_GET_ENC_A: 1937 // already busy? 1938 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1939 // calculate confirm using aes128 engine - step 1 1940 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); 1941 sm_next_responding_state(connection); 1942 sm_aes128_start(setup->sm_tk, plaintext, connection); 1943 break; 1944 case SM_PH2_CALC_STK: 1945 // already busy? 1946 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1947 // calculate STK 1948 if (connection->sm_role){ 1949 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 1950 } else { 1951 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 1952 } 1953 sm_next_responding_state(connection); 1954 sm_aes128_start(setup->sm_tk, plaintext, connection); 1955 break; 1956 case SM_PH3_Y_GET_ENC: 1957 // already busy? 1958 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1959 // PH3B2 - calculate Y from - enc 1960 // Y = dm(DHK, Rand) 1961 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1962 sm_next_responding_state(connection); 1963 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1964 return; 1965 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 1966 uint8_t buffer[17]; 1967 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1968 reverse_128(setup->sm_local_confirm, &buffer[1]); 1969 if (connection->sm_role){ 1970 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 1971 } else { 1972 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 1973 } 1974 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1975 sm_timeout_reset(connection); 1976 return; 1977 } 1978 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 1979 sm_key_t stk_flipped; 1980 reverse_128(setup->sm_ltk, stk_flipped); 1981 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1982 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 1983 return; 1984 } 1985 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 1986 sm_key_t stk_flipped; 1987 reverse_128(setup->sm_ltk, stk_flipped); 1988 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1989 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 1990 return; 1991 } 1992 case SM_RESPONDER_PH4_SEND_LTK: { 1993 sm_key_t ltk_flipped; 1994 reverse_128(setup->sm_ltk, ltk_flipped); 1995 connection->sm_engine_state = SM_RESPONDER_IDLE; 1996 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 1997 return; 1998 } 1999 case SM_RESPONDER_PH4_Y_GET_ENC: 2000 // already busy? 2001 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2002 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2003 // Y = dm(DHK, Rand) 2004 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2005 sm_next_responding_state(connection); 2006 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2007 return; 2008 2009 case SM_PH3_DISTRIBUTE_KEYS: 2010 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2011 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2012 uint8_t buffer[17]; 2013 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2014 reverse_128(setup->sm_ltk, &buffer[1]); 2015 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2016 sm_timeout_reset(connection); 2017 return; 2018 } 2019 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2020 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2021 uint8_t buffer[11]; 2022 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2023 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2024 reverse_64(setup->sm_local_rand, &buffer[3]); 2025 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2026 sm_timeout_reset(connection); 2027 return; 2028 } 2029 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2030 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2031 uint8_t buffer[17]; 2032 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2033 reverse_128(sm_persistent_irk, &buffer[1]); 2034 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2035 sm_timeout_reset(connection); 2036 return; 2037 } 2038 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2039 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2040 bd_addr_t local_address; 2041 uint8_t buffer[8]; 2042 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2043 gap_advertisements_get_address(&buffer[1], local_address); 2044 reverse_bd_addr(local_address, &buffer[2]); 2045 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2046 sm_timeout_reset(connection); 2047 return; 2048 } 2049 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2050 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2051 2052 // hack to reproduce test runs 2053 if (test_use_fixed_local_csrk){ 2054 memset(setup->sm_local_csrk, 0xcc, 16); 2055 } 2056 2057 uint8_t buffer[17]; 2058 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2059 reverse_128(setup->sm_local_csrk, &buffer[1]); 2060 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2061 sm_timeout_reset(connection); 2062 return; 2063 } 2064 2065 // keys are sent 2066 if (connection->sm_role){ 2067 // slave -> receive master keys if any 2068 if (sm_key_distribution_all_received(connection)){ 2069 sm_key_distribution_handle_all_received(connection); 2070 connection->sm_engine_state = SM_RESPONDER_IDLE; 2071 sm_done_for_handle(connection->sm_handle); 2072 } else { 2073 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2074 } 2075 } else { 2076 // master -> all done 2077 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2078 sm_done_for_handle(connection->sm_handle); 2079 } 2080 break; 2081 2082 default: 2083 break; 2084 } 2085 2086 // check again if active connection was released 2087 if (sm_active_connection) break; 2088 } 2089 } 2090 2091 // note: aes engine is ready as we just got the aes result 2092 static void sm_handle_encryption_result(uint8_t * data){ 2093 2094 sm_aes128_state = SM_AES128_IDLE; 2095 2096 if (sm_address_resolution_ah_calculation_active){ 2097 sm_address_resolution_ah_calculation_active = 0; 2098 // compare calulated address against connecting device 2099 uint8_t hash[3]; 2100 reverse_24(data, hash); 2101 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2102 log_info("LE Device Lookup: matched resolvable private address"); 2103 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2104 return; 2105 } 2106 // no match, try next 2107 sm_address_resolution_test++; 2108 return; 2109 } 2110 2111 switch (dkg_state){ 2112 case DKG_W4_IRK: 2113 reverse_128(data, sm_persistent_irk); 2114 log_info_key("irk", sm_persistent_irk); 2115 dkg_next_state(); 2116 return; 2117 case DKG_W4_DHK: 2118 reverse_128(data, sm_persistent_dhk); 2119 log_info_key("dhk", sm_persistent_dhk); 2120 dkg_next_state(); 2121 // SM Init Finished 2122 return; 2123 default: 2124 break; 2125 } 2126 2127 switch (rau_state){ 2128 case RAU_W4_ENC: 2129 reverse_24(data, &sm_random_address[3]); 2130 rau_next_state(); 2131 return; 2132 default: 2133 break; 2134 } 2135 2136 switch (sm_cmac_state){ 2137 case CMAC_W4_SUBKEYS: 2138 case CMAC_W4_MI: 2139 case CMAC_W4_MLAST: 2140 { 2141 sm_key_t t; 2142 reverse_128(data, t); 2143 sm_cmac_handle_encryption_result(t); 2144 } 2145 return; 2146 default: 2147 break; 2148 } 2149 2150 // retrieve sm_connection provided to sm_aes128_start_encryption 2151 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2152 if (!connection) return; 2153 switch (connection->sm_engine_state){ 2154 case SM_PH2_C1_W4_ENC_A: 2155 case SM_PH2_C1_W4_ENC_C: 2156 { 2157 sm_key_t t2; 2158 reverse_128(data, t2); 2159 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2160 } 2161 sm_next_responding_state(connection); 2162 return; 2163 case SM_PH2_C1_W4_ENC_B: 2164 reverse_128(data, setup->sm_local_confirm); 2165 log_info_key("c1!", setup->sm_local_confirm); 2166 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2167 return; 2168 case SM_PH2_C1_W4_ENC_D: 2169 { 2170 sm_key_t peer_confirm_test; 2171 reverse_128(data, peer_confirm_test); 2172 log_info_key("c1!", peer_confirm_test); 2173 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2174 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2175 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2176 return; 2177 } 2178 if (connection->sm_role){ 2179 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2180 } else { 2181 connection->sm_engine_state = SM_PH2_CALC_STK; 2182 } 2183 } 2184 return; 2185 case SM_PH2_W4_STK: 2186 reverse_128(data, setup->sm_ltk); 2187 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2188 log_info_key("stk", setup->sm_ltk); 2189 if (connection->sm_role){ 2190 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2191 } else { 2192 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2193 } 2194 return; 2195 case SM_PH3_Y_W4_ENC:{ 2196 sm_key_t y128; 2197 reverse_128(data, y128); 2198 setup->sm_local_y = big_endian_read_16(y128, 14); 2199 log_info_hex16("y", setup->sm_local_y); 2200 // PH3B3 - calculate EDIV 2201 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2202 log_info_hex16("ediv", setup->sm_local_ediv); 2203 // PH3B4 - calculate LTK - enc 2204 // LTK = d1(ER, DIV, 0)) 2205 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2206 return; 2207 } 2208 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2209 sm_key_t y128; 2210 reverse_128(data, y128); 2211 setup->sm_local_y = big_endian_read_16(y128, 14); 2212 log_info_hex16("y", setup->sm_local_y); 2213 2214 // PH3B3 - calculate DIV 2215 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2216 log_info_hex16("ediv", setup->sm_local_ediv); 2217 // PH3B4 - calculate LTK - enc 2218 // LTK = d1(ER, DIV, 0)) 2219 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2220 return; 2221 } 2222 case SM_PH3_LTK_W4_ENC: 2223 reverse_128(data, setup->sm_ltk); 2224 log_info_key("ltk", setup->sm_ltk); 2225 // calc CSRK next 2226 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2227 return; 2228 case SM_PH3_CSRK_W4_ENC: 2229 reverse_128(data, setup->sm_local_csrk); 2230 log_info_key("csrk", setup->sm_local_csrk); 2231 if (setup->sm_key_distribution_send_set){ 2232 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2233 } else { 2234 // no keys to send, just continue 2235 if (connection->sm_role){ 2236 // slave -> receive master keys 2237 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2238 } else { 2239 // master -> all done 2240 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2241 sm_done_for_handle(connection->sm_handle); 2242 } 2243 } 2244 return; 2245 case SM_RESPONDER_PH4_LTK_W4_ENC: 2246 reverse_128(data, setup->sm_ltk); 2247 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2248 log_info_key("ltk", setup->sm_ltk); 2249 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 2250 return; 2251 default: 2252 break; 2253 } 2254 } 2255 2256 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2257 static void sm_handle_random_result(uint8_t * data){ 2258 2259 switch (rau_state){ 2260 case RAU_W4_RANDOM: 2261 // non-resolvable vs. resolvable 2262 switch (gap_random_adress_type){ 2263 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2264 // resolvable: use random as prand and calc address hash 2265 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2266 memcpy(sm_random_address, data, 3); 2267 sm_random_address[0] &= 0x3f; 2268 sm_random_address[0] |= 0x40; 2269 rau_state = RAU_GET_ENC; 2270 break; 2271 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2272 default: 2273 // "The two most significant bits of the address shall be equal to ‘0’"" 2274 memcpy(sm_random_address, data, 6); 2275 sm_random_address[0] &= 0x3f; 2276 rau_state = RAU_SET_ADDRESS; 2277 break; 2278 } 2279 return; 2280 default: 2281 break; 2282 } 2283 2284 // retrieve sm_connection provided to sm_random_start 2285 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2286 if (!connection) return; 2287 switch (connection->sm_engine_state){ 2288 case SM_PH2_W4_RANDOM_TK: 2289 { 2290 // map random to 0-999999 without speding much cycles on a modulus operation 2291 uint32_t tk = little_endian_read_32(data,0); 2292 tk = tk & 0xfffff; // 1048575 2293 if (tk >= 999999){ 2294 tk = tk - 999999; 2295 } 2296 sm_reset_tk(); 2297 big_endian_store_32(setup->sm_tk, 12, tk); 2298 if (connection->sm_role){ 2299 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2300 } else { 2301 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2302 sm_trigger_user_response(connection); 2303 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2304 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2305 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2306 } 2307 } 2308 return; 2309 } 2310 case SM_PH2_C1_W4_RANDOM_A: 2311 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2312 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2313 return; 2314 case SM_PH2_C1_W4_RANDOM_B: 2315 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2316 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2317 return; 2318 case SM_PH3_W4_RANDOM: 2319 reverse_64(data, setup->sm_local_rand); 2320 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2321 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2322 // no db for authenticated flag hack: store flag in bit 4 of LSB 2323 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2324 connection->sm_engine_state = SM_PH3_GET_DIV; 2325 return; 2326 case SM_PH3_W4_DIV: 2327 // use 16 bit from random value as div 2328 setup->sm_local_div = big_endian_read_16(data, 0); 2329 log_info_hex16("div", setup->sm_local_div); 2330 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2331 return; 2332 default: 2333 break; 2334 } 2335 } 2336 2337 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2338 2339 sm_connection_t * sm_conn; 2340 hci_con_handle_t con_handle; 2341 2342 switch (packet_type) { 2343 2344 case HCI_EVENT_PACKET: 2345 switch (hci_event_packet_get_type(packet)) { 2346 2347 case BTSTACK_EVENT_STATE: 2348 // bt stack activated, get started 2349 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2350 log_info("HCI Working!"); 2351 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2352 rau_state = RAU_IDLE; 2353 sm_run(); 2354 } 2355 break; 2356 2357 case HCI_EVENT_LE_META: 2358 switch (packet[2]) { 2359 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2360 2361 log_info("sm: connected"); 2362 2363 if (packet[3]) return; // connection failed 2364 2365 con_handle = little_endian_read_16(packet, 4); 2366 sm_conn = sm_get_connection_for_handle(con_handle); 2367 if (!sm_conn) break; 2368 2369 sm_conn->sm_handle = con_handle; 2370 sm_conn->sm_role = packet[6]; 2371 sm_conn->sm_peer_addr_type = packet[7]; 2372 reverse_bd_addr(&packet[8], 2373 sm_conn->sm_peer_address); 2374 2375 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2376 2377 // reset security properties 2378 sm_conn->sm_connection_encrypted = 0; 2379 sm_conn->sm_connection_authenticated = 0; 2380 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2381 sm_conn->sm_le_db_index = -1; 2382 2383 // prepare CSRK lookup (does not involve setup) 2384 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2385 2386 // just connected -> everything else happens in sm_run() 2387 if (sm_conn->sm_role){ 2388 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2389 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2390 if (sm_slave_request_security) { 2391 // request security if requested by app 2392 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2393 } else { 2394 // otherwise, wait for pairing request 2395 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2396 } 2397 } 2398 break; 2399 } else { 2400 // master 2401 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2402 } 2403 break; 2404 2405 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2406 con_handle = little_endian_read_16(packet, 3); 2407 sm_conn = sm_get_connection_for_handle(con_handle); 2408 if (!sm_conn) break; 2409 2410 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2411 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2412 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2413 break; 2414 } 2415 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2416 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2417 break; 2418 } 2419 2420 // assume that we don't have a LTK for ediv == 0 and random == null 2421 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 2422 log_info("LTK Request: ediv & random are empty"); 2423 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2424 break; 2425 } 2426 2427 // store rand and ediv 2428 reverse_64(&packet[5], sm_conn->sm_local_rand); 2429 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2430 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 2431 break; 2432 2433 default: 2434 break; 2435 } 2436 break; 2437 2438 case HCI_EVENT_ENCRYPTION_CHANGE: 2439 con_handle = little_endian_read_16(packet, 3); 2440 sm_conn = sm_get_connection_for_handle(con_handle); 2441 if (!sm_conn) break; 2442 2443 sm_conn->sm_connection_encrypted = packet[5]; 2444 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2445 sm_conn->sm_actual_encryption_key_size); 2446 log_info("event handler, state %u", sm_conn->sm_engine_state); 2447 if (!sm_conn->sm_connection_encrypted) break; 2448 // continue if part of initial pairing 2449 switch (sm_conn->sm_engine_state){ 2450 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2451 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2452 sm_done_for_handle(sm_conn->sm_handle); 2453 break; 2454 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2455 if (sm_conn->sm_role){ 2456 // slave 2457 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2458 } else { 2459 // master 2460 if (sm_key_distribution_all_received(sm_conn)){ 2461 // skip receiving keys as there are none 2462 sm_key_distribution_handle_all_received(sm_conn); 2463 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2464 } else { 2465 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2466 } 2467 } 2468 break; 2469 default: 2470 break; 2471 } 2472 break; 2473 2474 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2475 con_handle = little_endian_read_16(packet, 3); 2476 sm_conn = sm_get_connection_for_handle(con_handle); 2477 if (!sm_conn) break; 2478 2479 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2480 log_info("event handler, state %u", sm_conn->sm_engine_state); 2481 // continue if part of initial pairing 2482 switch (sm_conn->sm_engine_state){ 2483 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2484 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2485 sm_done_for_handle(sm_conn->sm_handle); 2486 break; 2487 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2488 if (sm_conn->sm_role){ 2489 // slave 2490 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2491 } else { 2492 // master 2493 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2494 } 2495 break; 2496 default: 2497 break; 2498 } 2499 break; 2500 2501 2502 case HCI_EVENT_DISCONNECTION_COMPLETE: 2503 con_handle = little_endian_read_16(packet, 3); 2504 sm_done_for_handle(con_handle); 2505 sm_conn = sm_get_connection_for_handle(con_handle); 2506 if (!sm_conn) break; 2507 2508 // delete stored bonding on disconnect with authentication failure in ph0 2509 if (sm_conn->sm_role == 0 2510 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2511 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2512 le_device_db_remove(sm_conn->sm_le_db_index); 2513 } 2514 2515 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2516 sm_conn->sm_handle = 0; 2517 break; 2518 2519 case HCI_EVENT_COMMAND_COMPLETE: 2520 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2521 sm_handle_encryption_result(&packet[6]); 2522 break; 2523 } 2524 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2525 sm_handle_random_result(&packet[6]); 2526 break; 2527 } 2528 break; 2529 default: 2530 break; 2531 } 2532 break; 2533 default: 2534 break; 2535 } 2536 2537 sm_run(); 2538 } 2539 2540 static inline int sm_calc_actual_encryption_key_size(int other){ 2541 if (other < sm_min_encryption_key_size) return 0; 2542 if (other < sm_max_encryption_key_size) return other; 2543 return sm_max_encryption_key_size; 2544 } 2545 2546 /** 2547 * @return ok 2548 */ 2549 static int sm_validate_stk_generation_method(void){ 2550 // check if STK generation method is acceptable by client 2551 switch (setup->sm_stk_generation_method){ 2552 case JUST_WORKS: 2553 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2554 case PK_RESP_INPUT: 2555 case PK_INIT_INPUT: 2556 case OK_BOTH_INPUT: 2557 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2558 case OOB: 2559 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2560 case NK_BOTH_INPUT: 2561 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 2562 return 1; 2563 default: 2564 return 0; 2565 } 2566 } 2567 2568 // helper for sm_pdu_handler, calls sm_run on exit 2569 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 2570 setup->sm_pairing_failed_reason = reason; 2571 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2572 } 2573 2574 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 2575 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 2576 } 2577 2578 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2579 2580 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 2581 sm_run(); 2582 } 2583 2584 if (packet_type != SM_DATA_PACKET) return; 2585 2586 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2587 if (!sm_conn) return; 2588 2589 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2590 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2591 return; 2592 } 2593 2594 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2595 2596 int err; 2597 2598 switch (sm_conn->sm_engine_state){ 2599 2600 // a sm timeout requries a new physical connection 2601 case SM_GENERAL_TIMEOUT: 2602 return; 2603 2604 // Initiator 2605 case SM_INITIATOR_CONNECTED: 2606 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2607 sm_pdu_received_in_wrong_state(sm_conn); 2608 break; 2609 } 2610 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2611 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2612 break; 2613 } 2614 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2615 uint16_t ediv; 2616 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2617 if (ediv){ 2618 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2619 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2620 } else { 2621 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2622 } 2623 break; 2624 } 2625 // otherwise, store security request 2626 sm_conn->sm_security_request_received = 1; 2627 break; 2628 2629 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2630 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2631 sm_pdu_received_in_wrong_state(sm_conn); 2632 break; 2633 } 2634 // store pairing request 2635 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2636 err = sm_stk_generation_init(sm_conn); 2637 if (err){ 2638 setup->sm_pairing_failed_reason = err; 2639 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2640 break; 2641 } 2642 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2643 if (setup->sm_use_secure_connections){ 2644 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2645 if (setup->sm_stk_generation_method == JUST_WORKS){ 2646 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2647 sm_trigger_user_response(sm_conn); 2648 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2649 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2650 } 2651 } else { 2652 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2653 } 2654 break; 2655 } 2656 #endif 2657 // generate random number first, if we need to show passkey 2658 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2659 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2660 break; 2661 } 2662 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2663 sm_trigger_user_response(sm_conn); 2664 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2665 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2666 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2667 } 2668 break; 2669 2670 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2671 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2672 sm_pdu_received_in_wrong_state(sm_conn); 2673 break; 2674 } 2675 2676 // store s_confirm 2677 reverse_128(&packet[1], setup->sm_peer_confirm); 2678 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2679 break; 2680 2681 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2682 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2683 sm_pdu_received_in_wrong_state(sm_conn); 2684 break;; 2685 } 2686 2687 // received random value 2688 reverse_128(&packet[1], setup->sm_peer_random); 2689 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2690 break; 2691 2692 // Responder 2693 case SM_RESPONDER_IDLE: 2694 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2695 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2696 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2697 sm_pdu_received_in_wrong_state(sm_conn); 2698 break;; 2699 } 2700 2701 // store pairing request 2702 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2703 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2704 break; 2705 2706 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2707 case SM_SC_W4_PUBLIC_KEY_COMMAND: 2708 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 2709 sm_pdu_received_in_wrong_state(sm_conn); 2710 break; 2711 } 2712 2713 // store public key for DH Key calculation 2714 reverse_256(&packet[01], setup->sm_peer_qx); 2715 reverse_256(&packet[33], setup->sm_peer_qy); 2716 2717 #ifdef USE_MBEDTLS_FOR_ECDH 2718 // validate public key 2719 mbedtls_ecp_group grp; 2720 mbedtls_ecp_group_init( &grp ); 2721 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 2722 2723 mbedtls_ecp_point Q; 2724 mbedtls_ecp_point_init( &Q ); 2725 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 2726 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 2727 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 2728 err = mbedtls_ecp_check_pubkey(&grp, &Q); 2729 if (err){ 2730 log_error("sm: peer public key invalid %x", err); 2731 // uses "unspecified reason", there is no "public key invalid" error code 2732 sm_pdu_received_in_wrong_state(sm_conn); 2733 break; 2734 } 2735 #endif 2736 if (sm_conn->sm_role){ 2737 // responder 2738 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2739 } else { 2740 // initiator 2741 // stk generation method 2742 // passkey entry: notify app to show passkey or to request passkey 2743 switch (setup->sm_stk_generation_method){ 2744 case JUST_WORKS: 2745 case NK_BOTH_INPUT: 2746 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 2747 break; 2748 case PK_INIT_INPUT: 2749 case PK_RESP_INPUT: 2750 case OK_BOTH_INPUT: 2751 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 2752 break; 2753 case OOB: 2754 // TODO: implement SC OOB 2755 break; 2756 } 2757 } 2758 break; 2759 2760 case SM_SC_W4_CONFIRMATION: 2761 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2762 sm_pdu_received_in_wrong_state(sm_conn); 2763 break; 2764 } 2765 // received confirm value 2766 reverse_128(&packet[1], setup->sm_peer_confirm); 2767 2768 if (sm_conn->sm_role){ 2769 // responder 2770 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 2771 } else { 2772 // initiator 2773 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2774 } 2775 break; 2776 2777 case SM_SC_W4_PAIRING_RANDOM: 2778 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2779 sm_pdu_received_in_wrong_state(sm_conn); 2780 break; 2781 } 2782 2783 // received random value 2784 reverse_128(&packet[1], setup->sm_peer_nonce); 2785 2786 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 2787 uint8_t z = 0; 2788 int passkey_entry = 0; 2789 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 2790 // some form of passkey 2791 passkey_entry = 1; 2792 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 2793 // sm_passkey_bit was increased before sending confirm value 2794 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 2795 } 2796 // only check for JUST WORK/NC in initiator role AND passkey entry 2797 if (sm_conn->sm_role || passkey_entry) { 2798 sm_key_t confirm_value; 2799 #ifdef USE_MBEDTLS_FOR_ECDH 2800 uint8_t local_qx[32]; 2801 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 2802 f4(confirm_value, setup->sm_peer_qx, local_qx, setup->sm_peer_nonce, z); 2803 #endif 2804 if (0 != memcmp(confirm_value, setup->sm_peer_confirm, 16)){ 2805 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 2806 break; 2807 } 2808 } 2809 2810 if (sm_conn->sm_role){ 2811 // Responder 2812 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2813 } else { 2814 // Initiator role 2815 switch (setup->sm_stk_generation_method){ 2816 case JUST_WORKS: 2817 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 2818 break; 2819 2820 case NK_BOTH_INPUT: { 2821 // calc Va if numeric comparison 2822 // TODO: use AES Engine to calculate g2 2823 uint8_t value[32]; 2824 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 2825 uint32_t va = g2(value, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce) % 1000000; 2826 big_endian_store_32(setup->sm_tk, 12, va); 2827 sm_trigger_user_response(sm_conn); 2828 break; 2829 } 2830 case PK_INIT_INPUT: 2831 case PK_RESP_INPUT: 2832 case OK_BOTH_INPUT: 2833 if (setup->sm_passkey_bit < 20) { 2834 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 2835 } else { 2836 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 2837 } 2838 break; 2839 case OOB: 2840 // TODO: implement SC OOB 2841 break; 2842 } 2843 } 2844 break; 2845 2846 case SM_SC_W4_DHKEY_CHECK_COMMAND: 2847 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 2848 sm_pdu_received_in_wrong_state(sm_conn); 2849 break; 2850 } 2851 // store DHKey Check 2852 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 2853 2854 // validate E = f6() 2855 sm_key56_t bd_addr_master, bd_addr_slave; 2856 bd_addr_master[0] = setup->sm_m_addr_type; 2857 bd_addr_slave[0] = setup->sm_s_addr_type; 2858 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 2859 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 2860 2861 uint8_t iocap_a[3]; 2862 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 2863 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 2864 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 2865 uint8_t iocap_b[3]; 2866 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 2867 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 2868 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 2869 sm_key_t peer_dhkey_check; 2870 if (sm_conn->sm_role){ 2871 // responder 2872 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); 2873 } else { 2874 // initiator 2875 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); 2876 } 2877 2878 if (0 != memcmp(setup->sm_peer_dhkey_check, peer_dhkey_check, 16) ){ 2879 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 2880 break; 2881 } 2882 2883 if (sm_conn->sm_role){ 2884 // responder 2885 // for numeric comparison, we need to wait for user confirm 2886 if (setup->sm_stk_generation_method == NK_BOTH_INPUT && setup->sm_user_response != SM_USER_RESPONSE_CONFIRM){ 2887 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 2888 } else { 2889 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 2890 } 2891 } else { 2892 // initiator 2893 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2894 } 2895 break; 2896 #endif 2897 2898 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 2899 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2900 sm_pdu_received_in_wrong_state(sm_conn); 2901 break; 2902 } 2903 2904 // received confirm value 2905 reverse_128(&packet[1], setup->sm_peer_confirm); 2906 2907 // notify client to hide shown passkey 2908 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2909 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 2910 } 2911 2912 // handle user cancel pairing? 2913 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 2914 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2915 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2916 break; 2917 } 2918 2919 // wait for user action? 2920 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 2921 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2922 break; 2923 } 2924 2925 // calculate and send local_confirm 2926 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2927 break; 2928 2929 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 2930 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2931 sm_pdu_received_in_wrong_state(sm_conn); 2932 break;; 2933 } 2934 2935 // received random value 2936 reverse_128(&packet[1], setup->sm_peer_random); 2937 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2938 break; 2939 2940 case SM_PH3_RECEIVE_KEYS: 2941 switch(packet[0]){ 2942 case SM_CODE_ENCRYPTION_INFORMATION: 2943 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2944 reverse_128(&packet[1], setup->sm_peer_ltk); 2945 break; 2946 2947 case SM_CODE_MASTER_IDENTIFICATION: 2948 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2949 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 2950 reverse_64(&packet[3], setup->sm_peer_rand); 2951 break; 2952 2953 case SM_CODE_IDENTITY_INFORMATION: 2954 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2955 reverse_128(&packet[1], setup->sm_peer_irk); 2956 break; 2957 2958 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 2959 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2960 setup->sm_peer_addr_type = packet[1]; 2961 reverse_bd_addr(&packet[2], setup->sm_peer_address); 2962 break; 2963 2964 case SM_CODE_SIGNING_INFORMATION: 2965 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2966 reverse_128(&packet[1], setup->sm_peer_csrk); 2967 break; 2968 default: 2969 // Unexpected PDU 2970 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 2971 break; 2972 } 2973 // done with key distribution? 2974 if (sm_key_distribution_all_received(sm_conn)){ 2975 2976 sm_key_distribution_handle_all_received(sm_conn); 2977 2978 if (sm_conn->sm_role){ 2979 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2980 sm_done_for_handle(sm_conn->sm_handle); 2981 } else { 2982 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2983 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2984 if (setup->sm_use_secure_connections){ 2985 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2986 } 2987 #endif 2988 } 2989 } 2990 break; 2991 default: 2992 // Unexpected PDU 2993 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 2994 break; 2995 } 2996 2997 // try to send preparared packet 2998 sm_run(); 2999 } 3000 3001 // Security Manager Client API 3002 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3003 sm_get_oob_data = get_oob_data_callback; 3004 } 3005 3006 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3007 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3008 } 3009 3010 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3011 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3012 } 3013 3014 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3015 sm_min_encryption_key_size = min_size; 3016 sm_max_encryption_key_size = max_size; 3017 } 3018 3019 void sm_set_authentication_requirements(uint8_t auth_req){ 3020 sm_auth_req = auth_req; 3021 } 3022 3023 void sm_set_io_capabilities(io_capability_t io_capability){ 3024 sm_io_capabilities = io_capability; 3025 } 3026 3027 void sm_set_request_security(int enable){ 3028 sm_slave_request_security = enable; 3029 } 3030 3031 void sm_set_er(sm_key_t er){ 3032 memcpy(sm_persistent_er, er, 16); 3033 } 3034 3035 void sm_set_ir(sm_key_t ir){ 3036 memcpy(sm_persistent_ir, ir, 16); 3037 } 3038 3039 // Testing support only 3040 void sm_test_set_irk(sm_key_t irk){ 3041 memcpy(sm_persistent_irk, irk, 16); 3042 sm_persistent_irk_ready = 1; 3043 } 3044 3045 void sm_test_use_fixed_local_csrk(void){ 3046 test_use_fixed_local_csrk = 1; 3047 } 3048 3049 void sm_init(void){ 3050 // set some (BTstack default) ER and IR 3051 int i; 3052 sm_key_t er; 3053 sm_key_t ir; 3054 for (i=0;i<16;i++){ 3055 er[i] = 0x30 + i; 3056 ir[i] = 0x90 + i; 3057 } 3058 sm_set_er(er); 3059 sm_set_ir(ir); 3060 // defaults 3061 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3062 | SM_STK_GENERATION_METHOD_OOB 3063 | SM_STK_GENERATION_METHOD_PASSKEY 3064 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3065 3066 sm_max_encryption_key_size = 16; 3067 sm_min_encryption_key_size = 7; 3068 3069 sm_cmac_state = CMAC_IDLE; 3070 dkg_state = DKG_W4_WORKING; 3071 rau_state = RAU_W4_WORKING; 3072 sm_aes128_state = SM_AES128_IDLE; 3073 sm_address_resolution_test = -1; // no private address to resolve yet 3074 sm_address_resolution_ah_calculation_active = 0; 3075 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3076 sm_address_resolution_general_queue = NULL; 3077 3078 gap_random_adress_update_period = 15 * 60 * 1000L; 3079 3080 sm_active_connection = 0; 3081 3082 test_use_fixed_local_csrk = 0; 3083 3084 // register for HCI Events from HCI 3085 hci_event_callback_registration.callback = &sm_event_packet_handler; 3086 hci_add_event_handler(&hci_event_callback_registration); 3087 3088 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3089 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3090 3091 #ifdef USE_MBEDTLS_FOR_ECDH 3092 // TODO: calculate keypair using LE Random Number Generator 3093 // use test keypair from spec initially 3094 mbedtls_ecp_keypair_init(&le_keypair); 3095 mbedtls_ecp_group_load(&le_keypair.grp, MBEDTLS_ECP_DP_SECP256R1); 3096 mbedtls_mpi_read_string( &le_keypair.d, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3097 mbedtls_mpi_read_string( &le_keypair.Q.X, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3098 mbedtls_mpi_read_string( &le_keypair.Q.Y, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3099 mbedtls_mpi_read_string( &le_keypair.Q.Z, 16, "1"); 3100 // print keypair 3101 char buffer[100]; 3102 size_t len; 3103 mbedtls_mpi_write_string( &le_keypair.d, 16, buffer, sizeof(buffer), &len); 3104 log_info("d: %s", buffer); 3105 mbedtls_mpi_write_string( &le_keypair.Q.X, 16, buffer, sizeof(buffer), &len); 3106 log_info("X: %s", buffer); 3107 mbedtls_mpi_write_string( &le_keypair.Q.Y, 16, buffer, sizeof(buffer), &len); 3108 log_info("Y: %s", buffer); 3109 #endif 3110 } 3111 3112 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3113 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3114 if (!hci_con) return NULL; 3115 return &hci_con->sm_connection; 3116 } 3117 3118 // @returns 0 if not encrypted, 7-16 otherwise 3119 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3120 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3121 if (!sm_conn) return 0; // wrong connection 3122 if (!sm_conn->sm_connection_encrypted) return 0; 3123 return sm_conn->sm_actual_encryption_key_size; 3124 } 3125 3126 int sm_authenticated(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; // unencrypted connection cannot be authenticated 3130 return sm_conn->sm_connection_authenticated; 3131 } 3132 3133 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3134 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3135 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3136 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3137 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3138 return sm_conn->sm_connection_authorization_state; 3139 } 3140 3141 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3142 switch (sm_conn->sm_engine_state){ 3143 case SM_GENERAL_IDLE: 3144 case SM_RESPONDER_IDLE: 3145 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3146 sm_run(); 3147 break; 3148 default: 3149 break; 3150 } 3151 } 3152 3153 /** 3154 * @brief Trigger Security Request 3155 */ 3156 void sm_send_security_request(hci_con_handle_t con_handle){ 3157 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3158 if (!sm_conn) return; 3159 sm_send_security_request_for_connection(sm_conn); 3160 } 3161 3162 // request pairing 3163 void sm_request_pairing(hci_con_handle_t con_handle){ 3164 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3165 if (!sm_conn) return; // wrong connection 3166 3167 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3168 if (sm_conn->sm_role){ 3169 sm_send_security_request_for_connection(sm_conn); 3170 } else { 3171 // used as a trigger to start central/master/initiator security procedures 3172 uint16_t ediv; 3173 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3174 switch (sm_conn->sm_irk_lookup_state){ 3175 case IRK_LOOKUP_FAILED: 3176 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3177 break; 3178 case IRK_LOOKUP_SUCCEEDED: 3179 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 3180 if (ediv){ 3181 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3182 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3183 } else { 3184 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3185 } 3186 break; 3187 default: 3188 sm_conn->sm_bonding_requested = 1; 3189 break; 3190 } 3191 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3192 sm_conn->sm_bonding_requested = 1; 3193 } 3194 } 3195 sm_run(); 3196 } 3197 3198 // called by client app on authorization request 3199 void sm_authorization_decline(hci_con_handle_t con_handle){ 3200 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3201 if (!sm_conn) return; // wrong connection 3202 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3203 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3204 } 3205 3206 void sm_authorization_grant(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_GRANTED; 3210 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3211 } 3212 3213 // GAP Bonding API 3214 3215 void sm_bonding_decline(hci_con_handle_t con_handle){ 3216 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3217 if (!sm_conn) return; // wrong connection 3218 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3219 3220 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3221 switch (setup->sm_stk_generation_method){ 3222 case PK_RESP_INPUT: 3223 case PK_INIT_INPUT: 3224 case OK_BOTH_INPUT: 3225 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3226 break; 3227 case NK_BOTH_INPUT: 3228 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3229 break; 3230 case JUST_WORKS: 3231 case OOB: 3232 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3233 break; 3234 } 3235 } 3236 sm_run(); 3237 } 3238 3239 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3240 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3241 if (!sm_conn) return; // wrong connection 3242 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3243 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3244 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3245 3246 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3247 if (setup->sm_use_secure_connections){ 3248 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3249 } 3250 #endif 3251 } 3252 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3253 if (sm_conn->sm_role){ 3254 // responder 3255 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 3256 } else { 3257 // initiator 3258 // TODO handle intiator role 3259 } 3260 } 3261 sm_run(); 3262 } 3263 3264 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3265 // for now, it's the same 3266 sm_just_works_confirm(con_handle); 3267 } 3268 3269 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3270 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3271 if (!sm_conn) return; // wrong connection 3272 sm_reset_tk(); 3273 big_endian_store_32(setup->sm_tk, 12, passkey); 3274 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3275 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3276 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3277 } 3278 sm_run(); 3279 } 3280 3281 /** 3282 * @brief Identify device in LE Device DB 3283 * @param handle 3284 * @returns index from le_device_db or -1 if not found/identified 3285 */ 3286 int sm_le_device_index(hci_con_handle_t con_handle ){ 3287 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3288 if (!sm_conn) return -1; 3289 return sm_conn->sm_le_db_index; 3290 } 3291 3292 // GAP LE API 3293 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3294 gap_random_address_update_stop(); 3295 gap_random_adress_type = random_address_type; 3296 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3297 gap_random_address_update_start(); 3298 gap_random_address_trigger(); 3299 } 3300 3301 gap_random_address_type_t gap_random_address_get_mode(void){ 3302 return gap_random_adress_type; 3303 } 3304 3305 void gap_random_address_set_update_period(int period_ms){ 3306 gap_random_adress_update_period = period_ms; 3307 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3308 gap_random_address_update_stop(); 3309 gap_random_address_update_start(); 3310 } 3311 3312 void gap_random_address_set(bd_addr_t addr){ 3313 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3314 memcpy(sm_random_address, addr, 6); 3315 rau_state = RAU_SET_ADDRESS; 3316 sm_run(); 3317 } 3318 3319 /* 3320 * @brief Set Advertisement Paramters 3321 * @param adv_int_min 3322 * @param adv_int_max 3323 * @param adv_type 3324 * @param direct_address_type 3325 * @param direct_address 3326 * @param channel_map 3327 * @param filter_policy 3328 * 3329 * @note own_address_type is used from gap_random_address_set_mode 3330 */ 3331 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3332 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3333 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3334 direct_address_typ, direct_address, channel_map, filter_policy); 3335 } 3336 3337