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/sm.h" 44 #include "btstack_debug.h" 45 #include "btstack_event.h" 46 #include "btstack_linked_list.h" 47 #include "btstack_memory.h" 48 #include "gap.h" 49 #include "hci.h" 50 #include "l2cap.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 /* to dispatch sm event */ 180 static btstack_linked_list_t sm_event_handlers; 181 182 // 183 // Volume 3, Part H, Chapter 24 184 // "Security shall be initiated by the Security Manager in the device in the master role. 185 // The device in the slave role shall be the responding device." 186 // -> master := initiator, slave := responder 187 // 188 189 // data needed for security setup 190 typedef struct sm_setup_context { 191 192 btstack_timer_source_t sm_timeout; 193 194 // used in all phases 195 uint8_t sm_pairing_failed_reason; 196 197 // user response, (Phase 1 and/or 2) 198 uint8_t sm_user_response; 199 200 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 201 int sm_key_distribution_send_set; 202 int sm_key_distribution_received_set; 203 204 // Phase 2 (Pairing over SMP) 205 stk_generation_method_t sm_stk_generation_method; 206 sm_key_t sm_tk; 207 208 sm_key_t sm_c1_t3_value; // c1 calculation 209 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 210 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 211 sm_key_t sm_local_random; 212 sm_key_t sm_local_confirm; 213 sm_key_t sm_peer_random; 214 sm_key_t sm_peer_confirm; 215 uint8_t sm_m_addr_type; // address and type can be removed 216 uint8_t sm_s_addr_type; // '' 217 bd_addr_t sm_m_address; // '' 218 bd_addr_t sm_s_address; // '' 219 sm_key_t sm_ltk; 220 221 // Phase 3 222 223 // key distribution, we generate 224 uint16_t sm_local_y; 225 uint16_t sm_local_div; 226 uint16_t sm_local_ediv; 227 uint8_t sm_local_rand[8]; 228 sm_key_t sm_local_ltk; 229 sm_key_t sm_local_csrk; 230 sm_key_t sm_local_irk; 231 // sm_local_address/addr_type not needed 232 233 // key distribution, received from peer 234 uint16_t sm_peer_y; 235 uint16_t sm_peer_div; 236 uint16_t sm_peer_ediv; 237 uint8_t sm_peer_rand[8]; 238 sm_key_t sm_peer_ltk; 239 sm_key_t sm_peer_irk; 240 sm_key_t sm_peer_csrk; 241 uint8_t sm_peer_addr_type; 242 bd_addr_t sm_peer_address; 243 244 } sm_setup_context_t; 245 246 // 247 static sm_setup_context_t the_setup; 248 static sm_setup_context_t * setup = &the_setup; 249 250 // active connection - the one for which the_setup is used for 251 static uint16_t sm_active_connection = 0; 252 253 // @returns 1 if oob data is available 254 // stores oob data in provided 16 byte buffer if not null 255 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 256 257 // used to notify applicationss that user interaction is neccessary, see sm_notify_t below 258 static btstack_packet_handler_t sm_client_packet_handler = NULL; 259 260 // horizontal: initiator capabilities 261 // vertial: responder capabilities 262 static const stk_generation_method_t stk_generation_method[5][5] = { 263 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 264 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 265 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 266 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 267 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 268 }; 269 270 static void sm_run(void); 271 static void sm_done_for_handle(hci_con_handle_t con_handle); 272 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 273 static inline int sm_calc_actual_encryption_key_size(int other); 274 static int sm_validate_stk_generation_method(void); 275 276 static void log_info_hex16(const char * name, uint16_t value){ 277 log_info("%-6s 0x%04x", name, value); 278 } 279 280 // @returns 1 if all bytes are 0 281 static int sm_is_null_random(uint8_t random[8]){ 282 int i; 283 for (i=0; i < 8 ; i++){ 284 if (random[i]) return 0; 285 } 286 return 1; 287 } 288 289 // Key utils 290 static void sm_reset_tk(void){ 291 int i; 292 for (i=0;i<16;i++){ 293 setup->sm_tk[i] = 0; 294 } 295 } 296 297 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 298 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 299 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 300 int i; 301 for (i = max_encryption_size ; i < 16 ; i++){ 302 key[15-i] = 0; 303 } 304 } 305 306 // SMP Timeout implementation 307 308 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 309 // the Security Manager Timer shall be reset and started. 310 // 311 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 312 // 313 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 314 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 315 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 316 // established. 317 318 static void sm_timeout_handler(btstack_timer_source_t * timer){ 319 log_info("SM timeout"); 320 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 321 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 322 sm_done_for_handle(sm_conn->sm_handle); 323 324 // trigger handling of next ready connection 325 sm_run(); 326 } 327 static void sm_timeout_start(sm_connection_t * sm_conn){ 328 btstack_run_loop_remove_timer(&setup->sm_timeout); 329 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 330 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 331 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 332 btstack_run_loop_add_timer(&setup->sm_timeout); 333 } 334 static void sm_timeout_stop(void){ 335 btstack_run_loop_remove_timer(&setup->sm_timeout); 336 } 337 static void sm_timeout_reset(sm_connection_t * sm_conn){ 338 sm_timeout_stop(); 339 sm_timeout_start(sm_conn); 340 } 341 342 // end of sm timeout 343 344 // GAP Random Address updates 345 static gap_random_address_type_t gap_random_adress_type; 346 static btstack_timer_source_t gap_random_address_update_timer; 347 static uint32_t gap_random_adress_update_period; 348 349 static void gap_random_address_trigger(void){ 350 if (rau_state != RAU_IDLE) return; 351 log_info("gap_random_address_trigger"); 352 rau_state = RAU_GET_RANDOM; 353 sm_run(); 354 } 355 356 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 357 log_info("GAP Random Address Update due"); 358 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 359 btstack_run_loop_add_timer(&gap_random_address_update_timer); 360 gap_random_address_trigger(); 361 } 362 363 static void gap_random_address_update_start(void){ 364 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 365 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 366 btstack_run_loop_add_timer(&gap_random_address_update_timer); 367 } 368 369 static void gap_random_address_update_stop(void){ 370 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 371 } 372 373 374 static void sm_random_start(void * context){ 375 sm_random_context = context; 376 hci_send_cmd(&hci_le_rand); 377 } 378 379 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 380 // context is made availabe to aes128 result handler by this 381 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 382 sm_aes128_state = SM_AES128_ACTIVE; 383 sm_key_t key_flipped, plaintext_flipped; 384 reverse_128(key, key_flipped); 385 reverse_128(plaintext, plaintext_flipped); 386 sm_aes128_context = context; 387 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 388 } 389 390 // ah(k,r) helper 391 // r = padding || r 392 // r - 24 bit value 393 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 394 // r'= padding || r 395 memset(r_prime, 0, 16); 396 memcpy(&r_prime[13], r, 3); 397 } 398 399 // d1 helper 400 // d' = padding || r || d 401 // d,r - 16 bit values 402 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 403 // d'= padding || r || d 404 memset(d1_prime, 0, 16); 405 big_endian_store_16(d1_prime, 12, r); 406 big_endian_store_16(d1_prime, 14, d); 407 } 408 409 // dm helper 410 // r’ = padding || r 411 // r - 64 bit value 412 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 413 memset(r_prime, 0, 16); 414 memcpy(&r_prime[8], r, 8); 415 } 416 417 // calculate arguments for first AES128 operation in C1 function 418 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){ 419 420 // p1 = pres || preq || rat’ || iat’ 421 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 422 // cant octet of pres becomes the most significant octet of p1. 423 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 424 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 425 // p1 is 0x05000800000302070710000001010001." 426 427 sm_key_t p1; 428 reverse_56(pres, &p1[0]); 429 reverse_56(preq, &p1[7]); 430 p1[14] = rat; 431 p1[15] = iat; 432 log_info_key("p1", p1); 433 log_info_key("r", r); 434 435 // t1 = r xor p1 436 int i; 437 for (i=0;i<16;i++){ 438 t1[i] = r[i] ^ p1[i]; 439 } 440 log_info_key("t1", t1); 441 } 442 443 // calculate arguments for second AES128 operation in C1 function 444 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 445 // p2 = padding || ia || ra 446 // "The least significant octet of ra becomes the least significant octet of p2 and 447 // the most significant octet of padding becomes the most significant octet of p2. 448 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 449 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 450 451 sm_key_t p2; 452 memset(p2, 0, 16); 453 memcpy(&p2[4], ia, 6); 454 memcpy(&p2[10], ra, 6); 455 log_info_key("p2", p2); 456 457 // c1 = e(k, t2_xor_p2) 458 int i; 459 for (i=0;i<16;i++){ 460 t3[i] = t2[i] ^ p2[i]; 461 } 462 log_info_key("t3", t3); 463 } 464 465 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 466 log_info_key("r1", r1); 467 log_info_key("r2", r2); 468 memcpy(&r_prime[8], &r2[8], 8); 469 memcpy(&r_prime[0], &r1[8], 8); 470 } 471 472 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){ 473 event[0] = type; 474 event[1] = event_size - 2; 475 little_endian_store_16(event, 2, con_handle); 476 event[4] = addr_type; 477 reverse_bd_addr(address, &event[5]); 478 } 479 480 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 481 if (sm_client_packet_handler) { 482 sm_client_packet_handler(HCI_EVENT_PACKET, 0, packet, size); 483 } 484 // dispatch to all event handlers 485 btstack_linked_list_iterator_t it; 486 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 487 while (btstack_linked_list_iterator_has_next(&it)){ 488 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 489 entry->callback(packet_type, 0, packet, size); 490 } 491 } 492 493 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 494 uint8_t event[11]; 495 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 496 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 497 } 498 499 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){ 500 uint8_t event[15]; 501 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 502 little_endian_store_32(event, 11, passkey); 503 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 504 } 505 506 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){ 507 uint8_t event[13]; 508 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 509 little_endian_store_16(event, 11, index); 510 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 511 } 512 513 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){ 514 515 uint8_t event[18]; 516 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 517 event[11] = result; 518 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 519 } 520 521 // decide on stk generation based on 522 // - pairing request 523 // - io capabilities 524 // - OOB data availability 525 static void sm_setup_tk(void){ 526 527 // default: just works 528 setup->sm_stk_generation_method = JUST_WORKS; 529 530 // If both devices have out of band authentication data, then the Authentication 531 // Requirements Flags shall be ignored when selecting the pairing method and the 532 // Out of Band pairing method shall be used. 533 if (setup->sm_m_preq.oob_data_flag && setup->sm_s_pres.oob_data_flag){ 534 log_info("SM: have OOB data"); 535 log_info_key("OOB", setup->sm_tk); 536 setup->sm_stk_generation_method = OOB; 537 return; 538 } 539 540 // Reset TK as it has been setup in sm_init_setup 541 sm_reset_tk(); 542 543 // If both devices have not set the MITM option in the Authentication Requirements 544 // Flags, then the IO capabilities shall be ignored and the Just Works association 545 // model shall be used. 546 if ( ((setup->sm_m_preq.auth_req & SM_AUTHREQ_MITM_PROTECTION) == 0x00) && ((setup->sm_s_pres.auth_req & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 547 return; 548 } 549 550 // Also use just works if unknown io capabilites 551 if ((setup->sm_m_preq.io_capability > IO_CAPABILITY_KEYBOARD_DISPLAY) || (setup->sm_m_preq.io_capability > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 552 return; 553 } 554 555 // Otherwise the IO capabilities of the devices shall be used to determine the 556 // pairing method as defined in Table 2.4. 557 setup->sm_stk_generation_method = stk_generation_method[setup->sm_s_pres.io_capability][setup->sm_m_preq.io_capability]; 558 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 559 setup->sm_m_preq.io_capability, setup->sm_s_pres.io_capability, setup->sm_stk_generation_method); 560 } 561 562 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 563 int flags = 0; 564 if (key_set & SM_KEYDIST_ENC_KEY){ 565 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 566 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 567 } 568 if (key_set & SM_KEYDIST_ID_KEY){ 569 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 570 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 571 } 572 if (key_set & SM_KEYDIST_SIGN){ 573 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 574 } 575 return flags; 576 } 577 578 static void sm_setup_key_distribution(uint8_t key_set){ 579 setup->sm_key_distribution_received_set = 0; 580 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 581 } 582 583 // CSRK Key Lookup 584 585 586 static int sm_address_resolution_idle(void){ 587 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 588 } 589 590 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){ 591 memcpy(sm_address_resolution_address, addr, 6); 592 sm_address_resolution_addr_type = addr_type; 593 sm_address_resolution_test = 0; 594 sm_address_resolution_mode = mode; 595 sm_address_resolution_context = context; 596 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 597 } 598 599 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 600 // check if already in list 601 btstack_linked_list_iterator_t it; 602 sm_lookup_entry_t * entry; 603 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 604 while(btstack_linked_list_iterator_has_next(&it)){ 605 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 606 if (entry->address_type != address_type) continue; 607 if (memcmp(entry->address, address, 6)) continue; 608 // already in list 609 return BTSTACK_BUSY; 610 } 611 entry = btstack_memory_sm_lookup_entry_get(); 612 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 613 entry->address_type = (bd_addr_type_t) address_type; 614 memcpy(entry->address, address, 6); 615 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 616 sm_run(); 617 return 0; 618 } 619 620 // CMAC Implementation using AES128 engine 621 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 622 int i; 623 int carry = 0; 624 for (i=len-1; i >= 0 ; i--){ 625 int new_carry = data[i] >> 7; 626 data[i] = data[i] << 1 | carry; 627 carry = new_carry; 628 } 629 } 630 631 // 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 632 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 633 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 634 } 635 static inline void dkg_next_state(void){ 636 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 637 } 638 static inline void rau_next_state(void){ 639 rau_state = (random_address_update_t) (((int)rau_state) + 1); 640 } 641 static inline void sm_cmac_next_state(void){ 642 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 643 } 644 static int sm_cmac_last_block_complete(void){ 645 if (sm_cmac_message_len == 0) return 0; 646 return (sm_cmac_message_len & 0x0f) == 0; 647 } 648 static inline uint8_t sm_cmac_message_get_byte(int offset){ 649 if (offset >= sm_cmac_message_len) { 650 log_error("sm_cmac_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 651 return 0; 652 } 653 654 offset = sm_cmac_message_len - 1 - offset; 655 656 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 657 if (offset < 3){ 658 return sm_cmac_header[offset]; 659 } 660 int actual_message_len_incl_header = sm_cmac_message_len - 4; 661 if (offset < actual_message_len_incl_header){ 662 return sm_cmac_message[offset - 3]; 663 } 664 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 665 } 666 667 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])){ 668 memcpy(sm_cmac_k, k, 16); 669 sm_cmac_header[0] = opcode; 670 little_endian_store_16(sm_cmac_header, 1, con_handle); 671 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 672 sm_cmac_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 673 sm_cmac_message = message; 674 sm_cmac_done_handler = done_handler; 675 sm_cmac_block_current = 0; 676 memset(sm_cmac_x, 0, 16); 677 678 // step 2: n := ceil(len/const_Bsize); 679 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 680 681 // step 3: .. 682 if (sm_cmac_block_count==0){ 683 sm_cmac_block_count = 1; 684 } 685 686 log_info("sm_cmac_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 687 688 // first, we need to compute l for k1, k2, and m_last 689 sm_cmac_state = CMAC_CALC_SUBKEYS; 690 691 // let's go 692 sm_run(); 693 } 694 695 int sm_cmac_ready(void){ 696 return sm_cmac_state == CMAC_IDLE; 697 } 698 699 static void sm_cmac_handle_aes_engine_ready(void){ 700 switch (sm_cmac_state){ 701 case CMAC_CALC_SUBKEYS: { 702 sm_key_t const_zero; 703 memset(const_zero, 0, 16); 704 sm_cmac_next_state(); 705 sm_aes128_start(sm_cmac_k, const_zero, NULL); 706 break; 707 } 708 case CMAC_CALC_MI: { 709 int j; 710 sm_key_t y; 711 for (j=0;j<16;j++){ 712 y[j] = sm_cmac_x[j] ^ sm_cmac_message_get_byte(sm_cmac_block_current*16 + j); 713 } 714 sm_cmac_block_current++; 715 sm_cmac_next_state(); 716 sm_aes128_start(sm_cmac_k, y, NULL); 717 break; 718 } 719 case CMAC_CALC_MLAST: { 720 int i; 721 sm_key_t y; 722 for (i=0;i<16;i++){ 723 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 724 } 725 log_info_key("Y", y); 726 sm_cmac_block_current++; 727 sm_cmac_next_state(); 728 sm_aes128_start(sm_cmac_k, y, NULL); 729 break; 730 } 731 default: 732 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 733 break; 734 } 735 } 736 737 static void sm_cmac_handle_encryption_result(sm_key_t data){ 738 switch (sm_cmac_state){ 739 case CMAC_W4_SUBKEYS: { 740 sm_key_t k1; 741 memcpy(k1, data, 16); 742 sm_shift_left_by_one_bit_inplace(16, k1); 743 if (data[0] & 0x80){ 744 k1[15] ^= 0x87; 745 } 746 sm_key_t k2; 747 memcpy(k2, k1, 16); 748 sm_shift_left_by_one_bit_inplace(16, k2); 749 if (k1[0] & 0x80){ 750 k2[15] ^= 0x87; 751 } 752 753 log_info_key("k", sm_cmac_k); 754 log_info_key("k1", k1); 755 log_info_key("k2", k2); 756 757 // step 4: set m_last 758 int i; 759 if (sm_cmac_last_block_complete()){ 760 for (i=0;i<16;i++){ 761 sm_cmac_m_last[i] = sm_cmac_message_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 762 } 763 } else { 764 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 765 for (i=0;i<16;i++){ 766 if (i < valid_octets_in_last_block){ 767 sm_cmac_m_last[i] = sm_cmac_message_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 768 continue; 769 } 770 if (i == valid_octets_in_last_block){ 771 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 772 continue; 773 } 774 sm_cmac_m_last[i] = k2[i]; 775 } 776 } 777 778 // next 779 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 780 break; 781 } 782 case CMAC_W4_MI: 783 memcpy(sm_cmac_x, data, 16); 784 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 785 break; 786 case CMAC_W4_MLAST: 787 // done 788 log_info_key("CMAC", data); 789 sm_cmac_done_handler(data); 790 sm_cmac_state = CMAC_IDLE; 791 break; 792 default: 793 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 794 break; 795 } 796 } 797 798 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 799 // notify client for: JUST WORKS confirm, PASSKEY display or input 800 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 801 switch (setup->sm_stk_generation_method){ 802 case PK_RESP_INPUT: 803 if (sm_conn->sm_role){ 804 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 805 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 806 } else { 807 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)); 808 } 809 break; 810 case PK_INIT_INPUT: 811 if (sm_conn->sm_role){ 812 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)); 813 } else { 814 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 815 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 816 } 817 break; 818 case OK_BOTH_INPUT: 819 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 820 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 821 break; 822 case JUST_WORKS: 823 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 824 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 825 break; 826 case OOB: 827 // client already provided OOB data, let's skip notification. 828 break; 829 } 830 } 831 832 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 833 int recv_flags; 834 if (sm_conn->sm_role){ 835 // slave / responser 836 recv_flags = sm_key_distribution_flags_for_set(setup->sm_s_pres.initiator_key_distribution); 837 } else { 838 // master / initiator 839 recv_flags = sm_key_distribution_flags_for_set(setup->sm_s_pres.responder_key_distribution); 840 } 841 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 842 return recv_flags == setup->sm_key_distribution_received_set; 843 } 844 845 static void sm_done_for_handle(hci_con_handle_t con_handle){ 846 if (sm_active_connection == con_handle){ 847 sm_timeout_stop(); 848 sm_active_connection = 0; 849 log_info("sm: connection 0x%x released setup context", con_handle); 850 } 851 } 852 853 static int sm_key_distribution_flags_for_auth_req(void){ 854 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 855 if (sm_auth_req & SM_AUTHREQ_BONDING){ 856 // encryption information only if bonding requested 857 flags |= SM_KEYDIST_ENC_KEY; 858 } 859 return flags; 860 } 861 862 static void sm_init_setup(sm_connection_t * sm_conn){ 863 864 // fill in sm setup 865 sm_reset_tk(); 866 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 867 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 868 869 // query client for OOB data 870 int have_oob_data = 0; 871 if (sm_get_oob_data) { 872 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 873 } 874 875 sm_pairing_packet_t * local_packet; 876 if (sm_conn->sm_role){ 877 // slave 878 local_packet = &setup->sm_s_pres; 879 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 880 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 881 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 882 } else { 883 // master 884 local_packet = &setup->sm_m_preq; 885 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 886 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 887 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 888 889 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 890 setup->sm_m_preq.initiator_key_distribution = key_distribution_flags; 891 setup->sm_m_preq.responder_key_distribution = key_distribution_flags; 892 } 893 894 local_packet->io_capability = sm_io_capabilities; 895 local_packet->oob_data_flag = have_oob_data; 896 local_packet->auth_req = sm_auth_req; 897 local_packet->max_encryption_key_size = sm_max_encryption_key_size; 898 } 899 900 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 901 902 sm_pairing_packet_t * remote_packet; 903 int remote_key_request; 904 if (sm_conn->sm_role){ 905 // slave / responser 906 remote_packet = &setup->sm_m_preq; 907 remote_key_request = setup->sm_m_preq.responder_key_distribution; 908 } else { 909 // master / initiator 910 remote_packet = &setup->sm_s_pres; 911 remote_key_request = setup->sm_s_pres.initiator_key_distribution; 912 } 913 914 // check key size 915 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(remote_packet->max_encryption_key_size); 916 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 917 918 // setup key distribution 919 sm_setup_key_distribution(remote_key_request); 920 921 // identical to responder 922 923 // decide on STK generation method 924 sm_setup_tk(); 925 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 926 927 // check if STK generation method is acceptable by client 928 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 929 930 // JUST WORKS doens't provide authentication 931 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 932 933 return 0; 934 } 935 936 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 937 938 // cache and reset context 939 int matched_device_id = sm_address_resolution_test; 940 address_resolution_mode_t mode = sm_address_resolution_mode; 941 void * context = sm_address_resolution_context; 942 943 // reset context 944 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 945 sm_address_resolution_context = NULL; 946 sm_address_resolution_test = -1; 947 hci_con_handle_t con_handle = 0; 948 949 sm_connection_t * sm_connection; 950 uint16_t ediv; 951 switch (mode){ 952 case ADDRESS_RESOLUTION_GENERAL: 953 break; 954 case ADDRESS_RESOLUTION_FOR_CONNECTION: 955 sm_connection = (sm_connection_t *) context; 956 con_handle = sm_connection->sm_handle; 957 switch (event){ 958 case ADDRESS_RESOLUTION_SUCEEDED: 959 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 960 sm_connection->sm_le_db_index = matched_device_id; 961 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 962 if (sm_connection->sm_role) break; 963 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 964 sm_connection->sm_security_request_received = 0; 965 sm_connection->sm_bonding_requested = 0; 966 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 967 if (ediv){ 968 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 969 } else { 970 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 971 } 972 break; 973 case ADDRESS_RESOLUTION_FAILED: 974 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 975 if (sm_connection->sm_role) break; 976 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 977 sm_connection->sm_security_request_received = 0; 978 sm_connection->sm_bonding_requested = 0; 979 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 980 break; 981 } 982 break; 983 default: 984 break; 985 } 986 987 switch (event){ 988 case ADDRESS_RESOLUTION_SUCEEDED: 989 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 990 break; 991 case ADDRESS_RESOLUTION_FAILED: 992 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 993 break; 994 } 995 } 996 997 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 998 999 int le_db_index = -1; 1000 1001 // lookup device based on IRK 1002 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1003 int i; 1004 for (i=0; i < le_device_db_count(); i++){ 1005 sm_key_t irk; 1006 bd_addr_t address; 1007 int address_type; 1008 le_device_db_info(i, &address_type, address, irk); 1009 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1010 log_info("sm: device found for IRK, updating"); 1011 le_db_index = i; 1012 break; 1013 } 1014 } 1015 } 1016 1017 // if not found, lookup via public address if possible 1018 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1019 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1020 int i; 1021 for (i=0; i < le_device_db_count(); i++){ 1022 bd_addr_t address; 1023 int address_type; 1024 le_device_db_info(i, &address_type, address, NULL); 1025 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1026 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1027 log_info("sm: device found for public address, updating"); 1028 le_db_index = i; 1029 break; 1030 } 1031 } 1032 } 1033 1034 // if not found, add to db 1035 if (le_db_index < 0) { 1036 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1037 } 1038 1039 if (le_db_index >= 0){ 1040 le_device_db_local_counter_set(le_db_index, 0); 1041 1042 // store local CSRK 1043 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1044 log_info("sm: store local CSRK"); 1045 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1046 le_device_db_local_counter_set(le_db_index, 0); 1047 } 1048 1049 // store remote CSRK 1050 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1051 log_info("sm: store remote CSRK"); 1052 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1053 le_device_db_remote_counter_set(le_db_index, 0); 1054 } 1055 1056 // store encryption information 1057 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION 1058 && setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1059 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1060 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1061 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1062 } 1063 } 1064 1065 // keep le_db_index 1066 sm_conn->sm_le_db_index = le_db_index; 1067 } 1068 1069 static void sm_run(void){ 1070 1071 btstack_linked_list_iterator_t it; 1072 1073 // assert that we can send at least commands 1074 if (!hci_can_send_command_packet_now()) return; 1075 1076 // 1077 // non-connection related behaviour 1078 // 1079 1080 // distributed key generation 1081 switch (dkg_state){ 1082 case DKG_CALC_IRK: 1083 // already busy? 1084 if (sm_aes128_state == SM_AES128_IDLE) { 1085 // IRK = d1(IR, 1, 0) 1086 sm_key_t d1_prime; 1087 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1088 dkg_next_state(); 1089 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1090 return; 1091 } 1092 break; 1093 case DKG_CALC_DHK: 1094 // already busy? 1095 if (sm_aes128_state == SM_AES128_IDLE) { 1096 // DHK = d1(IR, 3, 0) 1097 sm_key_t d1_prime; 1098 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1099 dkg_next_state(); 1100 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1101 return; 1102 } 1103 break; 1104 default: 1105 break; 1106 } 1107 1108 // random address updates 1109 switch (rau_state){ 1110 case RAU_GET_RANDOM: 1111 rau_next_state(); 1112 sm_random_start(NULL); 1113 return; 1114 case RAU_GET_ENC: 1115 // already busy? 1116 if (sm_aes128_state == SM_AES128_IDLE) { 1117 sm_key_t r_prime; 1118 sm_ah_r_prime(sm_random_address, r_prime); 1119 rau_next_state(); 1120 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1121 return; 1122 } 1123 break; 1124 case RAU_SET_ADDRESS: 1125 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1126 rau_state = RAU_IDLE; 1127 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1128 return; 1129 default: 1130 break; 1131 } 1132 1133 // CMAC 1134 switch (sm_cmac_state){ 1135 case CMAC_CALC_SUBKEYS: 1136 case CMAC_CALC_MI: 1137 case CMAC_CALC_MLAST: 1138 // already busy? 1139 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1140 sm_cmac_handle_aes_engine_ready(); 1141 return; 1142 default: 1143 break; 1144 } 1145 1146 // CSRK Lookup 1147 // -- if csrk lookup ready, find connection that require csrk lookup 1148 if (sm_address_resolution_idle()){ 1149 hci_connections_get_iterator(&it); 1150 while(btstack_linked_list_iterator_has_next(&it)){ 1151 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1152 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1153 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1154 // and start lookup 1155 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); 1156 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1157 break; 1158 } 1159 } 1160 } 1161 1162 // -- if csrk lookup ready, resolved addresses for received addresses 1163 if (sm_address_resolution_idle()) { 1164 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1165 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1166 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1167 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1168 btstack_memory_sm_lookup_entry_free(entry); 1169 } 1170 } 1171 1172 // -- Continue with CSRK device lookup by public or resolvable private address 1173 if (!sm_address_resolution_idle()){ 1174 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1175 while (sm_address_resolution_test < le_device_db_count()){ 1176 int addr_type; 1177 bd_addr_t addr; 1178 sm_key_t irk; 1179 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1180 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1181 1182 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1183 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1184 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1185 break; 1186 } 1187 1188 if (sm_address_resolution_addr_type == 0){ 1189 sm_address_resolution_test++; 1190 continue; 1191 } 1192 1193 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1194 1195 log_info("LE Device Lookup: calculate AH"); 1196 log_info_key("IRK", irk); 1197 1198 sm_key_t r_prime; 1199 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1200 sm_address_resolution_ah_calculation_active = 1; 1201 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1202 return; 1203 } 1204 1205 if (sm_address_resolution_test >= le_device_db_count()){ 1206 log_info("LE Device Lookup: not found"); 1207 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1208 } 1209 } 1210 1211 1212 // 1213 // active connection handling 1214 // -- use loop to handle next connection if lock on setup context is released 1215 1216 while (1) { 1217 1218 // Find connections that requires setup context and make active if no other is locked 1219 hci_connections_get_iterator(&it); 1220 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1221 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1222 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1223 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1224 int done = 1; 1225 int err; 1226 int encryption_key_size; 1227 int authenticated; 1228 int authorized; 1229 switch (sm_connection->sm_engine_state) { 1230 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1231 // send packet if possible, 1232 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1233 uint8_t buffer[2]; 1234 buffer[0] = SM_CODE_SECURITY_REQUEST; 1235 buffer[1] = SM_AUTHREQ_BONDING; 1236 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1237 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1238 } 1239 // don't lock setup context yet 1240 done = 0; 1241 break; 1242 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1243 sm_init_setup(sm_connection); 1244 // recover pairing request 1245 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1246 err = sm_stk_generation_init(sm_connection); 1247 if (err){ 1248 setup->sm_pairing_failed_reason = err; 1249 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1250 break; 1251 } 1252 sm_timeout_start(sm_connection); 1253 // generate random number first, if we need to show passkey 1254 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1255 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1256 break; 1257 } 1258 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1259 break; 1260 case SM_INITIATOR_PH0_HAS_LTK: 1261 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1262 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1263 &encryption_key_size, &authenticated, &authorized); 1264 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1265 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1266 sm_connection->sm_connection_authenticated = authenticated; 1267 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1268 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1269 break; 1270 case SM_RESPONDER_PH0_RECEIVED_LTK: 1271 // re-establish previously used LTK using Rand and EDIV 1272 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1273 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1274 // re-establish used key encryption size 1275 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1276 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1277 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1278 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1279 log_info("sm: received ltk request with key size %u, authenticated %u", 1280 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1281 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1282 break; 1283 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1284 sm_init_setup(sm_connection); 1285 sm_timeout_start(sm_connection); 1286 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1287 break; 1288 default: 1289 done = 0; 1290 break; 1291 } 1292 if (done){ 1293 sm_active_connection = sm_connection->sm_handle; 1294 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1295 } 1296 } 1297 1298 // 1299 // active connection handling 1300 // 1301 1302 if (sm_active_connection == 0) return; 1303 1304 // assert that we could send a SM PDU - not needed for all of the following 1305 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) return; 1306 1307 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1308 if (!connection) return; 1309 1310 sm_key_t plaintext; 1311 int key_distribution_flags; 1312 1313 log_info("sm_run: state %u", connection->sm_engine_state); 1314 1315 // responding state 1316 switch (connection->sm_engine_state){ 1317 1318 // general 1319 case SM_GENERAL_SEND_PAIRING_FAILED: { 1320 uint8_t buffer[2]; 1321 buffer[0] = SM_CODE_PAIRING_FAILED; 1322 buffer[1] = setup->sm_pairing_failed_reason; 1323 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1324 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1325 sm_done_for_handle(connection->sm_handle); 1326 break; 1327 } 1328 1329 // initiator side 1330 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1331 sm_key_t peer_ltk_flipped; 1332 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1333 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1334 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1335 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1336 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1337 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1338 return; 1339 } 1340 1341 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1342 setup->sm_m_preq.code = SM_CODE_PAIRING_REQUEST; 1343 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1344 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1345 sm_timeout_reset(connection); 1346 break; 1347 1348 // responder side 1349 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1350 connection->sm_engine_state = SM_RESPONDER_IDLE; 1351 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1352 return; 1353 1354 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 1355 // echo initiator for now 1356 setup->sm_s_pres.code = SM_CODE_PAIRING_RESPONSE; 1357 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1358 setup->sm_s_pres.initiator_key_distribution = setup->sm_m_preq.initiator_key_distribution & key_distribution_flags; 1359 setup->sm_s_pres.responder_key_distribution = setup->sm_m_preq.responder_key_distribution & key_distribution_flags; 1360 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 1361 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 1362 sm_timeout_reset(connection); 1363 sm_trigger_user_response(connection); 1364 return; 1365 1366 case SM_PH2_SEND_PAIRING_RANDOM: { 1367 uint8_t buffer[17]; 1368 buffer[0] = SM_CODE_PAIRING_RANDOM; 1369 reverse_128(setup->sm_local_random, &buffer[1]); 1370 if (connection->sm_role){ 1371 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 1372 } else { 1373 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 1374 } 1375 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1376 sm_timeout_reset(connection); 1377 break; 1378 } 1379 1380 case SM_PH2_GET_RANDOM_TK: 1381 case SM_PH2_C1_GET_RANDOM_A: 1382 case SM_PH2_C1_GET_RANDOM_B: 1383 case SM_PH3_GET_RANDOM: 1384 case SM_PH3_GET_DIV: 1385 sm_next_responding_state(connection); 1386 sm_random_start(connection); 1387 return; 1388 1389 case SM_PH2_C1_GET_ENC_B: 1390 case SM_PH2_C1_GET_ENC_D: 1391 // already busy? 1392 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1393 sm_next_responding_state(connection); 1394 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 1395 return; 1396 1397 case SM_PH3_LTK_GET_ENC: 1398 case SM_RESPONDER_PH4_LTK_GET_ENC: 1399 // already busy? 1400 if (sm_aes128_state == SM_AES128_IDLE) { 1401 sm_key_t d_prime; 1402 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 1403 sm_next_responding_state(connection); 1404 sm_aes128_start(sm_persistent_er, d_prime, connection); 1405 return; 1406 } 1407 break; 1408 1409 case SM_PH3_CSRK_GET_ENC: 1410 // already busy? 1411 if (sm_aes128_state == SM_AES128_IDLE) { 1412 sm_key_t d_prime; 1413 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 1414 sm_next_responding_state(connection); 1415 sm_aes128_start(sm_persistent_er, d_prime, connection); 1416 return; 1417 } 1418 break; 1419 1420 case SM_PH2_C1_GET_ENC_C: 1421 // already busy? 1422 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1423 // calculate m_confirm using aes128 engine - step 1 1424 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); 1425 sm_next_responding_state(connection); 1426 sm_aes128_start(setup->sm_tk, plaintext, connection); 1427 break; 1428 case SM_PH2_C1_GET_ENC_A: 1429 // already busy? 1430 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1431 // calculate confirm using aes128 engine - step 1 1432 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); 1433 sm_next_responding_state(connection); 1434 sm_aes128_start(setup->sm_tk, plaintext, connection); 1435 break; 1436 case SM_PH2_CALC_STK: 1437 // already busy? 1438 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1439 // calculate STK 1440 if (connection->sm_role){ 1441 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 1442 } else { 1443 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 1444 } 1445 sm_next_responding_state(connection); 1446 sm_aes128_start(setup->sm_tk, plaintext, connection); 1447 break; 1448 case SM_PH3_Y_GET_ENC: 1449 // already busy? 1450 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1451 // PH3B2 - calculate Y from - enc 1452 // Y = dm(DHK, Rand) 1453 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1454 sm_next_responding_state(connection); 1455 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1456 return; 1457 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 1458 uint8_t buffer[17]; 1459 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1460 reverse_128(setup->sm_local_confirm, &buffer[1]); 1461 if (connection->sm_role){ 1462 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 1463 } else { 1464 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 1465 } 1466 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1467 sm_timeout_reset(connection); 1468 return; 1469 } 1470 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 1471 sm_key_t stk_flipped; 1472 reverse_128(setup->sm_ltk, stk_flipped); 1473 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1474 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 1475 return; 1476 } 1477 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 1478 sm_key_t stk_flipped; 1479 reverse_128(setup->sm_ltk, stk_flipped); 1480 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1481 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 1482 return; 1483 } 1484 case SM_RESPONDER_PH4_SEND_LTK: { 1485 sm_key_t ltk_flipped; 1486 reverse_128(setup->sm_ltk, ltk_flipped); 1487 connection->sm_engine_state = SM_RESPONDER_IDLE; 1488 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 1489 return; 1490 } 1491 case SM_RESPONDER_PH4_Y_GET_ENC: 1492 // already busy? 1493 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1494 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 1495 // Y = dm(DHK, Rand) 1496 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1497 sm_next_responding_state(connection); 1498 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1499 return; 1500 1501 case SM_PH3_DISTRIBUTE_KEYS: 1502 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 1503 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 1504 uint8_t buffer[17]; 1505 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 1506 reverse_128(setup->sm_ltk, &buffer[1]); 1507 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1508 sm_timeout_reset(connection); 1509 return; 1510 } 1511 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1512 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 1513 uint8_t buffer[11]; 1514 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 1515 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 1516 reverse_64(setup->sm_local_rand, &buffer[3]); 1517 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1518 sm_timeout_reset(connection); 1519 return; 1520 } 1521 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1522 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 1523 uint8_t buffer[17]; 1524 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 1525 reverse_128(sm_persistent_irk, &buffer[1]); 1526 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1527 sm_timeout_reset(connection); 1528 return; 1529 } 1530 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 1531 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 1532 bd_addr_t local_address; 1533 uint8_t buffer[8]; 1534 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 1535 gap_advertisements_get_address(&buffer[1], local_address); 1536 reverse_bd_addr(local_address, &buffer[2]); 1537 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1538 sm_timeout_reset(connection); 1539 return; 1540 } 1541 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1542 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 1543 1544 // hack to reproduce test runs 1545 if (test_use_fixed_local_csrk){ 1546 memset(setup->sm_local_csrk, 0xcc, 16); 1547 } 1548 1549 uint8_t buffer[17]; 1550 buffer[0] = SM_CODE_SIGNING_INFORMATION; 1551 reverse_128(setup->sm_local_csrk, &buffer[1]); 1552 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1553 sm_timeout_reset(connection); 1554 return; 1555 } 1556 1557 // keys are sent 1558 if (connection->sm_role){ 1559 // slave -> receive master keys if any 1560 if (sm_key_distribution_all_received(connection)){ 1561 sm_key_distribution_handle_all_received(connection); 1562 connection->sm_engine_state = SM_RESPONDER_IDLE; 1563 sm_done_for_handle(connection->sm_handle); 1564 } else { 1565 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1566 } 1567 } else { 1568 // master -> all done 1569 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1570 sm_done_for_handle(connection->sm_handle); 1571 } 1572 break; 1573 1574 default: 1575 break; 1576 } 1577 1578 // check again if active connection was released 1579 if (sm_active_connection) break; 1580 } 1581 } 1582 1583 // note: aes engine is ready as we just got the aes result 1584 static void sm_handle_encryption_result(uint8_t * data){ 1585 1586 sm_aes128_state = SM_AES128_IDLE; 1587 1588 if (sm_address_resolution_ah_calculation_active){ 1589 sm_address_resolution_ah_calculation_active = 0; 1590 // compare calulated address against connecting device 1591 uint8_t hash[3]; 1592 reverse_24(data, hash); 1593 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 1594 log_info("LE Device Lookup: matched resolvable private address"); 1595 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1596 return; 1597 } 1598 // no match, try next 1599 sm_address_resolution_test++; 1600 return; 1601 } 1602 1603 switch (dkg_state){ 1604 case DKG_W4_IRK: 1605 reverse_128(data, sm_persistent_irk); 1606 log_info_key("irk", sm_persistent_irk); 1607 dkg_next_state(); 1608 return; 1609 case DKG_W4_DHK: 1610 reverse_128(data, sm_persistent_dhk); 1611 log_info_key("dhk", sm_persistent_dhk); 1612 dkg_next_state(); 1613 // SM Init Finished 1614 return; 1615 default: 1616 break; 1617 } 1618 1619 switch (rau_state){ 1620 case RAU_W4_ENC: 1621 reverse_24(data, &sm_random_address[3]); 1622 rau_next_state(); 1623 return; 1624 default: 1625 break; 1626 } 1627 1628 switch (sm_cmac_state){ 1629 case CMAC_W4_SUBKEYS: 1630 case CMAC_W4_MI: 1631 case CMAC_W4_MLAST: 1632 { 1633 sm_key_t t; 1634 reverse_128(data, t); 1635 sm_cmac_handle_encryption_result(t); 1636 } 1637 return; 1638 default: 1639 break; 1640 } 1641 1642 // retrieve sm_connection provided to sm_aes128_start_encryption 1643 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 1644 if (!connection) return; 1645 switch (connection->sm_engine_state){ 1646 case SM_PH2_C1_W4_ENC_A: 1647 case SM_PH2_C1_W4_ENC_C: 1648 { 1649 sm_key_t t2; 1650 reverse_128(data, t2); 1651 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 1652 } 1653 sm_next_responding_state(connection); 1654 return; 1655 case SM_PH2_C1_W4_ENC_B: 1656 reverse_128(data, setup->sm_local_confirm); 1657 log_info_key("c1!", setup->sm_local_confirm); 1658 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 1659 return; 1660 case SM_PH2_C1_W4_ENC_D: 1661 { 1662 sm_key_t peer_confirm_test; 1663 reverse_128(data, peer_confirm_test); 1664 log_info_key("c1!", peer_confirm_test); 1665 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 1666 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 1667 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1668 return; 1669 } 1670 if (connection->sm_role){ 1671 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 1672 } else { 1673 connection->sm_engine_state = SM_PH2_CALC_STK; 1674 } 1675 } 1676 return; 1677 case SM_PH2_W4_STK: 1678 reverse_128(data, setup->sm_ltk); 1679 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 1680 log_info_key("stk", setup->sm_ltk); 1681 if (connection->sm_role){ 1682 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 1683 } else { 1684 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1685 } 1686 return; 1687 case SM_PH3_Y_W4_ENC:{ 1688 sm_key_t y128; 1689 reverse_128(data, y128); 1690 setup->sm_local_y = big_endian_read_16(y128, 14); 1691 log_info_hex16("y", setup->sm_local_y); 1692 // PH3B3 - calculate EDIV 1693 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 1694 log_info_hex16("ediv", setup->sm_local_ediv); 1695 // PH3B4 - calculate LTK - enc 1696 // LTK = d1(ER, DIV, 0)) 1697 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 1698 return; 1699 } 1700 case SM_RESPONDER_PH4_Y_W4_ENC:{ 1701 sm_key_t y128; 1702 reverse_128(data, y128); 1703 setup->sm_local_y = big_endian_read_16(y128, 14); 1704 log_info_hex16("y", setup->sm_local_y); 1705 1706 // PH3B3 - calculate DIV 1707 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 1708 log_info_hex16("ediv", setup->sm_local_ediv); 1709 // PH3B4 - calculate LTK - enc 1710 // LTK = d1(ER, DIV, 0)) 1711 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 1712 return; 1713 } 1714 case SM_PH3_LTK_W4_ENC: 1715 reverse_128(data, setup->sm_ltk); 1716 log_info_key("ltk", setup->sm_ltk); 1717 // calc CSRK next 1718 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 1719 return; 1720 case SM_PH3_CSRK_W4_ENC: 1721 reverse_128(data, setup->sm_local_csrk); 1722 log_info_key("csrk", setup->sm_local_csrk); 1723 if (setup->sm_key_distribution_send_set){ 1724 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 1725 } else { 1726 // no keys to send, just continue 1727 if (connection->sm_role){ 1728 // slave -> receive master keys 1729 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1730 } else { 1731 // master -> all done 1732 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1733 sm_done_for_handle(connection->sm_handle); 1734 } 1735 } 1736 return; 1737 case SM_RESPONDER_PH4_LTK_W4_ENC: 1738 reverse_128(data, setup->sm_ltk); 1739 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 1740 log_info_key("ltk", setup->sm_ltk); 1741 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 1742 return; 1743 default: 1744 break; 1745 } 1746 } 1747 1748 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 1749 static void sm_handle_random_result(uint8_t * data){ 1750 1751 switch (rau_state){ 1752 case RAU_W4_RANDOM: 1753 // non-resolvable vs. resolvable 1754 switch (gap_random_adress_type){ 1755 case GAP_RANDOM_ADDRESS_RESOLVABLE: 1756 // resolvable: use random as prand and calc address hash 1757 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 1758 memcpy(sm_random_address, data, 3); 1759 sm_random_address[0] &= 0x3f; 1760 sm_random_address[0] |= 0x40; 1761 rau_state = RAU_GET_ENC; 1762 break; 1763 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 1764 default: 1765 // "The two most significant bits of the address shall be equal to ‘0’"" 1766 memcpy(sm_random_address, data, 6); 1767 sm_random_address[0] &= 0x3f; 1768 rau_state = RAU_SET_ADDRESS; 1769 break; 1770 } 1771 return; 1772 default: 1773 break; 1774 } 1775 1776 // retrieve sm_connection provided to sm_random_start 1777 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 1778 if (!connection) return; 1779 switch (connection->sm_engine_state){ 1780 case SM_PH2_W4_RANDOM_TK: 1781 { 1782 // map random to 0-999999 without speding much cycles on a modulus operation 1783 uint32_t tk = little_endian_read_32(data,0); 1784 tk = tk & 0xfffff; // 1048575 1785 if (tk >= 999999){ 1786 tk = tk - 999999; 1787 } 1788 sm_reset_tk(); 1789 big_endian_store_32(setup->sm_tk, 12, tk); 1790 if (connection->sm_role){ 1791 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1792 } else { 1793 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 1794 sm_trigger_user_response(connection); 1795 // response_idle == nothing <--> sm_trigger_user_response() did not require response 1796 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 1797 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 1798 } 1799 } 1800 return; 1801 } 1802 case SM_PH2_C1_W4_RANDOM_A: 1803 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 1804 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 1805 return; 1806 case SM_PH2_C1_W4_RANDOM_B: 1807 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 1808 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 1809 return; 1810 case SM_PH3_W4_RANDOM: 1811 reverse_64(data, setup->sm_local_rand); 1812 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1813 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 1814 // no db for authenticated flag hack: store flag in bit 4 of LSB 1815 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 1816 connection->sm_engine_state = SM_PH3_GET_DIV; 1817 return; 1818 case SM_PH3_W4_DIV: 1819 // use 16 bit from random value as div 1820 setup->sm_local_div = big_endian_read_16(data, 0); 1821 log_info_hex16("div", setup->sm_local_div); 1822 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 1823 return; 1824 default: 1825 break; 1826 } 1827 } 1828 1829 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 1830 1831 sm_connection_t * sm_conn; 1832 hci_con_handle_t con_handle; 1833 1834 switch (packet_type) { 1835 1836 case HCI_EVENT_PACKET: 1837 switch (hci_event_packet_get_type(packet)) { 1838 1839 case BTSTACK_EVENT_STATE: 1840 // bt stack activated, get started 1841 if (packet[2] == HCI_STATE_WORKING) { 1842 log_info("HCI Working!"); 1843 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 1844 rau_state = RAU_IDLE; 1845 sm_run(); 1846 } 1847 break; 1848 1849 case HCI_EVENT_LE_META: 1850 switch (packet[2]) { 1851 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 1852 1853 log_info("sm: connected"); 1854 1855 if (packet[3]) return; // connection failed 1856 1857 con_handle = little_endian_read_16(packet, 4); 1858 sm_conn = sm_get_connection_for_handle(con_handle); 1859 if (!sm_conn) break; 1860 1861 sm_conn->sm_handle = con_handle; 1862 sm_conn->sm_role = packet[6]; 1863 sm_conn->sm_peer_addr_type = packet[7]; 1864 reverse_bd_addr(&packet[8], 1865 sm_conn->sm_peer_address); 1866 1867 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 1868 1869 // reset security properties 1870 sm_conn->sm_connection_encrypted = 0; 1871 sm_conn->sm_connection_authenticated = 0; 1872 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 1873 sm_conn->sm_le_db_index = -1; 1874 1875 // prepare CSRK lookup (does not involve setup) 1876 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 1877 1878 // just connected -> everything else happens in sm_run() 1879 if (sm_conn->sm_role){ 1880 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 1881 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 1882 if (sm_slave_request_security) { 1883 // request security if requested by app 1884 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1885 } else { 1886 // otherwise, wait for pairing request 1887 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1888 } 1889 } 1890 break; 1891 } else { 1892 // master 1893 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1894 } 1895 break; 1896 1897 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 1898 con_handle = little_endian_read_16(packet, 3); 1899 sm_conn = sm_get_connection_for_handle(con_handle); 1900 if (!sm_conn) break; 1901 1902 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 1903 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 1904 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 1905 break; 1906 } 1907 1908 // assume that we don't have a LTK for ediv == 0 and random == null 1909 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 1910 log_info("LTK Request: ediv & random are empty"); 1911 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1912 break; 1913 } 1914 1915 // store rand and ediv 1916 reverse_64(&packet[5], sm_conn->sm_local_rand); 1917 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 1918 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 1919 break; 1920 1921 default: 1922 break; 1923 } 1924 break; 1925 1926 case HCI_EVENT_ENCRYPTION_CHANGE: 1927 con_handle = little_endian_read_16(packet, 3); 1928 sm_conn = sm_get_connection_for_handle(con_handle); 1929 if (!sm_conn) break; 1930 1931 sm_conn->sm_connection_encrypted = packet[5]; 1932 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 1933 sm_conn->sm_actual_encryption_key_size); 1934 log_info("event handler, state %u", sm_conn->sm_engine_state); 1935 if (!sm_conn->sm_connection_encrypted) break; 1936 // continue if part of initial pairing 1937 switch (sm_conn->sm_engine_state){ 1938 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 1939 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1940 sm_done_for_handle(sm_conn->sm_handle); 1941 break; 1942 case SM_PH2_W4_CONNECTION_ENCRYPTED: 1943 if (sm_conn->sm_role){ 1944 // slave 1945 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1946 } else { 1947 // master 1948 if (sm_key_distribution_all_received(sm_conn)){ 1949 // skip receiving keys as there are none 1950 sm_key_distribution_handle_all_received(sm_conn); 1951 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1952 } else { 1953 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1954 } 1955 } 1956 break; 1957 default: 1958 break; 1959 } 1960 break; 1961 1962 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 1963 con_handle = little_endian_read_16(packet, 3); 1964 sm_conn = sm_get_connection_for_handle(con_handle); 1965 if (!sm_conn) break; 1966 1967 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 1968 log_info("event handler, state %u", sm_conn->sm_engine_state); 1969 // continue if part of initial pairing 1970 switch (sm_conn->sm_engine_state){ 1971 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 1972 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1973 sm_done_for_handle(sm_conn->sm_handle); 1974 break; 1975 case SM_PH2_W4_CONNECTION_ENCRYPTED: 1976 if (sm_conn->sm_role){ 1977 // slave 1978 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1979 } else { 1980 // master 1981 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1982 } 1983 break; 1984 default: 1985 break; 1986 } 1987 break; 1988 1989 1990 case HCI_EVENT_DISCONNECTION_COMPLETE: 1991 con_handle = little_endian_read_16(packet, 3); 1992 sm_done_for_handle(con_handle); 1993 sm_conn = sm_get_connection_for_handle(con_handle); 1994 if (!sm_conn) break; 1995 1996 // delete stored bonding on disconnect with authentication failure in ph0 1997 if (sm_conn->sm_role == 0 1998 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 1999 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2000 le_device_db_remove(sm_conn->sm_le_db_index); 2001 } 2002 2003 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2004 sm_conn->sm_handle = 0; 2005 break; 2006 2007 case HCI_EVENT_COMMAND_COMPLETE: 2008 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2009 sm_handle_encryption_result(&packet[6]); 2010 break; 2011 } 2012 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2013 sm_handle_random_result(&packet[6]); 2014 break; 2015 } 2016 break; 2017 default: 2018 break; 2019 } 2020 break; 2021 default: 2022 break; 2023 } 2024 2025 sm_run(); 2026 } 2027 2028 static inline int sm_calc_actual_encryption_key_size(int other){ 2029 if (other < sm_min_encryption_key_size) return 0; 2030 if (other < sm_max_encryption_key_size) return other; 2031 return sm_max_encryption_key_size; 2032 } 2033 2034 /** 2035 * @return ok 2036 */ 2037 static int sm_validate_stk_generation_method(void){ 2038 // check if STK generation method is acceptable by client 2039 switch (setup->sm_stk_generation_method){ 2040 case JUST_WORKS: 2041 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2042 case PK_RESP_INPUT: 2043 case PK_INIT_INPUT: 2044 case OK_BOTH_INPUT: 2045 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2046 case OOB: 2047 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2048 default: 2049 return 0; 2050 } 2051 } 2052 2053 // helper for sm_pdu_handler, calls sm_run on exit 2054 static void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 2055 setup->sm_pairing_failed_reason = SM_REASON_UNSPECIFIED_REASON; 2056 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2057 sm_done_for_handle(sm_conn->sm_handle); 2058 } 2059 2060 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2061 2062 if (packet_type != SM_DATA_PACKET) return; 2063 2064 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2065 if (!sm_conn) return; 2066 2067 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2068 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2069 return; 2070 } 2071 2072 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2073 2074 int err; 2075 2076 switch (sm_conn->sm_engine_state){ 2077 2078 // a sm timeout requries a new physical connection 2079 case SM_GENERAL_TIMEOUT: 2080 return; 2081 2082 // Initiator 2083 case SM_INITIATOR_CONNECTED: 2084 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2085 sm_pdu_received_in_wrong_state(sm_conn); 2086 break; 2087 } 2088 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2089 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2090 break; 2091 } 2092 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2093 uint16_t ediv; 2094 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2095 if (ediv){ 2096 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2097 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2098 } else { 2099 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2100 } 2101 break; 2102 } 2103 // otherwise, store security request 2104 sm_conn->sm_security_request_received = 1; 2105 break; 2106 2107 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2108 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2109 sm_pdu_received_in_wrong_state(sm_conn); 2110 break; 2111 } 2112 // store pairing request 2113 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2114 err = sm_stk_generation_init(sm_conn); 2115 if (err){ 2116 setup->sm_pairing_failed_reason = err; 2117 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2118 break; 2119 } 2120 // generate random number first, if we need to show passkey 2121 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2122 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2123 break; 2124 } 2125 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2126 sm_trigger_user_response(sm_conn); 2127 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2128 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2129 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2130 } 2131 break; 2132 2133 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2134 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2135 sm_pdu_received_in_wrong_state(sm_conn); 2136 break; 2137 } 2138 2139 // store s_confirm 2140 reverse_128(&packet[1], setup->sm_peer_confirm); 2141 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2142 break; 2143 2144 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2145 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2146 sm_pdu_received_in_wrong_state(sm_conn); 2147 break;; 2148 } 2149 2150 // received random value 2151 reverse_128(&packet[1], setup->sm_peer_random); 2152 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2153 break; 2154 2155 // Responder 2156 case SM_RESPONDER_IDLE: 2157 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2158 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2159 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2160 sm_pdu_received_in_wrong_state(sm_conn); 2161 break;; 2162 } 2163 2164 // store pairing request 2165 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2166 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2167 break; 2168 2169 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 2170 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2171 sm_pdu_received_in_wrong_state(sm_conn); 2172 break;; 2173 } 2174 2175 // received confirm value 2176 reverse_128(&packet[1], setup->sm_peer_confirm); 2177 2178 // notify client to hide shown passkey 2179 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2180 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 2181 } 2182 2183 // handle user cancel pairing? 2184 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 2185 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2186 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2187 break; 2188 } 2189 2190 // wait for user action? 2191 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 2192 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2193 break; 2194 } 2195 2196 // calculate and send local_confirm 2197 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2198 break; 2199 2200 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 2201 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2202 sm_pdu_received_in_wrong_state(sm_conn); 2203 break;; 2204 } 2205 2206 // received random value 2207 reverse_128(&packet[1], setup->sm_peer_random); 2208 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2209 break; 2210 2211 case SM_PH3_RECEIVE_KEYS: 2212 switch(packet[0]){ 2213 case SM_CODE_ENCRYPTION_INFORMATION: 2214 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2215 reverse_128(&packet[1], setup->sm_peer_ltk); 2216 break; 2217 2218 case SM_CODE_MASTER_IDENTIFICATION: 2219 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2220 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 2221 reverse_64(&packet[3], setup->sm_peer_rand); 2222 break; 2223 2224 case SM_CODE_IDENTITY_INFORMATION: 2225 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2226 reverse_128(&packet[1], setup->sm_peer_irk); 2227 break; 2228 2229 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 2230 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2231 setup->sm_peer_addr_type = packet[1]; 2232 reverse_bd_addr(&packet[2], setup->sm_peer_address); 2233 break; 2234 2235 case SM_CODE_SIGNING_INFORMATION: 2236 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2237 reverse_128(&packet[1], setup->sm_peer_csrk); 2238 break; 2239 default: 2240 // Unexpected PDU 2241 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 2242 break; 2243 } 2244 // done with key distribution? 2245 if (sm_key_distribution_all_received(sm_conn)){ 2246 2247 sm_key_distribution_handle_all_received(sm_conn); 2248 2249 if (sm_conn->sm_role){ 2250 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2251 sm_done_for_handle(sm_conn->sm_handle); 2252 } else { 2253 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2254 } 2255 } 2256 break; 2257 default: 2258 // Unexpected PDU 2259 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 2260 break; 2261 } 2262 2263 // try to send preparared packet 2264 sm_run(); 2265 } 2266 2267 // Security Manager Client API 2268 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 2269 sm_get_oob_data = get_oob_data_callback; 2270 } 2271 2272 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 2273 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 2274 } 2275 2276 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 2277 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 2278 } 2279 2280 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 2281 sm_min_encryption_key_size = min_size; 2282 sm_max_encryption_key_size = max_size; 2283 } 2284 2285 void sm_set_authentication_requirements(uint8_t auth_req){ 2286 sm_auth_req = auth_req; 2287 } 2288 2289 void sm_set_io_capabilities(io_capability_t io_capability){ 2290 sm_io_capabilities = io_capability; 2291 } 2292 2293 void sm_set_request_security(int enable){ 2294 sm_slave_request_security = enable; 2295 } 2296 2297 void sm_set_er(sm_key_t er){ 2298 memcpy(sm_persistent_er, er, 16); 2299 } 2300 2301 void sm_set_ir(sm_key_t ir){ 2302 memcpy(sm_persistent_ir, ir, 16); 2303 } 2304 2305 // Testing support only 2306 void sm_test_set_irk(sm_key_t irk){ 2307 memcpy(sm_persistent_irk, irk, 16); 2308 sm_persistent_irk_ready = 1; 2309 } 2310 2311 void sm_test_use_fixed_local_csrk(void){ 2312 test_use_fixed_local_csrk = 1; 2313 } 2314 2315 void sm_init(void){ 2316 // set some (BTstack default) ER and IR 2317 int i; 2318 sm_key_t er; 2319 sm_key_t ir; 2320 for (i=0;i<16;i++){ 2321 er[i] = 0x30 + i; 2322 ir[i] = 0x90 + i; 2323 } 2324 sm_set_er(er); 2325 sm_set_ir(ir); 2326 // defaults 2327 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 2328 | SM_STK_GENERATION_METHOD_OOB 2329 | SM_STK_GENERATION_METHOD_PASSKEY; 2330 sm_max_encryption_key_size = 16; 2331 sm_min_encryption_key_size = 7; 2332 2333 sm_cmac_state = CMAC_IDLE; 2334 dkg_state = DKG_W4_WORKING; 2335 rau_state = RAU_W4_WORKING; 2336 sm_aes128_state = SM_AES128_IDLE; 2337 sm_address_resolution_test = -1; // no private address to resolve yet 2338 sm_address_resolution_ah_calculation_active = 0; 2339 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 2340 sm_address_resolution_general_queue = NULL; 2341 2342 gap_random_adress_update_period = 15 * 60 * 1000L; 2343 2344 sm_active_connection = 0; 2345 2346 test_use_fixed_local_csrk = 0; 2347 2348 // register for HCI Events from HCI 2349 hci_event_callback_registration.callback = &sm_event_packet_handler; 2350 hci_add_event_handler(&hci_event_callback_registration); 2351 2352 // and L2CAP PDUs 2353 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2354 } 2355 2356 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 2357 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 2358 if (!hci_con) return NULL; 2359 return &hci_con->sm_connection; 2360 } 2361 2362 // @returns 0 if not encrypted, 7-16 otherwise 2363 int sm_encryption_key_size(hci_con_handle_t con_handle){ 2364 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2365 if (!sm_conn) return 0; // wrong connection 2366 if (!sm_conn->sm_connection_encrypted) return 0; 2367 return sm_conn->sm_actual_encryption_key_size; 2368 } 2369 2370 int sm_authenticated(hci_con_handle_t con_handle){ 2371 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2372 if (!sm_conn) return 0; // wrong connection 2373 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 2374 return sm_conn->sm_connection_authenticated; 2375 } 2376 2377 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 2378 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2379 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 2380 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 2381 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 2382 return sm_conn->sm_connection_authorization_state; 2383 } 2384 2385 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 2386 switch (sm_conn->sm_engine_state){ 2387 case SM_GENERAL_IDLE: 2388 case SM_RESPONDER_IDLE: 2389 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2390 sm_run(); 2391 break; 2392 default: 2393 break; 2394 } 2395 } 2396 2397 /** 2398 * @brief Trigger Security Request 2399 */ 2400 void sm_send_security_request(hci_con_handle_t con_handle){ 2401 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2402 if (!sm_conn) return; 2403 sm_send_security_request_for_connection(sm_conn); 2404 } 2405 2406 // request pairing 2407 void sm_request_pairing(hci_con_handle_t con_handle){ 2408 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2409 if (!sm_conn) return; // wrong connection 2410 2411 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 2412 if (sm_conn->sm_role){ 2413 sm_send_security_request_for_connection(sm_conn); 2414 } else { 2415 // used as a trigger to start central/master/initiator security procedures 2416 uint16_t ediv; 2417 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 2418 switch (sm_conn->sm_irk_lookup_state){ 2419 case IRK_LOOKUP_FAILED: 2420 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2421 break; 2422 case IRK_LOOKUP_SUCCEEDED: 2423 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2424 if (ediv){ 2425 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2426 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2427 } else { 2428 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2429 } 2430 break; 2431 default: 2432 sm_conn->sm_bonding_requested = 1; 2433 break; 2434 } 2435 } 2436 } 2437 sm_run(); 2438 } 2439 2440 // called by client app on authorization request 2441 void sm_authorization_decline(hci_con_handle_t con_handle){ 2442 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2443 if (!sm_conn) return; // wrong connection 2444 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 2445 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 2446 } 2447 2448 void sm_authorization_grant(hci_con_handle_t con_handle){ 2449 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2450 if (!sm_conn) return; // wrong connection 2451 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 2452 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 2453 } 2454 2455 // GAP Bonding API 2456 2457 void sm_bonding_decline(hci_con_handle_t con_handle){ 2458 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2459 if (!sm_conn) return; // wrong connection 2460 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 2461 2462 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2463 sm_done_for_handle(sm_conn->sm_handle); 2464 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2465 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2466 } 2467 sm_run(); 2468 } 2469 2470 void sm_just_works_confirm(hci_con_handle_t con_handle){ 2471 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2472 if (!sm_conn) return; // wrong connection 2473 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 2474 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2475 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2476 } 2477 sm_run(); 2478 } 2479 2480 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 2481 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2482 if (!sm_conn) return; // wrong connection 2483 sm_reset_tk(); 2484 big_endian_store_32(setup->sm_tk, 12, passkey); 2485 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 2486 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2487 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2488 } 2489 sm_run(); 2490 } 2491 2492 /** 2493 * @brief Identify device in LE Device DB 2494 * @param handle 2495 * @returns index from le_device_db or -1 if not found/identified 2496 */ 2497 int sm_le_device_index(hci_con_handle_t con_handle ){ 2498 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2499 if (!sm_conn) return -1; 2500 return sm_conn->sm_le_db_index; 2501 } 2502 2503 // GAP LE API 2504 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 2505 gap_random_address_update_stop(); 2506 gap_random_adress_type = random_address_type; 2507 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 2508 gap_random_address_update_start(); 2509 gap_random_address_trigger(); 2510 } 2511 2512 gap_random_address_type_t gap_random_address_get_mode(void){ 2513 return gap_random_adress_type; 2514 } 2515 2516 void gap_random_address_set_update_period(int period_ms){ 2517 gap_random_adress_update_period = period_ms; 2518 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 2519 gap_random_address_update_stop(); 2520 gap_random_address_update_start(); 2521 } 2522 2523 void gap_random_address_set(bd_addr_t addr){ 2524 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 2525 memcpy(sm_random_address, addr, 6); 2526 rau_state = RAU_SET_ADDRESS; 2527 sm_run(); 2528 } 2529 2530 /* 2531 * @brief Set Advertisement Paramters 2532 * @param adv_int_min 2533 * @param adv_int_max 2534 * @param adv_type 2535 * @param direct_address_type 2536 * @param direct_address 2537 * @param channel_map 2538 * @param filter_policy 2539 * 2540 * @note own_address_type is used from gap_random_address_set_mode 2541 */ 2542 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 2543 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 2544 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 2545 direct_address_typ, direct_address, channel_map, filter_policy); 2546 } 2547 2548