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 175 static cmac_state_t sm_cmac_state; 176 static sm_key_t sm_cmac_k; 177 static uint8_t sm_cmac_header[3]; 178 static uint16_t sm_cmac_message_len; 179 static uint8_t * sm_cmac_message; 180 static uint8_t sm_cmac_sign_counter[4]; 181 static sm_key_t sm_cmac_m_last; 182 static sm_key_t sm_cmac_x; 183 static uint8_t sm_cmac_block_current; 184 static uint8_t sm_cmac_block_count; 185 static void (*sm_cmac_done_handler)(uint8_t hash[8]); 186 187 // resolvable private address lookup / CSRK calculation 188 static int sm_address_resolution_test; 189 static int sm_address_resolution_ah_calculation_active; 190 static uint8_t sm_address_resolution_addr_type; 191 static bd_addr_t sm_address_resolution_address; 192 static void * sm_address_resolution_context; 193 static address_resolution_mode_t sm_address_resolution_mode; 194 static btstack_linked_list_t sm_address_resolution_general_queue; 195 196 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 197 static sm_aes128_state_t sm_aes128_state; 198 static void * sm_aes128_context; 199 200 // random engine. store context (ususally sm_connection_t) 201 static void * sm_random_context; 202 203 // to receive hci events 204 static btstack_packet_callback_registration_t hci_event_callback_registration; 205 206 /* to dispatch sm event */ 207 static btstack_linked_list_t sm_event_handlers; 208 209 // Software ECDH implementation provided by mbedtls 210 #ifdef USE_MBEDTLS_FOR_ECDH 211 mbedtls_ecp_keypair le_keypair; 212 #endif 213 214 // 215 // Volume 3, Part H, Chapter 24 216 // "Security shall be initiated by the Security Manager in the device in the master role. 217 // The device in the slave role shall be the responding device." 218 // -> master := initiator, slave := responder 219 // 220 221 // data needed for security setup 222 typedef struct sm_setup_context { 223 224 btstack_timer_source_t sm_timeout; 225 226 // used in all phases 227 uint8_t sm_pairing_failed_reason; 228 229 // user response, (Phase 1 and/or 2) 230 uint8_t sm_user_response; 231 232 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 233 int sm_key_distribution_send_set; 234 int sm_key_distribution_received_set; 235 236 // Phase 2 (Pairing over SMP) 237 stk_generation_method_t sm_stk_generation_method; 238 sm_key_t sm_tk; 239 uint8_t sm_use_secure_connections; 240 241 sm_key_t sm_c1_t3_value; // c1 calculation 242 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 243 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 244 sm_key_t sm_local_random; 245 sm_key_t sm_local_confirm; 246 sm_key_t sm_peer_random; 247 sm_key_t sm_peer_confirm; 248 uint8_t sm_m_addr_type; // address and type can be removed 249 uint8_t sm_s_addr_type; // '' 250 bd_addr_t sm_m_address; // '' 251 bd_addr_t sm_s_address; // '' 252 sm_key_t sm_ltk; 253 254 #ifdef ENABLE_LE_SECURE_CONNECTIONS 255 uint8_t sm_peer_qx[32]; 256 uint8_t sm_peer_qy[32]; 257 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 258 sm_key_t sm_local_nonce; // might be combined with sm_local_random 259 sm_key_t sm_peer_dhkey_check; 260 sm_key_t sm_local_dhkey_check; 261 sm_key_t sm_ra; 262 sm_key_t sm_rb; 263 sm_key_t sm_mackey; 264 uint8_t sm_passkey_bit; 265 #endif 266 267 // Phase 3 268 269 // key distribution, we generate 270 uint16_t sm_local_y; 271 uint16_t sm_local_div; 272 uint16_t sm_local_ediv; 273 uint8_t sm_local_rand[8]; 274 sm_key_t sm_local_ltk; 275 sm_key_t sm_local_csrk; 276 sm_key_t sm_local_irk; 277 // sm_local_address/addr_type not needed 278 279 // key distribution, received from peer 280 uint16_t sm_peer_y; 281 uint16_t sm_peer_div; 282 uint16_t sm_peer_ediv; 283 uint8_t sm_peer_rand[8]; 284 sm_key_t sm_peer_ltk; 285 sm_key_t sm_peer_irk; 286 sm_key_t sm_peer_csrk; 287 uint8_t sm_peer_addr_type; 288 bd_addr_t sm_peer_address; 289 290 } sm_setup_context_t; 291 292 // 293 static sm_setup_context_t the_setup; 294 static sm_setup_context_t * setup = &the_setup; 295 296 // active connection - the one for which the_setup is used for 297 static uint16_t sm_active_connection = 0; 298 299 // @returns 1 if oob data is available 300 // stores oob data in provided 16 byte buffer if not null 301 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 302 303 // used to notify applicationss that user interaction is neccessary, see sm_notify_t below 304 static btstack_packet_handler_t sm_client_packet_handler = NULL; 305 306 // horizontal: initiator capabilities 307 // vertial: responder capabilities 308 static const stk_generation_method_t stk_generation_method [5] [5] = { 309 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 310 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 311 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 312 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 313 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 314 }; 315 316 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 317 #ifdef ENABLE_LE_SECURE_CONNECTIONS 318 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 319 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 320 { JUST_WORKS, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 321 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 322 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 323 { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, 324 }; 325 #endif 326 327 static void sm_run(void); 328 static void sm_done_for_handle(hci_con_handle_t con_handle); 329 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 330 static inline int sm_calc_actual_encryption_key_size(int other); 331 static int sm_validate_stk_generation_method(void); 332 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data); 333 334 static void log_info_hex16(const char * name, uint16_t value){ 335 log_info("%-6s 0x%04x", name, value); 336 } 337 338 // @returns 1 if all bytes are 0 339 static int sm_is_null_random(uint8_t random[8]){ 340 int i; 341 for (i=0; i < 8 ; i++){ 342 if (random[i]) return 0; 343 } 344 return 1; 345 } 346 347 // Key utils 348 static void sm_reset_tk(void){ 349 int i; 350 for (i=0;i<16;i++){ 351 setup->sm_tk[i] = 0; 352 } 353 } 354 355 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 356 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 357 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 358 int i; 359 for (i = max_encryption_size ; i < 16 ; i++){ 360 key[15-i] = 0; 361 } 362 } 363 364 // SMP Timeout implementation 365 366 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 367 // the Security Manager Timer shall be reset and started. 368 // 369 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 370 // 371 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 372 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 373 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 374 // established. 375 376 static void sm_timeout_handler(btstack_timer_source_t * timer){ 377 log_info("SM timeout"); 378 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 379 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 380 sm_done_for_handle(sm_conn->sm_handle); 381 382 // trigger handling of next ready connection 383 sm_run(); 384 } 385 static void sm_timeout_start(sm_connection_t * sm_conn){ 386 btstack_run_loop_remove_timer(&setup->sm_timeout); 387 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 388 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 389 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 390 btstack_run_loop_add_timer(&setup->sm_timeout); 391 } 392 static void sm_timeout_stop(void){ 393 btstack_run_loop_remove_timer(&setup->sm_timeout); 394 } 395 static void sm_timeout_reset(sm_connection_t * sm_conn){ 396 sm_timeout_stop(); 397 sm_timeout_start(sm_conn); 398 } 399 400 // end of sm timeout 401 402 // GAP Random Address updates 403 static gap_random_address_type_t gap_random_adress_type; 404 static btstack_timer_source_t gap_random_address_update_timer; 405 static uint32_t gap_random_adress_update_period; 406 407 static void gap_random_address_trigger(void){ 408 if (rau_state != RAU_IDLE) return; 409 log_info("gap_random_address_trigger"); 410 rau_state = RAU_GET_RANDOM; 411 sm_run(); 412 } 413 414 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 415 log_info("GAP Random Address Update due"); 416 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 417 btstack_run_loop_add_timer(&gap_random_address_update_timer); 418 gap_random_address_trigger(); 419 } 420 421 static void gap_random_address_update_start(void){ 422 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 423 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 424 btstack_run_loop_add_timer(&gap_random_address_update_timer); 425 } 426 427 static void gap_random_address_update_stop(void){ 428 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 429 } 430 431 432 static void sm_random_start(void * context){ 433 sm_random_context = context; 434 hci_send_cmd(&hci_le_rand); 435 } 436 437 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 438 // context is made availabe to aes128 result handler by this 439 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 440 sm_aes128_state = SM_AES128_ACTIVE; 441 sm_key_t key_flipped, plaintext_flipped; 442 reverse_128(key, key_flipped); 443 reverse_128(plaintext, plaintext_flipped); 444 sm_aes128_context = context; 445 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 446 } 447 448 // ah(k,r) helper 449 // r = padding || r 450 // r - 24 bit value 451 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 452 // r'= padding || r 453 memset(r_prime, 0, 16); 454 memcpy(&r_prime[13], r, 3); 455 } 456 457 // d1 helper 458 // d' = padding || r || d 459 // d,r - 16 bit values 460 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 461 // d'= padding || r || d 462 memset(d1_prime, 0, 16); 463 big_endian_store_16(d1_prime, 12, r); 464 big_endian_store_16(d1_prime, 14, d); 465 } 466 467 // dm helper 468 // r’ = padding || r 469 // r - 64 bit value 470 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 471 memset(r_prime, 0, 16); 472 memcpy(&r_prime[8], r, 8); 473 } 474 475 // calculate arguments for first AES128 operation in C1 function 476 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){ 477 478 // p1 = pres || preq || rat’ || iat’ 479 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 480 // cant octet of pres becomes the most significant octet of p1. 481 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 482 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 483 // p1 is 0x05000800000302070710000001010001." 484 485 sm_key_t p1; 486 reverse_56(pres, &p1[0]); 487 reverse_56(preq, &p1[7]); 488 p1[14] = rat; 489 p1[15] = iat; 490 log_info_key("p1", p1); 491 log_info_key("r", r); 492 493 // t1 = r xor p1 494 int i; 495 for (i=0;i<16;i++){ 496 t1[i] = r[i] ^ p1[i]; 497 } 498 log_info_key("t1", t1); 499 } 500 501 // calculate arguments for second AES128 operation in C1 function 502 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 503 // p2 = padding || ia || ra 504 // "The least significant octet of ra becomes the least significant octet of p2 and 505 // the most significant octet of padding becomes the most significant octet of p2. 506 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 507 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 508 509 sm_key_t p2; 510 memset(p2, 0, 16); 511 memcpy(&p2[4], ia, 6); 512 memcpy(&p2[10], ra, 6); 513 log_info_key("p2", p2); 514 515 // c1 = e(k, t2_xor_p2) 516 int i; 517 for (i=0;i<16;i++){ 518 t3[i] = t2[i] ^ p2[i]; 519 } 520 log_info_key("t3", t3); 521 } 522 523 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 524 log_info_key("r1", r1); 525 log_info_key("r2", r2); 526 memcpy(&r_prime[8], &r2[8], 8); 527 memcpy(&r_prime[0], &r1[8], 8); 528 } 529 530 #ifdef ENABLE_LE_SECURE_CONNECTIONS 531 // Software implementations of crypto toolbox for LE Secure Connection 532 // TODO: replace with code to use AES Engine of HCI Controller 533 typedef uint8_t sm_key24_t[3]; 534 typedef uint8_t sm_key56_t[7]; 535 typedef uint8_t sm_key256_t[32]; 536 537 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ 538 uint32_t rk[RKLENGTH(KEYBITS)]; 539 int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); 540 rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); 541 } 542 543 static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ 544 memcpy(k1, k0, 16); 545 sm_shift_left_by_one_bit_inplace(16, k1); 546 if (k0[0] & 0x80){ 547 k1[15] ^= 0x87; 548 } 549 memcpy(k2, k1, 16); 550 sm_shift_left_by_one_bit_inplace(16, k2); 551 if (k1[0] & 0x80){ 552 k2[15] ^= 0x87; 553 } 554 } 555 556 static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ 557 sm_key_t k0, k1, k2, zero; 558 memset(zero, 0, 16); 559 560 aes128_calc_cyphertext(key, zero, k0); 561 calc_subkeys(k0, k1, k2); 562 563 int cmac_block_count = (cmac_message_len + 15) / 16; 564 565 // step 3: .. 566 if (cmac_block_count==0){ 567 cmac_block_count = 1; 568 } 569 570 // step 4: set m_last 571 sm_key_t cmac_m_last; 572 int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; 573 int i; 574 if (sm_cmac_last_block_complete){ 575 for (i=0;i<16;i++){ 576 cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; 577 } 578 } else { 579 int valid_octets_in_last_block = cmac_message_len & 0x0f; 580 for (i=0;i<16;i++){ 581 if (i < valid_octets_in_last_block){ 582 cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; 583 continue; 584 } 585 if (i == valid_octets_in_last_block){ 586 cmac_m_last[i] = 0x80 ^ k2[i]; 587 continue; 588 } 589 cmac_m_last[i] = k2[i]; 590 } 591 } 592 593 // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); 594 // LOG_KEY(cmac_m_last); 595 596 // Step 5 597 sm_key_t cmac_x; 598 memset(cmac_x, 0, 16); 599 600 // Step 6 601 sm_key_t sm_cmac_y; 602 for (int block = 0 ; block < cmac_block_count-1 ; block++){ 603 for (i=0;i<16;i++){ 604 sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; 605 } 606 aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); 607 } 608 for (i=0;i<16;i++){ 609 sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; 610 } 611 612 // Step 7 613 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); 614 } 615 616 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){ 617 uint8_t buffer[65]; 618 memcpy(buffer, u, 32); 619 memcpy(buffer+32, v, 32); 620 buffer[64] = z; 621 log_info("f4 key"); 622 log_info_hexdump(x, 16); 623 log_info("f4 message"); 624 log_info_hexdump(buffer, sizeof(buffer)); 625 aes_cmac(res, x, buffer, sizeof(buffer)); 626 log_info("f4 result"); 627 log_info_hexdump(res, sizeof(sm_key_t)); 628 } 629 630 const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 631 const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 632 const uint8_t f5_length[] = { 0x01, 0x00}; 633 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){ 634 // T = AES-CMACSAL_T(W) 635 sm_key_t t; 636 aes_cmac(t, f5_salt, w, 32); 637 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 638 uint8_t buffer[53]; 639 buffer[0] = 0; 640 memcpy(buffer+01, f5_key_id, 4); 641 memcpy(buffer+05, n1, 16); 642 memcpy(buffer+21, n2, 16); 643 memcpy(buffer+37, a1, 7); 644 memcpy(buffer+44, a2, 7); 645 memcpy(buffer+51, f5_length, 2); 646 log_info("f5 DHKEY"); 647 log_info_hexdump(w, 32); 648 log_info("f5 key"); 649 log_info_hexdump(t, 16); 650 log_info("f5 message for MacKey"); 651 log_info_hexdump(buffer, sizeof(buffer)); 652 aes_cmac(res, t, buffer, sizeof(buffer)); 653 // hexdump2(res, 16); 654 // || AES-CMACT (Counter = 1 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the LTK 655 buffer[0] = 1; 656 // hexdump2(buffer, sizeof(buffer)); 657 log_info("f5 message for LTK"); 658 log_info_hexdump(buffer, sizeof(buffer)); 659 aes_cmac(res+16, t, buffer, sizeof(buffer)); 660 // hexdump2(res+16, 16); 661 } 662 663 // f6(W, N1, N2, R, IOcap, A1, A2) = AES-CMACW (N1 || N2 || R || IOcap || A1 || A2 664 // - W is 128 bits 665 // - N1 is 128 bits 666 // - N2 is 128 bits 667 // - R is 128 bits 668 // - IOcap is 24 bits 669 // - A1 is 56 bits 670 // - A2 is 56 bits 671 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){ 672 uint8_t buffer[65]; 673 memcpy(buffer, n1, 16); 674 memcpy(buffer+16, n2, 16); 675 memcpy(buffer+32, r, 16); 676 memcpy(buffer+48, io_cap, 3); 677 memcpy(buffer+51, a1, 7); 678 memcpy(buffer+58, a2, 7); 679 log_info("f6 key"); 680 log_info_hexdump(w, 16); 681 log_info("f6 message"); 682 log_info_hexdump(buffer, sizeof(buffer)); 683 aes_cmac(res, w, buffer,sizeof(buffer)); 684 log_info("f6 result"); 685 log_info_hexdump(res, 16); 686 } 687 688 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 689 // - U is 256 bits 690 // - V is 256 bits 691 // - X is 128 bits 692 // - Y is 128 bits 693 static uint32_t g2(const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 694 uint8_t buffer[80]; 695 memcpy(buffer, u, 32); 696 memcpy(buffer+32, v, 32); 697 memcpy(buffer+64, y, 16); 698 sm_key_t cmac; 699 log_info("g2 key"); 700 log_info_hexdump(x, 16); 701 log_info("g2 message"); 702 log_info_hexdump(buffer, sizeof(buffer)); 703 aes_cmac(cmac, x, buffer, sizeof(buffer)); 704 log_info("g2 result"); 705 log_info_hexdump(x, 16); 706 return big_endian_read_32(cmac, 12); 707 } 708 709 #if 0 710 // h6(W, keyID) = AES-CMACW(keyID) 711 // - W is 128 bits 712 // - keyID is 32 bits 713 static void h6(sm_key_t res, const sm_key_t w, const uint32_t key_id){ 714 uint8_t key_id_buffer[4]; 715 big_endian_store_32(key_id_buffer, 0, key_id); 716 aes_cmac(res, w, key_id_buffer, 4); 717 } 718 #endif 719 #endif 720 721 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){ 722 event[0] = type; 723 event[1] = event_size - 2; 724 little_endian_store_16(event, 2, con_handle); 725 event[4] = addr_type; 726 reverse_bd_addr(address, &event[5]); 727 } 728 729 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 730 if (sm_client_packet_handler) { 731 sm_client_packet_handler(HCI_EVENT_PACKET, 0, packet, size); 732 } 733 // dispatch to all event handlers 734 btstack_linked_list_iterator_t it; 735 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 736 while (btstack_linked_list_iterator_has_next(&it)){ 737 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 738 entry->callback(packet_type, 0, packet, size); 739 } 740 } 741 742 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 743 uint8_t event[11]; 744 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 745 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 746 } 747 748 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){ 749 uint8_t event[15]; 750 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 751 little_endian_store_32(event, 11, passkey); 752 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 753 } 754 755 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){ 756 uint8_t event[13]; 757 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 758 little_endian_store_16(event, 11, index); 759 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 760 } 761 762 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){ 763 764 uint8_t event[18]; 765 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 766 event[11] = result; 767 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 768 } 769 770 // decide on stk generation based on 771 // - pairing request 772 // - io capabilities 773 // - OOB data availability 774 static void sm_setup_tk(void){ 775 776 // default: just works 777 setup->sm_stk_generation_method = JUST_WORKS; 778 779 #ifdef ENABLE_LE_SECURE_CONNECTIONS 780 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 781 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 782 & SM_AUTHREQ_SECURE_CONNECTION ) != 0; 783 memset(setup->sm_ra, 0, 16); 784 memset(setup->sm_rb, 0, 16); 785 #else 786 setup->sm_use_secure_connections = 0; 787 #endif 788 789 // If both devices have not set the MITM option in the Authentication Requirements 790 // Flags, then the IO capabilities shall be ignored and the Just Works association 791 // model shall be used. 792 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 793 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 794 log_info("SM: MITM not required by both -> JUST WORKS"); 795 return; 796 } 797 798 // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient 799 800 // If both devices have out of band authentication data, then the Authentication 801 // Requirements Flags shall be ignored when selecting the pairing method and the 802 // Out of Band pairing method shall be used. 803 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 804 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 805 log_info("SM: have OOB data"); 806 log_info_key("OOB", setup->sm_tk); 807 setup->sm_stk_generation_method = OOB; 808 return; 809 } 810 811 // Reset TK as it has been setup in sm_init_setup 812 sm_reset_tk(); 813 814 // Also use just works if unknown io capabilites 815 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)){ 816 return; 817 } 818 819 // Otherwise the IO capabilities of the devices shall be used to determine the 820 // pairing method as defined in Table 2.4. 821 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 822 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 823 824 #ifdef ENABLE_LE_SECURE_CONNECTIONS 825 if (setup->sm_use_secure_connections){ 826 generation_method = stk_generation_method_with_secure_connection; 827 } 828 #endif 829 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)]; 830 831 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 832 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); 833 } 834 835 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 836 int flags = 0; 837 if (key_set & SM_KEYDIST_ENC_KEY){ 838 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 839 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 840 } 841 if (key_set & SM_KEYDIST_ID_KEY){ 842 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 843 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 844 } 845 if (key_set & SM_KEYDIST_SIGN){ 846 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 847 } 848 return flags; 849 } 850 851 static void sm_setup_key_distribution(uint8_t key_set){ 852 setup->sm_key_distribution_received_set = 0; 853 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 854 } 855 856 // CSRK Key Lookup 857 858 859 static int sm_address_resolution_idle(void){ 860 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 861 } 862 863 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){ 864 memcpy(sm_address_resolution_address, addr, 6); 865 sm_address_resolution_addr_type = addr_type; 866 sm_address_resolution_test = 0; 867 sm_address_resolution_mode = mode; 868 sm_address_resolution_context = context; 869 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 870 } 871 872 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 873 // check if already in list 874 btstack_linked_list_iterator_t it; 875 sm_lookup_entry_t * entry; 876 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 877 while(btstack_linked_list_iterator_has_next(&it)){ 878 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 879 if (entry->address_type != address_type) continue; 880 if (memcmp(entry->address, address, 6)) continue; 881 // already in list 882 return BTSTACK_BUSY; 883 } 884 entry = btstack_memory_sm_lookup_entry_get(); 885 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 886 entry->address_type = (bd_addr_type_t) address_type; 887 memcpy(entry->address, address, 6); 888 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 889 sm_run(); 890 return 0; 891 } 892 893 // CMAC Implementation using AES128 engine 894 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 895 int i; 896 int carry = 0; 897 for (i=len-1; i >= 0 ; i--){ 898 int new_carry = data[i] >> 7; 899 data[i] = data[i] << 1 | carry; 900 carry = new_carry; 901 } 902 } 903 904 // 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 905 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 906 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 907 } 908 static inline void dkg_next_state(void){ 909 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 910 } 911 static inline void rau_next_state(void){ 912 rau_state = (random_address_update_t) (((int)rau_state) + 1); 913 } 914 static inline void sm_cmac_next_state(void){ 915 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 916 } 917 static int sm_cmac_last_block_complete(void){ 918 if (sm_cmac_message_len == 0) return 0; 919 return (sm_cmac_message_len & 0x0f) == 0; 920 } 921 static inline uint8_t sm_cmac_message_get_byte(int offset){ 922 if (offset >= sm_cmac_message_len) { 923 log_error("sm_cmac_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 924 return 0; 925 } 926 927 offset = sm_cmac_message_len - 1 - offset; 928 929 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 930 if (offset < 3){ 931 return sm_cmac_header[offset]; 932 } 933 int actual_message_len_incl_header = sm_cmac_message_len - 4; 934 if (offset < actual_message_len_incl_header){ 935 return sm_cmac_message[offset - 3]; 936 } 937 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 938 } 939 940 void sm_cmac_start(sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t hash[8])){ 941 memcpy(sm_cmac_k, k, 16); 942 sm_cmac_header[0] = opcode; 943 little_endian_store_16(sm_cmac_header, 1, con_handle); 944 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 945 sm_cmac_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 946 sm_cmac_message = message; 947 sm_cmac_done_handler = done_handler; 948 sm_cmac_block_current = 0; 949 memset(sm_cmac_x, 0, 16); 950 951 // step 2: n := ceil(len/const_Bsize); 952 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 953 954 // step 3: .. 955 if (sm_cmac_block_count==0){ 956 sm_cmac_block_count = 1; 957 } 958 959 log_info("sm_cmac_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 960 961 // first, we need to compute l for k1, k2, and m_last 962 sm_cmac_state = CMAC_CALC_SUBKEYS; 963 964 // let's go 965 sm_run(); 966 } 967 968 int sm_cmac_ready(void){ 969 return sm_cmac_state == CMAC_IDLE; 970 } 971 972 static void sm_cmac_handle_aes_engine_ready(void){ 973 switch (sm_cmac_state){ 974 case CMAC_CALC_SUBKEYS: { 975 sm_key_t const_zero; 976 memset(const_zero, 0, 16); 977 sm_cmac_next_state(); 978 sm_aes128_start(sm_cmac_k, const_zero, NULL); 979 break; 980 } 981 case CMAC_CALC_MI: { 982 int j; 983 sm_key_t y; 984 for (j=0;j<16;j++){ 985 y[j] = sm_cmac_x[j] ^ sm_cmac_message_get_byte(sm_cmac_block_current*16 + j); 986 } 987 sm_cmac_block_current++; 988 sm_cmac_next_state(); 989 sm_aes128_start(sm_cmac_k, y, NULL); 990 break; 991 } 992 case CMAC_CALC_MLAST: { 993 int i; 994 sm_key_t y; 995 for (i=0;i<16;i++){ 996 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 997 } 998 log_info_key("Y", y); 999 sm_cmac_block_current++; 1000 sm_cmac_next_state(); 1001 sm_aes128_start(sm_cmac_k, y, NULL); 1002 break; 1003 } 1004 default: 1005 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 1006 break; 1007 } 1008 } 1009 1010 static void sm_cmac_handle_encryption_result(sm_key_t data){ 1011 switch (sm_cmac_state){ 1012 case CMAC_W4_SUBKEYS: { 1013 sm_key_t k1; 1014 memcpy(k1, data, 16); 1015 sm_shift_left_by_one_bit_inplace(16, k1); 1016 if (data[0] & 0x80){ 1017 k1[15] ^= 0x87; 1018 } 1019 sm_key_t k2; 1020 memcpy(k2, k1, 16); 1021 sm_shift_left_by_one_bit_inplace(16, k2); 1022 if (k1[0] & 0x80){ 1023 k2[15] ^= 0x87; 1024 } 1025 1026 log_info_key("k", sm_cmac_k); 1027 log_info_key("k1", k1); 1028 log_info_key("k2", k2); 1029 1030 // step 4: set m_last 1031 int i; 1032 if (sm_cmac_last_block_complete()){ 1033 for (i=0;i<16;i++){ 1034 sm_cmac_m_last[i] = sm_cmac_message_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 1035 } 1036 } else { 1037 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 1038 for (i=0;i<16;i++){ 1039 if (i < valid_octets_in_last_block){ 1040 sm_cmac_m_last[i] = sm_cmac_message_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 1041 continue; 1042 } 1043 if (i == valid_octets_in_last_block){ 1044 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 1045 continue; 1046 } 1047 sm_cmac_m_last[i] = k2[i]; 1048 } 1049 } 1050 1051 // next 1052 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1053 break; 1054 } 1055 case CMAC_W4_MI: 1056 memcpy(sm_cmac_x, data, 16); 1057 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 1058 break; 1059 case CMAC_W4_MLAST: 1060 // done 1061 log_info_key("CMAC", data); 1062 sm_cmac_done_handler(data); 1063 sm_cmac_state = CMAC_IDLE; 1064 break; 1065 default: 1066 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 1067 break; 1068 } 1069 } 1070 1071 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 1072 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1073 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1074 switch (setup->sm_stk_generation_method){ 1075 case PK_RESP_INPUT: 1076 if (sm_conn->sm_role){ 1077 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1078 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1079 } else { 1080 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)); 1081 } 1082 break; 1083 case PK_INIT_INPUT: 1084 if (sm_conn->sm_role){ 1085 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)); 1086 } else { 1087 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1088 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1089 } 1090 break; 1091 case OK_BOTH_INPUT: 1092 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1093 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1094 break; 1095 case NK_BOTH_INPUT: 1096 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1097 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)); 1098 break; 1099 case JUST_WORKS: 1100 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1101 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1102 break; 1103 case OOB: 1104 // client already provided OOB data, let's skip notification. 1105 break; 1106 } 1107 } 1108 1109 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1110 int recv_flags; 1111 if (sm_conn->sm_role){ 1112 // slave / responder 1113 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1114 } else { 1115 // master / initiator 1116 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1117 } 1118 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1119 return recv_flags == setup->sm_key_distribution_received_set; 1120 } 1121 1122 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1123 if (sm_active_connection == con_handle){ 1124 sm_timeout_stop(); 1125 sm_active_connection = 0; 1126 log_info("sm: connection 0x%x released setup context", con_handle); 1127 } 1128 } 1129 1130 static int sm_key_distribution_flags_for_auth_req(void){ 1131 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 1132 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1133 // encryption information only if bonding requested 1134 flags |= SM_KEYDIST_ENC_KEY; 1135 } 1136 return flags; 1137 } 1138 1139 static void sm_init_setup(sm_connection_t * sm_conn){ 1140 1141 // fill in sm setup 1142 sm_reset_tk(); 1143 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1144 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1145 1146 // query client for OOB data 1147 int have_oob_data = 0; 1148 if (sm_get_oob_data) { 1149 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1150 } 1151 1152 sm_pairing_packet_t * local_packet; 1153 if (sm_conn->sm_role){ 1154 // slave 1155 local_packet = &setup->sm_s_pres; 1156 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 1157 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1158 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1159 } else { 1160 // master 1161 local_packet = &setup->sm_m_preq; 1162 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 1163 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1164 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1165 1166 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1167 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1168 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1169 } 1170 1171 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1172 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 1173 sm_pairing_packet_set_auth_req(*local_packet, sm_auth_req); 1174 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1175 } 1176 1177 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1178 1179 sm_pairing_packet_t * remote_packet; 1180 int remote_key_request; 1181 if (sm_conn->sm_role){ 1182 // slave / responder 1183 remote_packet = &setup->sm_m_preq; 1184 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1185 } else { 1186 // master / initiator 1187 remote_packet = &setup->sm_s_pres; 1188 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1189 } 1190 1191 // check key size 1192 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1193 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 1194 1195 // decide on STK generation method 1196 sm_setup_tk(); 1197 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1198 1199 // check if STK generation method is acceptable by client 1200 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1201 1202 // identical to responder 1203 sm_setup_key_distribution(remote_key_request); 1204 1205 // JUST WORKS doens't provide authentication 1206 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 1207 1208 return 0; 1209 } 1210 1211 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1212 1213 // cache and reset context 1214 int matched_device_id = sm_address_resolution_test; 1215 address_resolution_mode_t mode = sm_address_resolution_mode; 1216 void * context = sm_address_resolution_context; 1217 1218 // reset context 1219 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1220 sm_address_resolution_context = NULL; 1221 sm_address_resolution_test = -1; 1222 hci_con_handle_t con_handle = 0; 1223 1224 sm_connection_t * sm_connection; 1225 uint16_t ediv; 1226 switch (mode){ 1227 case ADDRESS_RESOLUTION_GENERAL: 1228 break; 1229 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1230 sm_connection = (sm_connection_t *) context; 1231 con_handle = sm_connection->sm_handle; 1232 switch (event){ 1233 case ADDRESS_RESOLUTION_SUCEEDED: 1234 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1235 sm_connection->sm_le_db_index = matched_device_id; 1236 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1237 if (sm_connection->sm_role) break; 1238 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1239 sm_connection->sm_security_request_received = 0; 1240 sm_connection->sm_bonding_requested = 0; 1241 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 1242 if (ediv){ 1243 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1244 } else { 1245 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1246 } 1247 break; 1248 case ADDRESS_RESOLUTION_FAILED: 1249 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1250 if (sm_connection->sm_role) break; 1251 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 1252 sm_connection->sm_security_request_received = 0; 1253 sm_connection->sm_bonding_requested = 0; 1254 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1255 break; 1256 } 1257 break; 1258 default: 1259 break; 1260 } 1261 1262 switch (event){ 1263 case ADDRESS_RESOLUTION_SUCEEDED: 1264 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1265 break; 1266 case ADDRESS_RESOLUTION_FAILED: 1267 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1268 break; 1269 } 1270 } 1271 1272 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1273 1274 int le_db_index = -1; 1275 1276 // lookup device based on IRK 1277 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1278 int i; 1279 for (i=0; i < le_device_db_count(); i++){ 1280 sm_key_t irk; 1281 bd_addr_t address; 1282 int address_type; 1283 le_device_db_info(i, &address_type, address, irk); 1284 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1285 log_info("sm: device found for IRK, updating"); 1286 le_db_index = i; 1287 break; 1288 } 1289 } 1290 } 1291 1292 // if not found, lookup via public address if possible 1293 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1294 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1295 int i; 1296 for (i=0; i < le_device_db_count(); i++){ 1297 bd_addr_t address; 1298 int address_type; 1299 le_device_db_info(i, &address_type, address, NULL); 1300 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1301 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1302 log_info("sm: device found for public address, updating"); 1303 le_db_index = i; 1304 break; 1305 } 1306 } 1307 } 1308 1309 // if not found, add to db 1310 if (le_db_index < 0) { 1311 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1312 } 1313 1314 if (le_db_index >= 0){ 1315 le_device_db_local_counter_set(le_db_index, 0); 1316 1317 // store local CSRK 1318 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1319 log_info("sm: store local CSRK"); 1320 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1321 le_device_db_local_counter_set(le_db_index, 0); 1322 } 1323 1324 // store remote CSRK 1325 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1326 log_info("sm: store remote CSRK"); 1327 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1328 le_device_db_remote_counter_set(le_db_index, 0); 1329 } 1330 1331 // store encryption information 1332 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION 1333 && setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1334 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1335 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1336 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1337 } 1338 } 1339 1340 // keep le_db_index 1341 sm_conn->sm_le_db_index = le_db_index; 1342 } 1343 1344 static void sm_run(void){ 1345 1346 btstack_linked_list_iterator_t it; 1347 1348 // assert that we can send at least commands 1349 if (!hci_can_send_command_packet_now()) return; 1350 1351 // 1352 // non-connection related behaviour 1353 // 1354 1355 // distributed key generation 1356 switch (dkg_state){ 1357 case DKG_CALC_IRK: 1358 // already busy? 1359 if (sm_aes128_state == SM_AES128_IDLE) { 1360 // IRK = d1(IR, 1, 0) 1361 sm_key_t d1_prime; 1362 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1363 dkg_next_state(); 1364 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1365 return; 1366 } 1367 break; 1368 case DKG_CALC_DHK: 1369 // already busy? 1370 if (sm_aes128_state == SM_AES128_IDLE) { 1371 // DHK = d1(IR, 3, 0) 1372 sm_key_t d1_prime; 1373 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1374 dkg_next_state(); 1375 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1376 return; 1377 } 1378 break; 1379 default: 1380 break; 1381 } 1382 1383 // random address updates 1384 switch (rau_state){ 1385 case RAU_GET_RANDOM: 1386 rau_next_state(); 1387 sm_random_start(NULL); 1388 return; 1389 case RAU_GET_ENC: 1390 // already busy? 1391 if (sm_aes128_state == SM_AES128_IDLE) { 1392 sm_key_t r_prime; 1393 sm_ah_r_prime(sm_random_address, r_prime); 1394 rau_next_state(); 1395 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1396 return; 1397 } 1398 break; 1399 case RAU_SET_ADDRESS: 1400 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1401 rau_state = RAU_IDLE; 1402 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1403 return; 1404 default: 1405 break; 1406 } 1407 1408 // CMAC 1409 switch (sm_cmac_state){ 1410 case CMAC_CALC_SUBKEYS: 1411 case CMAC_CALC_MI: 1412 case CMAC_CALC_MLAST: 1413 // already busy? 1414 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1415 sm_cmac_handle_aes_engine_ready(); 1416 return; 1417 default: 1418 break; 1419 } 1420 1421 // CSRK Lookup 1422 // -- if csrk lookup ready, find connection that require csrk lookup 1423 if (sm_address_resolution_idle()){ 1424 hci_connections_get_iterator(&it); 1425 while(btstack_linked_list_iterator_has_next(&it)){ 1426 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1427 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1428 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1429 // and start lookup 1430 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); 1431 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1432 break; 1433 } 1434 } 1435 } 1436 1437 // -- if csrk lookup ready, resolved addresses for received addresses 1438 if (sm_address_resolution_idle()) { 1439 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1440 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1441 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1442 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1443 btstack_memory_sm_lookup_entry_free(entry); 1444 } 1445 } 1446 1447 // -- Continue with CSRK device lookup by public or resolvable private address 1448 if (!sm_address_resolution_idle()){ 1449 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1450 while (sm_address_resolution_test < le_device_db_count()){ 1451 int addr_type; 1452 bd_addr_t addr; 1453 sm_key_t irk; 1454 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1455 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1456 1457 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1458 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1459 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1460 break; 1461 } 1462 1463 if (sm_address_resolution_addr_type == 0){ 1464 sm_address_resolution_test++; 1465 continue; 1466 } 1467 1468 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1469 1470 log_info("LE Device Lookup: calculate AH"); 1471 log_info_key("IRK", irk); 1472 1473 sm_key_t r_prime; 1474 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1475 sm_address_resolution_ah_calculation_active = 1; 1476 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1477 return; 1478 } 1479 1480 if (sm_address_resolution_test >= le_device_db_count()){ 1481 log_info("LE Device Lookup: not found"); 1482 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1483 } 1484 } 1485 1486 1487 // 1488 // active connection handling 1489 // -- use loop to handle next connection if lock on setup context is released 1490 1491 while (1) { 1492 1493 // Find connections that requires setup context and make active if no other is locked 1494 hci_connections_get_iterator(&it); 1495 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1496 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1497 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1498 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1499 int done = 1; 1500 int err; 1501 int encryption_key_size; 1502 int authenticated; 1503 int authorized; 1504 switch (sm_connection->sm_engine_state) { 1505 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1506 // send packet if possible, 1507 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1508 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1509 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1510 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1511 } else { 1512 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1513 } 1514 // don't lock setup context yet 1515 done = 0; 1516 break; 1517 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1518 sm_init_setup(sm_connection); 1519 // recover pairing request 1520 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1521 err = sm_stk_generation_init(sm_connection); 1522 if (err){ 1523 setup->sm_pairing_failed_reason = err; 1524 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1525 break; 1526 } 1527 sm_timeout_start(sm_connection); 1528 // generate random number first, if we need to show passkey 1529 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1530 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1531 break; 1532 } 1533 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1534 break; 1535 case SM_INITIATOR_PH0_HAS_LTK: 1536 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1537 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1538 &encryption_key_size, &authenticated, &authorized); 1539 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1540 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1541 sm_connection->sm_connection_authenticated = authenticated; 1542 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1543 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1544 break; 1545 case SM_RESPONDER_PH0_RECEIVED_LTK: 1546 // re-establish previously used LTK using Rand and EDIV 1547 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1548 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1549 // re-establish used key encryption size 1550 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1551 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1552 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1553 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1554 log_info("sm: received ltk request with key size %u, authenticated %u", 1555 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1556 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1557 break; 1558 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1559 sm_init_setup(sm_connection); 1560 sm_timeout_start(sm_connection); 1561 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1562 break; 1563 default: 1564 done = 0; 1565 break; 1566 } 1567 if (done){ 1568 sm_active_connection = sm_connection->sm_handle; 1569 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1570 } 1571 } 1572 1573 // 1574 // active connection handling 1575 // 1576 1577 if (sm_active_connection == 0) return; 1578 1579 // assert that we could send a SM PDU - not needed for all of the following 1580 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1581 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1582 return; 1583 } 1584 1585 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1586 if (!connection) return; 1587 1588 sm_key_t plaintext; 1589 int key_distribution_flags; 1590 1591 log_info("sm_run: state %u", connection->sm_engine_state); 1592 1593 // responding state 1594 switch (connection->sm_engine_state){ 1595 1596 // general 1597 case SM_GENERAL_SEND_PAIRING_FAILED: { 1598 uint8_t buffer[2]; 1599 buffer[0] = SM_CODE_PAIRING_FAILED; 1600 buffer[1] = setup->sm_pairing_failed_reason; 1601 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1602 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1603 sm_done_for_handle(connection->sm_handle); 1604 break; 1605 } 1606 1607 // initiator side 1608 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1609 sm_key_t peer_ltk_flipped; 1610 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1611 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1612 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1613 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1614 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1615 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1616 return; 1617 } 1618 1619 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1620 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 1621 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1622 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1623 sm_timeout_reset(connection); 1624 break; 1625 1626 // responder side 1627 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1628 connection->sm_engine_state = SM_RESPONDER_IDLE; 1629 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1630 return; 1631 1632 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1633 case SM_PH2_SEND_PUBLIC_KEY_COMMAND: { 1634 uint8_t buffer[65]; 1635 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 1636 // 1637 #ifdef USE_MBEDTLS_FOR_ECDH 1638 uint8_t value[32]; 1639 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1640 reverse_256(value, &buffer[1]); 1641 mbedtls_mpi_write_binary(&le_keypair.Q.Y, value, sizeof(value)); 1642 reverse_256(value, &buffer[33]); 1643 #endif 1644 // TODO: use random generator to generate nonce 1645 1646 // generate 128-bit nonce 1647 int i; 1648 for (i=0;i<16;i++){ 1649 setup->sm_local_nonce[i] = rand() & 0xff; 1650 } 1651 1652 // stk generation method 1653 // passkey entry: notify app to show passkey or to request passkey 1654 switch (setup->sm_stk_generation_method){ 1655 case JUST_WORKS: 1656 case NK_BOTH_INPUT: 1657 if (connection->sm_role){ 1658 connection->sm_engine_state = SM_PH2_SEND_CONFIRMATION; 1659 } else { 1660 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PUBLIC_KEY_COMMAND; 1661 } 1662 break; 1663 case PK_INIT_INPUT: 1664 case PK_RESP_INPUT: 1665 case OK_BOTH_INPUT: 1666 // hack for testing: assume user entered '000000' 1667 // memset(setup->sm_tk, 0, 16); 1668 memcpy(setup->sm_ra, setup->sm_tk, 16); 1669 memcpy(setup->sm_rb, setup->sm_tk, 16); 1670 setup->sm_passkey_bit = 0; 1671 if (connection->sm_role){ 1672 // responder 1673 connection->sm_engine_state = SM_PH2_W4_CONFIRMATION; 1674 } else { 1675 // initiator 1676 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PUBLIC_KEY_COMMAND; 1677 } 1678 sm_trigger_user_response(connection); 1679 break; 1680 case OOB: 1681 // TODO: implement SC OOB 1682 break; 1683 } 1684 1685 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1686 sm_timeout_reset(connection); 1687 break; 1688 } 1689 case SM_PH2_SEND_CONFIRMATION: { 1690 uint8_t buffer[17]; 1691 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1692 #ifdef USE_MBEDTLS_FOR_ECDH 1693 uint8_t z = 0; 1694 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 1695 // some form of passkey 1696 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1697 z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 1698 setup->sm_passkey_bit++; 1699 } 1700 1701 // TODO: use AES Engine to calculate commitment value using f4 1702 uint8_t value[32]; 1703 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1704 sm_key_t confirm_value; 1705 f4(confirm_value, value, setup->sm_peer_qx, setup->sm_local_nonce, z); 1706 reverse_128(confirm_value, &buffer[1]); 1707 #endif 1708 if (connection->sm_role){ 1709 connection->sm_engine_state = SM_PH2_W4_PAIRING_RANDOM; 1710 } else { 1711 connection->sm_engine_state = SM_PH2_W4_CONFIRMATION; 1712 } 1713 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1714 sm_timeout_reset(connection); 1715 break; 1716 } 1717 case SM_PH2_SEND_PAIRING_RANDOM_SC: { 1718 uint8_t buffer[17]; 1719 buffer[0] = SM_CODE_PAIRING_RANDOM; 1720 reverse_128(setup->sm_local_nonce, &buffer[1]); 1721 1722 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 1723 if (connection->sm_role){ 1724 // responder 1725 connection->sm_engine_state = SM_PH2_W4_CONFIRMATION; 1726 } else { 1727 // initiator 1728 connection->sm_engine_state = SM_PH2_W4_PAIRING_RANDOM; 1729 } 1730 } else { 1731 if (connection->sm_role){ 1732 // responder 1733 connection->sm_engine_state = SM_PH2_W4_DHKEY_CHECK_COMMAND; 1734 if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ 1735 // calc Vb if numeric comparison 1736 // TODO: use AES Engine to calculate g2 1737 uint8_t value[32]; 1738 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 1739 uint32_t vb = g2(setup->sm_peer_qx, value, setup->sm_peer_nonce, setup->sm_local_nonce) % 1000000; 1740 big_endian_store_32(setup->sm_tk, 12, vb); 1741 sm_trigger_user_response(connection); 1742 } 1743 } else { 1744 // initiator 1745 connection->sm_engine_state = SM_PH2_W4_PAIRING_RANDOM; 1746 } 1747 } 1748 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1749 sm_timeout_reset(connection); 1750 break; 1751 } 1752 case SM_PH2_SEND_DHKEY_CHECK_COMMAND: { 1753 1754 uint8_t buffer[17]; 1755 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 1756 #ifdef USE_MBEDTLS_FOR_ECDH 1757 // calculate DHKEY 1758 mbedtls_ecp_group grp; 1759 mbedtls_ecp_group_init( &grp ); 1760 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 1761 mbedtls_ecp_point Q; 1762 mbedtls_ecp_point_init( &Q ); 1763 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 1764 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 1765 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 1766 1767 // da * Pb 1768 mbedtls_ecp_point DH; 1769 mbedtls_ecp_point_init( &DH ); 1770 mbedtls_ecp_mul(&grp, &DH, &le_keypair.d, &Q, NULL, NULL); 1771 sm_key256_t dhkey; 1772 mbedtls_mpi_write_binary(&DH.X, dhkey, 32); 1773 log_info("dhkey"); 1774 log_info_hexdump(dhkey, 32); 1775 1776 // calculate LTK + MacKey 1777 sm_key256_t ltk_mackey; 1778 sm_key56_t bd_addr_master, bd_addr_slave; 1779 bd_addr_master[0] = setup->sm_m_addr_type; 1780 bd_addr_slave[0] = setup->sm_s_addr_type; 1781 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1782 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1783 if (connection->sm_role){ 1784 // responder 1785 f5(ltk_mackey, dhkey, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1786 } else { 1787 // initiator 1788 f5(ltk_mackey, dhkey, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1789 } 1790 // store LTK 1791 memcpy(setup->sm_ltk, <k_mackey[16], 16); 1792 1793 // calc DHKCheck 1794 memcpy(setup->sm_mackey, <k_mackey[0], 16); 1795 1796 // TODO: checks 1797 1798 uint8_t iocap_a[3]; 1799 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1800 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1801 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1802 uint8_t iocap_b[3]; 1803 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1804 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1805 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1806 if (connection->sm_role){ 1807 // responder 1808 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); 1809 } else { 1810 // initiator 1811 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); 1812 } 1813 #endif 1814 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 1815 if (connection->sm_role){ 1816 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST_SC; 1817 } else { 1818 connection->sm_engine_state = SM_PH2_W4_DHKEY_CHECK_COMMAND; 1819 } 1820 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1821 sm_timeout_reset(connection); 1822 break; 1823 } 1824 1825 #endif 1826 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 1827 // echo initiator for now 1828 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 1829 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1830 1831 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 1832 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1833 if (setup->sm_use_secure_connections){ 1834 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PUBLIC_KEY_COMMAND; 1835 // skip LTK/EDIV for SC 1836 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 1837 } 1838 #endif 1839 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); 1840 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); 1841 1842 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 1843 sm_timeout_reset(connection); 1844 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 1845 if (setup->sm_stk_generation_method == JUST_WORKS){ 1846 sm_trigger_user_response(connection); 1847 } 1848 return; 1849 1850 case SM_PH2_SEND_PAIRING_RANDOM: { 1851 uint8_t buffer[17]; 1852 buffer[0] = SM_CODE_PAIRING_RANDOM; 1853 reverse_128(setup->sm_local_random, &buffer[1]); 1854 if (connection->sm_role){ 1855 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 1856 } else { 1857 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 1858 } 1859 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1860 sm_timeout_reset(connection); 1861 break; 1862 } 1863 1864 case SM_PH2_GET_RANDOM_TK: 1865 case SM_PH2_C1_GET_RANDOM_A: 1866 case SM_PH2_C1_GET_RANDOM_B: 1867 case SM_PH3_GET_RANDOM: 1868 case SM_PH3_GET_DIV: 1869 sm_next_responding_state(connection); 1870 sm_random_start(connection); 1871 return; 1872 1873 case SM_PH2_C1_GET_ENC_B: 1874 case SM_PH2_C1_GET_ENC_D: 1875 // already busy? 1876 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1877 sm_next_responding_state(connection); 1878 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 1879 return; 1880 1881 case SM_PH3_LTK_GET_ENC: 1882 case SM_RESPONDER_PH4_LTK_GET_ENC: 1883 // already busy? 1884 if (sm_aes128_state == SM_AES128_IDLE) { 1885 sm_key_t d_prime; 1886 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 1887 sm_next_responding_state(connection); 1888 sm_aes128_start(sm_persistent_er, d_prime, connection); 1889 return; 1890 } 1891 break; 1892 1893 case SM_PH3_CSRK_GET_ENC: 1894 // already busy? 1895 if (sm_aes128_state == SM_AES128_IDLE) { 1896 sm_key_t d_prime; 1897 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 1898 sm_next_responding_state(connection); 1899 sm_aes128_start(sm_persistent_er, d_prime, connection); 1900 return; 1901 } 1902 break; 1903 1904 case SM_PH2_C1_GET_ENC_C: 1905 // already busy? 1906 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1907 // calculate m_confirm using aes128 engine - step 1 1908 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); 1909 sm_next_responding_state(connection); 1910 sm_aes128_start(setup->sm_tk, plaintext, connection); 1911 break; 1912 case SM_PH2_C1_GET_ENC_A: 1913 // already busy? 1914 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1915 // calculate confirm using aes128 engine - step 1 1916 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); 1917 sm_next_responding_state(connection); 1918 sm_aes128_start(setup->sm_tk, plaintext, connection); 1919 break; 1920 case SM_PH2_CALC_STK: 1921 // already busy? 1922 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1923 // calculate STK 1924 if (connection->sm_role){ 1925 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 1926 } else { 1927 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 1928 } 1929 sm_next_responding_state(connection); 1930 sm_aes128_start(setup->sm_tk, plaintext, connection); 1931 break; 1932 case SM_PH3_Y_GET_ENC: 1933 // already busy? 1934 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1935 // PH3B2 - calculate Y from - enc 1936 // Y = dm(DHK, Rand) 1937 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1938 sm_next_responding_state(connection); 1939 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1940 return; 1941 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 1942 uint8_t buffer[17]; 1943 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1944 reverse_128(setup->sm_local_confirm, &buffer[1]); 1945 if (connection->sm_role){ 1946 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 1947 } else { 1948 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 1949 } 1950 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1951 sm_timeout_reset(connection); 1952 return; 1953 } 1954 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 1955 sm_key_t stk_flipped; 1956 reverse_128(setup->sm_ltk, stk_flipped); 1957 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1958 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 1959 return; 1960 } 1961 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 1962 sm_key_t stk_flipped; 1963 reverse_128(setup->sm_ltk, stk_flipped); 1964 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1965 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 1966 return; 1967 } 1968 case SM_RESPONDER_PH4_SEND_LTK: { 1969 sm_key_t ltk_flipped; 1970 reverse_128(setup->sm_ltk, ltk_flipped); 1971 connection->sm_engine_state = SM_RESPONDER_IDLE; 1972 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 1973 return; 1974 } 1975 case SM_RESPONDER_PH4_Y_GET_ENC: 1976 // already busy? 1977 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1978 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 1979 // Y = dm(DHK, Rand) 1980 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1981 sm_next_responding_state(connection); 1982 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1983 return; 1984 1985 case SM_PH3_DISTRIBUTE_KEYS: 1986 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 1987 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 1988 uint8_t buffer[17]; 1989 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 1990 reverse_128(setup->sm_ltk, &buffer[1]); 1991 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1992 sm_timeout_reset(connection); 1993 return; 1994 } 1995 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1996 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 1997 uint8_t buffer[11]; 1998 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 1999 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2000 reverse_64(setup->sm_local_rand, &buffer[3]); 2001 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2002 sm_timeout_reset(connection); 2003 return; 2004 } 2005 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2006 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2007 uint8_t buffer[17]; 2008 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2009 reverse_128(sm_persistent_irk, &buffer[1]); 2010 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2011 sm_timeout_reset(connection); 2012 return; 2013 } 2014 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2015 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2016 bd_addr_t local_address; 2017 uint8_t buffer[8]; 2018 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2019 gap_advertisements_get_address(&buffer[1], local_address); 2020 reverse_bd_addr(local_address, &buffer[2]); 2021 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2022 sm_timeout_reset(connection); 2023 return; 2024 } 2025 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2026 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2027 2028 // hack to reproduce test runs 2029 if (test_use_fixed_local_csrk){ 2030 memset(setup->sm_local_csrk, 0xcc, 16); 2031 } 2032 2033 uint8_t buffer[17]; 2034 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2035 reverse_128(setup->sm_local_csrk, &buffer[1]); 2036 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2037 sm_timeout_reset(connection); 2038 return; 2039 } 2040 2041 // keys are sent 2042 if (connection->sm_role){ 2043 // slave -> receive master keys if any 2044 if (sm_key_distribution_all_received(connection)){ 2045 sm_key_distribution_handle_all_received(connection); 2046 connection->sm_engine_state = SM_RESPONDER_IDLE; 2047 sm_done_for_handle(connection->sm_handle); 2048 } else { 2049 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2050 } 2051 } else { 2052 // master -> all done 2053 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2054 sm_done_for_handle(connection->sm_handle); 2055 } 2056 break; 2057 2058 default: 2059 break; 2060 } 2061 2062 // check again if active connection was released 2063 if (sm_active_connection) break; 2064 } 2065 } 2066 2067 // note: aes engine is ready as we just got the aes result 2068 static void sm_handle_encryption_result(uint8_t * data){ 2069 2070 sm_aes128_state = SM_AES128_IDLE; 2071 2072 if (sm_address_resolution_ah_calculation_active){ 2073 sm_address_resolution_ah_calculation_active = 0; 2074 // compare calulated address against connecting device 2075 uint8_t hash[3]; 2076 reverse_24(data, hash); 2077 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 2078 log_info("LE Device Lookup: matched resolvable private address"); 2079 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2080 return; 2081 } 2082 // no match, try next 2083 sm_address_resolution_test++; 2084 return; 2085 } 2086 2087 switch (dkg_state){ 2088 case DKG_W4_IRK: 2089 reverse_128(data, sm_persistent_irk); 2090 log_info_key("irk", sm_persistent_irk); 2091 dkg_next_state(); 2092 return; 2093 case DKG_W4_DHK: 2094 reverse_128(data, sm_persistent_dhk); 2095 log_info_key("dhk", sm_persistent_dhk); 2096 dkg_next_state(); 2097 // SM Init Finished 2098 return; 2099 default: 2100 break; 2101 } 2102 2103 switch (rau_state){ 2104 case RAU_W4_ENC: 2105 reverse_24(data, &sm_random_address[3]); 2106 rau_next_state(); 2107 return; 2108 default: 2109 break; 2110 } 2111 2112 switch (sm_cmac_state){ 2113 case CMAC_W4_SUBKEYS: 2114 case CMAC_W4_MI: 2115 case CMAC_W4_MLAST: 2116 { 2117 sm_key_t t; 2118 reverse_128(data, t); 2119 sm_cmac_handle_encryption_result(t); 2120 } 2121 return; 2122 default: 2123 break; 2124 } 2125 2126 // retrieve sm_connection provided to sm_aes128_start_encryption 2127 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 2128 if (!connection) return; 2129 switch (connection->sm_engine_state){ 2130 case SM_PH2_C1_W4_ENC_A: 2131 case SM_PH2_C1_W4_ENC_C: 2132 { 2133 sm_key_t t2; 2134 reverse_128(data, t2); 2135 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2136 } 2137 sm_next_responding_state(connection); 2138 return; 2139 case SM_PH2_C1_W4_ENC_B: 2140 reverse_128(data, setup->sm_local_confirm); 2141 log_info_key("c1!", setup->sm_local_confirm); 2142 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2143 return; 2144 case SM_PH2_C1_W4_ENC_D: 2145 { 2146 sm_key_t peer_confirm_test; 2147 reverse_128(data, peer_confirm_test); 2148 log_info_key("c1!", peer_confirm_test); 2149 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 2150 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2151 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2152 return; 2153 } 2154 if (connection->sm_role){ 2155 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2156 } else { 2157 connection->sm_engine_state = SM_PH2_CALC_STK; 2158 } 2159 } 2160 return; 2161 case SM_PH2_W4_STK: 2162 reverse_128(data, setup->sm_ltk); 2163 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2164 log_info_key("stk", setup->sm_ltk); 2165 if (connection->sm_role){ 2166 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2167 } else { 2168 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2169 } 2170 return; 2171 case SM_PH3_Y_W4_ENC:{ 2172 sm_key_t y128; 2173 reverse_128(data, y128); 2174 setup->sm_local_y = big_endian_read_16(y128, 14); 2175 log_info_hex16("y", setup->sm_local_y); 2176 // PH3B3 - calculate EDIV 2177 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2178 log_info_hex16("ediv", setup->sm_local_ediv); 2179 // PH3B4 - calculate LTK - enc 2180 // LTK = d1(ER, DIV, 0)) 2181 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 2182 return; 2183 } 2184 case SM_RESPONDER_PH4_Y_W4_ENC:{ 2185 sm_key_t y128; 2186 reverse_128(data, y128); 2187 setup->sm_local_y = big_endian_read_16(y128, 14); 2188 log_info_hex16("y", setup->sm_local_y); 2189 2190 // PH3B3 - calculate DIV 2191 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2192 log_info_hex16("ediv", setup->sm_local_ediv); 2193 // PH3B4 - calculate LTK - enc 2194 // LTK = d1(ER, DIV, 0)) 2195 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 2196 return; 2197 } 2198 case SM_PH3_LTK_W4_ENC: 2199 reverse_128(data, setup->sm_ltk); 2200 log_info_key("ltk", setup->sm_ltk); 2201 // calc CSRK next 2202 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 2203 return; 2204 case SM_PH3_CSRK_W4_ENC: 2205 reverse_128(data, setup->sm_local_csrk); 2206 log_info_key("csrk", setup->sm_local_csrk); 2207 if (setup->sm_key_distribution_send_set){ 2208 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2209 } else { 2210 // no keys to send, just continue 2211 if (connection->sm_role){ 2212 // slave -> receive master keys 2213 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2214 } else { 2215 // master -> all done 2216 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 2217 sm_done_for_handle(connection->sm_handle); 2218 } 2219 } 2220 return; 2221 case SM_RESPONDER_PH4_LTK_W4_ENC: 2222 reverse_128(data, setup->sm_ltk); 2223 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2224 log_info_key("ltk", setup->sm_ltk); 2225 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 2226 return; 2227 default: 2228 break; 2229 } 2230 } 2231 2232 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 2233 static void sm_handle_random_result(uint8_t * data){ 2234 2235 switch (rau_state){ 2236 case RAU_W4_RANDOM: 2237 // non-resolvable vs. resolvable 2238 switch (gap_random_adress_type){ 2239 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2240 // resolvable: use random as prand and calc address hash 2241 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 2242 memcpy(sm_random_address, data, 3); 2243 sm_random_address[0] &= 0x3f; 2244 sm_random_address[0] |= 0x40; 2245 rau_state = RAU_GET_ENC; 2246 break; 2247 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2248 default: 2249 // "The two most significant bits of the address shall be equal to ‘0’"" 2250 memcpy(sm_random_address, data, 6); 2251 sm_random_address[0] &= 0x3f; 2252 rau_state = RAU_SET_ADDRESS; 2253 break; 2254 } 2255 return; 2256 default: 2257 break; 2258 } 2259 2260 // retrieve sm_connection provided to sm_random_start 2261 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 2262 if (!connection) return; 2263 switch (connection->sm_engine_state){ 2264 case SM_PH2_W4_RANDOM_TK: 2265 { 2266 // map random to 0-999999 without speding much cycles on a modulus operation 2267 uint32_t tk = little_endian_read_32(data,0); 2268 tk = tk & 0xfffff; // 1048575 2269 if (tk >= 999999){ 2270 tk = tk - 999999; 2271 } 2272 sm_reset_tk(); 2273 big_endian_store_32(setup->sm_tk, 12, tk); 2274 if (connection->sm_role){ 2275 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2276 } else { 2277 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2278 sm_trigger_user_response(connection); 2279 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2280 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2281 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2282 } 2283 } 2284 return; 2285 } 2286 case SM_PH2_C1_W4_RANDOM_A: 2287 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 2288 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 2289 return; 2290 case SM_PH2_C1_W4_RANDOM_B: 2291 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 2292 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 2293 return; 2294 case SM_PH3_W4_RANDOM: 2295 reverse_64(data, setup->sm_local_rand); 2296 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 2297 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 2298 // no db for authenticated flag hack: store flag in bit 4 of LSB 2299 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 2300 connection->sm_engine_state = SM_PH3_GET_DIV; 2301 return; 2302 case SM_PH3_W4_DIV: 2303 // use 16 bit from random value as div 2304 setup->sm_local_div = big_endian_read_16(data, 0); 2305 log_info_hex16("div", setup->sm_local_div); 2306 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 2307 return; 2308 default: 2309 break; 2310 } 2311 } 2312 2313 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 2314 2315 sm_connection_t * sm_conn; 2316 hci_con_handle_t con_handle; 2317 2318 switch (packet_type) { 2319 2320 case HCI_EVENT_PACKET: 2321 switch (hci_event_packet_get_type(packet)) { 2322 2323 case BTSTACK_EVENT_STATE: 2324 // bt stack activated, get started 2325 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 2326 log_info("HCI Working!"); 2327 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 2328 rau_state = RAU_IDLE; 2329 sm_run(); 2330 } 2331 break; 2332 2333 case HCI_EVENT_LE_META: 2334 switch (packet[2]) { 2335 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 2336 2337 log_info("sm: connected"); 2338 2339 if (packet[3]) return; // connection failed 2340 2341 con_handle = little_endian_read_16(packet, 4); 2342 sm_conn = sm_get_connection_for_handle(con_handle); 2343 if (!sm_conn) break; 2344 2345 sm_conn->sm_handle = con_handle; 2346 sm_conn->sm_role = packet[6]; 2347 sm_conn->sm_peer_addr_type = packet[7]; 2348 reverse_bd_addr(&packet[8], 2349 sm_conn->sm_peer_address); 2350 2351 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 2352 2353 // reset security properties 2354 sm_conn->sm_connection_encrypted = 0; 2355 sm_conn->sm_connection_authenticated = 0; 2356 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 2357 sm_conn->sm_le_db_index = -1; 2358 2359 // prepare CSRK lookup (does not involve setup) 2360 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 2361 2362 // just connected -> everything else happens in sm_run() 2363 if (sm_conn->sm_role){ 2364 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 2365 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 2366 if (sm_slave_request_security) { 2367 // request security if requested by app 2368 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2369 } else { 2370 // otherwise, wait for pairing request 2371 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2372 } 2373 } 2374 break; 2375 } else { 2376 // master 2377 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2378 } 2379 break; 2380 2381 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 2382 con_handle = little_endian_read_16(packet, 3); 2383 sm_conn = sm_get_connection_for_handle(con_handle); 2384 if (!sm_conn) break; 2385 2386 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 2387 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 2388 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 2389 break; 2390 } 2391 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST_SC){ 2392 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2393 break; 2394 } 2395 2396 // assume that we don't have a LTK for ediv == 0 and random == null 2397 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 2398 log_info("LTK Request: ediv & random are empty"); 2399 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 2400 break; 2401 } 2402 2403 // store rand and ediv 2404 reverse_64(&packet[5], sm_conn->sm_local_rand); 2405 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 2406 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 2407 break; 2408 2409 default: 2410 break; 2411 } 2412 break; 2413 2414 case HCI_EVENT_ENCRYPTION_CHANGE: 2415 con_handle = little_endian_read_16(packet, 3); 2416 sm_conn = sm_get_connection_for_handle(con_handle); 2417 if (!sm_conn) break; 2418 2419 sm_conn->sm_connection_encrypted = packet[5]; 2420 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 2421 sm_conn->sm_actual_encryption_key_size); 2422 log_info("event handler, state %u", sm_conn->sm_engine_state); 2423 if (!sm_conn->sm_connection_encrypted) break; 2424 // continue if part of initial pairing 2425 switch (sm_conn->sm_engine_state){ 2426 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2427 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2428 sm_done_for_handle(sm_conn->sm_handle); 2429 break; 2430 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2431 if (sm_conn->sm_role){ 2432 // slave 2433 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2434 } else { 2435 // master 2436 if (sm_key_distribution_all_received(sm_conn)){ 2437 // skip receiving keys as there are none 2438 sm_key_distribution_handle_all_received(sm_conn); 2439 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2440 } else { 2441 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2442 } 2443 } 2444 break; 2445 default: 2446 break; 2447 } 2448 break; 2449 2450 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 2451 con_handle = little_endian_read_16(packet, 3); 2452 sm_conn = sm_get_connection_for_handle(con_handle); 2453 if (!sm_conn) break; 2454 2455 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 2456 log_info("event handler, state %u", sm_conn->sm_engine_state); 2457 // continue if part of initial pairing 2458 switch (sm_conn->sm_engine_state){ 2459 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 2460 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 2461 sm_done_for_handle(sm_conn->sm_handle); 2462 break; 2463 case SM_PH2_W4_CONNECTION_ENCRYPTED: 2464 if (sm_conn->sm_role){ 2465 // slave 2466 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2467 } else { 2468 // master 2469 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2470 } 2471 break; 2472 default: 2473 break; 2474 } 2475 break; 2476 2477 2478 case HCI_EVENT_DISCONNECTION_COMPLETE: 2479 con_handle = little_endian_read_16(packet, 3); 2480 sm_done_for_handle(con_handle); 2481 sm_conn = sm_get_connection_for_handle(con_handle); 2482 if (!sm_conn) break; 2483 2484 // delete stored bonding on disconnect with authentication failure in ph0 2485 if (sm_conn->sm_role == 0 2486 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2487 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2488 le_device_db_remove(sm_conn->sm_le_db_index); 2489 } 2490 2491 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2492 sm_conn->sm_handle = 0; 2493 break; 2494 2495 case HCI_EVENT_COMMAND_COMPLETE: 2496 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2497 sm_handle_encryption_result(&packet[6]); 2498 break; 2499 } 2500 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2501 sm_handle_random_result(&packet[6]); 2502 break; 2503 } 2504 break; 2505 default: 2506 break; 2507 } 2508 break; 2509 default: 2510 break; 2511 } 2512 2513 sm_run(); 2514 } 2515 2516 static inline int sm_calc_actual_encryption_key_size(int other){ 2517 if (other < sm_min_encryption_key_size) return 0; 2518 if (other < sm_max_encryption_key_size) return other; 2519 return sm_max_encryption_key_size; 2520 } 2521 2522 /** 2523 * @return ok 2524 */ 2525 static int sm_validate_stk_generation_method(void){ 2526 // check if STK generation method is acceptable by client 2527 switch (setup->sm_stk_generation_method){ 2528 case JUST_WORKS: 2529 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2530 case PK_RESP_INPUT: 2531 case PK_INIT_INPUT: 2532 case OK_BOTH_INPUT: 2533 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2534 case OOB: 2535 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2536 case NK_BOTH_INPUT: 2537 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; 2538 return 1; 2539 default: 2540 return 0; 2541 } 2542 } 2543 2544 // helper for sm_pdu_handler, calls sm_run on exit 2545 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 2546 setup->sm_pairing_failed_reason = reason; 2547 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2548 } 2549 2550 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 2551 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 2552 } 2553 2554 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2555 2556 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 2557 sm_run(); 2558 } 2559 2560 if (packet_type != SM_DATA_PACKET) return; 2561 2562 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2563 if (!sm_conn) return; 2564 2565 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2566 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2567 return; 2568 } 2569 2570 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2571 2572 int err; 2573 2574 switch (sm_conn->sm_engine_state){ 2575 2576 // a sm timeout requries a new physical connection 2577 case SM_GENERAL_TIMEOUT: 2578 return; 2579 2580 // Initiator 2581 case SM_INITIATOR_CONNECTED: 2582 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2583 sm_pdu_received_in_wrong_state(sm_conn); 2584 break; 2585 } 2586 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2587 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2588 break; 2589 } 2590 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2591 uint16_t ediv; 2592 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2593 if (ediv){ 2594 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2595 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2596 } else { 2597 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2598 } 2599 break; 2600 } 2601 // otherwise, store security request 2602 sm_conn->sm_security_request_received = 1; 2603 break; 2604 2605 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2606 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2607 sm_pdu_received_in_wrong_state(sm_conn); 2608 break; 2609 } 2610 // store pairing request 2611 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2612 err = sm_stk_generation_init(sm_conn); 2613 if (err){ 2614 setup->sm_pairing_failed_reason = err; 2615 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2616 break; 2617 } 2618 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2619 if (setup->sm_use_secure_connections){ 2620 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2621 if (setup->sm_stk_generation_method == JUST_WORKS){ 2622 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2623 sm_trigger_user_response(sm_conn); 2624 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2625 sm_conn->sm_engine_state = SM_PH2_SEND_PUBLIC_KEY_COMMAND; 2626 } 2627 } else { 2628 sm_conn->sm_engine_state = SM_PH2_SEND_PUBLIC_KEY_COMMAND; 2629 } 2630 break; 2631 } 2632 #endif 2633 // generate random number first, if we need to show passkey 2634 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2635 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2636 break; 2637 } 2638 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2639 sm_trigger_user_response(sm_conn); 2640 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2641 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2642 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2643 } 2644 break; 2645 2646 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2647 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2648 sm_pdu_received_in_wrong_state(sm_conn); 2649 break; 2650 } 2651 2652 // store s_confirm 2653 reverse_128(&packet[1], setup->sm_peer_confirm); 2654 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2655 break; 2656 2657 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2658 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2659 sm_pdu_received_in_wrong_state(sm_conn); 2660 break;; 2661 } 2662 2663 // received random value 2664 reverse_128(&packet[1], setup->sm_peer_random); 2665 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2666 break; 2667 2668 // Responder 2669 case SM_RESPONDER_IDLE: 2670 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2671 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2672 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2673 sm_pdu_received_in_wrong_state(sm_conn); 2674 break;; 2675 } 2676 2677 // store pairing request 2678 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2679 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2680 break; 2681 2682 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2683 case SM_RESPONDER_PH2_W4_PUBLIC_KEY_COMMAND: 2684 if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ 2685 sm_pdu_received_in_wrong_state(sm_conn); 2686 break; 2687 } 2688 2689 // store public key for DH Key calculation 2690 reverse_256(&packet[01], setup->sm_peer_qx); 2691 reverse_256(&packet[33], setup->sm_peer_qy); 2692 2693 #ifdef USE_MBEDTLS_FOR_ECDH 2694 // validate public key 2695 mbedtls_ecp_group grp; 2696 mbedtls_ecp_group_init( &grp ); 2697 mbedtls_ecp_group_load(&grp, MBEDTLS_ECP_DP_SECP256R1); 2698 2699 mbedtls_ecp_point Q; 2700 mbedtls_ecp_point_init( &Q ); 2701 mbedtls_mpi_read_binary(&Q.X, setup->sm_peer_qx, 32); 2702 mbedtls_mpi_read_binary(&Q.Y, setup->sm_peer_qy, 32); 2703 mbedtls_mpi_read_string(&Q.Z, 16, "1" ); 2704 err = mbedtls_ecp_check_pubkey(&grp, &Q); 2705 if (err){ 2706 log_error("sm: peer public key invalid %x", err); 2707 // uses "unspecified reason", there is no "public key invalid" error code 2708 sm_pdu_received_in_wrong_state(sm_conn); 2709 break; 2710 } 2711 #endif 2712 if (sm_conn->sm_role){ 2713 // responder 2714 sm_conn->sm_engine_state = SM_PH2_SEND_PUBLIC_KEY_COMMAND; 2715 } else { 2716 // initiator 2717 // stk generation method 2718 // passkey entry: notify app to show passkey or to request passkey 2719 switch (setup->sm_stk_generation_method){ 2720 case JUST_WORKS: 2721 case NK_BOTH_INPUT: 2722 sm_conn->sm_engine_state = SM_PH2_W4_CONFIRMATION; 2723 break; 2724 case PK_INIT_INPUT: 2725 case PK_RESP_INPUT: 2726 case OK_BOTH_INPUT: 2727 sm_conn->sm_engine_state = SM_PH2_SEND_CONFIRMATION; 2728 break; 2729 case OOB: 2730 // TODO: implement SC OOB 2731 break; 2732 } 2733 } 2734 break; 2735 2736 case SM_PH2_W4_CONFIRMATION: 2737 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2738 sm_pdu_received_in_wrong_state(sm_conn); 2739 break; 2740 } 2741 // received confirm value 2742 reverse_128(&packet[1], setup->sm_peer_confirm); 2743 2744 if (sm_conn->sm_role){ 2745 // responder 2746 sm_conn->sm_engine_state = SM_PH2_SEND_CONFIRMATION; 2747 } else { 2748 // initiator 2749 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM_SC; 2750 } 2751 break; 2752 2753 case SM_PH2_W4_PAIRING_RANDOM: 2754 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2755 sm_pdu_received_in_wrong_state(sm_conn); 2756 break; 2757 } 2758 2759 // received random value 2760 reverse_128(&packet[1], setup->sm_peer_nonce); 2761 2762 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 2763 uint8_t z = 0; 2764 int passkey_entry = 0; 2765 if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ 2766 // some form of passkey 2767 passkey_entry = 1; 2768 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 2769 // sm_passkey_bit was increased before sending confirm value 2770 z = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); 2771 } 2772 // only check for JUST WORK/NC in initiator role AND passkey entry 2773 if (sm_conn->sm_role || passkey_entry) { 2774 sm_key_t confirm_value; 2775 #ifdef USE_MBEDTLS_FOR_ECDH 2776 uint8_t local_qx[32]; 2777 mbedtls_mpi_write_binary(&le_keypair.Q.X, local_qx, sizeof(local_qx)); 2778 f4(confirm_value, setup->sm_peer_qx, local_qx, setup->sm_peer_nonce, z); 2779 #endif 2780 if (0 != memcmp(confirm_value, setup->sm_peer_confirm, 16)){ 2781 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 2782 break; 2783 } 2784 } 2785 2786 if (sm_conn->sm_role){ 2787 // Responder 2788 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM_SC; 2789 } else { 2790 // Initiator role 2791 switch (setup->sm_stk_generation_method){ 2792 case JUST_WORKS: 2793 sm_conn->sm_engine_state = SM_PH2_SEND_DHKEY_CHECK_COMMAND; 2794 break; 2795 2796 case NK_BOTH_INPUT: { 2797 // calc Va if numeric comparison 2798 // TODO: use AES Engine to calculate g2 2799 uint8_t value[32]; 2800 mbedtls_mpi_write_binary(&le_keypair.Q.X, value, sizeof(value)); 2801 uint32_t va = g2(value, setup->sm_peer_qx, setup->sm_local_nonce, setup->sm_peer_nonce) % 1000000; 2802 big_endian_store_32(setup->sm_tk, 12, va); 2803 sm_trigger_user_response(sm_conn); 2804 break; 2805 } 2806 case PK_INIT_INPUT: 2807 case PK_RESP_INPUT: 2808 case OK_BOTH_INPUT: 2809 if (setup->sm_passkey_bit < 20) { 2810 sm_conn->sm_engine_state = SM_PH2_SEND_CONFIRMATION; 2811 } else { 2812 sm_conn->sm_engine_state = SM_PH2_SEND_DHKEY_CHECK_COMMAND; 2813 } 2814 break; 2815 case OOB: 2816 // TODO: implement SC OOB 2817 break; 2818 } 2819 } 2820 break; 2821 2822 case SM_PH2_W4_DHKEY_CHECK_COMMAND: 2823 if (packet[0] != SM_CODE_PAIRING_DHKEY_CHECK){ 2824 sm_pdu_received_in_wrong_state(sm_conn); 2825 break; 2826 } 2827 // store DHKey Check 2828 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 2829 2830 // validate E = f6() 2831 sm_key56_t bd_addr_master, bd_addr_slave; 2832 bd_addr_master[0] = setup->sm_m_addr_type; 2833 bd_addr_slave[0] = setup->sm_s_addr_type; 2834 memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 2835 memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 2836 2837 uint8_t iocap_a[3]; 2838 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 2839 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 2840 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 2841 uint8_t iocap_b[3]; 2842 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 2843 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 2844 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 2845 sm_key_t peer_dhkey_check; 2846 if (sm_conn->sm_role){ 2847 // responder 2848 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); 2849 } else { 2850 // initiator 2851 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); 2852 } 2853 2854 if (0 != memcmp(setup->sm_peer_dhkey_check, peer_dhkey_check, 16) ){ 2855 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 2856 break; 2857 } 2858 2859 if (sm_conn->sm_role){ 2860 // responder 2861 // for numeric comparison, we need to wait for user confirm 2862 if (setup->sm_stk_generation_method == NK_BOTH_INPUT && setup->sm_user_response != SM_USER_RESPONSE_CONFIRM){ 2863 sm_conn->sm_engine_state = SM_PH2_W4_USER_RESPONSE; 2864 } else { 2865 sm_conn->sm_engine_state = SM_PH2_SEND_DHKEY_CHECK_COMMAND; 2866 } 2867 } else { 2868 // initiator 2869 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2870 } 2871 break; 2872 #endif 2873 2874 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 2875 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2876 sm_pdu_received_in_wrong_state(sm_conn); 2877 break; 2878 } 2879 2880 // received confirm value 2881 reverse_128(&packet[1], setup->sm_peer_confirm); 2882 2883 // notify client to hide shown passkey 2884 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2885 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 2886 } 2887 2888 // handle user cancel pairing? 2889 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 2890 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2891 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2892 break; 2893 } 2894 2895 // wait for user action? 2896 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 2897 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2898 break; 2899 } 2900 2901 // calculate and send local_confirm 2902 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2903 break; 2904 2905 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 2906 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2907 sm_pdu_received_in_wrong_state(sm_conn); 2908 break;; 2909 } 2910 2911 // received random value 2912 reverse_128(&packet[1], setup->sm_peer_random); 2913 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2914 break; 2915 2916 case SM_PH3_RECEIVE_KEYS: 2917 switch(packet[0]){ 2918 case SM_CODE_ENCRYPTION_INFORMATION: 2919 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2920 reverse_128(&packet[1], setup->sm_peer_ltk); 2921 break; 2922 2923 case SM_CODE_MASTER_IDENTIFICATION: 2924 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2925 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 2926 reverse_64(&packet[3], setup->sm_peer_rand); 2927 break; 2928 2929 case SM_CODE_IDENTITY_INFORMATION: 2930 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2931 reverse_128(&packet[1], setup->sm_peer_irk); 2932 break; 2933 2934 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 2935 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2936 setup->sm_peer_addr_type = packet[1]; 2937 reverse_bd_addr(&packet[2], setup->sm_peer_address); 2938 break; 2939 2940 case SM_CODE_SIGNING_INFORMATION: 2941 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2942 reverse_128(&packet[1], setup->sm_peer_csrk); 2943 break; 2944 default: 2945 // Unexpected PDU 2946 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 2947 break; 2948 } 2949 // done with key distribution? 2950 if (sm_key_distribution_all_received(sm_conn)){ 2951 2952 sm_key_distribution_handle_all_received(sm_conn); 2953 2954 if (sm_conn->sm_role){ 2955 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2956 sm_done_for_handle(sm_conn->sm_handle); 2957 } else { 2958 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2959 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2960 if (setup->sm_use_secure_connections){ 2961 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2962 } 2963 #endif 2964 } 2965 } 2966 break; 2967 default: 2968 // Unexpected PDU 2969 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 2970 break; 2971 } 2972 2973 // try to send preparared packet 2974 sm_run(); 2975 } 2976 2977 // Security Manager Client API 2978 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 2979 sm_get_oob_data = get_oob_data_callback; 2980 } 2981 2982 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 2983 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 2984 } 2985 2986 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 2987 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 2988 } 2989 2990 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 2991 sm_min_encryption_key_size = min_size; 2992 sm_max_encryption_key_size = max_size; 2993 } 2994 2995 void sm_set_authentication_requirements(uint8_t auth_req){ 2996 sm_auth_req = auth_req; 2997 } 2998 2999 void sm_set_io_capabilities(io_capability_t io_capability){ 3000 sm_io_capabilities = io_capability; 3001 } 3002 3003 void sm_set_request_security(int enable){ 3004 sm_slave_request_security = enable; 3005 } 3006 3007 void sm_set_er(sm_key_t er){ 3008 memcpy(sm_persistent_er, er, 16); 3009 } 3010 3011 void sm_set_ir(sm_key_t ir){ 3012 memcpy(sm_persistent_ir, ir, 16); 3013 } 3014 3015 // Testing support only 3016 void sm_test_set_irk(sm_key_t irk){ 3017 memcpy(sm_persistent_irk, irk, 16); 3018 sm_persistent_irk_ready = 1; 3019 } 3020 3021 void sm_test_use_fixed_local_csrk(void){ 3022 test_use_fixed_local_csrk = 1; 3023 } 3024 3025 void sm_init(void){ 3026 // set some (BTstack default) ER and IR 3027 int i; 3028 sm_key_t er; 3029 sm_key_t ir; 3030 for (i=0;i<16;i++){ 3031 er[i] = 0x30 + i; 3032 ir[i] = 0x90 + i; 3033 } 3034 sm_set_er(er); 3035 sm_set_ir(ir); 3036 // defaults 3037 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 3038 | SM_STK_GENERATION_METHOD_OOB 3039 | SM_STK_GENERATION_METHOD_PASSKEY 3040 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 3041 3042 sm_max_encryption_key_size = 16; 3043 sm_min_encryption_key_size = 7; 3044 3045 sm_cmac_state = CMAC_IDLE; 3046 dkg_state = DKG_W4_WORKING; 3047 rau_state = RAU_W4_WORKING; 3048 sm_aes128_state = SM_AES128_IDLE; 3049 sm_address_resolution_test = -1; // no private address to resolve yet 3050 sm_address_resolution_ah_calculation_active = 0; 3051 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 3052 sm_address_resolution_general_queue = NULL; 3053 3054 gap_random_adress_update_period = 15 * 60 * 1000L; 3055 3056 sm_active_connection = 0; 3057 3058 test_use_fixed_local_csrk = 0; 3059 3060 // register for HCI Events from HCI 3061 hci_event_callback_registration.callback = &sm_event_packet_handler; 3062 hci_add_event_handler(&hci_event_callback_registration); 3063 3064 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 3065 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 3066 3067 #ifdef USE_MBEDTLS_FOR_ECDH 3068 // TODO: calculate keypair using LE Random Number Generator 3069 // use test keypair from spec initially 3070 mbedtls_ecp_keypair_init(&le_keypair); 3071 mbedtls_ecp_group_load(&le_keypair.grp, MBEDTLS_ECP_DP_SECP256R1); 3072 mbedtls_mpi_read_string( &le_keypair.d, 16, "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"); 3073 mbedtls_mpi_read_string( &le_keypair.Q.X, 16, "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"); 3074 mbedtls_mpi_read_string( &le_keypair.Q.Y, 16, "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"); 3075 mbedtls_mpi_read_string( &le_keypair.Q.Z, 16, "1"); 3076 // print keypair 3077 char buffer[100]; 3078 size_t len; 3079 mbedtls_mpi_write_string( &le_keypair.d, 16, buffer, sizeof(buffer), &len); 3080 log_info("d: %s", buffer); 3081 mbedtls_mpi_write_string( &le_keypair.Q.X, 16, buffer, sizeof(buffer), &len); 3082 log_info("X: %s", buffer); 3083 mbedtls_mpi_write_string( &le_keypair.Q.Y, 16, buffer, sizeof(buffer), &len); 3084 log_info("Y: %s", buffer); 3085 #endif 3086 } 3087 3088 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 3089 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 3090 if (!hci_con) return NULL; 3091 return &hci_con->sm_connection; 3092 } 3093 3094 // @returns 0 if not encrypted, 7-16 otherwise 3095 int sm_encryption_key_size(hci_con_handle_t con_handle){ 3096 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3097 if (!sm_conn) return 0; // wrong connection 3098 if (!sm_conn->sm_connection_encrypted) return 0; 3099 return sm_conn->sm_actual_encryption_key_size; 3100 } 3101 3102 int sm_authenticated(hci_con_handle_t con_handle){ 3103 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3104 if (!sm_conn) return 0; // wrong connection 3105 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 3106 return sm_conn->sm_connection_authenticated; 3107 } 3108 3109 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 3110 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3111 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 3112 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 3113 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 3114 return sm_conn->sm_connection_authorization_state; 3115 } 3116 3117 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 3118 switch (sm_conn->sm_engine_state){ 3119 case SM_GENERAL_IDLE: 3120 case SM_RESPONDER_IDLE: 3121 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3122 sm_run(); 3123 break; 3124 default: 3125 break; 3126 } 3127 } 3128 3129 /** 3130 * @brief Trigger Security Request 3131 */ 3132 void sm_send_security_request(hci_con_handle_t con_handle){ 3133 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3134 if (!sm_conn) return; 3135 sm_send_security_request_for_connection(sm_conn); 3136 } 3137 3138 // request pairing 3139 void sm_request_pairing(hci_con_handle_t con_handle){ 3140 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3141 if (!sm_conn) return; // wrong connection 3142 3143 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 3144 if (sm_conn->sm_role){ 3145 sm_send_security_request_for_connection(sm_conn); 3146 } else { 3147 // used as a trigger to start central/master/initiator security procedures 3148 uint16_t ediv; 3149 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 3150 switch (sm_conn->sm_irk_lookup_state){ 3151 case IRK_LOOKUP_FAILED: 3152 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3153 break; 3154 case IRK_LOOKUP_SUCCEEDED: 3155 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 3156 if (ediv){ 3157 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 3158 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3159 } else { 3160 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3161 } 3162 break; 3163 default: 3164 sm_conn->sm_bonding_requested = 1; 3165 break; 3166 } 3167 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3168 sm_conn->sm_bonding_requested = 1; 3169 } 3170 } 3171 sm_run(); 3172 } 3173 3174 // called by client app on authorization request 3175 void sm_authorization_decline(hci_con_handle_t con_handle){ 3176 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3177 if (!sm_conn) return; // wrong connection 3178 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 3179 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 3180 } 3181 3182 void sm_authorization_grant(hci_con_handle_t con_handle){ 3183 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3184 if (!sm_conn) return; // wrong connection 3185 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 3186 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 3187 } 3188 3189 // GAP Bonding API 3190 3191 void sm_bonding_decline(hci_con_handle_t con_handle){ 3192 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3193 if (!sm_conn) return; // wrong connection 3194 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 3195 3196 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3197 switch (setup->sm_stk_generation_method){ 3198 case PK_RESP_INPUT: 3199 case PK_INIT_INPUT: 3200 case OK_BOTH_INPUT: 3201 sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); 3202 break; 3203 case NK_BOTH_INPUT: 3204 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 3205 break; 3206 case JUST_WORKS: 3207 case OOB: 3208 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 3209 break; 3210 } 3211 } 3212 sm_run(); 3213 } 3214 3215 void sm_just_works_confirm(hci_con_handle_t con_handle){ 3216 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3217 if (!sm_conn) return; // wrong connection 3218 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 3219 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3220 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3221 3222 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3223 if (setup->sm_use_secure_connections){ 3224 sm_conn->sm_engine_state = SM_PH2_SEND_PUBLIC_KEY_COMMAND; 3225 } 3226 #endif 3227 } 3228 if (sm_conn->sm_engine_state == SM_PH2_W4_USER_RESPONSE){ 3229 if (sm_conn->sm_role){ 3230 // responder 3231 sm_conn->sm_engine_state = SM_PH2_SEND_DHKEY_CHECK_COMMAND; 3232 } else { 3233 // initiator 3234 // TODO handle intiator role 3235 } 3236 } 3237 sm_run(); 3238 } 3239 3240 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 3241 // for now, it's the same 3242 sm_just_works_confirm(con_handle); 3243 } 3244 3245 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 3246 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3247 if (!sm_conn) return; // wrong connection 3248 sm_reset_tk(); 3249 big_endian_store_32(setup->sm_tk, 12, passkey); 3250 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 3251 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 3252 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 3253 } 3254 sm_run(); 3255 } 3256 3257 /** 3258 * @brief Identify device in LE Device DB 3259 * @param handle 3260 * @returns index from le_device_db or -1 if not found/identified 3261 */ 3262 int sm_le_device_index(hci_con_handle_t con_handle ){ 3263 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3264 if (!sm_conn) return -1; 3265 return sm_conn->sm_le_db_index; 3266 } 3267 3268 // GAP LE API 3269 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 3270 gap_random_address_update_stop(); 3271 gap_random_adress_type = random_address_type; 3272 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3273 gap_random_address_update_start(); 3274 gap_random_address_trigger(); 3275 } 3276 3277 gap_random_address_type_t gap_random_address_get_mode(void){ 3278 return gap_random_adress_type; 3279 } 3280 3281 void gap_random_address_set_update_period(int period_ms){ 3282 gap_random_adress_update_period = period_ms; 3283 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 3284 gap_random_address_update_stop(); 3285 gap_random_address_update_start(); 3286 } 3287 3288 void gap_random_address_set(bd_addr_t addr){ 3289 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 3290 memcpy(sm_random_address, addr, 6); 3291 rau_state = RAU_SET_ADDRESS; 3292 sm_run(); 3293 } 3294 3295 /* 3296 * @brief Set Advertisement Paramters 3297 * @param adv_int_min 3298 * @param adv_int_max 3299 * @param adv_type 3300 * @param direct_address_type 3301 * @param direct_address 3302 * @param channel_map 3303 * @param filter_policy 3304 * 3305 * @note own_address_type is used from gap_random_address_set_mode 3306 */ 3307 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 3308 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 3309 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 3310 direct_address_typ, direct_address, channel_map, filter_policy); 3311 } 3312 3313