1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "ble/le_device_db.h" 43 #include "ble/core.h" 44 #include "ble/sm.h" 45 #include "btstack_debug.h" 46 #include "btstack_event.h" 47 #include "btstack_linked_list.h" 48 #include "btstack_memory.h" 49 #include "gap.h" 50 #include "hci.h" 51 #include "l2cap.h" 52 53 #ifdef ENABLE_LE_SECURE_CONNECTIONS 54 // TODO: remove software AES 55 #include "rijndael.h" 56 #endif 57 58 #if defined(ENABLE_LE_SECURE_CONNECTIONS) && !defined(HAVE_HCI_CONTROLLER_DHKEY_SUPPORT) 59 #define USE_MBEDTLS_FOR_ECDH 60 #endif 61 62 // Software ECDH implementation provided by mbedtls 63 #ifdef USE_MBEDTLS_FOR_ECDH 64 #if !defined(MBEDTLS_CONFIG_FILE) 65 #include "mbedtls/config.h" 66 #else 67 #include MBEDTLS_CONFIG_FILE 68 #endif 69 #if defined(MBEDTLS_PLATFORM_C) 70 #include "mbedtls/platform.h" 71 #else 72 #include <stdio.h> 73 #define mbedtls_printf printf 74 #endif 75 #include "mbedtls/ecp.h" 76 #endif 77 78 // 79 // SM internal types and globals 80 // 81 82 typedef enum { 83 DKG_W4_WORKING, 84 DKG_CALC_IRK, 85 DKG_W4_IRK, 86 DKG_CALC_DHK, 87 DKG_W4_DHK, 88 DKG_READY 89 } derived_key_generation_t; 90 91 typedef enum { 92 RAU_W4_WORKING, 93 RAU_IDLE, 94 RAU_GET_RANDOM, 95 RAU_W4_RANDOM, 96 RAU_GET_ENC, 97 RAU_W4_ENC, 98 RAU_SET_ADDRESS, 99 } random_address_update_t; 100 101 typedef enum { 102 CMAC_IDLE, 103 CMAC_CALC_SUBKEYS, 104 CMAC_W4_SUBKEYS, 105 CMAC_CALC_MI, 106 CMAC_W4_MI, 107 CMAC_CALC_MLAST, 108 CMAC_W4_MLAST 109 } cmac_state_t; 110 111 typedef enum { 112 JUST_WORKS, 113 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 114 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 115 OK_BOTH_INPUT, // Only input on both, both input PK 116 NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides 117 OOB // OOB available on both sides 118 } stk_generation_method_t; 119 120 typedef enum { 121 SM_USER_RESPONSE_IDLE, 122 SM_USER_RESPONSE_PENDING, 123 SM_USER_RESPONSE_CONFIRM, 124 SM_USER_RESPONSE_PASSKEY, 125 SM_USER_RESPONSE_DECLINE 126 } sm_user_response_t; 127 128 typedef enum { 129 SM_AES128_IDLE, 130 SM_AES128_ACTIVE 131 } sm_aes128_state_t; 132 133 typedef enum { 134 ADDRESS_RESOLUTION_IDLE, 135 ADDRESS_RESOLUTION_GENERAL, 136 ADDRESS_RESOLUTION_FOR_CONNECTION, 137 } address_resolution_mode_t; 138 139 typedef enum { 140 ADDRESS_RESOLUTION_SUCEEDED, 141 ADDRESS_RESOLUTION_FAILED, 142 } address_resolution_event_t; 143 // 144 // GLOBAL DATA 145 // 146 147 static uint8_t test_use_fixed_local_csrk; 148 149 // configuration 150 static uint8_t sm_accepted_stk_generation_methods; 151 static uint8_t sm_max_encryption_key_size; 152 static uint8_t sm_min_encryption_key_size; 153 static uint8_t sm_auth_req = 0; 154 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 155 static uint8_t sm_slave_request_security; 156 157 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 158 static sm_key_t sm_persistent_er; 159 static sm_key_t sm_persistent_ir; 160 161 // derived from sm_persistent_ir 162 static sm_key_t sm_persistent_dhk; 163 static sm_key_t sm_persistent_irk; 164 static uint8_t sm_persistent_irk_ready = 0; // used for testing 165 static derived_key_generation_t dkg_state; 166 167 // derived from sm_persistent_er 168 // .. 169 170 // random address update 171 static random_address_update_t rau_state; 172 static bd_addr_t sm_random_address; 173 174 // CMAC Calculation: General 175 static cmac_state_t sm_cmac_state; 176 static uint16_t sm_cmac_message_len; 177 static sm_key_t sm_cmac_k; 178 static sm_key_t sm_cmac_x; 179 static sm_key_t sm_cmac_m_last; 180 static uint8_t sm_cmac_block_current; 181 static uint8_t sm_cmac_block_count; 182 static uint8_t (*sm_cmac_get_byte)(uint16_t offset); 183 static void (*sm_cmac_done_handler)(uint8_t * hash); 184 185 // CMAC for ATT Signed Writes 186 static uint8_t sm_cmac_header[3]; 187 static const uint8_t * sm_cmac_message; 188 static uint8_t sm_cmac_sign_counter[4]; 189 190 // CMAC for Secure Connection functions 191 #ifdef ENABLE_LE_SECURE_CONNECTIONS 192 static sm_connection_t * sm_cmac_connection; 193 static uint8_t sm_cmac_sc_buffer[80]; 194 #endif 195 196 // resolvable private address lookup / CSRK calculation 197 static int sm_address_resolution_test; 198 static int sm_address_resolution_ah_calculation_active; 199 static uint8_t sm_address_resolution_addr_type; 200 static bd_addr_t sm_address_resolution_address; 201 static void * sm_address_resolution_context; 202 static address_resolution_mode_t sm_address_resolution_mode; 203 static btstack_linked_list_t sm_address_resolution_general_queue; 204 205 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 206 static sm_aes128_state_t sm_aes128_state; 207 static void * sm_aes128_context; 208 209 // random engine. store context (ususally sm_connection_t) 210 static void * sm_random_context; 211 212 // to receive hci events 213 static btstack_packet_callback_registration_t hci_event_callback_registration; 214 215 /* to dispatch sm event */ 216 static btstack_linked_list_t sm_event_handlers; 217 218 // Software ECDH implementation provided by mbedtls 219 #ifdef USE_MBEDTLS_FOR_ECDH 220 mbedtls_ecp_keypair le_keypair; 221 #endif 222 223 // 224 // Volume 3, Part H, Chapter 24 225 // "Security shall be initiated by the Security Manager in the device in the master role. 226 // The device in the slave role shall be the responding device." 227 // -> master := initiator, slave := responder 228 // 229 230 // data needed for security setup 231 typedef struct sm_setup_context { 232 233 btstack_timer_source_t sm_timeout; 234 235 // used in all phases 236 uint8_t sm_pairing_failed_reason; 237 238 // user response, (Phase 1 and/or 2) 239 uint8_t sm_user_response; 240 241 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 242 int sm_key_distribution_send_set; 243 int sm_key_distribution_received_set; 244 245 // Phase 2 (Pairing over SMP) 246 stk_generation_method_t sm_stk_generation_method; 247 sm_key_t sm_tk; 248 uint8_t sm_use_secure_connections; 249 250 sm_key_t sm_c1_t3_value; // c1 calculation 251 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 252 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 253 sm_key_t sm_local_random; 254 sm_key_t sm_local_confirm; 255 sm_key_t sm_peer_random; 256 sm_key_t sm_peer_confirm; 257 uint8_t sm_m_addr_type; // address and type can be removed 258 uint8_t sm_s_addr_type; // '' 259 bd_addr_t sm_m_address; // '' 260 bd_addr_t sm_s_address; // '' 261 sm_key_t sm_ltk; 262 263 #ifdef ENABLE_LE_SECURE_CONNECTIONS 264 uint8_t sm_peer_qx[32]; 265 uint8_t sm_peer_qy[32]; 266 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 267 sm_key_t sm_local_nonce; // might be combined with sm_local_random 268 sm_key_t sm_peer_dhkey_check; 269 sm_key_t sm_local_dhkey_check; 270 sm_key_t sm_ra; 271 sm_key_t sm_rb; 272 sm_key_t sm_mackey; 273 uint8_t sm_passkey_bit; 274 #endif 275 276 // Phase 3 277 278 // key distribution, we generate 279 uint16_t sm_local_y; 280 uint16_t sm_local_div; 281 uint16_t sm_local_ediv; 282 uint8_t sm_local_rand[8]; 283 sm_key_t sm_local_ltk; 284 sm_key_t sm_local_csrk; 285 sm_key_t sm_local_irk; 286 // sm_local_address/addr_type not needed 287 288 // key distribution, received from peer 289 uint16_t sm_peer_y; 290 uint16_t sm_peer_div; 291 uint16_t sm_peer_ediv; 292 uint8_t sm_peer_rand[8]; 293 sm_key_t sm_peer_ltk; 294 sm_key_t sm_peer_irk; 295 sm_key_t sm_peer_csrk; 296 uint8_t sm_peer_addr_type; 297 bd_addr_t sm_peer_address; 298 299 } sm_setup_context_t; 300 301 // 302 static sm_setup_context_t the_setup; 303 static sm_setup_context_t * setup = &the_setup; 304 305 // active connection - the one for which the_setup is used for 306 static uint16_t sm_active_connection = 0; 307 308 // @returns 1 if oob data is available 309 // stores oob data in provided 16 byte buffer if not null 310 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 311 312 // used to notify applicationss that user interaction is neccessary, see sm_notify_t below 313 static btstack_packet_handler_t sm_client_packet_handler = NULL; 314 315 // horizontal: initiator capabilities 316 // vertial: responder capabilities 317 static const stk_generation_method_t stk_generation_method [5] [5] = { 318 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 319 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 320 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 321 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 322 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 323 }; 324 325 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 326 #ifdef ENABLE_LE_SECURE_CONNECTIONS 327 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 328 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 329 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 330 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 331 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 332 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 333 }; 334 #endif 335 336 static void sm_run(void); 337 static void sm_done_for_handle(hci_con_handle_t con_handle); 338 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 339 static inline int sm_calc_actual_encryption_key_size(int other); 340 static int sm_validate_stk_generation_method(void); 341 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 342 343 static void log_info_hex16(const char * name, uint16_t value){ 344 log_info("%-6s 0x%04x", name, value); 345 } 346 347 // @returns 1 if all bytes are 0 348 static int sm_is_null_random(uint8_t random[8]){ 349 int i; 350 for (i=0; i < 8 ; i++){ 351 if (random[i]) return 0; 352 } 353 return 1; 354 } 355 356 // Key utils 357 static void sm_reset_tk(void){ 358 int i; 359 for (i=0;i<16;i++){ 360 setup->sm_tk[i] = 0; 361 } 362 } 363 364 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 365 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 366 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 367 int i; 368 for (i = max_encryption_size ; i < 16 ; i++){ 369 key[15-i] = 0; 370 } 371 } 372 373 // SMP Timeout implementation 374 375 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 376 // the Security Manager Timer shall be reset and started. 377 // 378 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 379 // 380 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 381 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 382 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 383 // established. 384 385 static void sm_timeout_handler(btstack_timer_source_t * timer){ 386 log_info("SM timeout"); 387 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 388 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 389 sm_done_for_handle(sm_conn->sm_handle); 390 391 // trigger handling of next ready connection 392 sm_run(); 393 } 394 static void sm_timeout_start(sm_connection_t * sm_conn){ 395 btstack_run_loop_remove_timer(&setup->sm_timeout); 396 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 397 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 398 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 399 btstack_run_loop_add_timer(&setup->sm_timeout); 400 } 401 static void sm_timeout_stop(void){ 402 btstack_run_loop_remove_timer(&setup->sm_timeout); 403 } 404 static void sm_timeout_reset(sm_connection_t * sm_conn){ 405 sm_timeout_stop(); 406 sm_timeout_start(sm_conn); 407 } 408 409 // end of sm timeout 410 411 // GAP Random Address updates 412 static gap_random_address_type_t gap_random_adress_type; 413 static btstack_timer_source_t gap_random_address_update_timer; 414 static uint32_t gap_random_adress_update_period; 415 416 static void gap_random_address_trigger(void){ 417 if (rau_state != RAU_IDLE) return; 418 log_info("gap_random_address_trigger"); 419 rau_state = RAU_GET_RANDOM; 420 sm_run(); 421 } 422 423 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 424 log_info("GAP Random Address Update due"); 425 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 426 btstack_run_loop_add_timer(&gap_random_address_update_timer); 427 gap_random_address_trigger(); 428 } 429 430 static void gap_random_address_update_start(void){ 431 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 432 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 433 btstack_run_loop_add_timer(&gap_random_address_update_timer); 434 } 435 436 static void gap_random_address_update_stop(void){ 437 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 438 } 439 440 441 static void sm_random_start(void * context){ 442 sm_random_context = context; 443 hci_send_cmd(&hci_le_rand); 444 } 445 446 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 447 // context is made availabe to aes128 result handler by this 448 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 449 sm_aes128_state = SM_AES128_ACTIVE; 450 sm_key_t key_flipped, plaintext_flipped; 451 reverse_128(key, key_flipped); 452 reverse_128(plaintext, plaintext_flipped); 453 sm_aes128_context = context; 454 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 455 } 456 457 // ah(k,r) helper 458 // r = padding || r 459 // r - 24 bit value 460 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 461 // r'= padding || r 462 memset(r_prime, 0, 16); 463 memcpy(&r_prime[13], r, 3); 464 } 465 466 // d1 helper 467 // d' = padding || r || d 468 // d,r - 16 bit values 469 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 470 // d'= padding || r || d 471 memset(d1_prime, 0, 16); 472 big_endian_store_16(d1_prime, 12, r); 473 big_endian_store_16(d1_prime, 14, d); 474 } 475 476 // dm helper 477 // r’ = padding || r 478 // r - 64 bit value 479 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 480 memset(r_prime, 0, 16); 481 memcpy(&r_prime[8], r, 8); 482 } 483 484 // calculate arguments for first AES128 operation in C1 function 485 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, sm_key_t t1){ 486 487 // p1 = pres || preq || rat’ || iat’ 488 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 489 // cant octet of pres becomes the most significant octet of p1. 490 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 491 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 492 // p1 is 0x05000800000302070710000001010001." 493 494 sm_key_t p1; 495 reverse_56(pres, &p1[0]); 496 reverse_56(preq, &p1[7]); 497 p1[14] = rat; 498 p1[15] = iat; 499 log_info_key("p1", p1); 500 log_info_key("r", r); 501 502 // t1 = r xor p1 503 int i; 504 for (i=0;i<16;i++){ 505 t1[i] = r[i] ^ p1[i]; 506 } 507 log_info_key("t1", t1); 508 } 509 510 // calculate arguments for second AES128 operation in C1 function 511 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 512 // p2 = padding || ia || ra 513 // "The least significant octet of ra becomes the least significant octet of p2 and 514 // the most significant octet of padding becomes the most significant octet of p2. 515 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 516 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 517 518 sm_key_t p2; 519 memset(p2, 0, 16); 520 memcpy(&p2[4], ia, 6); 521 memcpy(&p2[10], ra, 6); 522 log_info_key("p2", p2); 523 524 // c1 = e(k, t2_xor_p2) 525 int i; 526 for (i=0;i<16;i++){ 527 t3[i] = t2[i] ^ p2[i]; 528 } 529 log_info_key("t3", t3); 530 } 531 532 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 533 log_info_key("r1", r1); 534 log_info_key("r2", r2); 535 memcpy(&r_prime[8], &r2[8], 8); 536 memcpy(&r_prime[0], &r1[8], 8); 537 } 538 539 #ifdef ENABLE_LE_SECURE_CONNECTIONS 540 // Software implementations of crypto toolbox for LE Secure Connection 541 // TODO: replace with code to use AES Engine of HCI Controller 542 typedef uint8_t sm_key24_t[3]; 543 typedef uint8_t sm_key56_t[7]; 544 typedef uint8_t sm_key256_t[32]; 545 546 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 547 uint32_t rk[RKLENGTH(KEYBITS)]; 548 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 549 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 550 } 551 552 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 553 memcpy(k1, k0, 16); 554 sm_shift_left_by_one_bit_inplace(16, k1); 555 if (k0[0] & 0x80){ 556 k1[15] ^= 0x87; 557 } 558 memcpy(k2, k1, 16); 559 sm_shift_left_by_one_bit_inplace(16, k2); 560 if (k1[0] & 0x80){ 561 k2[15] ^= 0x87; 562 } 563 } 564 565 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 566 sm_key_t k0, k1, k2, zero; 567 memset(zero, 0, 16); 568 569 aes128_calc_cyphertext(key, zero, k0); 570 calc_subkeys(k0, k1, k2); 571 572 int cmac_block_count = (cmac_message_len + 15) / 16; 573 574 // step 3: .. 575 if (cmac_block_count==0){ 576 cmac_block_count = 1; 577 } 578 579 // step 4: set m_last 580 sm_key_t cmac_m_last; 581 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 582 int i; 583 if (sm_cmac_last_block_complete){ 584 for (i=0;i<16;i++){ 585 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 586 } 587 } else { 588 int valid_octets_in_last_block = cmac_message_len & 0x0f; 589 for (i=0;i<16;i++){ 590 if (i < valid_octets_in_last_block){ 591 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 592 continue; 593 } 594 if (i == valid_octets_in_last_block){ 595 cmac_m_last[i] = 0x80 ^ k2[i]; 596 continue; 597 } 598 cmac_m_last[i] = k2[i]; 599 } 600 } 601 602 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 603 // LOG_KEY(cmac_m_last); 604 605 // Step 5 606 sm_key_t cmac_x; 607 memset(cmac_x, 0, 16); 608 609 // Step 6 610 sm_key_t sm_cmac_y; 611 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 612 for (i=0;i<16;i++){ 613 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 614 } 615 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 616 } 617 for (i=0;i<16;i++){ 618 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 619 } 620 621 // Step 7 622 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 623 } 624 625 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){ 626 uint8_t buffer[65]; 627 memcpy(buffer, u, 32); 628 memcpy(buffer+32, v, 32); 629 buffer[64] = z; 630 log_info("f4 key"); 631 log_info_hexdump(x, 16); 632 log_info("f4 message"); 633 log_info_hexdump(buffer, sizeof(buffer)); 634 aes_cmac(res, x, buffer, sizeof(buffer)); 635 log_info("f4 result"); 636 log_info_hexdump(res, sizeof(sm_key_t)); 637 } 638 639 const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 640 const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 641 const uint8_t f5_length[] = { 0x01, 0x00}; 642 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){ 643 // T = AES-CMACSAL_T(W) 644 sm_key_t t; 645 aes_cmac(t, f5_salt, w, 32); 646 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 647 uint8_t buffer[53]; 648 buffer[0] = 0; 649 memcpy(buffer+01, f5_key_id, 4); 650 memcpy(buffer+05, n1, 16); 651 memcpy(buffer+21, n2, 16); 652 memcpy(buffer+37, a1, 7); 653 memcpy(buffer+44, a2, 7); 654 memcpy(buffer+51, f5_length, 2); 655 log_info("f5 DHKEY"); 656 log_info_hexdump(w, 32); 657 log_info("f5 key"); 658 log_info_hexdump(t, 16); 659 log_info("f5 message for MacKey"); 660 log_info_hexdump(buffer, sizeof(buffer)); 661 aes_cmac(res, t, buffer, sizeof(buffer)); 662 // hexdump2(res, 16); 663 // || AES-CMACT (Counter = 1 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the LTK 664 buffer[0] = 1; 665 // hexdump2(buffer, sizeof(buffer)); 666 log_info("f5 message for LTK"); 667 log_info_hexdump(buffer, sizeof(buffer)); 668 aes_cmac(res+16, t, buffer, sizeof(buffer)); 669 // hexdump2(res+16, 16); 670 } 671 672 // f6(W, N1, N2, R, IOcap, A1, A2) = AES-CMACW (N1 || N2 || R || IOcap || A1 || A2 673 // - W is 128 bits 674 // - N1 is 128 bits 675 // - N2 is 128 bits 676 // - R is 128 bits 677 // - IOcap is 24 bits 678 // - A1 is 56 bits 679 // - A2 is 56 bits 680 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){ 681 uint8_t buffer[65]; 682 memcpy(buffer, n1, 16); 683 memcpy(buffer+16, n2, 16); 684 memcpy(buffer+32, r, 16); 685 memcpy(buffer+48, io_cap, 3); 686 memcpy(buffer+51, a1, 7); 687 memcpy(buffer+58, a2, 7); 688 log_info("f6 key"); 689 log_info_hexdump(w, 16); 690 log_info("f6 message"); 691 log_info_hexdump(buffer, sizeof(buffer)); 692 aes_cmac(res, w, buffer,sizeof(buffer)); 693 log_info("f6 result"); 694 log_info_hexdump(res, 16); 695 } 696 697 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 698 // - U is 256 bits 699 // - V is 256 bits 700 // - X is 128 bits 701 // - Y is 128 bits 702 static uint32_t g2(const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 703 uint8_t buffer[80]; 704 memcpy(buffer, u, 32); 705 memcpy(buffer+32, v, 32); 706 memcpy(buffer+64, y, 16); 707 sm_key_t cmac; 708 log_info("g2 key"); 709 log_info_hexdump(x, 16); 710 log_info("g2 message"); 711 log_info_hexdump(buffer, sizeof(buffer)); 712 aes_cmac(cmac, x, buffer, sizeof(buffer)); 713 log_info("g2 result"); 714 log_info_hexdump(x, 16); 715 return big_endian_read_32(cmac, 12); 716 } 717 718 #if 0 719 // h6(W, keyID) = AES-CMACW(keyID) 720 // - W is 128 bits 721 // - keyID is 32 bits 722 static void h6(sm_key_t res, const sm_key_t w, const uint32_t key_id){ 723 uint8_t key_id_buffer[4]; 724 big_endian_store_32(key_id_buffer, 0, key_id); 725 aes_cmac(res, w, key_id_buffer, 4); 726 } 727 #endif 728 #endif 729 730 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){ 731 event[0] = type; 732 event[1] = event_size - 2; 733 little_endian_store_16(event, 2, con_handle); 734 event[4] = addr_type; 735 reverse_bd_addr(address, &event[5]); 736 } 737 738 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 739 if (sm_client_packet_handler) { 740 sm_client_packet_handler(HCI_EVENT_PACKET, 0, packet, size); 741 } 742 // dispatch to all event handlers 743 btstack_linked_list_iterator_t it; 744 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 745 while (btstack_linked_list_iterator_has_next(&it)){ 746 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 747 entry->callback(packet_type, 0, packet, size); 748 } 749 } 750 751 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 752 uint8_t event[11]; 753 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 754 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 755 } 756 757 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){ 758 uint8_t event[15]; 759 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 760 little_endian_store_32(event, 11, passkey); 761 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 762 } 763 764 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){ 765 uint8_t event[13]; 766 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 767 little_endian_store_16(event, 11, index); 768 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 769 } 770 771 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){ 772 773 uint8_t event[18]; 774 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 775 event[11] = result; 776 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 777 } 778 779 // decide on stk generation based on 780 // - pairing request 781 // - io capabilities 782 // - OOB data availability 783 static void sm_setup_tk(void){ 784 785 // default: just works 786 setup->sm_stk_generation_method = JUST_WORKS; 787 788 #ifdef ENABLE_LE_SECURE_CONNECTIONS 789 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 790 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 791 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 792 memset(setup->sm_ra, 0, 16); 793 memset(setup->sm_rb, 0, 16); 794 #else 795 setup->sm_use_secure_connections = 0; 796 #endif 797 798 // If both devices have not set the MITM option in the Authentication Requirements 799 // Flags, then the IO capabilities shall be ignored and the Just Works association 800 // model shall be used. 801 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 802 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 803 log_info("SM: MITM not required by both -> JUST WORKS"); 804 return; 805 } 806 807 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 808 809 // If both devices have out of band authentication data, then the Authentication 810 // Requirements Flags shall be ignored when selecting the pairing method and the 811 // Out of Band pairing method shall be used. 812 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 813 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 814 log_info("SM: have OOB data"); 815 log_info_key("OOB", setup->sm_tk); 816 setup->sm_stk_generation_method = OOB; 817 return; 818 } 819 820 // Reset TK as it has been setup in sm_init_setup 821 sm_reset_tk(); 822 823 // Also use just works if unknown io capabilites 824 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)){ 825 return; 826 } 827 828 // Otherwise the IO capabilities of the devices shall be used to determine the 829 // pairing method as defined in Table 2.4. 830 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 831 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 832 833 #ifdef ENABLE_LE_SECURE_CONNECTIONS 834 // table not define by default 835 if (setup->sm_use_secure_connections){ 836 generation_method = stk_generation_method_with_secure_connection; 837 } 838 #endif 839 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)]; 840 841 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 842 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); 843 } 844 845 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 846 int flags = 0; 847 if (key_set & SM_KEYDIST_ENC_KEY){ 848 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 849 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 850 } 851 if (key_set & SM_KEYDIST_ID_KEY){ 852 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 853 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 854 } 855 if (key_set & SM_KEYDIST_SIGN){ 856 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 857 } 858 return flags; 859 } 860 861 static void sm_setup_key_distribution(uint8_t key_set){ 862 setup->sm_key_distribution_received_set = 0; 863 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 864 } 865 866 // CSRK Key Lookup 867 868 869 static int sm_address_resolution_idle(void){ 870 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 871 } 872 873 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){ 874 memcpy(sm_address_resolution_address, addr, 6); 875 sm_address_resolution_addr_type = addr_type; 876 sm_address_resolution_test = 0; 877 sm_address_resolution_mode = mode; 878 sm_address_resolution_context = context; 879 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 880 } 881 882 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 883 // check if already in list 884 btstack_linked_list_iterator_t it; 885 sm_lookup_entry_t * entry; 886 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 887 while(btstack_linked_list_iterator_has_next(&it)){ 888 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 889 if (entry->address_type != address_type) continue; 890 if (memcmp(entry->address, address, 6)) continue; 891 // already in list 892 return BTSTACK_BUSY; 893 } 894 entry = btstack_memory_sm_lookup_entry_get(); 895 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 896 entry->address_type = (bd_addr_type_t) address_type; 897 memcpy(entry->address, address, 6); 898 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 899 sm_run(); 900 return 0; 901 } 902 903 // CMAC Implementation using AES128 engine 904 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 905 int i; 906 int carry = 0; 907 for (i=len-1; i >= 0 ; i--){ 908 int new_carry = data[i] >> 7; 909 data[i] = data[i] << 1 | carry; 910 carry = new_carry; 911 } 912 } 913 914 // 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 915 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 916 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 917 } 918 static inline void dkg_next_state(void){ 919 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 920 } 921 static inline void rau_next_state(void){ 922 rau_state = (random_address_update_t) (((int)rau_state) + 1); 923 } 924 925 // CMAC calculation using AES Engine 926 927 static inline void sm_cmac_next_state(void){ 928 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 929 } 930 931 static int sm_cmac_last_block_complete(void){ 932 if (sm_cmac_message_len == 0) return 0; 933 return (sm_cmac_message_len & 0x0f) == 0; 934 } 935 936 static inline uint8_t sm_cmac_message_get_byte(uint16_t offset){ 937 if (offset >= sm_cmac_message_len) { 938 log_error("sm_cmac_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 939 return 0; 940 } 941 942 offset = sm_cmac_message_len - 1 - offset; 943 944 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 945 if (offset < 3){ 946 return sm_cmac_header[offset]; 947 } 948 int actual_message_len_incl_header = sm_cmac_message_len - 4; 949 if (offset < actual_message_len_incl_header){ 950 return sm_cmac_message[offset - 3]; 951 } 952 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 953 } 954 955 // generic cmac calculation 956 void sm_cmac_general_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t hash[8])){ 957 // Generalized CMAC 958 memcpy(sm_cmac_k, key, 16); 959 memset(sm_cmac_x, 0, 16); 960 sm_cmac_block_current = 0; 961 sm_cmac_message_len = message_len; 962 sm_cmac_done_handler = done_callback; 963 sm_cmac_get_byte = get_byte_callback; 964 965 // step 2: n := ceil(len/const_Bsize); 966 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 967 968 // step 3: .. 969 if (sm_cmac_block_count==0){ 970 sm_cmac_block_count = 1; 971 } 972 973 log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 974 975 // first, we need to compute l for k1, k2, and m_last 976 sm_cmac_state = CMAC_CALC_SUBKEYS; 977 978 // let's go 979 sm_run(); 980 } 981 982 // cmac for ATT Message signing 983 void sm_cmac_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 984 // ATT Message Signing 985 sm_cmac_header[0] = opcode; 986 little_endian_store_16(sm_cmac_header, 1, con_handle); 987 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 988 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 989 sm_cmac_message = message; 990 sm_cmac_general_start(k, total_message_len, &sm_cmac_message_get_byte, done_handler); 991 } 992 993 int sm_cmac_ready(void){ 994 return sm_cmac_state == CMAC_IDLE; 995 } 996 997 static void sm_cmac_handle_aes_engine_ready(void){ 998 switch (sm_cmac_state){ 999 case CMAC_CALC_SUBKEYS: { 1000 sm_key_t const_zero; 1001 memset(const_zero, 0, 16); 1002 sm_cmac_next_state(); 1003 sm_aes128_start(sm_cmac_k, const_zero, NULL); 1004 break; 1005 } 1006 case CMAC_CALC_MI: { 1007 int j; 1008 sm_key_t y; 1009 for (j=0;j<16;j++){ 1010 y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); 1011 } 1012 sm_cmac_block_current++; 1013 sm_cmac_next_state(); 1014 sm_aes128_start(sm_cmac_k, y, NULL); 1015 break; 1016 } 1017 case CMAC_CALC_MLAST: { 1018 int i; 1019 sm_key_t y; 1020 for (i=0;i<16;i++){ 1021 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 1022 } 1023 log_info_key("Y", y); 1024 sm_cmac_block_current++; 1025 sm_cmac_next_state(); 1026 sm_aes128_start(sm_cmac_k, y, NULL); 1027 break; 1028 } 1029 default: 1030 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 1031 break; 1032 } 1033 } 1034 1035 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1036 switch (sm_cmac_state){ 1037 case CMAC_W4_SUBKEYS: { 1038 sm_key_t k1; 1039 memcpy(k1, data, 16); 1040 sm_shift_left_by_one_bit_inplace(16, k1); 1041 if (data[0] & 0x80){ 1042 k1[15] ^= 0x87; 1043 } 1044 sm_key_t k2; 1045 memcpy(k2, k1, 16); 1046 sm_shift_left_by_one_bit_inplace(16, k2); 1047 if (k1[0] & 0x80){ 1048 k2[15] ^= 0x87; 1049 } 1050 1051 log_info_key("k", sm_cmac_k); 1052 log_info_key("k1", k1); 1053 log_info_key("k2", k2); 1054 1055 // step 4: set m_last 1056 int i; 1057 if (sm_cmac_last_block_complete()){ 1058 for (i=0;i<16;i++){ 1059 sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1060 } 1061 } else { 1062 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1063 for (i=0;i<16;i++){ 1064 if (i < valid_octets_in_last_block){ 1065 sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1066 continue; 1067 } 1068 if (i == valid_octets_in_last_block){ 1069 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1070 continue; 1071 } 1072 sm_cmac_m_last[i] = k2[i]; 1073 } 1074 } 1075 1076 // next 1077 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1078 break; 1079 } 1080 case CMAC_W4_MI: 1081 memcpy(sm_cmac_x, data, 16); 1082 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1083 break; 1084 case CMAC_W4_MLAST: 1085 // done 1086 log_info_key("CMAC", data); 1087 sm_cmac_done_handler(data); 1088 sm_cmac_state = CMAC_IDLE; 1089 break; 1090 default: 1091 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1092 break; 1093 } 1094 } 1095 1096 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1097 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1098 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1099 switch (setup->sm_stk_generation_method){ 1100 case PK_RESP_INPUT: 1101 if (sm_conn->sm_role){ 1102 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1103 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1104 } else { 1105 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)); 1106 } 1107 break; 1108 case PK_INIT_INPUT: 1109 if (sm_conn->sm_role){ 1110 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)); 1111 } else { 1112 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1113 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1114 } 1115 break; 1116 case OK_BOTH_INPUT: 1117 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1118 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1119 break; 1120 case NK_BOTH_INPUT: 1121 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1122 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)); 1123 break; 1124 case JUST_WORKS: 1125 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1126 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1127 break; 1128 case OOB: 1129 // client already provided OOB data, let's skip notification. 1130 break; 1131 } 1132 } 1133 1134 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1135 int recv_flags; 1136 if (sm_conn->sm_role){ 1137 // slave / responder 1138 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1139 } else { 1140 // master / initiator 1141 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1142 } 1143 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1144 return recv_flags == setup->sm_key_distribution_received_set; 1145 } 1146 1147 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1148 if (sm_active_connection == con_handle){ 1149 sm_timeout_stop(); 1150 sm_active_connection = 0; 1151 log_info("sm: connection 0x%x released setup context", con_handle); 1152 } 1153 } 1154 1155 static int sm_key_distribution_flags_for_auth_req(void){ 1156 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1157 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1158 // encryption information only if bonding requested 1159 flags |= SM_KEYDIST_ENC_KEY; 1160 } 1161 return flags; 1162 } 1163 1164 static void sm_init_setup(sm_connection_t * sm_conn){ 1165 1166 // fill in sm setup 1167 sm_reset_tk(); 1168 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1169 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1170 1171 // query client for OOB data 1172 int have_oob_data = 0; 1173 if (sm_get_oob_data) { 1174 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1175 } 1176 1177 sm_pairing_packet_t * local_packet; 1178 if (sm_conn->sm_role){ 1179 // slave 1180 local_packet = &setup->sm_s_pres; 1181 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1182 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1183 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1184 } else { 1185 // master 1186 local_packet = &setup->sm_m_preq; 1187 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1188 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1189 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1190 1191 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1192 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1193 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1194 } 1195 1196 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1197 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1198 sm_pairing_packet_set_auth_req(*local_packet, sm_auth_req); 1199 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1200 } 1201 1202 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1203 1204 sm_pairing_packet_t * remote_packet; 1205 int remote_key_request; 1206 if (sm_conn->sm_role){ 1207 // slave / responder 1208 remote_packet = &setup->sm_m_preq; 1209 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1210 } else { 1211 // master / initiator 1212 remote_packet = &setup->sm_s_pres; 1213 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1214 } 1215 1216 // check key size 1217 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1218 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1219 1220 // decide on STK generation method 1221 sm_setup_tk(); 1222 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1223 1224 // check if STK generation method is acceptable by client 1225 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1226 1227 // identical to responder 1228 sm_setup_key_distribution(remote_key_request); 1229 1230 // JUST WORKS doens't provide authentication 1231 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1232 1233 return 0; 1234 } 1235 1236 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1237 1238 // cache and reset context 1239 int matched_device_id = sm_address_resolution_test; 1240 address_resolution_mode_t mode = sm_address_resolution_mode; 1241 void * context = sm_address_resolution_context; 1242 1243 // reset context 1244 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1245 sm_address_resolution_context = NULL; 1246 sm_address_resolution_test = -1; 1247 hci_con_handle_t con_handle = 0; 1248 1249 sm_connection_t * sm_connection; 1250 uint16_t ediv; 1251 switch (mode){ 1252 case ADDRESS_RESOLUTION_GENERAL: 1253 break; 1254 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1255 sm_connection = (sm_connection_t *) context; 1256 con_handle = sm_connection->sm_handle; 1257 switch (event){ 1258 case ADDRESS_RESOLUTION_SUCEEDED: 1259 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1260 sm_connection->sm_le_db_index = matched_device_id; 1261 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1262 if (sm_connection->sm_role) break; 1263 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1264 sm_connection->sm_security_request_received = 0; 1265 sm_connection->sm_bonding_requested = 0; 1266 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 1267 if (ediv){ 1268 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1269 } else { 1270 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1271 } 1272 break; 1273 case ADDRESS_RESOLUTION_FAILED: 1274 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1275 if (sm_connection->sm_role) break; 1276 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1277 sm_connection->sm_security_request_received = 0; 1278 sm_connection->sm_bonding_requested = 0; 1279 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1280 break; 1281 } 1282 break; 1283 default: 1284 break; 1285 } 1286 1287 switch (event){ 1288 case ADDRESS_RESOLUTION_SUCEEDED: 1289 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1290 break; 1291 case ADDRESS_RESOLUTION_FAILED: 1292 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1293 break; 1294 } 1295 } 1296 1297 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1298 1299 int le_db_index = -1; 1300 1301 // lookup device based on IRK 1302 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1303 int i; 1304 for (i=0; i < le_device_db_count(); i++){ 1305 sm_key_t irk; 1306 bd_addr_t address; 1307 int address_type; 1308 le_device_db_info(i, &address_type, address, irk); 1309 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1310 log_info("sm: device found for IRK, updating"); 1311 le_db_index = i; 1312 break; 1313 } 1314 } 1315 } 1316 1317 // if not found, lookup via public address if possible 1318 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1319 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1320 int i; 1321 for (i=0; i < le_device_db_count(); i++){ 1322 bd_addr_t address; 1323 int address_type; 1324 le_device_db_info(i, &address_type, address, NULL); 1325 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1326 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1327 log_info("sm: device found for public address, updating"); 1328 le_db_index = i; 1329 break; 1330 } 1331 } 1332 } 1333 1334 // if not found, add to db 1335 if (le_db_index < 0) { 1336 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1337 } 1338 1339 if (le_db_index >= 0){ 1340 le_device_db_local_counter_set(le_db_index, 0); 1341 1342 // store local CSRK 1343 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1344 log_info("sm: store local CSRK"); 1345 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1346 le_device_db_local_counter_set(le_db_index, 0); 1347 } 1348 1349 // store remote CSRK 1350 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1351 log_info("sm: store remote CSRK"); 1352 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1353 le_device_db_remote_counter_set(le_db_index, 0); 1354 } 1355 1356 // store encryption information 1357 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION 1358 && setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1359 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1360 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1361 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1362 } 1363 } 1364 1365 // keep le_db_index 1366 sm_conn->sm_le_db_index = le_db_index; 1367 } 1368 1369 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1370 static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ 1371 return sm_cmac_sc_buffer[offset]; 1372 } 1373 static void sm_sc_cmac_done(uint8_t * hash){ 1374 switch (sm_cmac_connection->sm_engine_state){ 1375 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1376 memcpy(setup->sm_local_confirm, hash, 16); 1377 sm_cmac_connection->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1378 break; 1379 default: 1380 log_error("sm_sc_cmac_done in state %u", sm_cmac_connection->sm_engine_state); 1381 break; 1382 } 1383 sm_cmac_connection = 0; 1384 sm_run(); 1385 } 1386 1387 static void f4_engine(sm_connection_t * sm_conn, sm_key_t res, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, uint8_t z){ 1388 sm_cmac_connection = sm_conn; 1389 memcpy(sm_cmac_sc_buffer, u, 32); 1390 memcpy(sm_cmac_sc_buffer+32, v, 32); 1391 sm_cmac_sc_buffer[64] = z; 1392 log_info("f4 key"); 1393 log_info_hexdump(x, 16); 1394 log_info("f4 message"); 1395 log_info_hexdump(sm_cmac_sc_buffer, sizeof(sm_cmac_sc_buffer)); 1396 sm_cmac_general_start(x, 65, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); 1397 } 1398 1399 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1400 uint8_t z = 0; 1401 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1402 // some form of passkey 1403 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1404 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1405 setup->sm_passkey_bit++; 1406 } 1407 #ifdef USE_MBEDTLS_FOR_ECDH 1408 uint8_t value[32]; 1409 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1410 #endif 1411 f4_engine(sm_conn, setup->sm_local_confirm, value, setup->sm_peer_qx, setup->sm_local_nonce, z); 1412 } 1413 #endif 1414 1415 static void sm_run(void){ 1416 1417 btstack_linked_list_iterator_t it; 1418 1419 // assert that we can send at least commands 1420 if (!hci_can_send_command_packet_now()) return; 1421 1422 // 1423 // non-connection related behaviour 1424 // 1425 1426 // distributed key generation 1427 switch (dkg_state){ 1428 case DKG_CALC_IRK: 1429 // already busy? 1430 if (sm_aes128_state == SM_AES128_IDLE) { 1431 // IRK = d1(IR, 1, 0) 1432 sm_key_t d1_prime; 1433 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1434 dkg_next_state(); 1435 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1436 return; 1437 } 1438 break; 1439 case DKG_CALC_DHK: 1440 // already busy? 1441 if (sm_aes128_state == SM_AES128_IDLE) { 1442 // DHK = d1(IR, 3, 0) 1443 sm_key_t d1_prime; 1444 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1445 dkg_next_state(); 1446 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1447 return; 1448 } 1449 break; 1450 default: 1451 break; 1452 } 1453 1454 // random address updates 1455 switch (rau_state){ 1456 case RAU_GET_RANDOM: 1457 rau_next_state(); 1458 sm_random_start(NULL); 1459 return; 1460 case RAU_GET_ENC: 1461 // already busy? 1462 if (sm_aes128_state == SM_AES128_IDLE) { 1463 sm_key_t r_prime; 1464 sm_ah_r_prime(sm_random_address, r_prime); 1465 rau_next_state(); 1466 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1467 return; 1468 } 1469 break; 1470 case RAU_SET_ADDRESS: 1471 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1472 rau_state = RAU_IDLE; 1473 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1474 return; 1475 default: 1476 break; 1477 } 1478 1479 // CMAC 1480 switch (sm_cmac_state){ 1481 case CMAC_CALC_SUBKEYS: 1482 case CMAC_CALC_MI: 1483 case CMAC_CALC_MLAST: 1484 // already busy? 1485 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1486 sm_cmac_handle_aes_engine_ready(); 1487 return; 1488 default: 1489 break; 1490 } 1491 1492 // CSRK Lookup 1493 // -- if csrk lookup ready, find connection that require csrk lookup 1494 if (sm_address_resolution_idle()){ 1495 hci_connections_get_iterator(&it); 1496 while(btstack_linked_list_iterator_has_next(&it)){ 1497 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1498 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1499 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1500 // and start lookup 1501 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); 1502 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1503 break; 1504 } 1505 } 1506 } 1507 1508 // -- if csrk lookup ready, resolved addresses for received addresses 1509 if (sm_address_resolution_idle()) { 1510 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1511 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1512 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1513 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1514 btstack_memory_sm_lookup_entry_free(entry); 1515 } 1516 } 1517 1518 // -- Continue with CSRK device lookup by public or resolvable private address 1519 if (!sm_address_resolution_idle()){ 1520 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1521 while (sm_address_resolution_test < le_device_db_count()){ 1522 int addr_type; 1523 bd_addr_t addr; 1524 sm_key_t irk; 1525 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1526 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1527 1528 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1529 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1530 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1531 break; 1532 } 1533 1534 if (sm_address_resolution_addr_type == 0){ 1535 sm_address_resolution_test++; 1536 continue; 1537 } 1538 1539 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1540 1541 log_info("LE Device Lookup: calculate AH"); 1542 log_info_key("IRK", irk); 1543 1544 sm_key_t r_prime; 1545 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1546 sm_address_resolution_ah_calculation_active = 1; 1547 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1548 return; 1549 } 1550 1551 if (sm_address_resolution_test >= le_device_db_count()){ 1552 log_info("LE Device Lookup: not found"); 1553 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1554 } 1555 } 1556 1557 1558 // 1559 // active connection handling 1560 // -- use loop to handle next connection if lock on setup context is released 1561 1562 while (1) { 1563 1564 // Find connections that requires setup context and make active if no other is locked 1565 hci_connections_get_iterator(&it); 1566 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1567 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1568 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1569 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1570 int done = 1; 1571 int err; 1572 int encryption_key_size; 1573 int authenticated; 1574 int authorized; 1575 switch (sm_connection->sm_engine_state) { 1576 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1577 // send packet if possible, 1578 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1579 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1580 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1581 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1582 } else { 1583 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1584 } 1585 // don't lock setup context yet 1586 done = 0; 1587 break; 1588 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1589 sm_init_setup(sm_connection); 1590 // recover pairing request 1591 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1592 err = sm_stk_generation_init(sm_connection); 1593 if (err){ 1594 setup->sm_pairing_failed_reason = err; 1595 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1596 break; 1597 } 1598 sm_timeout_start(sm_connection); 1599 // generate random number first, if we need to show passkey 1600 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1601 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1602 break; 1603 } 1604 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1605 break; 1606 case SM_INITIATOR_PH0_HAS_LTK: 1607 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1608 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1609 &encryption_key_size, &authenticated, &authorized); 1610 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1611 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1612 sm_connection->sm_connection_authenticated = authenticated; 1613 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1614 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1615 break; 1616 case SM_RESPONDER_PH0_RECEIVED_LTK: 1617 // re-establish previously used LTK using Rand and EDIV 1618 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1619 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1620 // re-establish used key encryption size 1621 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1622 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1623 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1624 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1625 log_info("sm: received ltk request with key size %u, authenticated %u", 1626 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1627 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1628 break; 1629 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1630 sm_init_setup(sm_connection); 1631 sm_timeout_start(sm_connection); 1632 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1633 break; 1634 default: 1635 done = 0; 1636 break; 1637 } 1638 if (done){ 1639 sm_active_connection = sm_connection->sm_handle; 1640 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1641 } 1642 } 1643 1644 // 1645 // active connection handling 1646 // 1647 1648 if (sm_active_connection == 0) return; 1649 1650 // assert that we could send a SM PDU - not needed for all of the following 1651 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1652 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1653 return; 1654 } 1655 1656 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1657 if (!connection) return; 1658 1659 sm_key_t plaintext; 1660 int key_distribution_flags; 1661 1662 log_info("sm_run: state %u", connection->sm_engine_state); 1663 1664 // responding state 1665 switch (connection->sm_engine_state){ 1666 1667 // general 1668 case SM_GENERAL_SEND_PAIRING_FAILED: { 1669 uint8_t buffer[2]; 1670 buffer[0] = SM_CODE_PAIRING_FAILED; 1671 buffer[1] = setup->sm_pairing_failed_reason; 1672 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1673 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1674 sm_done_for_handle(connection->sm_handle); 1675 break; 1676 } 1677 1678 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1679 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 1680 if (!sm_cmac_ready()) break; 1681 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 1682 sm_sc_calculate_local_confirm(connection); 1683 break; 1684 #endif 1685 // initiator side 1686 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1687 sm_key_t peer_ltk_flipped; 1688 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1689 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1690 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1691 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1692 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1693 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1694 return; 1695 } 1696 1697 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1698 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 1699 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1700 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1701 sm_timeout_reset(connection); 1702 break; 1703 1704 // responder side 1705 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1706 connection->sm_engine_state = SM_RESPONDER_IDLE; 1707 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1708 return; 1709 1710 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1711 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 1712 uint8_t buffer[65]; 1713 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 1714 // 1715 #ifdef USE_MBEDTLS_FOR_ECDH 1716 uint8_t value[32]; 1717 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1718 reverse_256(value, &buffer[1]); 1719 mbedtls_mpi_write_binary(&le_keypair.Q.Y, value, sizeof(value)); 1720 reverse_256(value, &buffer[33]); 1721 #endif 1722 // TODO: use random generator to generate nonce 1723 1724 // generate 128-bit nonce 1725 int i; 1726 for (i=0;i<16;i++){ 1727 setup->sm_local_nonce[i] = rand() & 0xff; 1728 } 1729 1730 // stk generation method 1731 // passkey entry: notify app to show passkey or to request passkey 1732 switch (setup->sm_stk_generation_method){ 1733 case JUST_WORKS: 1734 case NK_BOTH_INPUT: 1735 if (connection->sm_role){ 1736 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1737 } else { 1738 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1739 } 1740 break; 1741 case PK_INIT_INPUT: 1742 case PK_RESP_INPUT: 1743 case OK_BOTH_INPUT: 1744 // hack for testing: assume user entered '000000' 1745 // memset(setup->sm_tk, 0, 16); 1746 memcpy(setup->sm_ra, setup->sm_tk, 16); 1747 memcpy(setup->sm_rb, setup->sm_tk, 16); 1748 setup->sm_passkey_bit = 0; 1749 if (connection->sm_role){ 1750 // responder 1751 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1752 } else { 1753 // initiator 1754 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1755 } 1756 sm_trigger_user_response(connection); 1757 break; 1758 case OOB: 1759 // TODO: implement SC OOB 1760 break; 1761 } 1762 1763 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1764 sm_timeout_reset(connection); 1765 break; 1766 } 1767 case SM_SC_SEND_CONFIRMATION: { 1768 uint8_t buffer[17]; 1769 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1770 reverse_128(setup->sm_local_confirm, &buffer[1]); 1771 if (connection->sm_role){ 1772 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1773 } else { 1774 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1775 } 1776 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1777 sm_timeout_reset(connection); 1778 break; 1779 } 1780 case SM_SC_SEND_PAIRING_RANDOM: { 1781 uint8_t buffer[17]; 1782 buffer[0] = SM_CODE_PAIRING_RANDOM; 1783 reverse_128(setup->sm_local_nonce, &buffer[1]); 1784 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 1785 if (connection->sm_role){ 1786 // responder 1787 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 1788 } else { 1789 // initiator 1790 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1791 } 1792 } else { 1793 if (connection->sm_role){ 1794 // responder 1795 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1796 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 1797 // calc Vb if numeric comparison 1798 // TODO: use AES Engine to calculate g2 1799 uint8_t value[32]; 1800 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1801 uint32_t vb = g2(setup->sm_peer_qx, value, setup->sm_peer_nonce, setup->sm_local_nonce) % 1000000; 1802 big_endian_store_32(setup->sm_tk, 12, vb); 1803 sm_trigger_user_response(connection); 1804 } 1805 } else { 1806 // initiator 1807 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 1808 } 1809 } 1810 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1811 sm_timeout_reset(connection); 1812 break; 1813 } 1814 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 1815 1816 uint8_t buffer[17]; 1817 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 1818 #ifdef USE_MBEDTLS_FOR_ECDH 1819 // calculate DHKEY 1820 mbedtls_ecp_group grp; 1821 mbedtls_ecp_group_init( &grp ); 1822 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 1823 mbedtls_ecp_point Q; 1824 mbedtls_ecp_point_init( &Q ); 1825 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1826 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1827 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1828 1829 // da * Pb 1830 mbedtls_ecp_point DH; 1831 mbedtls_ecp_point_init( &DH ); 1832 mbedtls_ecp_mul(&grp, &DH, &le_keypair.d, &Q, NULL, NULL); 1833 sm_key256_t dhkey; 1834 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1835 log_info("dhkey"); 1836 log_info_hexdump(dhkey, 32); 1837 1838 // calculate LTK + MacKey 1839 sm_key256_t ltk_mackey; 1840 sm_key56_t bd_addr_master, bd_addr_slave; 1841 bd_addr_master[0] = setup->sm_m_addr_type; 1842 bd_addr_slave[0] = setup->sm_s_addr_type; 1843 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1844 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1845 if (connection->sm_role){ 1846 // responder 1847 f5(ltk_mackey, dhkey, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1848 } else { 1849 // initiator 1850 f5(ltk_mackey, dhkey, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1851 } 1852 // store LTK 1853 memcpy(setup->sm_ltk, <k_mackey[16], 16); 1854 1855 // calc DHKCheck 1856 memcpy(setup->sm_mackey, <k_mackey[0], 16); 1857 1858 // TODO: checks 1859 1860 uint8_t iocap_a[3]; 1861 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1862 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1863 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1864 uint8_t iocap_b[3]; 1865 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1866 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1867 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1868 if (connection->sm_role){ 1869 // responder 1870 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); 1871 } else { 1872 // initiator 1873 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); 1874 } 1875 #endif 1876 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 1877 if (connection->sm_role){ 1878 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 1879 } else { 1880 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1881 } 1882 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1883 sm_timeout_reset(connection); 1884 break; 1885 } 1886 1887 #endif 1888 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 1889 // echo initiator for now 1890 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 1891 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1892 1893 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 1894 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1895 if (setup->sm_use_secure_connections){ 1896 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 1897 // skip LTK/EDIV for SC 1898 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 1899 } 1900 #endif 1901 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); 1902 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); 1903 1904 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 1905 sm_timeout_reset(connection); 1906 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 1907 if (setup->sm_stk_generation_method == JUST_WORKS){ 1908 sm_trigger_user_response(connection); 1909 } 1910 return; 1911 1912 case SM_PH2_SEND_PAIRING_RANDOM: { 1913 uint8_t buffer[17]; 1914 buffer[0] = SM_CODE_PAIRING_RANDOM; 1915 reverse_128(setup->sm_local_random, &buffer[1]); 1916 if (connection->sm_role){ 1917 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 1918 } else { 1919 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 1920 } 1921 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1922 sm_timeout_reset(connection); 1923 break; 1924 } 1925 1926 case SM_PH2_GET_RANDOM_TK: 1927 case SM_PH2_C1_GET_RANDOM_A: 1928 case SM_PH2_C1_GET_RANDOM_B: 1929 case SM_PH3_GET_RANDOM: 1930 case SM_PH3_GET_DIV: 1931 sm_next_responding_state(connection); 1932 sm_random_start(connection); 1933 return; 1934 1935 case SM_PH2_C1_GET_ENC_B: 1936 case SM_PH2_C1_GET_ENC_D: 1937 // already busy? 1938 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1939 sm_next_responding_state(connection); 1940 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 1941 return; 1942 1943 case SM_PH3_LTK_GET_ENC: 1944 case SM_RESPONDER_PH4_LTK_GET_ENC: 1945 // already busy? 1946 if (sm_aes128_state == SM_AES128_IDLE) { 1947 sm_key_t d_prime; 1948 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 1949 sm_next_responding_state(connection); 1950 sm_aes128_start(sm_persistent_er, d_prime, connection); 1951 return; 1952 } 1953 break; 1954 1955 case SM_PH3_CSRK_GET_ENC: 1956 // already busy? 1957 if (sm_aes128_state == SM_AES128_IDLE) { 1958 sm_key_t d_prime; 1959 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 1960 sm_next_responding_state(connection); 1961 sm_aes128_start(sm_persistent_er, d_prime, connection); 1962 return; 1963 } 1964 break; 1965 1966 case SM_PH2_C1_GET_ENC_C: 1967 // already busy? 1968 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1969 // calculate m_confirm using aes128 engine - step 1 1970 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); 1971 sm_next_responding_state(connection); 1972 sm_aes128_start(setup->sm_tk, plaintext, connection); 1973 break; 1974 case SM_PH2_C1_GET_ENC_A: 1975 // already busy? 1976 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1977 // calculate confirm using aes128 engine - step 1 1978 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); 1979 sm_next_responding_state(connection); 1980 sm_aes128_start(setup->sm_tk, plaintext, connection); 1981 break; 1982 case SM_PH2_CALC_STK: 1983 // already busy? 1984 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1985 // calculate STK 1986 if (connection->sm_role){ 1987 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 1988 } else { 1989 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 1990 } 1991 sm_next_responding_state(connection); 1992 sm_aes128_start(setup->sm_tk, plaintext, connection); 1993 break; 1994 case SM_PH3_Y_GET_ENC: 1995 // already busy? 1996 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1997 // PH3B2 - calculate Y from - enc 1998 // Y = dm(DHK, Rand) 1999 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2000 sm_next_responding_state(connection); 2001 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2002 return; 2003 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2004 uint8_t buffer[17]; 2005 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2006 reverse_128(setup->sm_local_confirm, &buffer[1]); 2007 if (connection->sm_role){ 2008 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2009 } else { 2010 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2011 } 2012 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2013 sm_timeout_reset(connection); 2014 return; 2015 } 2016 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2017 sm_key_t stk_flipped; 2018 reverse_128(setup->sm_ltk, stk_flipped); 2019 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2020 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2021 return; 2022 } 2023 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2024 sm_key_t stk_flipped; 2025 reverse_128(setup->sm_ltk, stk_flipped); 2026 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2027 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2028 return; 2029 } 2030 case SM_RESPONDER_PH4_SEND_LTK: { 2031 sm_key_t ltk_flipped; 2032 reverse_128(setup->sm_ltk, ltk_flipped); 2033 connection->sm_engine_state = SM_RESPONDER_IDLE; 2034 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2035 return; 2036 } 2037 case SM_RESPONDER_PH4_Y_GET_ENC: 2038 // already busy? 2039 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2040 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2041 // Y = dm(DHK, Rand) 2042 sm_dm_r_prime(setup->sm_local_rand, plaintext); 2043 sm_next_responding_state(connection); 2044 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 2045 return; 2046 2047 case SM_PH3_DISTRIBUTE_KEYS: 2048 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2049 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2050 uint8_t buffer[17]; 2051 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2052 reverse_128(setup->sm_ltk, &buffer[1]); 2053 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2054 sm_timeout_reset(connection); 2055 return; 2056 } 2057 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2058 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2059 uint8_t buffer[11]; 2060 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2061 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2062 reverse_64(setup->sm_local_rand, &buffer[3]); 2063 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2064 sm_timeout_reset(connection); 2065 return; 2066 } 2067 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2068 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2069 uint8_t buffer[17]; 2070 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2071 reverse_128(sm_persistent_irk, &buffer[1]); 2072 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2073 sm_timeout_reset(connection); 2074 return; 2075 } 2076 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2077 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2078 bd_addr_t local_address; 2079 uint8_t buffer[8]; 2080 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2081 gap_advertisements_get_address(&buffer[1], local_address); 2082 reverse_bd_addr(local_address, &buffer[2]); 2083 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2084 sm_timeout_reset(connection); 2085 return; 2086 } 2087 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2088 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2089 2090 // hack to reproduce test runs 2091 if (test_use_fixed_local_csrk){ 2092 memset(setup->sm_local_csrk, 0xcc, 16); 2093 } 2094 2095 uint8_t buffer[17]; 2096 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2097 reverse_128(setup->sm_local_csrk, &buffer[1]); 2098 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2099 sm_timeout_reset(connection); 2100 return; 2101 } 2102 2103 // keys are sent 2104 if (connection->sm_role){ 2105 // slave -> receive master keys if any 2106 if (sm_key_distribution_all_received(connection)){ 2107 sm_key_distribution_handle_all_received(connection); 2108 connection->sm_engine_state = SM_RESPONDER_IDLE; 2109 sm_done_for_handle(connection->sm_handle); 2110 } else { 2111 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2112 } 2113 } else { 2114 // master -> all done 2115 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2116 sm_done_for_handle(connection->sm_handle); 2117 } 2118 break; 2119 2120 default: 2121 break; 2122 } 2123 2124 // check again if active connection was released 2125 if (sm_active_connection) break; 2126 } 2127 } 2128 2129 // note: aes engine is ready as we just got the aes result 2130 static void sm_handle_encryption_result(uint8_t * data){ 2131 2132 sm_aes128_state = SM_AES128_IDLE; 2133 2134 if (sm_address_resolution_ah_calculation_active){ 2135 sm_address_resolution_ah_calculation_active = 0; 2136 // compare calulated address against connecting device 2137 uint8_t hash[3]; 2138 reverse_24(data, hash); 2139 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2140 log_info("LE Device Lookup: matched resolvable private address"); 2141 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2142 return; 2143 } 2144 // no match, try next 2145 sm_address_resolution_test++; 2146 return; 2147 } 2148 2149 switch (dkg_state){ 2150 case DKG_W4_IRK: 2151 reverse_128(data, sm_persistent_irk); 2152 log_info_key("irk", sm_persistent_irk); 2153 dkg_next_state(); 2154 return; 2155 case DKG_W4_DHK: 2156 reverse_128(data, sm_persistent_dhk); 2157 log_info_key("dhk", sm_persistent_dhk); 2158 dkg_next_state(); 2159 // SM Init Finished 2160 return; 2161 default: 2162 break; 2163 } 2164 2165 switch (rau_state){ 2166 case RAU_W4_ENC: 2167 reverse_24(data, &sm_random_address[3]); 2168 rau_next_state(); 2169 return; 2170 default: 2171 break; 2172 } 2173 2174 switch (sm_cmac_state){ 2175 case CMAC_W4_SUBKEYS: 2176 case CMAC_W4_MI: 2177 case CMAC_W4_MLAST: 2178 { 2179 sm_key_t t; 2180 reverse_128(data, t); 2181 sm_cmac_handle_encryption_result(t); 2182 } 2183 return; 2184 default: 2185 break; 2186 } 2187 2188 // retrieve sm_connection provided to sm_aes128_start_encryption 2189 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2190 if (!connection) return; 2191 switch (connection->sm_engine_state){ 2192 case SM_PH2_C1_W4_ENC_A: 2193 case SM_PH2_C1_W4_ENC_C: 2194 { 2195 sm_key_t t2; 2196 reverse_128(data, t2); 2197 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2198 } 2199 sm_next_responding_state(connection); 2200 return; 2201 case SM_PH2_C1_W4_ENC_B: 2202 reverse_128(data, setup->sm_local_confirm); 2203 log_info_key("c1!", setup->sm_local_confirm); 2204 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2205 return; 2206 case SM_PH2_C1_W4_ENC_D: 2207 { 2208 sm_key_t peer_confirm_test; 2209 reverse_128(data, peer_confirm_test); 2210 log_info_key("c1!", peer_confirm_test); 2211 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2212 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2213 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2214 return; 2215 } 2216 if (connection->sm_role){ 2217 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2218 } else { 2219 connection->sm_engine_state = SM_PH2_CALC_STK; 2220 } 2221 } 2222 return; 2223 case SM_PH2_W4_STK: 2224 reverse_128(data, setup->sm_ltk); 2225 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2226 log_info_key("stk", setup->sm_ltk); 2227 if (connection->sm_role){ 2228 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2229 } else { 2230 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2231 } 2232 return; 2233 case SM_PH3_Y_W4_ENC:{ 2234 sm_key_t y128; 2235 reverse_128(data, y128); 2236 setup->sm_local_y = big_endian_read_16(y128, 14); 2237 log_info_hex16("y", setup->sm_local_y); 2238 // PH3B3 - calculate EDIV 2239 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2240 log_info_hex16("ediv", setup->sm_local_ediv); 2241 // PH3B4 - calculate LTK - enc 2242 // LTK = d1(ER, DIV, 0)) 2243 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2244 return; 2245 } 2246 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2247 sm_key_t y128; 2248 reverse_128(data, y128); 2249 setup->sm_local_y = big_endian_read_16(y128, 14); 2250 log_info_hex16("y", setup->sm_local_y); 2251 2252 // PH3B3 - calculate DIV 2253 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2254 log_info_hex16("ediv", setup->sm_local_ediv); 2255 // PH3B4 - calculate LTK - enc 2256 // LTK = d1(ER, DIV, 0)) 2257 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2258 return; 2259 } 2260 case SM_PH3_LTK_W4_ENC: 2261 reverse_128(data, setup->sm_ltk); 2262 log_info_key("ltk", setup->sm_ltk); 2263 // calc CSRK next 2264 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2265 return; 2266 case SM_PH3_CSRK_W4_ENC: 2267 reverse_128(data, setup->sm_local_csrk); 2268 log_info_key("csrk", setup->sm_local_csrk); 2269 if (setup->sm_key_distribution_send_set){ 2270 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2271 } else { 2272 // no keys to send, just continue 2273 if (connection->sm_role){ 2274 // slave -> receive master keys 2275 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2276 } else { 2277 // master -> all done 2278 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2279 sm_done_for_handle(connection->sm_handle); 2280 } 2281 } 2282 return; 2283 case SM_RESPONDER_PH4_LTK_W4_ENC: 2284 reverse_128(data, setup->sm_ltk); 2285 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2286 log_info_key("ltk", setup->sm_ltk); 2287 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 2288 return; 2289 default: 2290 break; 2291 } 2292 } 2293 2294 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2295 static void sm_handle_random_result(uint8_t * data){ 2296 2297 switch (rau_state){ 2298 case RAU_W4_RANDOM: 2299 // non-resolvable vs. resolvable 2300 switch (gap_random_adress_type){ 2301 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2302 // resolvable: use random as prand and calc address hash 2303 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2304 memcpy(sm_random_address, data, 3); 2305 sm_random_address[0] &= 0x3f; 2306 sm_random_address[0] |= 0x40; 2307 rau_state = RAU_GET_ENC; 2308 break; 2309 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2310 default: 2311 // "The two most significant bits of the address shall be equal to ‘0’"" 2312 memcpy(sm_random_address, data, 6); 2313 sm_random_address[0] &= 0x3f; 2314 rau_state = RAU_SET_ADDRESS; 2315 break; 2316 } 2317 return; 2318 default: 2319 break; 2320 } 2321 2322 // retrieve sm_connection provided to sm_random_start 2323 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2324 if (!connection) return; 2325 switch (connection->sm_engine_state){ 2326 case SM_PH2_W4_RANDOM_TK: 2327 { 2328 // map random to 0-999999 without speding much cycles on a modulus operation 2329 uint32_t tk = little_endian_read_32(data,0); 2330 tk = tk & 0xfffff; // 1048575 2331 if (tk >= 999999){ 2332 tk = tk - 999999; 2333 } 2334 sm_reset_tk(); 2335 big_endian_store_32(setup->sm_tk, 12, tk); 2336 if (connection->sm_role){ 2337 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2338 } else { 2339 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2340 sm_trigger_user_response(connection); 2341 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2342 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2343 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2344 } 2345 } 2346 return; 2347 } 2348 case SM_PH2_C1_W4_RANDOM_A: 2349 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2350 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2351 return; 2352 case SM_PH2_C1_W4_RANDOM_B: 2353 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2354 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2355 return; 2356 case SM_PH3_W4_RANDOM: 2357 reverse_64(data, setup->sm_local_rand); 2358 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2359 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2360 // no db for authenticated flag hack: store flag in bit 4 of LSB 2361 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2362 connection->sm_engine_state = SM_PH3_GET_DIV; 2363 return; 2364 case SM_PH3_W4_DIV: 2365 // use 16 bit from random value as div 2366 setup->sm_local_div = big_endian_read_16(data, 0); 2367 log_info_hex16("div", setup->sm_local_div); 2368 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2369 return; 2370 default: 2371 break; 2372 } 2373 } 2374 2375 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2376 2377 sm_connection_t * sm_conn; 2378 hci_con_handle_t con_handle; 2379 2380 switch (packet_type) { 2381 2382 case HCI_EVENT_PACKET: 2383 switch (hci_event_packet_get_type(packet)) { 2384 2385 case BTSTACK_EVENT_STATE: 2386 // bt stack activated, get started 2387 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2388 log_info("HCI Working!"); 2389 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2390 rau_state = RAU_IDLE; 2391 sm_run(); 2392 } 2393 break; 2394 2395 case HCI_EVENT_LE_META: 2396 switch (packet[2]) { 2397 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2398 2399 log_info("sm: connected"); 2400 2401 if (packet[3]) return; // connection failed 2402 2403 con_handle = little_endian_read_16(packet, 4); 2404 sm_conn = sm_get_connection_for_handle(con_handle); 2405 if (!sm_conn) break; 2406 2407 sm_conn->sm_handle = con_handle; 2408 sm_conn->sm_role = packet[6]; 2409 sm_conn->sm_peer_addr_type = packet[7]; 2410 reverse_bd_addr(&packet[8], 2411 sm_conn->sm_peer_address); 2412 2413 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2414 2415 // reset security properties 2416 sm_conn->sm_connection_encrypted = 0; 2417 sm_conn->sm_connection_authenticated = 0; 2418 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2419 sm_conn->sm_le_db_index = -1; 2420 2421 // prepare CSRK lookup (does not involve setup) 2422 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2423 2424 // just connected -> everything else happens in sm_run() 2425 if (sm_conn->sm_role){ 2426 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2427 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2428 if (sm_slave_request_security) { 2429 // request security if requested by app 2430 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2431 } else { 2432 // otherwise, wait for pairing request 2433 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2434 } 2435 } 2436 break; 2437 } else { 2438 // master 2439 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2440 } 2441 break; 2442 2443 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2444 con_handle = little_endian_read_16(packet, 3); 2445 sm_conn = sm_get_connection_for_handle(con_handle); 2446 if (!sm_conn) break; 2447 2448 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2449 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2450 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2451 break; 2452 } 2453 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 2454 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2455 break; 2456 } 2457 2458 // assume that we don't have a LTK for ediv == 0 and random == null 2459 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 2460 log_info("LTK Request: ediv & random are empty"); 2461 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2462 break; 2463 } 2464 2465 // store rand and ediv 2466 reverse_64(&packet[5], sm_conn->sm_local_rand); 2467 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2468 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 2469 break; 2470 2471 default: 2472 break; 2473 } 2474 break; 2475 2476 case HCI_EVENT_ENCRYPTION_CHANGE: 2477 con_handle = little_endian_read_16(packet, 3); 2478 sm_conn = sm_get_connection_for_handle(con_handle); 2479 if (!sm_conn) break; 2480 2481 sm_conn->sm_connection_encrypted = packet[5]; 2482 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2483 sm_conn->sm_actual_encryption_key_size); 2484 log_info("event handler, state %u", sm_conn->sm_engine_state); 2485 if (!sm_conn->sm_connection_encrypted) break; 2486 // continue if part of initial pairing 2487 switch (sm_conn->sm_engine_state){ 2488 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2489 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2490 sm_done_for_handle(sm_conn->sm_handle); 2491 break; 2492 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2493 if (sm_conn->sm_role){ 2494 // slave 2495 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2496 } else { 2497 // master 2498 if (sm_key_distribution_all_received(sm_conn)){ 2499 // skip receiving keys as there are none 2500 sm_key_distribution_handle_all_received(sm_conn); 2501 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2502 } else { 2503 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2504 } 2505 } 2506 break; 2507 default: 2508 break; 2509 } 2510 break; 2511 2512 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2513 con_handle = little_endian_read_16(packet, 3); 2514 sm_conn = sm_get_connection_for_handle(con_handle); 2515 if (!sm_conn) break; 2516 2517 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2518 log_info("event handler, state %u", sm_conn->sm_engine_state); 2519 // continue if part of initial pairing 2520 switch (sm_conn->sm_engine_state){ 2521 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2522 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2523 sm_done_for_handle(sm_conn->sm_handle); 2524 break; 2525 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2526 if (sm_conn->sm_role){ 2527 // slave 2528 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2529 } else { 2530 // master 2531 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2532 } 2533 break; 2534 default: 2535 break; 2536 } 2537 break; 2538 2539 2540 case HCI_EVENT_DISCONNECTION_COMPLETE: 2541 con_handle = little_endian_read_16(packet, 3); 2542 sm_done_for_handle(con_handle); 2543 sm_conn = sm_get_connection_for_handle(con_handle); 2544 if (!sm_conn) break; 2545 2546 // delete stored bonding on disconnect with authentication failure in ph0 2547 if (sm_conn->sm_role == 0 2548 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2549 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2550 le_device_db_remove(sm_conn->sm_le_db_index); 2551 } 2552 2553 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2554 sm_conn->sm_handle = 0; 2555 break; 2556 2557 case HCI_EVENT_COMMAND_COMPLETE: 2558 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2559 sm_handle_encryption_result(&packet[6]); 2560 break; 2561 } 2562 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2563 sm_handle_random_result(&packet[6]); 2564 break; 2565 } 2566 break; 2567 default: 2568 break; 2569 } 2570 break; 2571 default: 2572 break; 2573 } 2574 2575 sm_run(); 2576 } 2577 2578 static inline int sm_calc_actual_encryption_key_size(int other){ 2579 if (other < sm_min_encryption_key_size) return 0; 2580 if (other < sm_max_encryption_key_size) return other; 2581 return sm_max_encryption_key_size; 2582 } 2583 2584 /** 2585 * @return ok 2586 */ 2587 static int sm_validate_stk_generation_method(void){ 2588 // check if STK generation method is acceptable by client 2589 switch (setup->sm_stk_generation_method){ 2590 case JUST_WORKS: 2591 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2592 case PK_RESP_INPUT: 2593 case PK_INIT_INPUT: 2594 case OK_BOTH_INPUT: 2595 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2596 case OOB: 2597 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2598 case NK_BOTH_INPUT: 2599 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 2600 return 1; 2601 default: 2602 return 0; 2603 } 2604 } 2605 2606 // helper for sm_pdu_handler, calls sm_run on exit 2607 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 2608 setup->sm_pairing_failed_reason = reason; 2609 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2610 } 2611 2612 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 2613 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 2614 } 2615 2616 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2617 2618 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 2619 sm_run(); 2620 } 2621 2622 if (packet_type != SM_DATA_PACKET) return; 2623 2624 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2625 if (!sm_conn) return; 2626 2627 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2628 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2629 return; 2630 } 2631 2632 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2633 2634 int err; 2635 2636 switch (sm_conn->sm_engine_state){ 2637 2638 // a sm timeout requries a new physical connection 2639 case SM_GENERAL_TIMEOUT: 2640 return; 2641 2642 // Initiator 2643 case SM_INITIATOR_CONNECTED: 2644 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2645 sm_pdu_received_in_wrong_state(sm_conn); 2646 break; 2647 } 2648 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2649 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2650 break; 2651 } 2652 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2653 uint16_t ediv; 2654 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2655 if (ediv){ 2656 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2657 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2658 } else { 2659 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2660 } 2661 break; 2662 } 2663 // otherwise, store security request 2664 sm_conn->sm_security_request_received = 1; 2665 break; 2666 2667 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2668 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2669 sm_pdu_received_in_wrong_state(sm_conn); 2670 break; 2671 } 2672 // store pairing request 2673 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2674 err = sm_stk_generation_init(sm_conn); 2675 if (err){ 2676 setup->sm_pairing_failed_reason = err; 2677 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2678 break; 2679 } 2680 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2681 if (setup->sm_use_secure_connections){ 2682 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2683 if (setup->sm_stk_generation_method == JUST_WORKS){ 2684 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2685 sm_trigger_user_response(sm_conn); 2686 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2687 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2688 } 2689 } else { 2690 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2691 } 2692 break; 2693 } 2694 #endif 2695 // generate random number first, if we need to show passkey 2696 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2697 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2698 break; 2699 } 2700 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2701 sm_trigger_user_response(sm_conn); 2702 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2703 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2704 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2705 } 2706 break; 2707 2708 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2709 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2710 sm_pdu_received_in_wrong_state(sm_conn); 2711 break; 2712 } 2713 2714 // store s_confirm 2715 reverse_128(&packet[1], setup->sm_peer_confirm); 2716 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2717 break; 2718 2719 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2720 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2721 sm_pdu_received_in_wrong_state(sm_conn); 2722 break;; 2723 } 2724 2725 // received random value 2726 reverse_128(&packet[1], setup->sm_peer_random); 2727 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2728 break; 2729 2730 // Responder 2731 case SM_RESPONDER_IDLE: 2732 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2733 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2734 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2735 sm_pdu_received_in_wrong_state(sm_conn); 2736 break;; 2737 } 2738 2739 // store pairing request 2740 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2741 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2742 break; 2743 2744 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2745 case SM_SC_W4_PUBLIC_KEY_COMMAND: 2746 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 2747 sm_pdu_received_in_wrong_state(sm_conn); 2748 break; 2749 } 2750 2751 // store public key for DH Key calculation 2752 reverse_256(&packet[01], setup->sm_peer_qx); 2753 reverse_256(&packet[33], setup->sm_peer_qy); 2754 2755 #ifdef USE_MBEDTLS_FOR_ECDH 2756 // validate public key 2757 mbedtls_ecp_group grp; 2758 mbedtls_ecp_group_init( &grp ); 2759 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 2760 2761 mbedtls_ecp_point Q; 2762 mbedtls_ecp_point_init( &Q ); 2763 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 2764 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 2765 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 2766 err = mbedtls_ecp_check_pubkey(&grp, &Q); 2767 if (err){ 2768 log_error("sm: peer public key invalid %x", err); 2769 // uses "unspecified reason", there is no "public key invalid" error code 2770 sm_pdu_received_in_wrong_state(sm_conn); 2771 break; 2772 } 2773 #endif 2774 if (sm_conn->sm_role){ 2775 // responder 2776 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 2777 } else { 2778 // initiator 2779 // stk generation method 2780 // passkey entry: notify app to show passkey or to request passkey 2781 switch (setup->sm_stk_generation_method){ 2782 case JUST_WORKS: 2783 case NK_BOTH_INPUT: 2784 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 2785 break; 2786 case PK_INIT_INPUT: 2787 case PK_RESP_INPUT: 2788 case OK_BOTH_INPUT: 2789 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2790 break; 2791 case OOB: 2792 // TODO: implement SC OOB 2793 break; 2794 } 2795 } 2796 break; 2797 2798 case SM_SC_W4_CONFIRMATION: 2799 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2800 sm_pdu_received_in_wrong_state(sm_conn); 2801 break; 2802 } 2803 // received confirm value 2804 reverse_128(&packet[1], setup->sm_peer_confirm); 2805 2806 if (sm_conn->sm_role){ 2807 // responder 2808 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2809 } else { 2810 // initiator 2811 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2812 } 2813 break; 2814 2815 case SM_SC_W4_PAIRING_RANDOM: 2816 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2817 sm_pdu_received_in_wrong_state(sm_conn); 2818 break; 2819 } 2820 2821 // received random value 2822 reverse_128(&packet[1], setup->sm_peer_nonce); 2823 2824 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 2825 uint8_t z = 0; 2826 int passkey_entry = 0; 2827 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 2828 // some form of passkey 2829 passkey_entry = 1; 2830 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 2831 // sm_passkey_bit was increased before sending confirm value 2832 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 2833 } 2834 // only check for JUST WORK/NC in initiator role AND passkey entry 2835 if (sm_conn->sm_role || passkey_entry) { 2836 sm_key_t confirm_value; 2837 2838 #ifdef USE_MBEDTLS_FOR_ECDH 2839 uint8_t local_qx[32]; 2840 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 2841 f4(confirm_value, setup->sm_peer_qx, local_qx, setup->sm_peer_nonce, z); 2842 #endif 2843 if (0 != memcmp(confirm_value, setup->sm_peer_confirm, 16)){ 2844 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 2845 break; 2846 } 2847 } 2848 2849 if (sm_conn->sm_role){ 2850 // Responder 2851 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 2852 } else { 2853 // Initiator role 2854 switch (setup->sm_stk_generation_method){ 2855 case JUST_WORKS: 2856 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 2857 break; 2858 2859 case NK_BOTH_INPUT: { 2860 // calc Va if numeric comparison 2861 // TODO: use AES Engine to calculate g2 2862 uint8_t value[32]; 2863 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 2864 uint32_t va = g2(value, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce) % 1000000; 2865 big_endian_store_32(setup->sm_tk, 12, va); 2866 sm_trigger_user_response(sm_conn); 2867 break; 2868 } 2869 case PK_INIT_INPUT: 2870 case PK_RESP_INPUT: 2871 case OK_BOTH_INPUT: 2872 if (setup->sm_passkey_bit < 20) { 2873 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 2874 } else { 2875 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 2876 } 2877 break; 2878 case OOB: 2879 // TODO: implement SC OOB 2880 break; 2881 } 2882 } 2883 break; 2884 2885 case SM_SC_W4_DHKEY_CHECK_COMMAND: 2886 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 2887 sm_pdu_received_in_wrong_state(sm_conn); 2888 break; 2889 } 2890 // store DHKey Check 2891 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 2892 2893 // validate E = f6() 2894 sm_key56_t bd_addr_master, bd_addr_slave; 2895 bd_addr_master[0] = setup->sm_m_addr_type; 2896 bd_addr_slave[0] = setup->sm_s_addr_type; 2897 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 2898 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 2899 2900 uint8_t iocap_a[3]; 2901 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 2902 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 2903 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 2904 uint8_t iocap_b[3]; 2905 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 2906 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 2907 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 2908 sm_key_t peer_dhkey_check; 2909 if (sm_conn->sm_role){ 2910 // responder 2911 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); 2912 } else { 2913 // initiator 2914 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); 2915 } 2916 2917 if (0 != memcmp(setup->sm_peer_dhkey_check, peer_dhkey_check, 16) ){ 2918 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 2919 break; 2920 } 2921 2922 if (sm_conn->sm_role){ 2923 // responder 2924 // for numeric comparison, we need to wait for user confirm 2925 if (setup->sm_stk_generation_method == NK_BOTH_INPUT && setup->sm_user_response != SM_USER_RESPONSE_CONFIRM){ 2926 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 2927 } else { 2928 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 2929 } 2930 } else { 2931 // initiator 2932 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2933 } 2934 break; 2935 #endif 2936 2937 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 2938 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2939 sm_pdu_received_in_wrong_state(sm_conn); 2940 break; 2941 } 2942 2943 // received confirm value 2944 reverse_128(&packet[1], setup->sm_peer_confirm); 2945 2946 // notify client to hide shown passkey 2947 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2948 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 2949 } 2950 2951 // handle user cancel pairing? 2952 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 2953 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2954 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2955 break; 2956 } 2957 2958 // wait for user action? 2959 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 2960 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2961 break; 2962 } 2963 2964 // calculate and send local_confirm 2965 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2966 break; 2967 2968 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 2969 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2970 sm_pdu_received_in_wrong_state(sm_conn); 2971 break;; 2972 } 2973 2974 // received random value 2975 reverse_128(&packet[1], setup->sm_peer_random); 2976 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2977 break; 2978 2979 case SM_PH3_RECEIVE_KEYS: 2980 switch(packet[0]){ 2981 case SM_CODE_ENCRYPTION_INFORMATION: 2982 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2983 reverse_128(&packet[1], setup->sm_peer_ltk); 2984 break; 2985 2986 case SM_CODE_MASTER_IDENTIFICATION: 2987 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2988 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 2989 reverse_64(&packet[3], setup->sm_peer_rand); 2990 break; 2991 2992 case SM_CODE_IDENTITY_INFORMATION: 2993 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2994 reverse_128(&packet[1], setup->sm_peer_irk); 2995 break; 2996 2997 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 2998 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2999 setup->sm_peer_addr_type = packet[1]; 3000 reverse_bd_addr(&packet[2], setup->sm_peer_address); 3001 break; 3002 3003 case SM_CODE_SIGNING_INFORMATION: 3004 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 3005 reverse_128(&packet[1], setup->sm_peer_csrk); 3006 break; 3007 default: 3008 // Unexpected PDU 3009 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 3010 break; 3011 } 3012 // done with key distribution? 3013 if (sm_key_distribution_all_received(sm_conn)){ 3014 3015 sm_key_distribution_handle_all_received(sm_conn); 3016 3017 if (sm_conn->sm_role){ 3018 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3019 sm_done_for_handle(sm_conn->sm_handle); 3020 } else { 3021 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 3022 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3023 if (setup->sm_use_secure_connections){ 3024 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3025 } 3026 #endif 3027 } 3028 } 3029 break; 3030 default: 3031 // Unexpected PDU 3032 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 3033 break; 3034 } 3035 3036 // try to send preparared packet 3037 sm_run(); 3038 } 3039 3040 // Security Manager Client API 3041 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 3042 sm_get_oob_data = get_oob_data_callback; 3043 } 3044 3045 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 3046 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 3047 } 3048 3049 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 3050 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 3051 } 3052 3053 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 3054 sm_min_encryption_key_size = min_size; 3055 sm_max_encryption_key_size = max_size; 3056 } 3057 3058 void sm_set_authentication_requirements(uint8_t auth_req){ 3059 sm_auth_req = auth_req; 3060 } 3061 3062 void sm_set_io_capabilities(io_capability_t io_capability){ 3063 sm_io_capabilities = io_capability; 3064 } 3065 3066 void sm_set_request_security(int enable){ 3067 sm_slave_request_security = enable; 3068 } 3069 3070 void sm_set_er(sm_key_t er){ 3071 memcpy(sm_persistent_er, er, 16); 3072 } 3073 3074 void sm_set_ir(sm_key_t ir){ 3075 memcpy(sm_persistent_ir, ir, 16); 3076 } 3077 3078 // Testing support only 3079 void sm_test_set_irk(sm_key_t irk){ 3080 memcpy(sm_persistent_irk, irk, 16); 3081 sm_persistent_irk_ready = 1; 3082 } 3083 3084 void sm_test_use_fixed_local_csrk(void){ 3085 test_use_fixed_local_csrk = 1; 3086 } 3087 3088 void sm_init(void){ 3089 // set some (BTstack default) ER and IR 3090 int i; 3091 sm_key_t er; 3092 sm_key_t ir; 3093 for (i=0;i<16;i++){ 3094 er[i] = 0x30 + i; 3095 ir[i] = 0x90 + i; 3096 } 3097 sm_set_er(er); 3098 sm_set_ir(ir); 3099 // defaults 3100 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3101 | SM_STK_GENERATION_METHOD_OOB 3102 | SM_STK_GENERATION_METHOD_PASSKEY 3103 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3104 3105 sm_max_encryption_key_size = 16; 3106 sm_min_encryption_key_size = 7; 3107 3108 sm_cmac_state = CMAC_IDLE; 3109 dkg_state = DKG_W4_WORKING; 3110 rau_state = RAU_W4_WORKING; 3111 sm_aes128_state = SM_AES128_IDLE; 3112 sm_address_resolution_test = -1; // no private address to resolve yet 3113 sm_address_resolution_ah_calculation_active = 0; 3114 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3115 sm_address_resolution_general_queue = NULL; 3116 3117 gap_random_adress_update_period = 15 * 60 * 1000L; 3118 3119 sm_active_connection = 0; 3120 3121 test_use_fixed_local_csrk = 0; 3122 3123 // register for HCI Events from HCI 3124 hci_event_callback_registration.callback = &sm_event_packet_handler; 3125 hci_add_event_handler(&hci_event_callback_registration); 3126 3127 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3128 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3129 3130 #ifdef USE_MBEDTLS_FOR_ECDH 3131 // TODO: calculate keypair using LE Random Number Generator 3132 // use test keypair from spec initially 3133 mbedtls_ecp_keypair_init(&le_keypair); 3134 mbedtls_ecp_group_load(&le_keypair.grp, MBEDTLS_ECP_DP_SECP256R1); 3135 mbedtls_mpi_read_string( &le_keypair.d, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3136 mbedtls_mpi_read_string( &le_keypair.Q.X, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3137 mbedtls_mpi_read_string( &le_keypair.Q.Y, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3138 mbedtls_mpi_read_string( &le_keypair.Q.Z, 16, "1"); 3139 // print keypair 3140 char buffer[100]; 3141 size_t len; 3142 mbedtls_mpi_write_string( &le_keypair.d, 16, buffer, sizeof(buffer), &len); 3143 log_info("d: %s", buffer); 3144 mbedtls_mpi_write_string( &le_keypair.Q.X, 16, buffer, sizeof(buffer), &len); 3145 log_info("X: %s", buffer); 3146 mbedtls_mpi_write_string( &le_keypair.Q.Y, 16, buffer, sizeof(buffer), &len); 3147 log_info("Y: %s", buffer); 3148 #endif 3149 } 3150 3151 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3152 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3153 if (!hci_con) return NULL; 3154 return &hci_con->sm_connection; 3155 } 3156 3157 // @returns 0 if not encrypted, 7-16 otherwise 3158 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3159 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3160 if (!sm_conn) return 0; // wrong connection 3161 if (!sm_conn->sm_connection_encrypted) return 0; 3162 return sm_conn->sm_actual_encryption_key_size; 3163 } 3164 3165 int sm_authenticated(hci_con_handle_t con_handle){ 3166 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3167 if (!sm_conn) return 0; // wrong connection 3168 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3169 return sm_conn->sm_connection_authenticated; 3170 } 3171 3172 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3173 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3174 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3175 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3176 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3177 return sm_conn->sm_connection_authorization_state; 3178 } 3179 3180 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3181 switch (sm_conn->sm_engine_state){ 3182 case SM_GENERAL_IDLE: 3183 case SM_RESPONDER_IDLE: 3184 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3185 sm_run(); 3186 break; 3187 default: 3188 break; 3189 } 3190 } 3191 3192 /** 3193 * @brief Trigger Security Request 3194 */ 3195 void sm_send_security_request(hci_con_handle_t con_handle){ 3196 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3197 if (!sm_conn) return; 3198 sm_send_security_request_for_connection(sm_conn); 3199 } 3200 3201 // request pairing 3202 void sm_request_pairing(hci_con_handle_t con_handle){ 3203 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3204 if (!sm_conn) return; // wrong connection 3205 3206 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3207 if (sm_conn->sm_role){ 3208 sm_send_security_request_for_connection(sm_conn); 3209 } else { 3210 // used as a trigger to start central/master/initiator security procedures 3211 uint16_t ediv; 3212 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3213 switch (sm_conn->sm_irk_lookup_state){ 3214 case IRK_LOOKUP_FAILED: 3215 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3216 break; 3217 case IRK_LOOKUP_SUCCEEDED: 3218 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 3219 if (ediv){ 3220 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3221 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3222 } else { 3223 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3224 } 3225 break; 3226 default: 3227 sm_conn->sm_bonding_requested = 1; 3228 break; 3229 } 3230 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3231 sm_conn->sm_bonding_requested = 1; 3232 } 3233 } 3234 sm_run(); 3235 } 3236 3237 // called by client app on authorization request 3238 void sm_authorization_decline(hci_con_handle_t con_handle){ 3239 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3240 if (!sm_conn) return; // wrong connection 3241 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3242 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3243 } 3244 3245 void sm_authorization_grant(hci_con_handle_t con_handle){ 3246 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3247 if (!sm_conn) return; // wrong connection 3248 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3249 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3250 } 3251 3252 // GAP Bonding API 3253 3254 void sm_bonding_decline(hci_con_handle_t con_handle){ 3255 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3256 if (!sm_conn) return; // wrong connection 3257 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3258 3259 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3260 switch (setup->sm_stk_generation_method){ 3261 case PK_RESP_INPUT: 3262 case PK_INIT_INPUT: 3263 case OK_BOTH_INPUT: 3264 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3265 break; 3266 case NK_BOTH_INPUT: 3267 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3268 break; 3269 case JUST_WORKS: 3270 case OOB: 3271 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3272 break; 3273 } 3274 } 3275 sm_run(); 3276 } 3277 3278 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3279 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3280 if (!sm_conn) return; // wrong connection 3281 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3282 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3283 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3284 3285 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3286 if (setup->sm_use_secure_connections){ 3287 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3288 } 3289 #endif 3290 } 3291 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 3292 if (sm_conn->sm_role){ 3293 // responder 3294 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 3295 } else { 3296 // initiator 3297 // TODO handle intiator role 3298 } 3299 } 3300 sm_run(); 3301 } 3302 3303 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3304 // for now, it's the same 3305 sm_just_works_confirm(con_handle); 3306 } 3307 3308 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3309 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3310 if (!sm_conn) return; // wrong connection 3311 sm_reset_tk(); 3312 big_endian_store_32(setup->sm_tk, 12, passkey); 3313 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3314 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3315 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3316 } 3317 sm_run(); 3318 } 3319 3320 /** 3321 * @brief Identify device in LE Device DB 3322 * @param handle 3323 * @returns index from le_device_db or -1 if not found/identified 3324 */ 3325 int sm_le_device_index(hci_con_handle_t con_handle ){ 3326 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3327 if (!sm_conn) return -1; 3328 return sm_conn->sm_le_db_index; 3329 } 3330 3331 // GAP LE API 3332 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3333 gap_random_address_update_stop(); 3334 gap_random_adress_type = random_address_type; 3335 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3336 gap_random_address_update_start(); 3337 gap_random_address_trigger(); 3338 } 3339 3340 gap_random_address_type_t gap_random_address_get_mode(void){ 3341 return gap_random_adress_type; 3342 } 3343 3344 void gap_random_address_set_update_period(int period_ms){ 3345 gap_random_adress_update_period = period_ms; 3346 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3347 gap_random_address_update_stop(); 3348 gap_random_address_update_start(); 3349 } 3350 3351 void gap_random_address_set(bd_addr_t addr){ 3352 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3353 memcpy(sm_random_address, addr, 6); 3354 rau_state = RAU_SET_ADDRESS; 3355 sm_run(); 3356 } 3357 3358 /* 3359 * @brief Set Advertisement Paramters 3360 * @param adv_int_min 3361 * @param adv_int_max 3362 * @param adv_type 3363 * @param direct_address_type 3364 * @param direct_address 3365 * @param channel_map 3366 * @param filter_policy 3367 * 3368 * @note own_address_type is used from gap_random_address_set_mode 3369 */ 3370 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3371 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3372 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3373 direct_address_typ, direct_address, channel_map, filter_policy); 3374 } 3375 3376