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 "btstack_linked_list.h" 43 44 #include "btstack_memory.h" 45 #include "btstack_debug.h" 46 #include "hci.h" 47 #include "l2cap.h" 48 #include "ble/le_device_db.h" 49 #include "ble/sm.h" 50 #include "gap.h" 51 52 // 53 // SM internal types and globals 54 // 55 56 typedef enum { 57 DKG_W4_WORKING, 58 DKG_CALC_IRK, 59 DKG_W4_IRK, 60 DKG_CALC_DHK, 61 DKG_W4_DHK, 62 DKG_READY 63 } derived_key_generation_t; 64 65 typedef enum { 66 RAU_W4_WORKING, 67 RAU_IDLE, 68 RAU_GET_RANDOM, 69 RAU_W4_RANDOM, 70 RAU_GET_ENC, 71 RAU_W4_ENC, 72 RAU_SET_ADDRESS, 73 } random_address_update_t; 74 75 typedef enum { 76 CMAC_IDLE, 77 CMAC_CALC_SUBKEYS, 78 CMAC_W4_SUBKEYS, 79 CMAC_CALC_MI, 80 CMAC_W4_MI, 81 CMAC_CALC_MLAST, 82 CMAC_W4_MLAST 83 } cmac_state_t; 84 85 typedef enum { 86 JUST_WORKS, 87 PK_RESP_INPUT, // Initiator displays PK, initiator inputs PK 88 PK_INIT_INPUT, // Responder displays PK, responder inputs PK 89 OK_BOTH_INPUT, // Only input on both, both input PK 90 OOB // OOB available on both sides 91 } stk_generation_method_t; 92 93 typedef enum { 94 SM_USER_RESPONSE_IDLE, 95 SM_USER_RESPONSE_PENDING, 96 SM_USER_RESPONSE_CONFIRM, 97 SM_USER_RESPONSE_PASSKEY, 98 SM_USER_RESPONSE_DECLINE 99 } sm_user_response_t; 100 101 typedef enum { 102 SM_AES128_IDLE, 103 SM_AES128_ACTIVE 104 } sm_aes128_state_t; 105 106 typedef enum { 107 ADDRESS_RESOLUTION_IDLE, 108 ADDRESS_RESOLUTION_GENERAL, 109 ADDRESS_RESOLUTION_FOR_CONNECTION, 110 } address_resolution_mode_t; 111 112 typedef enum { 113 ADDRESS_RESOLUTION_SUCEEDED, 114 ADDRESS_RESOLUTION_FAILED, 115 } address_resolution_event_t; 116 // 117 // GLOBAL DATA 118 // 119 120 static uint8_t test_use_fixed_local_csrk; 121 122 // configuration 123 static uint8_t sm_accepted_stk_generation_methods; 124 static uint8_t sm_max_encryption_key_size; 125 static uint8_t sm_min_encryption_key_size; 126 static uint8_t sm_auth_req = 0; 127 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 128 static uint8_t sm_slave_request_security; 129 130 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 131 static sm_key_t sm_persistent_er; 132 static sm_key_t sm_persistent_ir; 133 134 // derived from sm_persistent_ir 135 static sm_key_t sm_persistent_dhk; 136 static sm_key_t sm_persistent_irk; 137 static uint8_t sm_persistent_irk_ready = 0; // used for testing 138 static derived_key_generation_t dkg_state; 139 140 // derived from sm_persistent_er 141 // .. 142 143 // random address update 144 static random_address_update_t rau_state; 145 static bd_addr_t sm_random_address; 146 147 // CMAC calculation 148 static cmac_state_t sm_cmac_state; 149 static sm_key_t sm_cmac_k; 150 static uint8_t sm_cmac_header[3]; 151 static uint16_t sm_cmac_message_len; 152 static uint8_t * sm_cmac_message; 153 static uint8_t sm_cmac_sign_counter[4]; 154 static sm_key_t sm_cmac_m_last; 155 static sm_key_t sm_cmac_x; 156 static uint8_t sm_cmac_block_current; 157 static uint8_t sm_cmac_block_count; 158 static void (*sm_cmac_done_handler)(uint8_t hash[8]); 159 160 // resolvable private address lookup / CSRK calculation 161 static int sm_address_resolution_test; 162 static int sm_address_resolution_ah_calculation_active; 163 static uint8_t sm_address_resolution_addr_type; 164 static bd_addr_t sm_address_resolution_address; 165 static void * sm_address_resolution_context; 166 static address_resolution_mode_t sm_address_resolution_mode; 167 static btstack_linked_list_t sm_address_resolution_general_queue; 168 169 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 170 static sm_aes128_state_t sm_aes128_state; 171 static void * sm_aes128_context; 172 173 // random engine. store context (ususally sm_connection_t) 174 static void * sm_random_context; 175 176 // to receive hci events 177 static btstack_packet_callback_registration_t hci_event_callback_registration; 178 179 // 180 // Volume 3, Part H, Chapter 24 181 // "Security shall be initiated by the Security Manager in the device in the master role. 182 // The device in the slave role shall be the responding device." 183 // -> master := initiator, slave := responder 184 // 185 186 // data needed for security setup 187 typedef struct sm_setup_context { 188 189 btstack_timer_source_t sm_timeout; 190 191 // used in all phases 192 uint8_t sm_pairing_failed_reason; 193 194 // user response, (Phase 1 and/or 2) 195 uint8_t sm_user_response; 196 197 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 198 int sm_key_distribution_send_set; 199 int sm_key_distribution_received_set; 200 201 // Phase 2 (Pairing over SMP) 202 stk_generation_method_t sm_stk_generation_method; 203 sm_key_t sm_tk; 204 205 sm_key_t sm_c1_t3_value; // c1 calculation 206 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 207 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 208 sm_key_t sm_local_random; 209 sm_key_t sm_local_confirm; 210 sm_key_t sm_peer_random; 211 sm_key_t sm_peer_confirm; 212 uint8_t sm_m_addr_type; // address and type can be removed 213 uint8_t sm_s_addr_type; // '' 214 bd_addr_t sm_m_address; // '' 215 bd_addr_t sm_s_address; // '' 216 sm_key_t sm_ltk; 217 218 // Phase 3 219 220 // key distribution, we generate 221 uint16_t sm_local_y; 222 uint16_t sm_local_div; 223 uint16_t sm_local_ediv; 224 uint8_t sm_local_rand[8]; 225 sm_key_t sm_local_ltk; 226 sm_key_t sm_local_csrk; 227 sm_key_t sm_local_irk; 228 // sm_local_address/addr_type not needed 229 230 // key distribution, received from peer 231 uint16_t sm_peer_y; 232 uint16_t sm_peer_div; 233 uint16_t sm_peer_ediv; 234 uint8_t sm_peer_rand[8]; 235 sm_key_t sm_peer_ltk; 236 sm_key_t sm_peer_irk; 237 sm_key_t sm_peer_csrk; 238 uint8_t sm_peer_addr_type; 239 bd_addr_t sm_peer_address; 240 241 } sm_setup_context_t; 242 243 // 244 static sm_setup_context_t the_setup; 245 static sm_setup_context_t * setup = &the_setup; 246 247 // active connection - the one for which the_setup is used for 248 static uint16_t sm_active_connection = 0; 249 250 // @returns 1 if oob data is available 251 // stores oob data in provided 16 byte buffer if not null 252 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 253 254 // used to notify applicationss that user interaction is neccessary, see sm_notify_t below 255 static btstack_packet_handler_t sm_client_packet_handler = NULL; 256 257 // horizontal: initiator capabilities 258 // vertial: responder capabilities 259 static const stk_generation_method_t stk_generation_method[5][5] = { 260 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 261 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 262 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 263 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 264 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 265 }; 266 267 static void sm_run(void); 268 static void sm_done_for_handle(uint16_t handle); 269 static sm_connection_t * sm_get_connection_for_handle(uint16_t handle); 270 static inline int sm_calc_actual_encryption_key_size(int other); 271 static int sm_validate_stk_generation_method(void); 272 273 static void log_info_hex16(const char * name, uint16_t value){ 274 log_info("%-6s 0x%04x", name, value); 275 } 276 277 // @returns 1 if all bytes are 0 278 static int sm_is_null_random(uint8_t random[8]){ 279 int i; 280 for (i=0; i < 8 ; i++){ 281 if (random[i]) return 0; 282 } 283 return 1; 284 } 285 286 // Key utils 287 static void sm_reset_tk(void){ 288 int i; 289 for (i=0;i<16;i++){ 290 setup->sm_tk[i] = 0; 291 } 292 } 293 294 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 295 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 296 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 297 int i; 298 for (i = max_encryption_size ; i < 16 ; i++){ 299 key[15-i] = 0; 300 } 301 } 302 303 // SMP Timeout implementation 304 305 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 306 // the Security Manager Timer shall be reset and started. 307 // 308 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 309 // 310 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 311 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 312 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 313 // established. 314 315 static void sm_timeout_handler(btstack_timer_source_t * timer){ 316 log_info("SM timeout"); 317 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 318 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 319 sm_done_for_handle(sm_conn->sm_handle); 320 321 // trigger handling of next ready connection 322 sm_run(); 323 } 324 static void sm_timeout_start(sm_connection_t * sm_conn){ 325 btstack_run_loop_remove_timer(&setup->sm_timeout); 326 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 327 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 328 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 329 btstack_run_loop_add_timer(&setup->sm_timeout); 330 } 331 static void sm_timeout_stop(void){ 332 btstack_run_loop_remove_timer(&setup->sm_timeout); 333 } 334 static void sm_timeout_reset(sm_connection_t * sm_conn){ 335 sm_timeout_stop(); 336 sm_timeout_start(sm_conn); 337 } 338 339 // end of sm timeout 340 341 // GAP Random Address updates 342 static gap_random_address_type_t gap_random_adress_type; 343 static btstack_timer_source_t gap_random_address_update_timer; 344 static uint32_t gap_random_adress_update_period; 345 346 static void gap_random_address_trigger(void){ 347 if (rau_state != RAU_IDLE) return; 348 log_info("gap_random_address_trigger"); 349 rau_state = RAU_GET_RANDOM; 350 sm_run(); 351 } 352 353 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 354 log_info("GAP Random Address Update due"); 355 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 356 btstack_run_loop_add_timer(&gap_random_address_update_timer); 357 gap_random_address_trigger(); 358 } 359 360 static void gap_random_address_update_start(void){ 361 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 362 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 363 btstack_run_loop_add_timer(&gap_random_address_update_timer); 364 } 365 366 static void gap_random_address_update_stop(void){ 367 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 368 } 369 370 371 static void sm_random_start(void * context){ 372 sm_random_context = context; 373 hci_send_cmd(&hci_le_rand); 374 } 375 376 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 377 // context is made availabe to aes128 result handler by this 378 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 379 sm_aes128_state = SM_AES128_ACTIVE; 380 sm_key_t key_flipped, plaintext_flipped; 381 swap128(key, key_flipped); 382 swap128(plaintext, plaintext_flipped); 383 sm_aes128_context = context; 384 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 385 } 386 387 // ah(k,r) helper 388 // r = padding || r 389 // r - 24 bit value 390 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 391 // r'= padding || r 392 memset(r_prime, 0, 16); 393 memcpy(&r_prime[13], r, 3); 394 } 395 396 // d1 helper 397 // d' = padding || r || d 398 // d,r - 16 bit values 399 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 400 // d'= padding || r || d 401 memset(d1_prime, 0, 16); 402 big_endian_store_16(d1_prime, 12, r); 403 big_endian_store_16(d1_prime, 14, d); 404 } 405 406 // dm helper 407 // r’ = padding || r 408 // r - 64 bit value 409 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 410 memset(r_prime, 0, 16); 411 memcpy(&r_prime[8], r, 8); 412 } 413 414 // calculate arguments for first AES128 operation in C1 function 415 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){ 416 417 // p1 = pres || preq || rat’ || iat’ 418 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 419 // cant octet of pres becomes the most significant octet of p1. 420 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 421 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 422 // p1 is 0x05000800000302070710000001010001." 423 424 sm_key_t p1; 425 swap56(pres, &p1[0]); 426 swap56(preq, &p1[7]); 427 p1[14] = rat; 428 p1[15] = iat; 429 log_key("p1", p1); 430 log_key("r", r); 431 432 // t1 = r xor p1 433 int i; 434 for (i=0;i<16;i++){ 435 t1[i] = r[i] ^ p1[i]; 436 } 437 log_key("t1", t1); 438 } 439 440 // calculate arguments for second AES128 operation in C1 function 441 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 442 // p2 = padding || ia || ra 443 // "The least significant octet of ra becomes the least significant octet of p2 and 444 // the most significant octet of padding becomes the most significant octet of p2. 445 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 446 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 447 448 sm_key_t p2; 449 memset(p2, 0, 16); 450 memcpy(&p2[4], ia, 6); 451 memcpy(&p2[10], ra, 6); 452 log_key("p2", p2); 453 454 // c1 = e(k, t2_xor_p2) 455 int i; 456 for (i=0;i<16;i++){ 457 t3[i] = t2[i] ^ p2[i]; 458 } 459 log_key("t3", t3); 460 } 461 462 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 463 log_key("r1", r1); 464 log_key("r2", r2); 465 memcpy(&r_prime[8], &r2[8], 8); 466 memcpy(&r_prime[0], &r1[8], 8); 467 } 468 469 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, uint16_t handle, uint8_t addr_type, bd_addr_t address){ 470 event[0] = type; 471 event[1] = event_size - 2; 472 little_endian_store_16(event, 2, handle); 473 event[4] = addr_type; 474 bt_flip_addr(&event[5], address); 475 } 476 477 static void sm_notify_client_base(uint8_t type, uint16_t handle, uint8_t addr_type, bd_addr_t address){ 478 uint8_t event[11]; 479 sm_setup_event_base(event, sizeof(event), type, handle, addr_type, address); 480 481 if (!sm_client_packet_handler) return; 482 sm_client_packet_handler(HCI_EVENT_PACKET, 0, event, sizeof(event)); 483 } 484 485 static void sm_notify_client_passkey(uint8_t type, uint16_t handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 486 uint8_t event[15]; 487 sm_setup_event_base(event, sizeof(event), type, handle, addr_type, address); 488 little_endian_store_32(event, 11, passkey); 489 490 if (!sm_client_packet_handler) return; 491 sm_client_packet_handler(HCI_EVENT_PACKET, 0, event, sizeof(event)); 492 } 493 494 static void sm_notify_client_index(uint8_t type, uint16_t handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 495 uint8_t event[13]; 496 sm_setup_event_base(event, sizeof(event), type, handle, addr_type, address); 497 little_endian_store_16(event, 11, index); 498 499 if (!sm_client_packet_handler) return; 500 sm_client_packet_handler(HCI_EVENT_PACKET, 0, event, sizeof(event)); 501 } 502 503 static void sm_notify_client_authorization(uint8_t type, uint16_t handle, uint8_t addr_type, bd_addr_t address, uint8_t result){ 504 505 uint8_t event[18]; 506 sm_setup_event_base(event, sizeof(event), type, handle, addr_type, address); 507 event[11] = result; 508 509 if (!sm_client_packet_handler) return; 510 sm_client_packet_handler(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 511 } 512 513 // decide on stk generation based on 514 // - pairing request 515 // - io capabilities 516 // - OOB data availability 517 static void sm_setup_tk(void){ 518 519 // default: just works 520 setup->sm_stk_generation_method = JUST_WORKS; 521 522 // If both devices have out of band authentication data, then the Authentication 523 // Requirements Flags shall be ignored when selecting the pairing method and the 524 // Out of Band pairing method shall be used. 525 if (setup->sm_m_preq.oob_data_flag && setup->sm_s_pres.oob_data_flag){ 526 log_info("SM: have OOB data"); 527 log_key("OOB", setup->sm_tk); 528 setup->sm_stk_generation_method = OOB; 529 return; 530 } 531 532 // Reset TK as it has been setup in sm_init_setup 533 sm_reset_tk(); 534 535 // If both devices have not set the MITM option in the Authentication Requirements 536 // Flags, then the IO capabilities shall be ignored and the Just Works association 537 // model shall be used. 538 if ( ((setup->sm_m_preq.auth_req & SM_AUTHREQ_MITM_PROTECTION) == 0x00) && ((setup->sm_s_pres.auth_req & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 539 return; 540 } 541 542 // Also use just works if unknown io capabilites 543 if ((setup->sm_m_preq.io_capability > IO_CAPABILITY_KEYBOARD_DISPLAY) || (setup->sm_m_preq.io_capability > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 544 return; 545 } 546 547 // Otherwise the IO capabilities of the devices shall be used to determine the 548 // pairing method as defined in Table 2.4. 549 setup->sm_stk_generation_method = stk_generation_method[setup->sm_s_pres.io_capability][setup->sm_m_preq.io_capability]; 550 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 551 setup->sm_m_preq.io_capability, setup->sm_s_pres.io_capability, setup->sm_stk_generation_method); 552 } 553 554 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 555 int flags = 0; 556 if (key_set & SM_KEYDIST_ENC_KEY){ 557 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 558 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 559 } 560 if (key_set & SM_KEYDIST_ID_KEY){ 561 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 562 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 563 } 564 if (key_set & SM_KEYDIST_SIGN){ 565 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 566 } 567 return flags; 568 } 569 570 static void sm_setup_key_distribution(uint8_t key_set){ 571 setup->sm_key_distribution_received_set = 0; 572 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 573 } 574 575 // CSRK Key Lookup 576 577 578 static int sm_address_resolution_idle(void){ 579 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 580 } 581 582 static void sm_address_resolution_start_lookup(uint8_t addr_type, uint16_t handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 583 memcpy(sm_address_resolution_address, addr, 6); 584 sm_address_resolution_addr_type = addr_type; 585 sm_address_resolution_test = 0; 586 sm_address_resolution_mode = mode; 587 sm_address_resolution_context = context; 588 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, handle, addr_type, addr); 589 } 590 591 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 592 // check if already in list 593 btstack_linked_list_iterator_t it; 594 sm_lookup_entry_t * entry; 595 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 596 while(btstack_linked_list_iterator_has_next(&it)){ 597 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 598 if (entry->address_type != address_type) continue; 599 if (memcmp(entry->address, address, 6)) continue; 600 // already in list 601 return BTSTACK_BUSY; 602 } 603 entry = btstack_memory_sm_lookup_entry_get(); 604 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 605 entry->address_type = (bd_addr_type_t) address_type; 606 memcpy(entry->address, address, 6); 607 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 608 sm_run(); 609 return 0; 610 } 611 612 // CMAC Implementation using AES128 engine 613 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 614 int i; 615 int carry = 0; 616 for (i=len-1; i >= 0 ; i--){ 617 int new_carry = data[i] >> 7; 618 data[i] = data[i] << 1 | carry; 619 carry = new_carry; 620 } 621 } 622 623 // 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 624 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 625 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 626 } 627 static inline void dkg_next_state(void){ 628 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 629 } 630 static inline void rau_next_state(void){ 631 rau_state = (random_address_update_t) (((int)rau_state) + 1); 632 } 633 static inline void sm_cmac_next_state(void){ 634 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 635 } 636 static int sm_cmac_last_block_complete(void){ 637 if (sm_cmac_message_len == 0) return 0; 638 return (sm_cmac_message_len & 0x0f) == 0; 639 } 640 static inline uint8_t sm_cmac_message_get_byte(int offset){ 641 if (offset >= sm_cmac_message_len) { 642 log_error("sm_cmac_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 643 return 0; 644 } 645 646 offset = sm_cmac_message_len - 1 - offset; 647 648 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 649 if (offset < 3){ 650 return sm_cmac_header[offset]; 651 } 652 int actual_message_len_incl_header = sm_cmac_message_len - 4; 653 if (offset < actual_message_len_incl_header){ 654 return sm_cmac_message[offset - 3]; 655 } 656 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 657 } 658 659 void sm_cmac_start(sm_key_t k, uint8_t opcode, uint16_t handle, uint16_t message_len, uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t hash[8])){ 660 memcpy(sm_cmac_k, k, 16); 661 sm_cmac_header[0] = opcode; 662 little_endian_store_16(sm_cmac_header, 1, handle); 663 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 664 sm_cmac_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 665 sm_cmac_message = message; 666 sm_cmac_done_handler = done_handler; 667 sm_cmac_block_current = 0; 668 memset(sm_cmac_x, 0, 16); 669 670 // step 2: n := ceil(len/const_Bsize); 671 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 672 673 // step 3: .. 674 if (sm_cmac_block_count==0){ 675 sm_cmac_block_count = 1; 676 } 677 678 log_info("sm_cmac_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 679 680 // first, we need to compute l for k1, k2, and m_last 681 sm_cmac_state = CMAC_CALC_SUBKEYS; 682 683 // let's go 684 sm_run(); 685 } 686 687 int sm_cmac_ready(void){ 688 return sm_cmac_state == CMAC_IDLE; 689 } 690 691 static void sm_cmac_handle_aes_engine_ready(void){ 692 switch (sm_cmac_state){ 693 case CMAC_CALC_SUBKEYS: { 694 sm_key_t const_zero; 695 memset(const_zero, 0, 16); 696 sm_cmac_next_state(); 697 sm_aes128_start(sm_cmac_k, const_zero, NULL); 698 break; 699 } 700 case CMAC_CALC_MI: { 701 int j; 702 sm_key_t y; 703 for (j=0;j<16;j++){ 704 y[j] = sm_cmac_x[j] ^ sm_cmac_message_get_byte(sm_cmac_block_current*16 + j); 705 } 706 sm_cmac_block_current++; 707 sm_cmac_next_state(); 708 sm_aes128_start(sm_cmac_k, y, NULL); 709 break; 710 } 711 case CMAC_CALC_MLAST: { 712 int i; 713 sm_key_t y; 714 for (i=0;i<16;i++){ 715 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 716 } 717 log_key("Y", y); 718 sm_cmac_block_current++; 719 sm_cmac_next_state(); 720 sm_aes128_start(sm_cmac_k, y, NULL); 721 break; 722 } 723 default: 724 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 725 break; 726 } 727 } 728 729 static void sm_cmac_handle_encryption_result(sm_key_t data){ 730 switch (sm_cmac_state){ 731 case CMAC_W4_SUBKEYS: { 732 sm_key_t k1; 733 memcpy(k1, data, 16); 734 sm_shift_left_by_one_bit_inplace(16, k1); 735 if (data[0] & 0x80){ 736 k1[15] ^= 0x87; 737 } 738 sm_key_t k2; 739 memcpy(k2, k1, 16); 740 sm_shift_left_by_one_bit_inplace(16, k2); 741 if (k1[0] & 0x80){ 742 k2[15] ^= 0x87; 743 } 744 745 log_key("k", sm_cmac_k); 746 log_key("k1", k1); 747 log_key("k2", k2); 748 749 // step 4: set m_last 750 int i; 751 if (sm_cmac_last_block_complete()){ 752 for (i=0;i<16;i++){ 753 sm_cmac_m_last[i] = sm_cmac_message_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 754 } 755 } else { 756 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 757 for (i=0;i<16;i++){ 758 if (i < valid_octets_in_last_block){ 759 sm_cmac_m_last[i] = sm_cmac_message_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 760 continue; 761 } 762 if (i == valid_octets_in_last_block){ 763 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 764 continue; 765 } 766 sm_cmac_m_last[i] = k2[i]; 767 } 768 } 769 770 // next 771 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 772 break; 773 } 774 case CMAC_W4_MI: 775 memcpy(sm_cmac_x, data, 16); 776 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 777 break; 778 case CMAC_W4_MLAST: 779 // done 780 log_key("CMAC", data); 781 sm_cmac_done_handler(data); 782 sm_cmac_state = CMAC_IDLE; 783 break; 784 default: 785 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 786 break; 787 } 788 } 789 790 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 791 // notify client for: JUST WORKS confirm, PASSKEY display or input 792 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 793 switch (setup->sm_stk_generation_method){ 794 case PK_RESP_INPUT: 795 if (sm_conn->sm_role){ 796 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 797 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 798 } else { 799 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, bit_endian_read_32(setup->sm_tk, 12)); 800 } 801 break; 802 case PK_INIT_INPUT: 803 if (sm_conn->sm_role){ 804 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, bit_endian_read_32(setup->sm_tk, 12)); 805 } else { 806 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 807 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 808 } 809 break; 810 case OK_BOTH_INPUT: 811 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 812 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 813 break; 814 case JUST_WORKS: 815 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 816 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 817 break; 818 case OOB: 819 // client already provided OOB data, let's skip notification. 820 break; 821 } 822 } 823 824 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 825 int recv_flags; 826 if (sm_conn->sm_role){ 827 // slave / responser 828 recv_flags = sm_key_distribution_flags_for_set(setup->sm_s_pres.initiator_key_distribution); 829 } else { 830 // master / initiator 831 recv_flags = sm_key_distribution_flags_for_set(setup->sm_s_pres.responder_key_distribution); 832 } 833 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 834 return recv_flags == setup->sm_key_distribution_received_set; 835 } 836 837 static void sm_done_for_handle(uint16_t handle){ 838 if (sm_active_connection == handle){ 839 sm_timeout_stop(); 840 sm_active_connection = 0; 841 log_info("sm: connection 0x%x released setup context", handle); 842 } 843 } 844 845 static int sm_key_distribution_flags_for_auth_req(void){ 846 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 847 if (sm_auth_req & SM_AUTHREQ_BONDING){ 848 // encryption information only if bonding requested 849 flags |= SM_KEYDIST_ENC_KEY; 850 } 851 return flags; 852 } 853 854 static void sm_init_setup(sm_connection_t * sm_conn){ 855 856 // fill in sm setup 857 sm_reset_tk(); 858 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 859 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 860 861 // query client for OOB data 862 int have_oob_data = 0; 863 if (sm_get_oob_data) { 864 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 865 } 866 867 sm_pairing_packet_t * local_packet; 868 if (sm_conn->sm_role){ 869 // slave 870 local_packet = &setup->sm_s_pres; 871 hci_le_advertisement_address(&setup->sm_s_addr_type, setup->sm_s_address); 872 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 873 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 874 } else { 875 // master 876 local_packet = &setup->sm_m_preq; 877 hci_le_advertisement_address(&setup->sm_m_addr_type, setup->sm_m_address); 878 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 879 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 880 881 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 882 setup->sm_m_preq.initiator_key_distribution = key_distribution_flags; 883 setup->sm_m_preq.responder_key_distribution = key_distribution_flags; 884 } 885 886 local_packet->io_capability = sm_io_capabilities; 887 local_packet->oob_data_flag = have_oob_data; 888 local_packet->auth_req = sm_auth_req; 889 local_packet->max_encryption_key_size = sm_max_encryption_key_size; 890 } 891 892 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 893 894 sm_pairing_packet_t * remote_packet; 895 int remote_key_request; 896 if (sm_conn->sm_role){ 897 // slave / responser 898 remote_packet = &setup->sm_m_preq; 899 remote_key_request = setup->sm_m_preq.responder_key_distribution; 900 } else { 901 // master / initiator 902 remote_packet = &setup->sm_s_pres; 903 remote_key_request = setup->sm_s_pres.initiator_key_distribution; 904 } 905 906 // check key size 907 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(remote_packet->max_encryption_key_size); 908 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 909 910 // setup key distribution 911 sm_setup_key_distribution(remote_key_request); 912 913 // identical to responder 914 915 // decide on STK generation method 916 sm_setup_tk(); 917 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 918 919 // check if STK generation method is acceptable by client 920 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 921 922 // JUST WORKS doens't provide authentication 923 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 924 925 return 0; 926 } 927 928 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 929 930 // cache and reset context 931 int matched_device_id = sm_address_resolution_test; 932 address_resolution_mode_t mode = sm_address_resolution_mode; 933 void * context = sm_address_resolution_context; 934 935 // reset context 936 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 937 sm_address_resolution_context = NULL; 938 sm_address_resolution_test = -1; 939 uint16_t handle = 0; 940 941 sm_connection_t * sm_connection; 942 uint16_t ediv; 943 switch (mode){ 944 case ADDRESS_RESOLUTION_GENERAL: 945 break; 946 case ADDRESS_RESOLUTION_FOR_CONNECTION: 947 sm_connection = (sm_connection_t *) context; 948 handle = sm_connection->sm_handle; 949 switch (event){ 950 case ADDRESS_RESOLUTION_SUCEEDED: 951 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 952 sm_connection->sm_le_db_index = matched_device_id; 953 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 954 if (sm_connection->sm_role) break; 955 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 956 sm_connection->sm_security_request_received = 0; 957 sm_connection->sm_bonding_requested = 0; 958 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 959 if (ediv){ 960 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 961 } else { 962 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 963 } 964 break; 965 case ADDRESS_RESOLUTION_FAILED: 966 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 967 if (sm_connection->sm_role) break; 968 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 969 sm_connection->sm_security_request_received = 0; 970 sm_connection->sm_bonding_requested = 0; 971 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 972 break; 973 } 974 break; 975 default: 976 break; 977 } 978 979 switch (event){ 980 case ADDRESS_RESOLUTION_SUCEEDED: 981 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 982 break; 983 case ADDRESS_RESOLUTION_FAILED: 984 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, handle, sm_address_resolution_addr_type, sm_address_resolution_address); 985 break; 986 } 987 } 988 989 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 990 991 int le_db_index = -1; 992 993 // lookup device based on IRK 994 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 995 int i; 996 for (i=0; i < le_device_db_count(); i++){ 997 sm_key_t irk; 998 bd_addr_t address; 999 int address_type; 1000 le_device_db_info(i, &address_type, address, irk); 1001 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1002 log_info("sm: device found for IRK, updating"); 1003 le_db_index = i; 1004 break; 1005 } 1006 } 1007 } 1008 1009 // if not found, lookup via public address if possible 1010 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1011 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1012 int i; 1013 for (i=0; i < le_device_db_count(); i++){ 1014 bd_addr_t address; 1015 int address_type; 1016 le_device_db_info(i, &address_type, address, NULL); 1017 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1018 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1019 log_info("sm: device found for public address, updating"); 1020 le_db_index = i; 1021 break; 1022 } 1023 } 1024 } 1025 1026 // if not found, add to db 1027 if (le_db_index < 0) { 1028 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1029 } 1030 1031 if (le_db_index >= 0){ 1032 le_device_db_local_counter_set(le_db_index, 0); 1033 1034 // store local CSRK 1035 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1036 log_info("sm: store local CSRK"); 1037 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1038 le_device_db_local_counter_set(le_db_index, 0); 1039 } 1040 1041 // store remote CSRK 1042 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1043 log_info("sm: store remote CSRK"); 1044 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1045 le_device_db_remote_counter_set(le_db_index, 0); 1046 } 1047 1048 // store encryption information 1049 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION 1050 && setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1051 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1052 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1053 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1054 } 1055 } 1056 1057 // keep le_db_index 1058 sm_conn->sm_le_db_index = le_db_index; 1059 } 1060 1061 static void sm_run(void){ 1062 1063 btstack_linked_list_iterator_t it; 1064 1065 // assert that we can send at least commands 1066 if (!hci_can_send_command_packet_now()) return; 1067 1068 // 1069 // non-connection related behaviour 1070 // 1071 1072 // distributed key generation 1073 switch (dkg_state){ 1074 case DKG_CALC_IRK: 1075 // already busy? 1076 if (sm_aes128_state == SM_AES128_IDLE) { 1077 // IRK = d1(IR, 1, 0) 1078 sm_key_t d1_prime; 1079 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1080 dkg_next_state(); 1081 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1082 return; 1083 } 1084 break; 1085 case DKG_CALC_DHK: 1086 // already busy? 1087 if (sm_aes128_state == SM_AES128_IDLE) { 1088 // DHK = d1(IR, 3, 0) 1089 sm_key_t d1_prime; 1090 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1091 dkg_next_state(); 1092 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1093 return; 1094 } 1095 break; 1096 default: 1097 break; 1098 } 1099 1100 // random address updates 1101 switch (rau_state){ 1102 case RAU_GET_RANDOM: 1103 rau_next_state(); 1104 sm_random_start(NULL); 1105 return; 1106 case RAU_GET_ENC: 1107 // already busy? 1108 if (sm_aes128_state == SM_AES128_IDLE) { 1109 sm_key_t r_prime; 1110 sm_ah_r_prime(sm_random_address, r_prime); 1111 rau_next_state(); 1112 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1113 return; 1114 } 1115 break; 1116 case RAU_SET_ADDRESS: 1117 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1118 rau_state = RAU_IDLE; 1119 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1120 return; 1121 default: 1122 break; 1123 } 1124 1125 // CMAC 1126 switch (sm_cmac_state){ 1127 case CMAC_CALC_SUBKEYS: 1128 case CMAC_CALC_MI: 1129 case CMAC_CALC_MLAST: 1130 // already busy? 1131 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1132 sm_cmac_handle_aes_engine_ready(); 1133 return; 1134 default: 1135 break; 1136 } 1137 1138 // CSRK Lookup 1139 // -- if csrk lookup ready, find connection that require csrk lookup 1140 if (sm_address_resolution_idle()){ 1141 hci_connections_get_iterator(&it); 1142 while(btstack_linked_list_iterator_has_next(&it)){ 1143 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1144 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1145 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1146 // and start lookup 1147 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); 1148 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1149 break; 1150 } 1151 } 1152 } 1153 1154 // -- if csrk lookup ready, resolved addresses for received addresses 1155 if (sm_address_resolution_idle()) { 1156 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1157 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1158 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1159 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1160 btstack_memory_sm_lookup_entry_free(entry); 1161 } 1162 } 1163 1164 // -- Continue with CSRK device lookup by public or resolvable private address 1165 if (!sm_address_resolution_idle()){ 1166 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1167 while (sm_address_resolution_test < le_device_db_count()){ 1168 int addr_type; 1169 bd_addr_t addr; 1170 sm_key_t irk; 1171 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1172 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1173 1174 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1175 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1176 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1177 break; 1178 } 1179 1180 if (sm_address_resolution_addr_type == 0){ 1181 sm_address_resolution_test++; 1182 continue; 1183 } 1184 1185 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1186 1187 log_info("LE Device Lookup: calculate AH"); 1188 log_key("IRK", irk); 1189 1190 sm_key_t r_prime; 1191 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1192 sm_address_resolution_ah_calculation_active = 1; 1193 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1194 return; 1195 } 1196 1197 if (sm_address_resolution_test >= le_device_db_count()){ 1198 log_info("LE Device Lookup: not found"); 1199 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1200 } 1201 } 1202 1203 1204 // 1205 // active connection handling 1206 // -- use loop to handle next connection if lock on setup context is released 1207 1208 while (1) { 1209 1210 // Find connections that requires setup context and make active if no other is locked 1211 hci_connections_get_iterator(&it); 1212 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1213 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1214 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1215 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1216 int done = 1; 1217 int err; 1218 int encryption_key_size; 1219 int authenticated; 1220 int authorized; 1221 switch (sm_connection->sm_engine_state) { 1222 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1223 // send packet if possible, 1224 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle)){ 1225 uint8_t buffer[2]; 1226 buffer[0] = SM_CODE_SECURITY_REQUEST; 1227 buffer[1] = SM_AUTHREQ_BONDING; 1228 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1229 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1230 } 1231 // don't lock setup context yet 1232 done = 0; 1233 break; 1234 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1235 sm_init_setup(sm_connection); 1236 // recover pairing request 1237 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1238 err = sm_stk_generation_init(sm_connection); 1239 if (err){ 1240 setup->sm_pairing_failed_reason = err; 1241 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1242 break; 1243 } 1244 sm_timeout_start(sm_connection); 1245 // generate random number first, if we need to show passkey 1246 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1247 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1248 break; 1249 } 1250 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1251 break; 1252 case SM_INITIATOR_PH0_HAS_LTK: 1253 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1254 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1255 &encryption_key_size, &authenticated, &authorized); 1256 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1257 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1258 sm_connection->sm_connection_authenticated = authenticated; 1259 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1260 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1261 break; 1262 case SM_RESPONDER_PH0_RECEIVED_LTK: 1263 // re-establish previously used LTK using Rand and EDIV 1264 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1265 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1266 // re-establish used key encryption size 1267 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1268 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1269 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1270 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1271 log_info("sm: received ltk request with key size %u, authenticated %u", 1272 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1273 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1274 break; 1275 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1276 sm_init_setup(sm_connection); 1277 sm_timeout_start(sm_connection); 1278 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1279 break; 1280 default: 1281 done = 0; 1282 break; 1283 } 1284 if (done){ 1285 sm_active_connection = sm_connection->sm_handle; 1286 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1287 } 1288 } 1289 1290 // 1291 // active connection handling 1292 // 1293 1294 if (sm_active_connection == 0) return; 1295 1296 // assert that we could send a SM PDU - not needed for all of the following 1297 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection)) return; 1298 1299 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1300 if (!connection) return; 1301 1302 sm_key_t plaintext; 1303 int key_distribution_flags; 1304 1305 log_info("sm_run: state %u", connection->sm_engine_state); 1306 1307 // responding state 1308 switch (connection->sm_engine_state){ 1309 1310 // general 1311 case SM_GENERAL_SEND_PAIRING_FAILED: { 1312 uint8_t buffer[2]; 1313 buffer[0] = SM_CODE_PAIRING_FAILED; 1314 buffer[1] = setup->sm_pairing_failed_reason; 1315 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1316 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1317 sm_done_for_handle(connection->sm_handle); 1318 break; 1319 } 1320 1321 // initiator side 1322 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1323 sm_key_t peer_ltk_flipped; 1324 swap128(setup->sm_peer_ltk, peer_ltk_flipped); 1325 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1326 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1327 uint32_t rand_high = bit_endian_read_32(setup->sm_peer_rand, 0); 1328 uint32_t rand_low = bit_endian_read_32(setup->sm_peer_rand, 4); 1329 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1330 return; 1331 } 1332 1333 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1334 setup->sm_m_preq.code = SM_CODE_PAIRING_REQUEST; 1335 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1336 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1337 sm_timeout_reset(connection); 1338 break; 1339 1340 // responder side 1341 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1342 connection->sm_engine_state = SM_RESPONDER_IDLE; 1343 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1344 return; 1345 1346 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 1347 // echo initiator for now 1348 setup->sm_s_pres.code = SM_CODE_PAIRING_RESPONSE; 1349 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1350 setup->sm_s_pres.initiator_key_distribution = setup->sm_m_preq.initiator_key_distribution & key_distribution_flags; 1351 setup->sm_s_pres.responder_key_distribution = setup->sm_m_preq.responder_key_distribution & key_distribution_flags; 1352 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 1353 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 1354 sm_timeout_reset(connection); 1355 sm_trigger_user_response(connection); 1356 return; 1357 1358 case SM_PH2_SEND_PAIRING_RANDOM: { 1359 uint8_t buffer[17]; 1360 buffer[0] = SM_CODE_PAIRING_RANDOM; 1361 swap128(setup->sm_local_random, &buffer[1]); 1362 if (connection->sm_role){ 1363 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 1364 } else { 1365 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 1366 } 1367 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1368 sm_timeout_reset(connection); 1369 break; 1370 } 1371 1372 case SM_PH2_GET_RANDOM_TK: 1373 case SM_PH2_C1_GET_RANDOM_A: 1374 case SM_PH2_C1_GET_RANDOM_B: 1375 case SM_PH3_GET_RANDOM: 1376 case SM_PH3_GET_DIV: 1377 sm_next_responding_state(connection); 1378 sm_random_start(connection); 1379 return; 1380 1381 case SM_PH2_C1_GET_ENC_B: 1382 case SM_PH2_C1_GET_ENC_D: 1383 // already busy? 1384 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1385 sm_next_responding_state(connection); 1386 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 1387 return; 1388 1389 case SM_PH3_LTK_GET_ENC: 1390 case SM_RESPONDER_PH4_LTK_GET_ENC: 1391 // already busy? 1392 if (sm_aes128_state == SM_AES128_IDLE) { 1393 sm_key_t d_prime; 1394 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 1395 sm_next_responding_state(connection); 1396 sm_aes128_start(sm_persistent_er, d_prime, connection); 1397 return; 1398 } 1399 break; 1400 1401 case SM_PH3_CSRK_GET_ENC: 1402 // already busy? 1403 if (sm_aes128_state == SM_AES128_IDLE) { 1404 sm_key_t d_prime; 1405 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 1406 sm_next_responding_state(connection); 1407 sm_aes128_start(sm_persistent_er, d_prime, connection); 1408 return; 1409 } 1410 break; 1411 1412 case SM_PH2_C1_GET_ENC_C: 1413 // already busy? 1414 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1415 // calculate m_confirm using aes128 engine - step 1 1416 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); 1417 sm_next_responding_state(connection); 1418 sm_aes128_start(setup->sm_tk, plaintext, connection); 1419 break; 1420 case SM_PH2_C1_GET_ENC_A: 1421 // already busy? 1422 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1423 // calculate confirm using aes128 engine - step 1 1424 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); 1425 sm_next_responding_state(connection); 1426 sm_aes128_start(setup->sm_tk, plaintext, connection); 1427 break; 1428 case SM_PH2_CALC_STK: 1429 // already busy? 1430 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1431 // calculate STK 1432 if (connection->sm_role){ 1433 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 1434 } else { 1435 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 1436 } 1437 sm_next_responding_state(connection); 1438 sm_aes128_start(setup->sm_tk, plaintext, connection); 1439 break; 1440 case SM_PH3_Y_GET_ENC: 1441 // already busy? 1442 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1443 // PH3B2 - calculate Y from - enc 1444 // Y = dm(DHK, Rand) 1445 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1446 sm_next_responding_state(connection); 1447 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1448 return; 1449 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 1450 uint8_t buffer[17]; 1451 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1452 swap128(setup->sm_local_confirm, &buffer[1]); 1453 if (connection->sm_role){ 1454 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 1455 } else { 1456 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 1457 } 1458 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1459 sm_timeout_reset(connection); 1460 return; 1461 } 1462 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 1463 sm_key_t stk_flipped; 1464 swap128(setup->sm_ltk, stk_flipped); 1465 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1466 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 1467 return; 1468 } 1469 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 1470 sm_key_t stk_flipped; 1471 swap128(setup->sm_ltk, stk_flipped); 1472 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1473 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 1474 return; 1475 } 1476 case SM_RESPONDER_PH4_SEND_LTK: { 1477 sm_key_t ltk_flipped; 1478 swap128(setup->sm_ltk, ltk_flipped); 1479 connection->sm_engine_state = SM_RESPONDER_IDLE; 1480 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 1481 return; 1482 } 1483 case SM_RESPONDER_PH4_Y_GET_ENC: 1484 // already busy? 1485 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1486 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 1487 // Y = dm(DHK, Rand) 1488 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1489 sm_next_responding_state(connection); 1490 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1491 return; 1492 1493 case SM_PH3_DISTRIBUTE_KEYS: 1494 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 1495 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 1496 uint8_t buffer[17]; 1497 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 1498 swap128(setup->sm_ltk, &buffer[1]); 1499 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1500 sm_timeout_reset(connection); 1501 return; 1502 } 1503 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1504 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 1505 uint8_t buffer[11]; 1506 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 1507 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 1508 swap64(setup->sm_local_rand, &buffer[3]); 1509 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1510 sm_timeout_reset(connection); 1511 return; 1512 } 1513 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1514 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 1515 uint8_t buffer[17]; 1516 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 1517 swap128(sm_persistent_irk, &buffer[1]); 1518 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1519 sm_timeout_reset(connection); 1520 return; 1521 } 1522 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 1523 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 1524 bd_addr_t local_address; 1525 uint8_t buffer[8]; 1526 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 1527 hci_le_advertisement_address(&buffer[1], local_address); 1528 bt_flip_addr(&buffer[2], local_address); 1529 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1530 sm_timeout_reset(connection); 1531 return; 1532 } 1533 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1534 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 1535 1536 // hack to reproduce test runs 1537 if (test_use_fixed_local_csrk){ 1538 memset(setup->sm_local_csrk, 0xcc, 16); 1539 } 1540 1541 uint8_t buffer[17]; 1542 buffer[0] = SM_CODE_SIGNING_INFORMATION; 1543 swap128(setup->sm_local_csrk, &buffer[1]); 1544 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1545 sm_timeout_reset(connection); 1546 return; 1547 } 1548 1549 // keys are sent 1550 if (connection->sm_role){ 1551 // slave -> receive master keys if any 1552 if (sm_key_distribution_all_received(connection)){ 1553 sm_key_distribution_handle_all_received(connection); 1554 connection->sm_engine_state = SM_RESPONDER_IDLE; 1555 sm_done_for_handle(connection->sm_handle); 1556 } else { 1557 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1558 } 1559 } else { 1560 // master -> all done 1561 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1562 sm_done_for_handle(connection->sm_handle); 1563 } 1564 break; 1565 1566 default: 1567 break; 1568 } 1569 1570 // check again if active connection was released 1571 if (sm_active_connection) break; 1572 } 1573 } 1574 1575 // note: aes engine is ready as we just got the aes result 1576 static void sm_handle_encryption_result(uint8_t * data){ 1577 1578 sm_aes128_state = SM_AES128_IDLE; 1579 1580 if (sm_address_resolution_ah_calculation_active){ 1581 sm_address_resolution_ah_calculation_active = 0; 1582 // compare calulated address against connecting device 1583 uint8_t hash[3]; 1584 swap24(data, hash); 1585 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 1586 log_info("LE Device Lookup: matched resolvable private address"); 1587 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1588 return; 1589 } 1590 // no match, try next 1591 sm_address_resolution_test++; 1592 return; 1593 } 1594 1595 switch (dkg_state){ 1596 case DKG_W4_IRK: 1597 swap128(data, sm_persistent_irk); 1598 log_key("irk", sm_persistent_irk); 1599 dkg_next_state(); 1600 return; 1601 case DKG_W4_DHK: 1602 swap128(data, sm_persistent_dhk); 1603 log_key("dhk", sm_persistent_dhk); 1604 dkg_next_state(); 1605 // SM Init Finished 1606 return; 1607 default: 1608 break; 1609 } 1610 1611 switch (rau_state){ 1612 case RAU_W4_ENC: 1613 swap24(data, &sm_random_address[3]); 1614 rau_next_state(); 1615 return; 1616 default: 1617 break; 1618 } 1619 1620 switch (sm_cmac_state){ 1621 case CMAC_W4_SUBKEYS: 1622 case CMAC_W4_MI: 1623 case CMAC_W4_MLAST: 1624 { 1625 sm_key_t t; 1626 swap128(data, t); 1627 sm_cmac_handle_encryption_result(t); 1628 } 1629 return; 1630 default: 1631 break; 1632 } 1633 1634 // retrieve sm_connection provided to sm_aes128_start_encryption 1635 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 1636 if (!connection) return; 1637 switch (connection->sm_engine_state){ 1638 case SM_PH2_C1_W4_ENC_A: 1639 case SM_PH2_C1_W4_ENC_C: 1640 { 1641 sm_key_t t2; 1642 swap128(data, t2); 1643 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 1644 } 1645 sm_next_responding_state(connection); 1646 return; 1647 case SM_PH2_C1_W4_ENC_B: 1648 swap128(data, setup->sm_local_confirm); 1649 log_key("c1!", setup->sm_local_confirm); 1650 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 1651 return; 1652 case SM_PH2_C1_W4_ENC_D: 1653 { 1654 sm_key_t peer_confirm_test; 1655 swap128(data, peer_confirm_test); 1656 log_key("c1!", peer_confirm_test); 1657 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 1658 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 1659 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1660 return; 1661 } 1662 if (connection->sm_role){ 1663 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 1664 } else { 1665 connection->sm_engine_state = SM_PH2_CALC_STK; 1666 } 1667 } 1668 return; 1669 case SM_PH2_W4_STK: 1670 swap128(data, setup->sm_ltk); 1671 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 1672 log_key("stk", setup->sm_ltk); 1673 if (connection->sm_role){ 1674 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 1675 } else { 1676 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1677 } 1678 return; 1679 case SM_PH3_Y_W4_ENC:{ 1680 sm_key_t y128; 1681 swap128(data, y128); 1682 setup->sm_local_y = big_endian_read_16(y128, 14); 1683 log_info_hex16("y", setup->sm_local_y); 1684 // PH3B3 - calculate EDIV 1685 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 1686 log_info_hex16("ediv", setup->sm_local_ediv); 1687 // PH3B4 - calculate LTK - enc 1688 // LTK = d1(ER, DIV, 0)) 1689 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 1690 return; 1691 } 1692 case SM_RESPONDER_PH4_Y_W4_ENC:{ 1693 sm_key_t y128; 1694 swap128(data, y128); 1695 setup->sm_local_y = big_endian_read_16(y128, 14); 1696 log_info_hex16("y", setup->sm_local_y); 1697 1698 // PH3B3 - calculate DIV 1699 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 1700 log_info_hex16("ediv", setup->sm_local_ediv); 1701 // PH3B4 - calculate LTK - enc 1702 // LTK = d1(ER, DIV, 0)) 1703 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 1704 return; 1705 } 1706 case SM_PH3_LTK_W4_ENC: 1707 swap128(data, setup->sm_ltk); 1708 log_key("ltk", setup->sm_ltk); 1709 // calc CSRK next 1710 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 1711 return; 1712 case SM_PH3_CSRK_W4_ENC: 1713 swap128(data, setup->sm_local_csrk); 1714 log_key("csrk", setup->sm_local_csrk); 1715 if (setup->sm_key_distribution_send_set){ 1716 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 1717 } else { 1718 // no keys to send, just continue 1719 if (connection->sm_role){ 1720 // slave -> receive master keys 1721 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1722 } else { 1723 // master -> all done 1724 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1725 sm_done_for_handle(connection->sm_handle); 1726 } 1727 } 1728 return; 1729 case SM_RESPONDER_PH4_LTK_W4_ENC: 1730 swap128(data, setup->sm_ltk); 1731 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 1732 log_key("ltk", setup->sm_ltk); 1733 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 1734 return; 1735 default: 1736 break; 1737 } 1738 } 1739 1740 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 1741 static void sm_handle_random_result(uint8_t * data){ 1742 1743 switch (rau_state){ 1744 case RAU_W4_RANDOM: 1745 // non-resolvable vs. resolvable 1746 switch (gap_random_adress_type){ 1747 case GAP_RANDOM_ADDRESS_RESOLVABLE: 1748 // resolvable: use random as prand and calc address hash 1749 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 1750 memcpy(sm_random_address, data, 3); 1751 sm_random_address[0] &= 0x3f; 1752 sm_random_address[0] |= 0x40; 1753 rau_state = RAU_GET_ENC; 1754 break; 1755 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 1756 default: 1757 // "The two most significant bits of the address shall be equal to ‘0’"" 1758 memcpy(sm_random_address, data, 6); 1759 sm_random_address[0] &= 0x3f; 1760 rau_state = RAU_SET_ADDRESS; 1761 break; 1762 } 1763 return; 1764 default: 1765 break; 1766 } 1767 1768 // retrieve sm_connection provided to sm_random_start 1769 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 1770 if (!connection) return; 1771 switch (connection->sm_engine_state){ 1772 case SM_PH2_W4_RANDOM_TK: 1773 { 1774 // map random to 0-999999 without speding much cycles on a modulus operation 1775 uint32_t tk = little_endian_read_32(data,0); 1776 tk = tk & 0xfffff; // 1048575 1777 if (tk >= 999999){ 1778 tk = tk - 999999; 1779 } 1780 sm_reset_tk(); 1781 big_endian_store_32(setup->sm_tk, 12, tk); 1782 if (connection->sm_role){ 1783 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1784 } else { 1785 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 1786 sm_trigger_user_response(connection); 1787 // response_idle == nothing <--> sm_trigger_user_response() did not require response 1788 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 1789 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 1790 } 1791 } 1792 return; 1793 } 1794 case SM_PH2_C1_W4_RANDOM_A: 1795 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 1796 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 1797 return; 1798 case SM_PH2_C1_W4_RANDOM_B: 1799 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 1800 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 1801 return; 1802 case SM_PH3_W4_RANDOM: 1803 swap64(data, setup->sm_local_rand); 1804 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1805 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 1806 // no db for authenticated flag hack: store flag in bit 4 of LSB 1807 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 1808 connection->sm_engine_state = SM_PH3_GET_DIV; 1809 return; 1810 case SM_PH3_W4_DIV: 1811 // use 16 bit from random value as div 1812 setup->sm_local_div = big_endian_read_16(data, 0); 1813 log_info_hex16("div", setup->sm_local_div); 1814 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 1815 return; 1816 default: 1817 break; 1818 } 1819 } 1820 1821 static void sm_event_packet_handler (uint8_t packet_type, uint8_t *packet, uint16_t size){ 1822 1823 sm_connection_t * sm_conn; 1824 uint16_t handle; 1825 1826 switch (packet_type) { 1827 1828 case HCI_EVENT_PACKET: 1829 switch (packet[0]) { 1830 1831 case BTSTACK_EVENT_STATE: 1832 // bt stack activated, get started 1833 if (packet[2] == HCI_STATE_WORKING) { 1834 log_info("HCI Working!"); 1835 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 1836 rau_state = RAU_IDLE; 1837 sm_run(); 1838 } 1839 break; 1840 1841 case HCI_EVENT_LE_META: 1842 switch (packet[2]) { 1843 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 1844 1845 log_info("sm: connected"); 1846 1847 if (packet[3]) return; // connection failed 1848 1849 handle = little_endian_read_16(packet, 4); 1850 sm_conn = sm_get_connection_for_handle(handle); 1851 if (!sm_conn) break; 1852 1853 sm_conn->sm_handle = handle; 1854 sm_conn->sm_role = packet[6]; 1855 sm_conn->sm_peer_addr_type = packet[7]; 1856 bt_flip_addr(sm_conn->sm_peer_address, &packet[8]); 1857 1858 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 1859 1860 // reset security properties 1861 sm_conn->sm_connection_encrypted = 0; 1862 sm_conn->sm_connection_authenticated = 0; 1863 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 1864 sm_conn->sm_le_db_index = -1; 1865 1866 // prepare CSRK lookup (does not involve setup) 1867 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 1868 1869 // just connected -> everything else happens in sm_run() 1870 if (sm_conn->sm_role){ 1871 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 1872 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 1873 if (sm_slave_request_security) { 1874 // request security if requested by app 1875 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1876 } else { 1877 // otherwise, wait for pairing request 1878 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1879 } 1880 } 1881 break; 1882 } else { 1883 // master 1884 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1885 } 1886 break; 1887 1888 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 1889 handle = little_endian_read_16(packet, 3); 1890 sm_conn = sm_get_connection_for_handle(handle); 1891 if (!sm_conn) break; 1892 1893 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 1894 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 1895 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 1896 break; 1897 } 1898 1899 // assume that we don't have a LTK for ediv == 0 and random == null 1900 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 1901 log_info("LTK Request: ediv & random are empty"); 1902 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1903 break; 1904 } 1905 1906 // store rand and ediv 1907 swap64(&packet[5], sm_conn->sm_local_rand); 1908 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 1909 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 1910 break; 1911 1912 default: 1913 break; 1914 } 1915 break; 1916 1917 case HCI_EVENT_ENCRYPTION_CHANGE: 1918 handle = little_endian_read_16(packet, 3); 1919 sm_conn = sm_get_connection_for_handle(handle); 1920 if (!sm_conn) break; 1921 1922 sm_conn->sm_connection_encrypted = packet[5]; 1923 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 1924 sm_conn->sm_actual_encryption_key_size); 1925 log_info("event handler, state %u", sm_conn->sm_engine_state); 1926 if (!sm_conn->sm_connection_encrypted) break; 1927 // continue if part of initial pairing 1928 switch (sm_conn->sm_engine_state){ 1929 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 1930 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1931 sm_done_for_handle(sm_conn->sm_handle); 1932 break; 1933 case SM_PH2_W4_CONNECTION_ENCRYPTED: 1934 if (sm_conn->sm_role){ 1935 // slave 1936 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1937 } else { 1938 // master 1939 if (sm_key_distribution_all_received(sm_conn)){ 1940 // skip receiving keys as there are none 1941 sm_key_distribution_handle_all_received(sm_conn); 1942 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1943 } else { 1944 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1945 } 1946 } 1947 break; 1948 default: 1949 break; 1950 } 1951 break; 1952 1953 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 1954 handle = little_endian_read_16(packet, 3); 1955 sm_conn = sm_get_connection_for_handle(handle); 1956 if (!sm_conn) break; 1957 1958 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 1959 log_info("event handler, state %u", sm_conn->sm_engine_state); 1960 // continue if part of initial pairing 1961 switch (sm_conn->sm_engine_state){ 1962 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 1963 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1964 sm_done_for_handle(sm_conn->sm_handle); 1965 break; 1966 case SM_PH2_W4_CONNECTION_ENCRYPTED: 1967 if (sm_conn->sm_role){ 1968 // slave 1969 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1970 } else { 1971 // master 1972 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1973 } 1974 break; 1975 default: 1976 break; 1977 } 1978 break; 1979 1980 1981 case HCI_EVENT_DISCONNECTION_COMPLETE: 1982 handle = little_endian_read_16(packet, 3); 1983 sm_done_for_handle(handle); 1984 sm_conn = sm_get_connection_for_handle(handle); 1985 if (!sm_conn) break; 1986 1987 // delete stored bonding on disconnect with authentication failure in ph0 1988 if (sm_conn->sm_role == 0 1989 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 1990 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 1991 le_device_db_remove(sm_conn->sm_le_db_index); 1992 } 1993 1994 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 1995 sm_conn->sm_handle = 0; 1996 break; 1997 1998 case HCI_EVENT_COMMAND_COMPLETE: 1999 if (COMMAND_COMPLETE_EVENT(packet, hci_le_encrypt)){ 2000 sm_handle_encryption_result(&packet[6]); 2001 break; 2002 } 2003 if (COMMAND_COMPLETE_EVENT(packet, hci_le_rand)){ 2004 sm_handle_random_result(&packet[6]); 2005 break; 2006 } 2007 } 2008 2009 // forward packet to higher layer 2010 if (sm_client_packet_handler){ 2011 sm_client_packet_handler(packet_type, 0, packet, size); 2012 } 2013 } 2014 2015 sm_run(); 2016 } 2017 2018 static inline int sm_calc_actual_encryption_key_size(int other){ 2019 if (other < sm_min_encryption_key_size) return 0; 2020 if (other < sm_max_encryption_key_size) return other; 2021 return sm_max_encryption_key_size; 2022 } 2023 2024 /** 2025 * @return ok 2026 */ 2027 static int sm_validate_stk_generation_method(void){ 2028 // check if STK generation method is acceptable by client 2029 switch (setup->sm_stk_generation_method){ 2030 case JUST_WORKS: 2031 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2032 case PK_RESP_INPUT: 2033 case PK_INIT_INPUT: 2034 case OK_BOTH_INPUT: 2035 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2036 case OOB: 2037 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2038 default: 2039 return 0; 2040 } 2041 } 2042 2043 // helper for sm_pdu_handler, calls sm_run on exit 2044 static void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 2045 setup->sm_pairing_failed_reason = SM_REASON_UNSPECIFIED_REASON; 2046 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2047 sm_done_for_handle(sm_conn->sm_handle); 2048 } 2049 2050 static void sm_pdu_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){ 2051 2052 if (packet_type != SM_DATA_PACKET) return; 2053 2054 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2055 if (!sm_conn) return; 2056 2057 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2058 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2059 return; 2060 } 2061 2062 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2063 2064 int err; 2065 2066 switch (sm_conn->sm_engine_state){ 2067 2068 // a sm timeout requries a new physical connection 2069 case SM_GENERAL_TIMEOUT: 2070 return; 2071 2072 // Initiator 2073 case SM_INITIATOR_CONNECTED: 2074 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2075 sm_pdu_received_in_wrong_state(sm_conn); 2076 break; 2077 } 2078 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2079 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2080 break; 2081 } 2082 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2083 uint16_t ediv; 2084 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2085 if (ediv){ 2086 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2087 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2088 } else { 2089 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2090 } 2091 break; 2092 } 2093 // otherwise, store security request 2094 sm_conn->sm_security_request_received = 1; 2095 break; 2096 2097 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2098 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2099 sm_pdu_received_in_wrong_state(sm_conn); 2100 break; 2101 } 2102 // store pairing request 2103 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2104 err = sm_stk_generation_init(sm_conn); 2105 if (err){ 2106 setup->sm_pairing_failed_reason = err; 2107 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2108 break; 2109 } 2110 // generate random number first, if we need to show passkey 2111 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2112 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2113 break; 2114 } 2115 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2116 sm_trigger_user_response(sm_conn); 2117 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2118 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2119 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2120 } 2121 break; 2122 2123 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2124 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2125 sm_pdu_received_in_wrong_state(sm_conn); 2126 break; 2127 } 2128 2129 // store s_confirm 2130 swap128(&packet[1], setup->sm_peer_confirm); 2131 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2132 break; 2133 2134 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2135 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2136 sm_pdu_received_in_wrong_state(sm_conn); 2137 break;; 2138 } 2139 2140 // received random value 2141 swap128(&packet[1], setup->sm_peer_random); 2142 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2143 break; 2144 2145 // Responder 2146 case SM_RESPONDER_IDLE: 2147 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2148 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2149 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2150 sm_pdu_received_in_wrong_state(sm_conn); 2151 break;; 2152 } 2153 2154 // store pairing request 2155 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2156 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2157 break; 2158 2159 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 2160 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2161 sm_pdu_received_in_wrong_state(sm_conn); 2162 break;; 2163 } 2164 2165 // received confirm value 2166 swap128(&packet[1], setup->sm_peer_confirm); 2167 2168 // notify client to hide shown passkey 2169 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2170 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 2171 } 2172 2173 // handle user cancel pairing? 2174 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 2175 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2176 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2177 break; 2178 } 2179 2180 // wait for user action? 2181 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 2182 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2183 break; 2184 } 2185 2186 // calculate and send local_confirm 2187 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2188 break; 2189 2190 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 2191 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2192 sm_pdu_received_in_wrong_state(sm_conn); 2193 break;; 2194 } 2195 2196 // received random value 2197 swap128(&packet[1], setup->sm_peer_random); 2198 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2199 break; 2200 2201 case SM_PH3_RECEIVE_KEYS: 2202 switch(packet[0]){ 2203 case SM_CODE_ENCRYPTION_INFORMATION: 2204 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2205 swap128(&packet[1], setup->sm_peer_ltk); 2206 break; 2207 2208 case SM_CODE_MASTER_IDENTIFICATION: 2209 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2210 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 2211 swap64(&packet[3], setup->sm_peer_rand); 2212 break; 2213 2214 case SM_CODE_IDENTITY_INFORMATION: 2215 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2216 swap128(&packet[1], setup->sm_peer_irk); 2217 break; 2218 2219 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 2220 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2221 setup->sm_peer_addr_type = packet[1]; 2222 bt_flip_addr(setup->sm_peer_address, &packet[2]); 2223 break; 2224 2225 case SM_CODE_SIGNING_INFORMATION: 2226 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2227 swap128(&packet[1], setup->sm_peer_csrk); 2228 break; 2229 default: 2230 // Unexpected PDU 2231 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 2232 break; 2233 } 2234 // done with key distribution? 2235 if (sm_key_distribution_all_received(sm_conn)){ 2236 2237 sm_key_distribution_handle_all_received(sm_conn); 2238 2239 if (sm_conn->sm_role){ 2240 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2241 sm_done_for_handle(sm_conn->sm_handle); 2242 } else { 2243 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2244 } 2245 } 2246 break; 2247 default: 2248 // Unexpected PDU 2249 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 2250 break; 2251 } 2252 2253 // try to send preparared packet 2254 sm_run(); 2255 } 2256 2257 // Security Manager Client API 2258 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 2259 sm_get_oob_data = get_oob_data_callback; 2260 } 2261 2262 void sm_register_packet_handler(btstack_packet_handler_t handler){ 2263 sm_client_packet_handler = handler; 2264 } 2265 2266 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 2267 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 2268 } 2269 2270 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 2271 sm_min_encryption_key_size = min_size; 2272 sm_max_encryption_key_size = max_size; 2273 } 2274 2275 void sm_set_authentication_requirements(uint8_t auth_req){ 2276 sm_auth_req = auth_req; 2277 } 2278 2279 void sm_set_io_capabilities(io_capability_t io_capability){ 2280 sm_io_capabilities = io_capability; 2281 } 2282 2283 void sm_set_request_security(int enable){ 2284 sm_slave_request_security = enable; 2285 } 2286 2287 void sm_set_er(sm_key_t er){ 2288 memcpy(sm_persistent_er, er, 16); 2289 } 2290 2291 void sm_set_ir(sm_key_t ir){ 2292 memcpy(sm_persistent_ir, ir, 16); 2293 } 2294 2295 // Testing support only 2296 void sm_test_set_irk(sm_key_t irk){ 2297 memcpy(sm_persistent_irk, irk, 16); 2298 sm_persistent_irk_ready = 1; 2299 } 2300 2301 void sm_test_use_fixed_local_csrk(void){ 2302 test_use_fixed_local_csrk = 1; 2303 } 2304 2305 void sm_init(void){ 2306 // set some (BTstack default) ER and IR 2307 int i; 2308 sm_key_t er; 2309 sm_key_t ir; 2310 for (i=0;i<16;i++){ 2311 er[i] = 0x30 + i; 2312 ir[i] = 0x90 + i; 2313 } 2314 sm_set_er(er); 2315 sm_set_ir(ir); 2316 // defaults 2317 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 2318 | SM_STK_GENERATION_METHOD_OOB 2319 | SM_STK_GENERATION_METHOD_PASSKEY; 2320 sm_max_encryption_key_size = 16; 2321 sm_min_encryption_key_size = 7; 2322 2323 sm_cmac_state = CMAC_IDLE; 2324 dkg_state = DKG_W4_WORKING; 2325 rau_state = RAU_W4_WORKING; 2326 sm_aes128_state = SM_AES128_IDLE; 2327 sm_address_resolution_test = -1; // no private address to resolve yet 2328 sm_address_resolution_ah_calculation_active = 0; 2329 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 2330 sm_address_resolution_general_queue = NULL; 2331 2332 gap_random_adress_update_period = 15 * 60 * 1000L; 2333 2334 sm_active_connection = 0; 2335 2336 test_use_fixed_local_csrk = 0; 2337 2338 // register for HCI Events from HCI 2339 hci_event_callback_registration.callback = &sm_event_packet_handler; 2340 hci_add_event_handler(&hci_event_callback_registration); 2341 2342 // and L2CAP PDUs 2343 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2344 } 2345 2346 static sm_connection_t * sm_get_connection_for_handle(uint16_t con_handle){ 2347 hci_connection_t * hci_con = hci_connection_for_handle((hci_con_handle_t) con_handle); 2348 if (!hci_con) return NULL; 2349 return &hci_con->sm_connection; 2350 } 2351 2352 // @returns 0 if not encrypted, 7-16 otherwise 2353 int sm_encryption_key_size(uint16_t handle){ 2354 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2355 if (!sm_conn) return 0; // wrong connection 2356 if (!sm_conn->sm_connection_encrypted) return 0; 2357 return sm_conn->sm_actual_encryption_key_size; 2358 } 2359 2360 int sm_authenticated(uint16_t handle){ 2361 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2362 if (!sm_conn) return 0; // wrong connection 2363 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 2364 return sm_conn->sm_connection_authenticated; 2365 } 2366 2367 authorization_state_t sm_authorization_state(uint16_t handle){ 2368 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2369 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 2370 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 2371 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 2372 return sm_conn->sm_connection_authorization_state; 2373 } 2374 2375 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 2376 switch (sm_conn->sm_engine_state){ 2377 case SM_GENERAL_IDLE: 2378 case SM_RESPONDER_IDLE: 2379 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2380 sm_run(); 2381 break; 2382 default: 2383 break; 2384 } 2385 } 2386 2387 /** 2388 * @brief Trigger Security Request 2389 */ 2390 void sm_send_security_request(uint16_t handle){ 2391 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2392 if (!sm_conn) return; 2393 sm_send_security_request_for_connection(sm_conn); 2394 } 2395 2396 // request pairing 2397 void sm_request_pairing(uint16_t handle){ 2398 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2399 if (!sm_conn) return; // wrong connection 2400 2401 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 2402 if (sm_conn->sm_role){ 2403 sm_send_security_request_for_connection(sm_conn); 2404 } else { 2405 // used as a trigger to start central/master/initiator security procedures 2406 uint16_t ediv; 2407 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 2408 switch (sm_conn->sm_irk_lookup_state){ 2409 case IRK_LOOKUP_FAILED: 2410 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2411 break; 2412 case IRK_LOOKUP_SUCCEEDED: 2413 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2414 if (ediv){ 2415 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2416 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2417 } else { 2418 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2419 } 2420 break; 2421 default: 2422 sm_conn->sm_bonding_requested = 1; 2423 break; 2424 } 2425 } 2426 } 2427 sm_run(); 2428 } 2429 2430 // called by client app on authorization request 2431 void sm_authorization_decline(uint16_t handle){ 2432 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2433 if (!sm_conn) return; // wrong connection 2434 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 2435 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 2436 } 2437 2438 void sm_authorization_grant(uint16_t handle){ 2439 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2440 if (!sm_conn) return; // wrong connection 2441 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 2442 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 2443 } 2444 2445 // GAP Bonding API 2446 2447 void sm_bonding_decline(uint16_t handle){ 2448 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2449 if (!sm_conn) return; // wrong connection 2450 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 2451 2452 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2453 sm_done_for_handle(sm_conn->sm_handle); 2454 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2455 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2456 } 2457 sm_run(); 2458 } 2459 2460 void sm_just_works_confirm(uint16_t handle){ 2461 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2462 if (!sm_conn) return; // wrong connection 2463 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 2464 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2465 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2466 } 2467 sm_run(); 2468 } 2469 2470 void sm_passkey_input(uint16_t handle, uint32_t passkey){ 2471 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2472 if (!sm_conn) return; // wrong connection 2473 sm_reset_tk(); 2474 big_endian_store_32(setup->sm_tk, 12, passkey); 2475 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 2476 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2477 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2478 } 2479 sm_run(); 2480 } 2481 2482 /** 2483 * @brief Identify device in LE Device DB 2484 * @param handle 2485 * @returns index from le_device_db or -1 if not found/identified 2486 */ 2487 int sm_le_device_index(uint16_t handle ){ 2488 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2489 if (!sm_conn) return -1; 2490 return sm_conn->sm_le_db_index; 2491 } 2492 2493 // GAP LE API 2494 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 2495 gap_random_address_update_stop(); 2496 gap_random_adress_type = random_address_type; 2497 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 2498 gap_random_address_update_start(); 2499 gap_random_address_trigger(); 2500 } 2501 2502 gap_random_address_type_t gap_random_address_get_mode(void){ 2503 return gap_random_adress_type; 2504 } 2505 2506 void gap_random_address_set_update_period(int period_ms){ 2507 gap_random_adress_update_period = period_ms; 2508 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 2509 gap_random_address_update_stop(); 2510 gap_random_address_update_start(); 2511 } 2512 2513 void gap_random_address_set(bd_addr_t addr){ 2514 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 2515 memcpy(sm_random_address, addr, 6); 2516 rau_state = RAU_SET_ADDRESS; 2517 sm_run(); 2518 } 2519 2520 /* 2521 * @brief Set Advertisement Paramters 2522 * @param adv_int_min 2523 * @param adv_int_max 2524 * @param adv_type 2525 * @param direct_address_type 2526 * @param direct_address 2527 * @param channel_map 2528 * @param filter_policy 2529 * 2530 * @note own_address_type is used from gap_random_address_set_mode 2531 */ 2532 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 2533 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 2534 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 2535 direct_address_typ, direct_address, channel_map, filter_policy); 2536 } 2537 2538