1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "ble/le_device_db.h" 43 #include "ble/core.h" 44 #include "ble/sm.h" 45 #include "btstack_debug.h" 46 #include "btstack_event.h" 47 #include "btstack_linked_list.h" 48 #include "btstack_memory.h" 49 #include "gap.h" 50 #include "hci.h" 51 #include "l2cap.h" 52 53 // 54 // SM internal types and globals 55 // 56 57 typedef enum { 58 DKG_W4_WORKING, 59 DKG_CALC_IRK, 60 DKG_W4_IRK, 61 DKG_CALC_DHK, 62 DKG_W4_DHK, 63 DKG_READY 64 } derived_key_generation_t; 65 66 typedef enum { 67 RAU_W4_WORKING, 68 RAU_IDLE, 69 RAU_GET_RANDOM, 70 RAU_W4_RANDOM, 71 RAU_GET_ENC, 72 RAU_W4_ENC, 73 RAU_SET_ADDRESS, 74 } random_address_update_t; 75 76 typedef enum { 77 CMAC_IDLE, 78 CMAC_CALC_SUBKEYS, 79 CMAC_W4_SUBKEYS, 80 CMAC_CALC_MI, 81 CMAC_W4_MI, 82 CMAC_CALC_MLAST, 83 CMAC_W4_MLAST 84 } cmac_state_t; 85 86 typedef enum { 87 JUST_WORKS, 88 PK_RESP_INPUT, // Initiator displays PK, initiator inputs PK 89 PK_INIT_INPUT, // Responder displays PK, responder inputs PK 90 OK_BOTH_INPUT, // Only input on both, both input PK 91 OOB // OOB available on both sides 92 } stk_generation_method_t; 93 94 typedef enum { 95 SM_USER_RESPONSE_IDLE, 96 SM_USER_RESPONSE_PENDING, 97 SM_USER_RESPONSE_CONFIRM, 98 SM_USER_RESPONSE_PASSKEY, 99 SM_USER_RESPONSE_DECLINE 100 } sm_user_response_t; 101 102 typedef enum { 103 SM_AES128_IDLE, 104 SM_AES128_ACTIVE 105 } sm_aes128_state_t; 106 107 typedef enum { 108 ADDRESS_RESOLUTION_IDLE, 109 ADDRESS_RESOLUTION_GENERAL, 110 ADDRESS_RESOLUTION_FOR_CONNECTION, 111 } address_resolution_mode_t; 112 113 typedef enum { 114 ADDRESS_RESOLUTION_SUCEEDED, 115 ADDRESS_RESOLUTION_FAILED, 116 } address_resolution_event_t; 117 // 118 // GLOBAL DATA 119 // 120 121 static uint8_t test_use_fixed_local_csrk; 122 123 // configuration 124 static uint8_t sm_accepted_stk_generation_methods; 125 static uint8_t sm_max_encryption_key_size; 126 static uint8_t sm_min_encryption_key_size; 127 static uint8_t sm_auth_req = 0; 128 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 129 static uint8_t sm_slave_request_security; 130 131 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 132 static sm_key_t sm_persistent_er; 133 static sm_key_t sm_persistent_ir; 134 135 // derived from sm_persistent_ir 136 static sm_key_t sm_persistent_dhk; 137 static sm_key_t sm_persistent_irk; 138 static uint8_t sm_persistent_irk_ready = 0; // used for testing 139 static derived_key_generation_t dkg_state; 140 141 // derived from sm_persistent_er 142 // .. 143 144 // random address update 145 static random_address_update_t rau_state; 146 static bd_addr_t sm_random_address; 147 148 // CMAC calculation 149 static cmac_state_t sm_cmac_state; 150 static sm_key_t sm_cmac_k; 151 static uint8_t sm_cmac_header[3]; 152 static uint16_t sm_cmac_message_len; 153 static uint8_t * sm_cmac_message; 154 static uint8_t sm_cmac_sign_counter[4]; 155 static sm_key_t sm_cmac_m_last; 156 static sm_key_t sm_cmac_x; 157 static uint8_t sm_cmac_block_current; 158 static uint8_t sm_cmac_block_count; 159 static void (*sm_cmac_done_handler)(uint8_t hash[8]); 160 161 // resolvable private address lookup / CSRK calculation 162 static int sm_address_resolution_test; 163 static int sm_address_resolution_ah_calculation_active; 164 static uint8_t sm_address_resolution_addr_type; 165 static bd_addr_t sm_address_resolution_address; 166 static void * sm_address_resolution_context; 167 static address_resolution_mode_t sm_address_resolution_mode; 168 static btstack_linked_list_t sm_address_resolution_general_queue; 169 170 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 171 static sm_aes128_state_t sm_aes128_state; 172 static void * sm_aes128_context; 173 174 // random engine. store context (ususally sm_connection_t) 175 static void * sm_random_context; 176 177 // to receive hci events 178 static btstack_packet_callback_registration_t hci_event_callback_registration; 179 180 /* to dispatch sm event */ 181 static btstack_linked_list_t sm_event_handlers; 182 183 // 184 // Volume 3, Part H, Chapter 24 185 // "Security shall be initiated by the Security Manager in the device in the master role. 186 // The device in the slave role shall be the responding device." 187 // -> master := initiator, slave := responder 188 // 189 190 // data needed for security setup 191 typedef struct sm_setup_context { 192 193 btstack_timer_source_t sm_timeout; 194 195 // used in all phases 196 uint8_t sm_pairing_failed_reason; 197 198 // user response, (Phase 1 and/or 2) 199 uint8_t sm_user_response; 200 201 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 202 int sm_key_distribution_send_set; 203 int sm_key_distribution_received_set; 204 205 // Phase 2 (Pairing over SMP) 206 stk_generation_method_t sm_stk_generation_method; 207 sm_key_t sm_tk; 208 209 sm_key_t sm_c1_t3_value; // c1 calculation 210 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 211 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 212 sm_key_t sm_local_random; 213 sm_key_t sm_local_confirm; 214 sm_key_t sm_peer_random; 215 sm_key_t sm_peer_confirm; 216 uint8_t sm_m_addr_type; // address and type can be removed 217 uint8_t sm_s_addr_type; // '' 218 bd_addr_t sm_m_address; // '' 219 bd_addr_t sm_s_address; // '' 220 sm_key_t sm_ltk; 221 222 // Phase 3 223 224 // key distribution, we generate 225 uint16_t sm_local_y; 226 uint16_t sm_local_div; 227 uint16_t sm_local_ediv; 228 uint8_t sm_local_rand[8]; 229 sm_key_t sm_local_ltk; 230 sm_key_t sm_local_csrk; 231 sm_key_t sm_local_irk; 232 // sm_local_address/addr_type not needed 233 234 // key distribution, received from peer 235 uint16_t sm_peer_y; 236 uint16_t sm_peer_div; 237 uint16_t sm_peer_ediv; 238 uint8_t sm_peer_rand[8]; 239 sm_key_t sm_peer_ltk; 240 sm_key_t sm_peer_irk; 241 sm_key_t sm_peer_csrk; 242 uint8_t sm_peer_addr_type; 243 bd_addr_t sm_peer_address; 244 245 } sm_setup_context_t; 246 247 // 248 static sm_setup_context_t the_setup; 249 static sm_setup_context_t * setup = &the_setup; 250 251 // active connection - the one for which the_setup is used for 252 static uint16_t sm_active_connection = 0; 253 254 // @returns 1 if oob data is available 255 // stores oob data in provided 16 byte buffer if not null 256 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 257 258 // used to notify applicationss that user interaction is neccessary, see sm_notify_t below 259 static btstack_packet_handler_t sm_client_packet_handler = NULL; 260 261 // horizontal: initiator capabilities 262 // vertial: responder capabilities 263 static const stk_generation_method_t stk_generation_method[5][5] = { 264 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 265 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 266 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 267 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 268 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 269 }; 270 271 static void sm_run(void); 272 static void sm_done_for_handle(hci_con_handle_t con_handle); 273 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 274 static inline int sm_calc_actual_encryption_key_size(int other); 275 static int sm_validate_stk_generation_method(void); 276 277 static void log_info_hex16(const char * name, uint16_t value){ 278 log_info("%-6s 0x%04x", name, value); 279 } 280 281 // @returns 1 if all bytes are 0 282 static int sm_is_null_random(uint8_t random[8]){ 283 int i; 284 for (i=0; i < 8 ; i++){ 285 if (random[i]) return 0; 286 } 287 return 1; 288 } 289 290 // Key utils 291 static void sm_reset_tk(void){ 292 int i; 293 for (i=0;i<16;i++){ 294 setup->sm_tk[i] = 0; 295 } 296 } 297 298 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 299 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 300 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 301 int i; 302 for (i = max_encryption_size ; i < 16 ; i++){ 303 key[15-i] = 0; 304 } 305 } 306 307 // SMP Timeout implementation 308 309 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 310 // the Security Manager Timer shall be reset and started. 311 // 312 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 313 // 314 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 315 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 316 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 317 // established. 318 319 static void sm_timeout_handler(btstack_timer_source_t * timer){ 320 log_info("SM timeout"); 321 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 322 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 323 sm_done_for_handle(sm_conn->sm_handle); 324 325 // trigger handling of next ready connection 326 sm_run(); 327 } 328 static void sm_timeout_start(sm_connection_t * sm_conn){ 329 btstack_run_loop_remove_timer(&setup->sm_timeout); 330 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 331 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 332 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 333 btstack_run_loop_add_timer(&setup->sm_timeout); 334 } 335 static void sm_timeout_stop(void){ 336 btstack_run_loop_remove_timer(&setup->sm_timeout); 337 } 338 static void sm_timeout_reset(sm_connection_t * sm_conn){ 339 sm_timeout_stop(); 340 sm_timeout_start(sm_conn); 341 } 342 343 // end of sm timeout 344 345 // GAP Random Address updates 346 static gap_random_address_type_t gap_random_adress_type; 347 static btstack_timer_source_t gap_random_address_update_timer; 348 static uint32_t gap_random_adress_update_period; 349 350 static void gap_random_address_trigger(void){ 351 if (rau_state != RAU_IDLE) return; 352 log_info("gap_random_address_trigger"); 353 rau_state = RAU_GET_RANDOM; 354 sm_run(); 355 } 356 357 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 358 log_info("GAP Random Address Update due"); 359 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 360 btstack_run_loop_add_timer(&gap_random_address_update_timer); 361 gap_random_address_trigger(); 362 } 363 364 static void gap_random_address_update_start(void){ 365 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 366 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 367 btstack_run_loop_add_timer(&gap_random_address_update_timer); 368 } 369 370 static void gap_random_address_update_stop(void){ 371 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 372 } 373 374 375 static void sm_random_start(void * context){ 376 sm_random_context = context; 377 hci_send_cmd(&hci_le_rand); 378 } 379 380 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 381 // context is made availabe to aes128 result handler by this 382 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 383 sm_aes128_state = SM_AES128_ACTIVE; 384 sm_key_t key_flipped, plaintext_flipped; 385 reverse_128(key, key_flipped); 386 reverse_128(plaintext, plaintext_flipped); 387 sm_aes128_context = context; 388 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 389 } 390 391 // ah(k,r) helper 392 // r = padding || r 393 // r - 24 bit value 394 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 395 // r'= padding || r 396 memset(r_prime, 0, 16); 397 memcpy(&r_prime[13], r, 3); 398 } 399 400 // d1 helper 401 // d' = padding || r || d 402 // d,r - 16 bit values 403 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 404 // d'= padding || r || d 405 memset(d1_prime, 0, 16); 406 big_endian_store_16(d1_prime, 12, r); 407 big_endian_store_16(d1_prime, 14, d); 408 } 409 410 // dm helper 411 // r’ = padding || r 412 // r - 64 bit value 413 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 414 memset(r_prime, 0, 16); 415 memcpy(&r_prime[8], r, 8); 416 } 417 418 // calculate arguments for first AES128 operation in C1 function 419 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){ 420 421 // p1 = pres || preq || rat’ || iat’ 422 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 423 // cant octet of pres becomes the most significant octet of p1. 424 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 425 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 426 // p1 is 0x05000800000302070710000001010001." 427 428 sm_key_t p1; 429 reverse_56(pres, &p1[0]); 430 reverse_56(preq, &p1[7]); 431 p1[14] = rat; 432 p1[15] = iat; 433 log_info_key("p1", p1); 434 log_info_key("r", r); 435 436 // t1 = r xor p1 437 int i; 438 for (i=0;i<16;i++){ 439 t1[i] = r[i] ^ p1[i]; 440 } 441 log_info_key("t1", t1); 442 } 443 444 // calculate arguments for second AES128 operation in C1 function 445 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 446 // p2 = padding || ia || ra 447 // "The least significant octet of ra becomes the least significant octet of p2 and 448 // the most significant octet of padding becomes the most significant octet of p2. 449 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 450 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 451 452 sm_key_t p2; 453 memset(p2, 0, 16); 454 memcpy(&p2[4], ia, 6); 455 memcpy(&p2[10], ra, 6); 456 log_info_key("p2", p2); 457 458 // c1 = e(k, t2_xor_p2) 459 int i; 460 for (i=0;i<16;i++){ 461 t3[i] = t2[i] ^ p2[i]; 462 } 463 log_info_key("t3", t3); 464 } 465 466 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 467 log_info_key("r1", r1); 468 log_info_key("r2", r2); 469 memcpy(&r_prime[8], &r2[8], 8); 470 memcpy(&r_prime[0], &r1[8], 8); 471 } 472 473 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){ 474 event[0] = type; 475 event[1] = event_size - 2; 476 little_endian_store_16(event, 2, con_handle); 477 event[4] = addr_type; 478 reverse_bd_addr(address, &event[5]); 479 } 480 481 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 482 if (sm_client_packet_handler) { 483 sm_client_packet_handler(HCI_EVENT_PACKET, 0, packet, size); 484 } 485 // dispatch to all event handlers 486 btstack_linked_list_iterator_t it; 487 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 488 while (btstack_linked_list_iterator_has_next(&it)){ 489 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 490 entry->callback(packet_type, 0, packet, size); 491 } 492 } 493 494 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 495 uint8_t event[11]; 496 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 497 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 498 } 499 500 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){ 501 uint8_t event[15]; 502 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 503 little_endian_store_32(event, 11, passkey); 504 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 505 } 506 507 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){ 508 uint8_t event[13]; 509 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 510 little_endian_store_16(event, 11, index); 511 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 512 } 513 514 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){ 515 516 uint8_t event[18]; 517 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 518 event[11] = result; 519 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 520 } 521 522 // decide on stk generation based on 523 // - pairing request 524 // - io capabilities 525 // - OOB data availability 526 static void sm_setup_tk(void){ 527 528 // default: just works 529 setup->sm_stk_generation_method = JUST_WORKS; 530 531 // If both devices have out of band authentication data, then the Authentication 532 // Requirements Flags shall be ignored when selecting the pairing method and the 533 // Out of Band pairing method shall be used. 534 if (setup->sm_m_preq.oob_data_flag && setup->sm_s_pres.oob_data_flag){ 535 log_info("SM: have OOB data"); 536 log_info_key("OOB", setup->sm_tk); 537 setup->sm_stk_generation_method = OOB; 538 return; 539 } 540 541 // Reset TK as it has been setup in sm_init_setup 542 sm_reset_tk(); 543 544 // If both devices have not set the MITM option in the Authentication Requirements 545 // Flags, then the IO capabilities shall be ignored and the Just Works association 546 // model shall be used. 547 if ( ((setup->sm_m_preq.auth_req & SM_AUTHREQ_MITM_PROTECTION) == 0x00) && ((setup->sm_s_pres.auth_req & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 548 return; 549 } 550 551 // Also use just works if unknown io capabilites 552 if ((setup->sm_m_preq.io_capability > IO_CAPABILITY_KEYBOARD_DISPLAY) || (setup->sm_m_preq.io_capability > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 553 return; 554 } 555 556 // Otherwise the IO capabilities of the devices shall be used to determine the 557 // pairing method as defined in Table 2.4. 558 setup->sm_stk_generation_method = stk_generation_method[setup->sm_s_pres.io_capability][setup->sm_m_preq.io_capability]; 559 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 560 setup->sm_m_preq.io_capability, setup->sm_s_pres.io_capability, setup->sm_stk_generation_method); 561 } 562 563 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 564 int flags = 0; 565 if (key_set & SM_KEYDIST_ENC_KEY){ 566 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 567 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 568 } 569 if (key_set & SM_KEYDIST_ID_KEY){ 570 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 571 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 572 } 573 if (key_set & SM_KEYDIST_SIGN){ 574 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 575 } 576 return flags; 577 } 578 579 static void sm_setup_key_distribution(uint8_t key_set){ 580 setup->sm_key_distribution_received_set = 0; 581 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 582 } 583 584 // CSRK Key Lookup 585 586 587 static int sm_address_resolution_idle(void){ 588 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 589 } 590 591 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){ 592 memcpy(sm_address_resolution_address, addr, 6); 593 sm_address_resolution_addr_type = addr_type; 594 sm_address_resolution_test = 0; 595 sm_address_resolution_mode = mode; 596 sm_address_resolution_context = context; 597 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 598 } 599 600 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 601 // check if already in list 602 btstack_linked_list_iterator_t it; 603 sm_lookup_entry_t * entry; 604 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 605 while(btstack_linked_list_iterator_has_next(&it)){ 606 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 607 if (entry->address_type != address_type) continue; 608 if (memcmp(entry->address, address, 6)) continue; 609 // already in list 610 return BTSTACK_BUSY; 611 } 612 entry = btstack_memory_sm_lookup_entry_get(); 613 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 614 entry->address_type = (bd_addr_type_t) address_type; 615 memcpy(entry->address, address, 6); 616 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 617 sm_run(); 618 return 0; 619 } 620 621 // CMAC Implementation using AES128 engine 622 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 623 int i; 624 int carry = 0; 625 for (i=len-1; i >= 0 ; i--){ 626 int new_carry = data[i] >> 7; 627 data[i] = data[i] << 1 | carry; 628 carry = new_carry; 629 } 630 } 631 632 // 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 633 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 634 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 635 } 636 static inline void dkg_next_state(void){ 637 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 638 } 639 static inline void rau_next_state(void){ 640 rau_state = (random_address_update_t) (((int)rau_state) + 1); 641 } 642 static inline void sm_cmac_next_state(void){ 643 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 644 } 645 static int sm_cmac_last_block_complete(void){ 646 if (sm_cmac_message_len == 0) return 0; 647 return (sm_cmac_message_len & 0x0f) == 0; 648 } 649 static inline uint8_t sm_cmac_message_get_byte(int offset){ 650 if (offset >= sm_cmac_message_len) { 651 log_error("sm_cmac_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 652 return 0; 653 } 654 655 offset = sm_cmac_message_len - 1 - offset; 656 657 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 658 if (offset < 3){ 659 return sm_cmac_header[offset]; 660 } 661 int actual_message_len_incl_header = sm_cmac_message_len - 4; 662 if (offset < actual_message_len_incl_header){ 663 return sm_cmac_message[offset - 3]; 664 } 665 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 666 } 667 668 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])){ 669 memcpy(sm_cmac_k, k, 16); 670 sm_cmac_header[0] = opcode; 671 little_endian_store_16(sm_cmac_header, 1, con_handle); 672 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 673 sm_cmac_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 674 sm_cmac_message = message; 675 sm_cmac_done_handler = done_handler; 676 sm_cmac_block_current = 0; 677 memset(sm_cmac_x, 0, 16); 678 679 // step 2: n := ceil(len/const_Bsize); 680 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 681 682 // step 3: .. 683 if (sm_cmac_block_count==0){ 684 sm_cmac_block_count = 1; 685 } 686 687 log_info("sm_cmac_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 688 689 // first, we need to compute l for k1, k2, and m_last 690 sm_cmac_state = CMAC_CALC_SUBKEYS; 691 692 // let's go 693 sm_run(); 694 } 695 696 int sm_cmac_ready(void){ 697 return sm_cmac_state == CMAC_IDLE; 698 } 699 700 static void sm_cmac_handle_aes_engine_ready(void){ 701 switch (sm_cmac_state){ 702 case CMAC_CALC_SUBKEYS: { 703 sm_key_t const_zero; 704 memset(const_zero, 0, 16); 705 sm_cmac_next_state(); 706 sm_aes128_start(sm_cmac_k, const_zero, NULL); 707 break; 708 } 709 case CMAC_CALC_MI: { 710 int j; 711 sm_key_t y; 712 for (j=0;j<16;j++){ 713 y[j] = sm_cmac_x[j] ^ sm_cmac_message_get_byte(sm_cmac_block_current*16 + j); 714 } 715 sm_cmac_block_current++; 716 sm_cmac_next_state(); 717 sm_aes128_start(sm_cmac_k, y, NULL); 718 break; 719 } 720 case CMAC_CALC_MLAST: { 721 int i; 722 sm_key_t y; 723 for (i=0;i<16;i++){ 724 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 725 } 726 log_info_key("Y", y); 727 sm_cmac_block_current++; 728 sm_cmac_next_state(); 729 sm_aes128_start(sm_cmac_k, y, NULL); 730 break; 731 } 732 default: 733 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 734 break; 735 } 736 } 737 738 static void sm_cmac_handle_encryption_result(sm_key_t data){ 739 switch (sm_cmac_state){ 740 case CMAC_W4_SUBKEYS: { 741 sm_key_t k1; 742 memcpy(k1, data, 16); 743 sm_shift_left_by_one_bit_inplace(16, k1); 744 if (data[0] & 0x80){ 745 k1[15] ^= 0x87; 746 } 747 sm_key_t k2; 748 memcpy(k2, k1, 16); 749 sm_shift_left_by_one_bit_inplace(16, k2); 750 if (k1[0] & 0x80){ 751 k2[15] ^= 0x87; 752 } 753 754 log_info_key("k", sm_cmac_k); 755 log_info_key("k1", k1); 756 log_info_key("k2", k2); 757 758 // step 4: set m_last 759 int i; 760 if (sm_cmac_last_block_complete()){ 761 for (i=0;i<16;i++){ 762 sm_cmac_m_last[i] = sm_cmac_message_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 763 } 764 } else { 765 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 766 for (i=0;i<16;i++){ 767 if (i < valid_octets_in_last_block){ 768 sm_cmac_m_last[i] = sm_cmac_message_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 769 continue; 770 } 771 if (i == valid_octets_in_last_block){ 772 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 773 continue; 774 } 775 sm_cmac_m_last[i] = k2[i]; 776 } 777 } 778 779 // next 780 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 781 break; 782 } 783 case CMAC_W4_MI: 784 memcpy(sm_cmac_x, data, 16); 785 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 786 break; 787 case CMAC_W4_MLAST: 788 // done 789 log_info_key("CMAC", data); 790 sm_cmac_done_handler(data); 791 sm_cmac_state = CMAC_IDLE; 792 break; 793 default: 794 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 795 break; 796 } 797 } 798 799 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 800 // notify client for: JUST WORKS confirm, PASSKEY display or input 801 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 802 switch (setup->sm_stk_generation_method){ 803 case PK_RESP_INPUT: 804 if (sm_conn->sm_role){ 805 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 806 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 807 } else { 808 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)); 809 } 810 break; 811 case PK_INIT_INPUT: 812 if (sm_conn->sm_role){ 813 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)); 814 } else { 815 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 816 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 817 } 818 break; 819 case OK_BOTH_INPUT: 820 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 821 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 822 break; 823 case JUST_WORKS: 824 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 825 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 826 break; 827 case OOB: 828 // client already provided OOB data, let's skip notification. 829 break; 830 } 831 } 832 833 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 834 int recv_flags; 835 if (sm_conn->sm_role){ 836 // slave / responser 837 recv_flags = sm_key_distribution_flags_for_set(setup->sm_s_pres.initiator_key_distribution); 838 } else { 839 // master / initiator 840 recv_flags = sm_key_distribution_flags_for_set(setup->sm_s_pres.responder_key_distribution); 841 } 842 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 843 return recv_flags == setup->sm_key_distribution_received_set; 844 } 845 846 static void sm_done_for_handle(hci_con_handle_t con_handle){ 847 if (sm_active_connection == con_handle){ 848 sm_timeout_stop(); 849 sm_active_connection = 0; 850 log_info("sm: connection 0x%x released setup context", con_handle); 851 } 852 } 853 854 static int sm_key_distribution_flags_for_auth_req(void){ 855 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 856 if (sm_auth_req & SM_AUTHREQ_BONDING){ 857 // encryption information only if bonding requested 858 flags |= SM_KEYDIST_ENC_KEY; 859 } 860 return flags; 861 } 862 863 static void sm_init_setup(sm_connection_t * sm_conn){ 864 865 // fill in sm setup 866 sm_reset_tk(); 867 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 868 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 869 870 // query client for OOB data 871 int have_oob_data = 0; 872 if (sm_get_oob_data) { 873 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 874 } 875 876 sm_pairing_packet_t * local_packet; 877 if (sm_conn->sm_role){ 878 // slave 879 local_packet = &setup->sm_s_pres; 880 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 881 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 882 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 883 } else { 884 // master 885 local_packet = &setup->sm_m_preq; 886 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 887 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 888 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 889 890 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 891 setup->sm_m_preq.initiator_key_distribution = key_distribution_flags; 892 setup->sm_m_preq.responder_key_distribution = key_distribution_flags; 893 } 894 895 local_packet->io_capability = sm_io_capabilities; 896 local_packet->oob_data_flag = have_oob_data; 897 local_packet->auth_req = sm_auth_req; 898 local_packet->max_encryption_key_size = sm_max_encryption_key_size; 899 } 900 901 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 902 903 sm_pairing_packet_t * remote_packet; 904 int remote_key_request; 905 if (sm_conn->sm_role){ 906 // slave / responser 907 remote_packet = &setup->sm_m_preq; 908 remote_key_request = setup->sm_m_preq.responder_key_distribution; 909 } else { 910 // master / initiator 911 remote_packet = &setup->sm_s_pres; 912 remote_key_request = setup->sm_s_pres.initiator_key_distribution; 913 } 914 915 // check key size 916 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(remote_packet->max_encryption_key_size); 917 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 918 919 // setup key distribution 920 sm_setup_key_distribution(remote_key_request); 921 922 // identical to responder 923 924 // decide on STK generation method 925 sm_setup_tk(); 926 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 927 928 // check if STK generation method is acceptable by client 929 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 930 931 // JUST WORKS doens't provide authentication 932 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 933 934 return 0; 935 } 936 937 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 938 939 // cache and reset context 940 int matched_device_id = sm_address_resolution_test; 941 address_resolution_mode_t mode = sm_address_resolution_mode; 942 void * context = sm_address_resolution_context; 943 944 // reset context 945 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 946 sm_address_resolution_context = NULL; 947 sm_address_resolution_test = -1; 948 hci_con_handle_t con_handle = 0; 949 950 sm_connection_t * sm_connection; 951 uint16_t ediv; 952 switch (mode){ 953 case ADDRESS_RESOLUTION_GENERAL: 954 break; 955 case ADDRESS_RESOLUTION_FOR_CONNECTION: 956 sm_connection = (sm_connection_t *) context; 957 con_handle = sm_connection->sm_handle; 958 switch (event){ 959 case ADDRESS_RESOLUTION_SUCEEDED: 960 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 961 sm_connection->sm_le_db_index = matched_device_id; 962 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 963 if (sm_connection->sm_role) break; 964 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 965 sm_connection->sm_security_request_received = 0; 966 sm_connection->sm_bonding_requested = 0; 967 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 968 if (ediv){ 969 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 970 } else { 971 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 972 } 973 break; 974 case ADDRESS_RESOLUTION_FAILED: 975 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 976 if (sm_connection->sm_role) break; 977 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 978 sm_connection->sm_security_request_received = 0; 979 sm_connection->sm_bonding_requested = 0; 980 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 981 break; 982 } 983 break; 984 default: 985 break; 986 } 987 988 switch (event){ 989 case ADDRESS_RESOLUTION_SUCEEDED: 990 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 991 break; 992 case ADDRESS_RESOLUTION_FAILED: 993 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 994 break; 995 } 996 } 997 998 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 999 1000 int le_db_index = -1; 1001 1002 // lookup device based on IRK 1003 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1004 int i; 1005 for (i=0; i < le_device_db_count(); i++){ 1006 sm_key_t irk; 1007 bd_addr_t address; 1008 int address_type; 1009 le_device_db_info(i, &address_type, address, irk); 1010 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1011 log_info("sm: device found for IRK, updating"); 1012 le_db_index = i; 1013 break; 1014 } 1015 } 1016 } 1017 1018 // if not found, lookup via public address if possible 1019 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1020 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1021 int i; 1022 for (i=0; i < le_device_db_count(); i++){ 1023 bd_addr_t address; 1024 int address_type; 1025 le_device_db_info(i, &address_type, address, NULL); 1026 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1027 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1028 log_info("sm: device found for public address, updating"); 1029 le_db_index = i; 1030 break; 1031 } 1032 } 1033 } 1034 1035 // if not found, add to db 1036 if (le_db_index < 0) { 1037 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1038 } 1039 1040 if (le_db_index >= 0){ 1041 le_device_db_local_counter_set(le_db_index, 0); 1042 1043 // store local CSRK 1044 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1045 log_info("sm: store local CSRK"); 1046 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1047 le_device_db_local_counter_set(le_db_index, 0); 1048 } 1049 1050 // store remote CSRK 1051 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1052 log_info("sm: store remote CSRK"); 1053 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1054 le_device_db_remote_counter_set(le_db_index, 0); 1055 } 1056 1057 // store encryption information 1058 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION 1059 && setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1060 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1061 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1062 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1063 } 1064 } 1065 1066 // keep le_db_index 1067 sm_conn->sm_le_db_index = le_db_index; 1068 } 1069 1070 static void sm_run(void){ 1071 1072 btstack_linked_list_iterator_t it; 1073 1074 // assert that we can send at least commands 1075 if (!hci_can_send_command_packet_now()) return; 1076 1077 // 1078 // non-connection related behaviour 1079 // 1080 1081 // distributed key generation 1082 switch (dkg_state){ 1083 case DKG_CALC_IRK: 1084 // already busy? 1085 if (sm_aes128_state == SM_AES128_IDLE) { 1086 // IRK = d1(IR, 1, 0) 1087 sm_key_t d1_prime; 1088 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1089 dkg_next_state(); 1090 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1091 return; 1092 } 1093 break; 1094 case DKG_CALC_DHK: 1095 // already busy? 1096 if (sm_aes128_state == SM_AES128_IDLE) { 1097 // DHK = d1(IR, 3, 0) 1098 sm_key_t d1_prime; 1099 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1100 dkg_next_state(); 1101 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1102 return; 1103 } 1104 break; 1105 default: 1106 break; 1107 } 1108 1109 // random address updates 1110 switch (rau_state){ 1111 case RAU_GET_RANDOM: 1112 rau_next_state(); 1113 sm_random_start(NULL); 1114 return; 1115 case RAU_GET_ENC: 1116 // already busy? 1117 if (sm_aes128_state == SM_AES128_IDLE) { 1118 sm_key_t r_prime; 1119 sm_ah_r_prime(sm_random_address, r_prime); 1120 rau_next_state(); 1121 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1122 return; 1123 } 1124 break; 1125 case RAU_SET_ADDRESS: 1126 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1127 rau_state = RAU_IDLE; 1128 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1129 return; 1130 default: 1131 break; 1132 } 1133 1134 // CMAC 1135 switch (sm_cmac_state){ 1136 case CMAC_CALC_SUBKEYS: 1137 case CMAC_CALC_MI: 1138 case CMAC_CALC_MLAST: 1139 // already busy? 1140 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1141 sm_cmac_handle_aes_engine_ready(); 1142 return; 1143 default: 1144 break; 1145 } 1146 1147 // CSRK Lookup 1148 // -- if csrk lookup ready, find connection that require csrk lookup 1149 if (sm_address_resolution_idle()){ 1150 hci_connections_get_iterator(&it); 1151 while(btstack_linked_list_iterator_has_next(&it)){ 1152 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1153 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1154 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1155 // and start lookup 1156 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); 1157 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1158 break; 1159 } 1160 } 1161 } 1162 1163 // -- if csrk lookup ready, resolved addresses for received addresses 1164 if (sm_address_resolution_idle()) { 1165 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1166 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1167 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1168 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1169 btstack_memory_sm_lookup_entry_free(entry); 1170 } 1171 } 1172 1173 // -- Continue with CSRK device lookup by public or resolvable private address 1174 if (!sm_address_resolution_idle()){ 1175 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1176 while (sm_address_resolution_test < le_device_db_count()){ 1177 int addr_type; 1178 bd_addr_t addr; 1179 sm_key_t irk; 1180 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1181 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1182 1183 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1184 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1185 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1186 break; 1187 } 1188 1189 if (sm_address_resolution_addr_type == 0){ 1190 sm_address_resolution_test++; 1191 continue; 1192 } 1193 1194 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1195 1196 log_info("LE Device Lookup: calculate AH"); 1197 log_info_key("IRK", irk); 1198 1199 sm_key_t r_prime; 1200 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1201 sm_address_resolution_ah_calculation_active = 1; 1202 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1203 return; 1204 } 1205 1206 if (sm_address_resolution_test >= le_device_db_count()){ 1207 log_info("LE Device Lookup: not found"); 1208 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1209 } 1210 } 1211 1212 1213 // 1214 // active connection handling 1215 // -- use loop to handle next connection if lock on setup context is released 1216 1217 while (1) { 1218 1219 // Find connections that requires setup context and make active if no other is locked 1220 hci_connections_get_iterator(&it); 1221 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1222 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1223 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1224 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1225 int done = 1; 1226 int err; 1227 int encryption_key_size; 1228 int authenticated; 1229 int authorized; 1230 switch (sm_connection->sm_engine_state) { 1231 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1232 // send packet if possible, 1233 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1234 uint8_t buffer[2]; 1235 buffer[0] = SM_CODE_SECURITY_REQUEST; 1236 buffer[1] = SM_AUTHREQ_BONDING; 1237 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1238 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1239 } 1240 // don't lock setup context yet 1241 done = 0; 1242 break; 1243 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1244 sm_init_setup(sm_connection); 1245 // recover pairing request 1246 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1247 err = sm_stk_generation_init(sm_connection); 1248 if (err){ 1249 setup->sm_pairing_failed_reason = err; 1250 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1251 break; 1252 } 1253 sm_timeout_start(sm_connection); 1254 // generate random number first, if we need to show passkey 1255 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1256 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1257 break; 1258 } 1259 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1260 break; 1261 case SM_INITIATOR_PH0_HAS_LTK: 1262 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1263 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1264 &encryption_key_size, &authenticated, &authorized); 1265 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1266 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1267 sm_connection->sm_connection_authenticated = authenticated; 1268 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1269 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1270 break; 1271 case SM_RESPONDER_PH0_RECEIVED_LTK: 1272 // re-establish previously used LTK using Rand and EDIV 1273 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1274 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1275 // re-establish used key encryption size 1276 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1277 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1278 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1279 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1280 log_info("sm: received ltk request with key size %u, authenticated %u", 1281 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1282 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1283 break; 1284 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1285 sm_init_setup(sm_connection); 1286 sm_timeout_start(sm_connection); 1287 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1288 break; 1289 default: 1290 done = 0; 1291 break; 1292 } 1293 if (done){ 1294 sm_active_connection = sm_connection->sm_handle; 1295 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1296 } 1297 } 1298 1299 // 1300 // active connection handling 1301 // 1302 1303 if (sm_active_connection == 0) return; 1304 1305 // assert that we could send a SM PDU - not needed for all of the following 1306 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) return; 1307 1308 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1309 if (!connection) return; 1310 1311 sm_key_t plaintext; 1312 int key_distribution_flags; 1313 1314 log_info("sm_run: state %u", connection->sm_engine_state); 1315 1316 // responding state 1317 switch (connection->sm_engine_state){ 1318 1319 // general 1320 case SM_GENERAL_SEND_PAIRING_FAILED: { 1321 uint8_t buffer[2]; 1322 buffer[0] = SM_CODE_PAIRING_FAILED; 1323 buffer[1] = setup->sm_pairing_failed_reason; 1324 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1325 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1326 sm_done_for_handle(connection->sm_handle); 1327 break; 1328 } 1329 1330 // initiator side 1331 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1332 sm_key_t peer_ltk_flipped; 1333 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1334 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1335 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1336 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1337 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1338 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1339 return; 1340 } 1341 1342 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1343 setup->sm_m_preq.code = SM_CODE_PAIRING_REQUEST; 1344 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1345 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1346 sm_timeout_reset(connection); 1347 break; 1348 1349 // responder side 1350 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1351 connection->sm_engine_state = SM_RESPONDER_IDLE; 1352 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1353 return; 1354 1355 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 1356 // echo initiator for now 1357 setup->sm_s_pres.code = SM_CODE_PAIRING_RESPONSE; 1358 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1359 setup->sm_s_pres.initiator_key_distribution = setup->sm_m_preq.initiator_key_distribution & key_distribution_flags; 1360 setup->sm_s_pres.responder_key_distribution = setup->sm_m_preq.responder_key_distribution & key_distribution_flags; 1361 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 1362 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 1363 sm_timeout_reset(connection); 1364 sm_trigger_user_response(connection); 1365 return; 1366 1367 case SM_PH2_SEND_PAIRING_RANDOM: { 1368 uint8_t buffer[17]; 1369 buffer[0] = SM_CODE_PAIRING_RANDOM; 1370 reverse_128(setup->sm_local_random, &buffer[1]); 1371 if (connection->sm_role){ 1372 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 1373 } else { 1374 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 1375 } 1376 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1377 sm_timeout_reset(connection); 1378 break; 1379 } 1380 1381 case SM_PH2_GET_RANDOM_TK: 1382 case SM_PH2_C1_GET_RANDOM_A: 1383 case SM_PH2_C1_GET_RANDOM_B: 1384 case SM_PH3_GET_RANDOM: 1385 case SM_PH3_GET_DIV: 1386 sm_next_responding_state(connection); 1387 sm_random_start(connection); 1388 return; 1389 1390 case SM_PH2_C1_GET_ENC_B: 1391 case SM_PH2_C1_GET_ENC_D: 1392 // already busy? 1393 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1394 sm_next_responding_state(connection); 1395 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 1396 return; 1397 1398 case SM_PH3_LTK_GET_ENC: 1399 case SM_RESPONDER_PH4_LTK_GET_ENC: 1400 // already busy? 1401 if (sm_aes128_state == SM_AES128_IDLE) { 1402 sm_key_t d_prime; 1403 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 1404 sm_next_responding_state(connection); 1405 sm_aes128_start(sm_persistent_er, d_prime, connection); 1406 return; 1407 } 1408 break; 1409 1410 case SM_PH3_CSRK_GET_ENC: 1411 // already busy? 1412 if (sm_aes128_state == SM_AES128_IDLE) { 1413 sm_key_t d_prime; 1414 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 1415 sm_next_responding_state(connection); 1416 sm_aes128_start(sm_persistent_er, d_prime, connection); 1417 return; 1418 } 1419 break; 1420 1421 case SM_PH2_C1_GET_ENC_C: 1422 // already busy? 1423 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1424 // calculate m_confirm using aes128 engine - step 1 1425 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); 1426 sm_next_responding_state(connection); 1427 sm_aes128_start(setup->sm_tk, plaintext, connection); 1428 break; 1429 case SM_PH2_C1_GET_ENC_A: 1430 // already busy? 1431 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1432 // calculate confirm using aes128 engine - step 1 1433 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); 1434 sm_next_responding_state(connection); 1435 sm_aes128_start(setup->sm_tk, plaintext, connection); 1436 break; 1437 case SM_PH2_CALC_STK: 1438 // already busy? 1439 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1440 // calculate STK 1441 if (connection->sm_role){ 1442 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 1443 } else { 1444 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 1445 } 1446 sm_next_responding_state(connection); 1447 sm_aes128_start(setup->sm_tk, plaintext, connection); 1448 break; 1449 case SM_PH3_Y_GET_ENC: 1450 // already busy? 1451 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1452 // PH3B2 - calculate Y from - enc 1453 // Y = dm(DHK, Rand) 1454 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1455 sm_next_responding_state(connection); 1456 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1457 return; 1458 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 1459 uint8_t buffer[17]; 1460 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1461 reverse_128(setup->sm_local_confirm, &buffer[1]); 1462 if (connection->sm_role){ 1463 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 1464 } else { 1465 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 1466 } 1467 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1468 sm_timeout_reset(connection); 1469 return; 1470 } 1471 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 1472 sm_key_t stk_flipped; 1473 reverse_128(setup->sm_ltk, stk_flipped); 1474 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1475 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 1476 return; 1477 } 1478 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 1479 sm_key_t stk_flipped; 1480 reverse_128(setup->sm_ltk, stk_flipped); 1481 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1482 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 1483 return; 1484 } 1485 case SM_RESPONDER_PH4_SEND_LTK: { 1486 sm_key_t ltk_flipped; 1487 reverse_128(setup->sm_ltk, ltk_flipped); 1488 connection->sm_engine_state = SM_RESPONDER_IDLE; 1489 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 1490 return; 1491 } 1492 case SM_RESPONDER_PH4_Y_GET_ENC: 1493 // already busy? 1494 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1495 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 1496 // Y = dm(DHK, Rand) 1497 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1498 sm_next_responding_state(connection); 1499 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1500 return; 1501 1502 case SM_PH3_DISTRIBUTE_KEYS: 1503 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 1504 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 1505 uint8_t buffer[17]; 1506 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 1507 reverse_128(setup->sm_ltk, &buffer[1]); 1508 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1509 sm_timeout_reset(connection); 1510 return; 1511 } 1512 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1513 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 1514 uint8_t buffer[11]; 1515 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 1516 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 1517 reverse_64(setup->sm_local_rand, &buffer[3]); 1518 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1519 sm_timeout_reset(connection); 1520 return; 1521 } 1522 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1523 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 1524 uint8_t buffer[17]; 1525 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 1526 reverse_128(sm_persistent_irk, &buffer[1]); 1527 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1528 sm_timeout_reset(connection); 1529 return; 1530 } 1531 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 1532 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 1533 bd_addr_t local_address; 1534 uint8_t buffer[8]; 1535 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 1536 gap_advertisements_get_address(&buffer[1], local_address); 1537 reverse_bd_addr(local_address, &buffer[2]); 1538 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1539 sm_timeout_reset(connection); 1540 return; 1541 } 1542 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1543 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 1544 1545 // hack to reproduce test runs 1546 if (test_use_fixed_local_csrk){ 1547 memset(setup->sm_local_csrk, 0xcc, 16); 1548 } 1549 1550 uint8_t buffer[17]; 1551 buffer[0] = SM_CODE_SIGNING_INFORMATION; 1552 reverse_128(setup->sm_local_csrk, &buffer[1]); 1553 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1554 sm_timeout_reset(connection); 1555 return; 1556 } 1557 1558 // keys are sent 1559 if (connection->sm_role){ 1560 // slave -> receive master keys if any 1561 if (sm_key_distribution_all_received(connection)){ 1562 sm_key_distribution_handle_all_received(connection); 1563 connection->sm_engine_state = SM_RESPONDER_IDLE; 1564 sm_done_for_handle(connection->sm_handle); 1565 } else { 1566 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1567 } 1568 } else { 1569 // master -> all done 1570 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1571 sm_done_for_handle(connection->sm_handle); 1572 } 1573 break; 1574 1575 default: 1576 break; 1577 } 1578 1579 // check again if active connection was released 1580 if (sm_active_connection) break; 1581 } 1582 } 1583 1584 // note: aes engine is ready as we just got the aes result 1585 static void sm_handle_encryption_result(uint8_t * data){ 1586 1587 sm_aes128_state = SM_AES128_IDLE; 1588 1589 if (sm_address_resolution_ah_calculation_active){ 1590 sm_address_resolution_ah_calculation_active = 0; 1591 // compare calulated address against connecting device 1592 uint8_t hash[3]; 1593 reverse_24(data, hash); 1594 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 1595 log_info("LE Device Lookup: matched resolvable private address"); 1596 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1597 return; 1598 } 1599 // no match, try next 1600 sm_address_resolution_test++; 1601 return; 1602 } 1603 1604 switch (dkg_state){ 1605 case DKG_W4_IRK: 1606 reverse_128(data, sm_persistent_irk); 1607 log_info_key("irk", sm_persistent_irk); 1608 dkg_next_state(); 1609 return; 1610 case DKG_W4_DHK: 1611 reverse_128(data, sm_persistent_dhk); 1612 log_info_key("dhk", sm_persistent_dhk); 1613 dkg_next_state(); 1614 // SM Init Finished 1615 return; 1616 default: 1617 break; 1618 } 1619 1620 switch (rau_state){ 1621 case RAU_W4_ENC: 1622 reverse_24(data, &sm_random_address[3]); 1623 rau_next_state(); 1624 return; 1625 default: 1626 break; 1627 } 1628 1629 switch (sm_cmac_state){ 1630 case CMAC_W4_SUBKEYS: 1631 case CMAC_W4_MI: 1632 case CMAC_W4_MLAST: 1633 { 1634 sm_key_t t; 1635 reverse_128(data, t); 1636 sm_cmac_handle_encryption_result(t); 1637 } 1638 return; 1639 default: 1640 break; 1641 } 1642 1643 // retrieve sm_connection provided to sm_aes128_start_encryption 1644 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 1645 if (!connection) return; 1646 switch (connection->sm_engine_state){ 1647 case SM_PH2_C1_W4_ENC_A: 1648 case SM_PH2_C1_W4_ENC_C: 1649 { 1650 sm_key_t t2; 1651 reverse_128(data, t2); 1652 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 1653 } 1654 sm_next_responding_state(connection); 1655 return; 1656 case SM_PH2_C1_W4_ENC_B: 1657 reverse_128(data, setup->sm_local_confirm); 1658 log_info_key("c1!", setup->sm_local_confirm); 1659 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 1660 return; 1661 case SM_PH2_C1_W4_ENC_D: 1662 { 1663 sm_key_t peer_confirm_test; 1664 reverse_128(data, peer_confirm_test); 1665 log_info_key("c1!", peer_confirm_test); 1666 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 1667 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 1668 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1669 return; 1670 } 1671 if (connection->sm_role){ 1672 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 1673 } else { 1674 connection->sm_engine_state = SM_PH2_CALC_STK; 1675 } 1676 } 1677 return; 1678 case SM_PH2_W4_STK: 1679 reverse_128(data, setup->sm_ltk); 1680 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 1681 log_info_key("stk", setup->sm_ltk); 1682 if (connection->sm_role){ 1683 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 1684 } else { 1685 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1686 } 1687 return; 1688 case SM_PH3_Y_W4_ENC:{ 1689 sm_key_t y128; 1690 reverse_128(data, y128); 1691 setup->sm_local_y = big_endian_read_16(y128, 14); 1692 log_info_hex16("y", setup->sm_local_y); 1693 // PH3B3 - calculate EDIV 1694 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 1695 log_info_hex16("ediv", setup->sm_local_ediv); 1696 // PH3B4 - calculate LTK - enc 1697 // LTK = d1(ER, DIV, 0)) 1698 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 1699 return; 1700 } 1701 case SM_RESPONDER_PH4_Y_W4_ENC:{ 1702 sm_key_t y128; 1703 reverse_128(data, y128); 1704 setup->sm_local_y = big_endian_read_16(y128, 14); 1705 log_info_hex16("y", setup->sm_local_y); 1706 1707 // PH3B3 - calculate DIV 1708 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 1709 log_info_hex16("ediv", setup->sm_local_ediv); 1710 // PH3B4 - calculate LTK - enc 1711 // LTK = d1(ER, DIV, 0)) 1712 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 1713 return; 1714 } 1715 case SM_PH3_LTK_W4_ENC: 1716 reverse_128(data, setup->sm_ltk); 1717 log_info_key("ltk", setup->sm_ltk); 1718 // calc CSRK next 1719 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 1720 return; 1721 case SM_PH3_CSRK_W4_ENC: 1722 reverse_128(data, setup->sm_local_csrk); 1723 log_info_key("csrk", setup->sm_local_csrk); 1724 if (setup->sm_key_distribution_send_set){ 1725 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 1726 } else { 1727 // no keys to send, just continue 1728 if (connection->sm_role){ 1729 // slave -> receive master keys 1730 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1731 } else { 1732 // master -> all done 1733 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1734 sm_done_for_handle(connection->sm_handle); 1735 } 1736 } 1737 return; 1738 case SM_RESPONDER_PH4_LTK_W4_ENC: 1739 reverse_128(data, setup->sm_ltk); 1740 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 1741 log_info_key("ltk", setup->sm_ltk); 1742 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 1743 return; 1744 default: 1745 break; 1746 } 1747 } 1748 1749 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 1750 static void sm_handle_random_result(uint8_t * data){ 1751 1752 switch (rau_state){ 1753 case RAU_W4_RANDOM: 1754 // non-resolvable vs. resolvable 1755 switch (gap_random_adress_type){ 1756 case GAP_RANDOM_ADDRESS_RESOLVABLE: 1757 // resolvable: use random as prand and calc address hash 1758 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 1759 memcpy(sm_random_address, data, 3); 1760 sm_random_address[0] &= 0x3f; 1761 sm_random_address[0] |= 0x40; 1762 rau_state = RAU_GET_ENC; 1763 break; 1764 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 1765 default: 1766 // "The two most significant bits of the address shall be equal to ‘0’"" 1767 memcpy(sm_random_address, data, 6); 1768 sm_random_address[0] &= 0x3f; 1769 rau_state = RAU_SET_ADDRESS; 1770 break; 1771 } 1772 return; 1773 default: 1774 break; 1775 } 1776 1777 // retrieve sm_connection provided to sm_random_start 1778 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 1779 if (!connection) return; 1780 switch (connection->sm_engine_state){ 1781 case SM_PH2_W4_RANDOM_TK: 1782 { 1783 // map random to 0-999999 without speding much cycles on a modulus operation 1784 uint32_t tk = little_endian_read_32(data,0); 1785 tk = tk & 0xfffff; // 1048575 1786 if (tk >= 999999){ 1787 tk = tk - 999999; 1788 } 1789 sm_reset_tk(); 1790 big_endian_store_32(setup->sm_tk, 12, tk); 1791 if (connection->sm_role){ 1792 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1793 } else { 1794 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 1795 sm_trigger_user_response(connection); 1796 // response_idle == nothing <--> sm_trigger_user_response() did not require response 1797 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 1798 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 1799 } 1800 } 1801 return; 1802 } 1803 case SM_PH2_C1_W4_RANDOM_A: 1804 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 1805 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 1806 return; 1807 case SM_PH2_C1_W4_RANDOM_B: 1808 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 1809 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 1810 return; 1811 case SM_PH3_W4_RANDOM: 1812 reverse_64(data, setup->sm_local_rand); 1813 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1814 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 1815 // no db for authenticated flag hack: store flag in bit 4 of LSB 1816 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 1817 connection->sm_engine_state = SM_PH3_GET_DIV; 1818 return; 1819 case SM_PH3_W4_DIV: 1820 // use 16 bit from random value as div 1821 setup->sm_local_div = big_endian_read_16(data, 0); 1822 log_info_hex16("div", setup->sm_local_div); 1823 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 1824 return; 1825 default: 1826 break; 1827 } 1828 } 1829 1830 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 1831 1832 sm_connection_t * sm_conn; 1833 hci_con_handle_t con_handle; 1834 1835 switch (packet_type) { 1836 1837 case HCI_EVENT_PACKET: 1838 switch (hci_event_packet_get_type(packet)) { 1839 1840 case BTSTACK_EVENT_STATE: 1841 // bt stack activated, get started 1842 if (packet[2] == HCI_STATE_WORKING) { 1843 log_info("HCI Working!"); 1844 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 1845 rau_state = RAU_IDLE; 1846 sm_run(); 1847 } 1848 break; 1849 1850 case HCI_EVENT_LE_META: 1851 switch (packet[2]) { 1852 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 1853 1854 log_info("sm: connected"); 1855 1856 if (packet[3]) return; // connection failed 1857 1858 con_handle = little_endian_read_16(packet, 4); 1859 sm_conn = sm_get_connection_for_handle(con_handle); 1860 if (!sm_conn) break; 1861 1862 sm_conn->sm_handle = con_handle; 1863 sm_conn->sm_role = packet[6]; 1864 sm_conn->sm_peer_addr_type = packet[7]; 1865 reverse_bd_addr(&packet[8], 1866 sm_conn->sm_peer_address); 1867 1868 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 1869 1870 // reset security properties 1871 sm_conn->sm_connection_encrypted = 0; 1872 sm_conn->sm_connection_authenticated = 0; 1873 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 1874 sm_conn->sm_le_db_index = -1; 1875 1876 // prepare CSRK lookup (does not involve setup) 1877 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 1878 1879 // just connected -> everything else happens in sm_run() 1880 if (sm_conn->sm_role){ 1881 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 1882 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 1883 if (sm_slave_request_security) { 1884 // request security if requested by app 1885 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1886 } else { 1887 // otherwise, wait for pairing request 1888 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1889 } 1890 } 1891 break; 1892 } else { 1893 // master 1894 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1895 } 1896 break; 1897 1898 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 1899 con_handle = little_endian_read_16(packet, 3); 1900 sm_conn = sm_get_connection_for_handle(con_handle); 1901 if (!sm_conn) break; 1902 1903 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 1904 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 1905 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 1906 break; 1907 } 1908 1909 // assume that we don't have a LTK for ediv == 0 and random == null 1910 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 1911 log_info("LTK Request: ediv & random are empty"); 1912 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1913 break; 1914 } 1915 1916 // store rand and ediv 1917 reverse_64(&packet[5], sm_conn->sm_local_rand); 1918 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 1919 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 1920 break; 1921 1922 default: 1923 break; 1924 } 1925 break; 1926 1927 case HCI_EVENT_ENCRYPTION_CHANGE: 1928 con_handle = little_endian_read_16(packet, 3); 1929 sm_conn = sm_get_connection_for_handle(con_handle); 1930 if (!sm_conn) break; 1931 1932 sm_conn->sm_connection_encrypted = packet[5]; 1933 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 1934 sm_conn->sm_actual_encryption_key_size); 1935 log_info("event handler, state %u", sm_conn->sm_engine_state); 1936 if (!sm_conn->sm_connection_encrypted) break; 1937 // continue if part of initial pairing 1938 switch (sm_conn->sm_engine_state){ 1939 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 1940 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1941 sm_done_for_handle(sm_conn->sm_handle); 1942 break; 1943 case SM_PH2_W4_CONNECTION_ENCRYPTED: 1944 if (sm_conn->sm_role){ 1945 // slave 1946 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1947 } else { 1948 // master 1949 if (sm_key_distribution_all_received(sm_conn)){ 1950 // skip receiving keys as there are none 1951 sm_key_distribution_handle_all_received(sm_conn); 1952 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1953 } else { 1954 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1955 } 1956 } 1957 break; 1958 default: 1959 break; 1960 } 1961 break; 1962 1963 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 1964 con_handle = little_endian_read_16(packet, 3); 1965 sm_conn = sm_get_connection_for_handle(con_handle); 1966 if (!sm_conn) break; 1967 1968 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 1969 log_info("event handler, state %u", sm_conn->sm_engine_state); 1970 // continue if part of initial pairing 1971 switch (sm_conn->sm_engine_state){ 1972 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 1973 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1974 sm_done_for_handle(sm_conn->sm_handle); 1975 break; 1976 case SM_PH2_W4_CONNECTION_ENCRYPTED: 1977 if (sm_conn->sm_role){ 1978 // slave 1979 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1980 } else { 1981 // master 1982 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1983 } 1984 break; 1985 default: 1986 break; 1987 } 1988 break; 1989 1990 1991 case HCI_EVENT_DISCONNECTION_COMPLETE: 1992 con_handle = little_endian_read_16(packet, 3); 1993 sm_done_for_handle(con_handle); 1994 sm_conn = sm_get_connection_for_handle(con_handle); 1995 if (!sm_conn) break; 1996 1997 // delete stored bonding on disconnect with authentication failure in ph0 1998 if (sm_conn->sm_role == 0 1999 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2000 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2001 le_device_db_remove(sm_conn->sm_le_db_index); 2002 } 2003 2004 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2005 sm_conn->sm_handle = 0; 2006 break; 2007 2008 case HCI_EVENT_COMMAND_COMPLETE: 2009 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2010 sm_handle_encryption_result(&packet[6]); 2011 break; 2012 } 2013 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2014 sm_handle_random_result(&packet[6]); 2015 break; 2016 } 2017 break; 2018 default: 2019 break; 2020 } 2021 break; 2022 default: 2023 break; 2024 } 2025 2026 sm_run(); 2027 } 2028 2029 static inline int sm_calc_actual_encryption_key_size(int other){ 2030 if (other < sm_min_encryption_key_size) return 0; 2031 if (other < sm_max_encryption_key_size) return other; 2032 return sm_max_encryption_key_size; 2033 } 2034 2035 /** 2036 * @return ok 2037 */ 2038 static int sm_validate_stk_generation_method(void){ 2039 // check if STK generation method is acceptable by client 2040 switch (setup->sm_stk_generation_method){ 2041 case JUST_WORKS: 2042 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2043 case PK_RESP_INPUT: 2044 case PK_INIT_INPUT: 2045 case OK_BOTH_INPUT: 2046 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2047 case OOB: 2048 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2049 default: 2050 return 0; 2051 } 2052 } 2053 2054 // helper for sm_pdu_handler, calls sm_run on exit 2055 static void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 2056 setup->sm_pairing_failed_reason = SM_REASON_UNSPECIFIED_REASON; 2057 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2058 sm_done_for_handle(sm_conn->sm_handle); 2059 } 2060 2061 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2062 2063 if (packet_type != SM_DATA_PACKET) return; 2064 2065 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2066 if (!sm_conn) return; 2067 2068 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2069 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2070 return; 2071 } 2072 2073 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2074 2075 int err; 2076 2077 switch (sm_conn->sm_engine_state){ 2078 2079 // a sm timeout requries a new physical connection 2080 case SM_GENERAL_TIMEOUT: 2081 return; 2082 2083 // Initiator 2084 case SM_INITIATOR_CONNECTED: 2085 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2086 sm_pdu_received_in_wrong_state(sm_conn); 2087 break; 2088 } 2089 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2090 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2091 break; 2092 } 2093 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2094 uint16_t ediv; 2095 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2096 if (ediv){ 2097 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2098 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2099 } else { 2100 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2101 } 2102 break; 2103 } 2104 // otherwise, store security request 2105 sm_conn->sm_security_request_received = 1; 2106 break; 2107 2108 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2109 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2110 sm_pdu_received_in_wrong_state(sm_conn); 2111 break; 2112 } 2113 // store pairing request 2114 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2115 err = sm_stk_generation_init(sm_conn); 2116 if (err){ 2117 setup->sm_pairing_failed_reason = err; 2118 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2119 break; 2120 } 2121 // generate random number first, if we need to show passkey 2122 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2123 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2124 break; 2125 } 2126 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2127 sm_trigger_user_response(sm_conn); 2128 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2129 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2130 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2131 } 2132 break; 2133 2134 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2135 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2136 sm_pdu_received_in_wrong_state(sm_conn); 2137 break; 2138 } 2139 2140 // store s_confirm 2141 reverse_128(&packet[1], setup->sm_peer_confirm); 2142 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2143 break; 2144 2145 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2146 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2147 sm_pdu_received_in_wrong_state(sm_conn); 2148 break;; 2149 } 2150 2151 // received random value 2152 reverse_128(&packet[1], setup->sm_peer_random); 2153 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2154 break; 2155 2156 // Responder 2157 case SM_RESPONDER_IDLE: 2158 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2159 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2160 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2161 sm_pdu_received_in_wrong_state(sm_conn); 2162 break;; 2163 } 2164 2165 // store pairing request 2166 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2167 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2168 break; 2169 2170 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 2171 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2172 sm_pdu_received_in_wrong_state(sm_conn); 2173 break;; 2174 } 2175 2176 // received confirm value 2177 reverse_128(&packet[1], setup->sm_peer_confirm); 2178 2179 // notify client to hide shown passkey 2180 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2181 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 2182 } 2183 2184 // handle user cancel pairing? 2185 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 2186 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2187 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2188 break; 2189 } 2190 2191 // wait for user action? 2192 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 2193 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2194 break; 2195 } 2196 2197 // calculate and send local_confirm 2198 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2199 break; 2200 2201 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 2202 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2203 sm_pdu_received_in_wrong_state(sm_conn); 2204 break;; 2205 } 2206 2207 // received random value 2208 reverse_128(&packet[1], setup->sm_peer_random); 2209 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2210 break; 2211 2212 case SM_PH3_RECEIVE_KEYS: 2213 switch(packet[0]){ 2214 case SM_CODE_ENCRYPTION_INFORMATION: 2215 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2216 reverse_128(&packet[1], setup->sm_peer_ltk); 2217 break; 2218 2219 case SM_CODE_MASTER_IDENTIFICATION: 2220 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2221 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 2222 reverse_64(&packet[3], setup->sm_peer_rand); 2223 break; 2224 2225 case SM_CODE_IDENTITY_INFORMATION: 2226 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2227 reverse_128(&packet[1], setup->sm_peer_irk); 2228 break; 2229 2230 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 2231 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2232 setup->sm_peer_addr_type = packet[1]; 2233 reverse_bd_addr(&packet[2], setup->sm_peer_address); 2234 break; 2235 2236 case SM_CODE_SIGNING_INFORMATION: 2237 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2238 reverse_128(&packet[1], setup->sm_peer_csrk); 2239 break; 2240 default: 2241 // Unexpected PDU 2242 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 2243 break; 2244 } 2245 // done with key distribution? 2246 if (sm_key_distribution_all_received(sm_conn)){ 2247 2248 sm_key_distribution_handle_all_received(sm_conn); 2249 2250 if (sm_conn->sm_role){ 2251 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2252 sm_done_for_handle(sm_conn->sm_handle); 2253 } else { 2254 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2255 } 2256 } 2257 break; 2258 default: 2259 // Unexpected PDU 2260 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 2261 break; 2262 } 2263 2264 // try to send preparared packet 2265 sm_run(); 2266 } 2267 2268 // Security Manager Client API 2269 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 2270 sm_get_oob_data = get_oob_data_callback; 2271 } 2272 2273 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 2274 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 2275 } 2276 2277 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 2278 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 2279 } 2280 2281 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 2282 sm_min_encryption_key_size = min_size; 2283 sm_max_encryption_key_size = max_size; 2284 } 2285 2286 void sm_set_authentication_requirements(uint8_t auth_req){ 2287 sm_auth_req = auth_req; 2288 } 2289 2290 void sm_set_io_capabilities(io_capability_t io_capability){ 2291 sm_io_capabilities = io_capability; 2292 } 2293 2294 void sm_set_request_security(int enable){ 2295 sm_slave_request_security = enable; 2296 } 2297 2298 void sm_set_er(sm_key_t er){ 2299 memcpy(sm_persistent_er, er, 16); 2300 } 2301 2302 void sm_set_ir(sm_key_t ir){ 2303 memcpy(sm_persistent_ir, ir, 16); 2304 } 2305 2306 // Testing support only 2307 void sm_test_set_irk(sm_key_t irk){ 2308 memcpy(sm_persistent_irk, irk, 16); 2309 sm_persistent_irk_ready = 1; 2310 } 2311 2312 void sm_test_use_fixed_local_csrk(void){ 2313 test_use_fixed_local_csrk = 1; 2314 } 2315 2316 void sm_init(void){ 2317 // set some (BTstack default) ER and IR 2318 int i; 2319 sm_key_t er; 2320 sm_key_t ir; 2321 for (i=0;i<16;i++){ 2322 er[i] = 0x30 + i; 2323 ir[i] = 0x90 + i; 2324 } 2325 sm_set_er(er); 2326 sm_set_ir(ir); 2327 // defaults 2328 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 2329 | SM_STK_GENERATION_METHOD_OOB 2330 | SM_STK_GENERATION_METHOD_PASSKEY; 2331 sm_max_encryption_key_size = 16; 2332 sm_min_encryption_key_size = 7; 2333 2334 sm_cmac_state = CMAC_IDLE; 2335 dkg_state = DKG_W4_WORKING; 2336 rau_state = RAU_W4_WORKING; 2337 sm_aes128_state = SM_AES128_IDLE; 2338 sm_address_resolution_test = -1; // no private address to resolve yet 2339 sm_address_resolution_ah_calculation_active = 0; 2340 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 2341 sm_address_resolution_general_queue = NULL; 2342 2343 gap_random_adress_update_period = 15 * 60 * 1000L; 2344 2345 sm_active_connection = 0; 2346 2347 test_use_fixed_local_csrk = 0; 2348 2349 // register for HCI Events from HCI 2350 hci_event_callback_registration.callback = &sm_event_packet_handler; 2351 hci_add_event_handler(&hci_event_callback_registration); 2352 2353 // and L2CAP PDUs 2354 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2355 } 2356 2357 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 2358 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 2359 if (!hci_con) return NULL; 2360 return &hci_con->sm_connection; 2361 } 2362 2363 // @returns 0 if not encrypted, 7-16 otherwise 2364 int sm_encryption_key_size(hci_con_handle_t con_handle){ 2365 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2366 if (!sm_conn) return 0; // wrong connection 2367 if (!sm_conn->sm_connection_encrypted) return 0; 2368 return sm_conn->sm_actual_encryption_key_size; 2369 } 2370 2371 int sm_authenticated(hci_con_handle_t con_handle){ 2372 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2373 if (!sm_conn) return 0; // wrong connection 2374 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 2375 return sm_conn->sm_connection_authenticated; 2376 } 2377 2378 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 2379 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2380 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 2381 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 2382 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 2383 return sm_conn->sm_connection_authorization_state; 2384 } 2385 2386 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 2387 switch (sm_conn->sm_engine_state){ 2388 case SM_GENERAL_IDLE: 2389 case SM_RESPONDER_IDLE: 2390 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2391 sm_run(); 2392 break; 2393 default: 2394 break; 2395 } 2396 } 2397 2398 /** 2399 * @brief Trigger Security Request 2400 */ 2401 void sm_send_security_request(hci_con_handle_t con_handle){ 2402 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2403 if (!sm_conn) return; 2404 sm_send_security_request_for_connection(sm_conn); 2405 } 2406 2407 // request pairing 2408 void sm_request_pairing(hci_con_handle_t con_handle){ 2409 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2410 if (!sm_conn) return; // wrong connection 2411 2412 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 2413 if (sm_conn->sm_role){ 2414 sm_send_security_request_for_connection(sm_conn); 2415 } else { 2416 // used as a trigger to start central/master/initiator security procedures 2417 uint16_t ediv; 2418 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 2419 switch (sm_conn->sm_irk_lookup_state){ 2420 case IRK_LOOKUP_FAILED: 2421 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2422 break; 2423 case IRK_LOOKUP_SUCCEEDED: 2424 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2425 if (ediv){ 2426 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2427 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2428 } else { 2429 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2430 } 2431 break; 2432 default: 2433 sm_conn->sm_bonding_requested = 1; 2434 break; 2435 } 2436 } 2437 } 2438 sm_run(); 2439 } 2440 2441 // called by client app on authorization request 2442 void sm_authorization_decline(hci_con_handle_t con_handle){ 2443 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2444 if (!sm_conn) return; // wrong connection 2445 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 2446 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 2447 } 2448 2449 void sm_authorization_grant(hci_con_handle_t con_handle){ 2450 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2451 if (!sm_conn) return; // wrong connection 2452 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 2453 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 2454 } 2455 2456 // GAP Bonding API 2457 2458 void sm_bonding_decline(hci_con_handle_t con_handle){ 2459 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2460 if (!sm_conn) return; // wrong connection 2461 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 2462 2463 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2464 sm_done_for_handle(sm_conn->sm_handle); 2465 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2466 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2467 } 2468 sm_run(); 2469 } 2470 2471 void sm_just_works_confirm(hci_con_handle_t con_handle){ 2472 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2473 if (!sm_conn) return; // wrong connection 2474 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 2475 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2476 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2477 } 2478 sm_run(); 2479 } 2480 2481 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 2482 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2483 if (!sm_conn) return; // wrong connection 2484 sm_reset_tk(); 2485 big_endian_store_32(setup->sm_tk, 12, passkey); 2486 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 2487 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2488 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2489 } 2490 sm_run(); 2491 } 2492 2493 /** 2494 * @brief Identify device in LE Device DB 2495 * @param handle 2496 * @returns index from le_device_db or -1 if not found/identified 2497 */ 2498 int sm_le_device_index(hci_con_handle_t con_handle ){ 2499 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2500 if (!sm_conn) return -1; 2501 return sm_conn->sm_le_db_index; 2502 } 2503 2504 // GAP LE API 2505 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 2506 gap_random_address_update_stop(); 2507 gap_random_adress_type = random_address_type; 2508 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 2509 gap_random_address_update_start(); 2510 gap_random_address_trigger(); 2511 } 2512 2513 gap_random_address_type_t gap_random_address_get_mode(void){ 2514 return gap_random_adress_type; 2515 } 2516 2517 void gap_random_address_set_update_period(int period_ms){ 2518 gap_random_adress_update_period = period_ms; 2519 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 2520 gap_random_address_update_stop(); 2521 gap_random_address_update_start(); 2522 } 2523 2524 void gap_random_address_set(bd_addr_t addr){ 2525 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 2526 memcpy(sm_random_address, addr, 6); 2527 rau_state = RAU_SET_ADDRESS; 2528 sm_run(); 2529 } 2530 2531 /* 2532 * @brief Set Advertisement Paramters 2533 * @param adv_int_min 2534 * @param adv_int_max 2535 * @param adv_type 2536 * @param direct_address_type 2537 * @param direct_address 2538 * @param channel_map 2539 * @param filter_policy 2540 * 2541 * @note own_address_type is used from gap_random_address_set_mode 2542 */ 2543 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 2544 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 2545 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 2546 direct_address_typ, direct_address, channel_map, filter_policy); 2547 } 2548 2549