1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "btstack_linked_list.h" 43 44 #include "btstack_memory.h" 45 #include "btstack_debug.h" 46 #include "hci.h" 47 #include "l2cap.h" 48 #include "ble/le_device_db.h" 49 #include "ble/sm.h" 50 #include "gap.h" 51 52 // 53 // SM internal types and globals 54 // 55 56 typedef enum { 57 DKG_W4_WORKING, 58 DKG_CALC_IRK, 59 DKG_W4_IRK, 60 DKG_CALC_DHK, 61 DKG_W4_DHK, 62 DKG_READY 63 } derived_key_generation_t; 64 65 typedef enum { 66 RAU_W4_WORKING, 67 RAU_IDLE, 68 RAU_GET_RANDOM, 69 RAU_W4_RANDOM, 70 RAU_GET_ENC, 71 RAU_W4_ENC, 72 RAU_SET_ADDRESS, 73 } random_address_update_t; 74 75 typedef enum { 76 CMAC_IDLE, 77 CMAC_CALC_SUBKEYS, 78 CMAC_W4_SUBKEYS, 79 CMAC_CALC_MI, 80 CMAC_W4_MI, 81 CMAC_CALC_MLAST, 82 CMAC_W4_MLAST 83 } cmac_state_t; 84 85 typedef enum { 86 JUST_WORKS, 87 PK_RESP_INPUT, // Initiator displays PK, initiator inputs PK 88 PK_INIT_INPUT, // Responder displays PK, responder inputs PK 89 OK_BOTH_INPUT, // Only input on both, both input PK 90 OOB // OOB available on both sides 91 } stk_generation_method_t; 92 93 typedef enum { 94 SM_USER_RESPONSE_IDLE, 95 SM_USER_RESPONSE_PENDING, 96 SM_USER_RESPONSE_CONFIRM, 97 SM_USER_RESPONSE_PASSKEY, 98 SM_USER_RESPONSE_DECLINE 99 } sm_user_response_t; 100 101 typedef enum { 102 SM_AES128_IDLE, 103 SM_AES128_ACTIVE 104 } sm_aes128_state_t; 105 106 typedef enum { 107 ADDRESS_RESOLUTION_IDLE, 108 ADDRESS_RESOLUTION_GENERAL, 109 ADDRESS_RESOLUTION_FOR_CONNECTION, 110 } address_resolution_mode_t; 111 112 typedef enum { 113 ADDRESS_RESOLUTION_SUCEEDED, 114 ADDRESS_RESOLUTION_FAILED, 115 } address_resolution_event_t; 116 // 117 // GLOBAL DATA 118 // 119 120 static uint8_t test_use_fixed_local_csrk; 121 122 // configuration 123 static uint8_t sm_accepted_stk_generation_methods; 124 static uint8_t sm_max_encryption_key_size; 125 static uint8_t sm_min_encryption_key_size; 126 static uint8_t sm_auth_req = 0; 127 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 128 static uint8_t sm_slave_request_security; 129 130 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 131 static sm_key_t sm_persistent_er; 132 static sm_key_t sm_persistent_ir; 133 134 // derived from sm_persistent_ir 135 static sm_key_t sm_persistent_dhk; 136 static sm_key_t sm_persistent_irk; 137 static uint8_t sm_persistent_irk_ready = 0; // used for testing 138 static derived_key_generation_t dkg_state; 139 140 // derived from sm_persistent_er 141 // .. 142 143 // random address update 144 static random_address_update_t rau_state; 145 static bd_addr_t sm_random_address; 146 147 // CMAC calculation 148 static cmac_state_t sm_cmac_state; 149 static sm_key_t sm_cmac_k; 150 static uint8_t sm_cmac_header[3]; 151 static uint16_t sm_cmac_message_len; 152 static uint8_t * sm_cmac_message; 153 static uint8_t sm_cmac_sign_counter[4]; 154 static sm_key_t sm_cmac_m_last; 155 static sm_key_t sm_cmac_x; 156 static uint8_t sm_cmac_block_current; 157 static uint8_t sm_cmac_block_count; 158 static void (*sm_cmac_done_handler)(uint8_t hash[8]); 159 160 // resolvable private address lookup / CSRK calculation 161 static int sm_address_resolution_test; 162 static int sm_address_resolution_ah_calculation_active; 163 static uint8_t sm_address_resolution_addr_type; 164 static bd_addr_t sm_address_resolution_address; 165 static void * sm_address_resolution_context; 166 static address_resolution_mode_t sm_address_resolution_mode; 167 static btstack_linked_list_t sm_address_resolution_general_queue; 168 169 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 170 static sm_aes128_state_t sm_aes128_state; 171 static void * sm_aes128_context; 172 173 // random engine. store context (ususally sm_connection_t) 174 static void * sm_random_context; 175 176 // 177 // Volume 3, Part H, Chapter 24 178 // "Security shall be initiated by the Security Manager in the device in the master role. 179 // The device in the slave role shall be the responding device." 180 // -> master := initiator, slave := responder 181 // 182 183 // data needed for security setup 184 typedef struct sm_setup_context { 185 186 btstack_timer_source_t sm_timeout; 187 188 // used in all phases 189 uint8_t sm_pairing_failed_reason; 190 191 // user response, (Phase 1 and/or 2) 192 uint8_t sm_user_response; 193 194 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 195 int sm_key_distribution_send_set; 196 int sm_key_distribution_received_set; 197 198 // Phase 2 (Pairing over SMP) 199 stk_generation_method_t sm_stk_generation_method; 200 sm_key_t sm_tk; 201 202 sm_key_t sm_c1_t3_value; // c1 calculation 203 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 204 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 205 sm_key_t sm_local_random; 206 sm_key_t sm_local_confirm; 207 sm_key_t sm_peer_random; 208 sm_key_t sm_peer_confirm; 209 uint8_t sm_m_addr_type; // address and type can be removed 210 uint8_t sm_s_addr_type; // '' 211 bd_addr_t sm_m_address; // '' 212 bd_addr_t sm_s_address; // '' 213 sm_key_t sm_ltk; 214 215 // Phase 3 216 217 // key distribution, we generate 218 uint16_t sm_local_y; 219 uint16_t sm_local_div; 220 uint16_t sm_local_ediv; 221 uint8_t sm_local_rand[8]; 222 sm_key_t sm_local_ltk; 223 sm_key_t sm_local_csrk; 224 sm_key_t sm_local_irk; 225 // sm_local_address/addr_type not needed 226 227 // key distribution, received from peer 228 uint16_t sm_peer_y; 229 uint16_t sm_peer_div; 230 uint16_t sm_peer_ediv; 231 uint8_t sm_peer_rand[8]; 232 sm_key_t sm_peer_ltk; 233 sm_key_t sm_peer_irk; 234 sm_key_t sm_peer_csrk; 235 uint8_t sm_peer_addr_type; 236 bd_addr_t sm_peer_address; 237 238 } sm_setup_context_t; 239 240 // 241 static sm_setup_context_t the_setup; 242 static sm_setup_context_t * setup = &the_setup; 243 244 // active connection - the one for which the_setup is used for 245 static uint16_t sm_active_connection = 0; 246 247 // @returns 1 if oob data is available 248 // stores oob data in provided 16 byte buffer if not null 249 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 250 251 // used to notify applicationss that user interaction is neccessary, see sm_notify_t below 252 static btstack_packet_handler_t sm_client_packet_handler = NULL; 253 254 // horizontal: initiator capabilities 255 // vertial: responder capabilities 256 static const stk_generation_method_t stk_generation_method[5][5] = { 257 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 258 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 259 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 260 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 261 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 262 }; 263 264 static void sm_run(void); 265 static void sm_done_for_handle(uint16_t handle); 266 static sm_connection_t * sm_get_connection_for_handle(uint16_t handle); 267 static inline int sm_calc_actual_encryption_key_size(int other); 268 static int sm_validate_stk_generation_method(void); 269 270 static void log_info_hex16(const char * name, uint16_t value){ 271 log_info("%-6s 0x%04x", name, value); 272 } 273 274 // @returns 1 if all bytes are 0 275 static int sm_is_null_random(uint8_t random[8]){ 276 int i; 277 for (i=0; i < 8 ; i++){ 278 if (random[i]) return 0; 279 } 280 return 1; 281 } 282 283 // Key utils 284 static void sm_reset_tk(void){ 285 int i; 286 for (i=0;i<16;i++){ 287 setup->sm_tk[i] = 0; 288 } 289 } 290 291 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 292 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 293 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 294 int i; 295 for (i = max_encryption_size ; i < 16 ; i++){ 296 key[15-i] = 0; 297 } 298 } 299 300 // SMP Timeout implementation 301 302 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 303 // the Security Manager Timer shall be reset and started. 304 // 305 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 306 // 307 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 308 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 309 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 310 // established. 311 312 static void sm_timeout_handler(btstack_timer_source_t * timer){ 313 log_info("SM timeout"); 314 sm_connection_t * sm_conn = (sm_connection_t *) btstack_linked_item_get_user((btstack_linked_item_t*) timer); 315 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 316 sm_done_for_handle(sm_conn->sm_handle); 317 318 // trigger handling of next ready connection 319 sm_run(); 320 } 321 static void sm_timeout_start(sm_connection_t * sm_conn){ 322 btstack_run_loop_remove_timer(&setup->sm_timeout); 323 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 324 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 325 btstack_linked_item_set_user((btstack_linked_item_t*) &setup->sm_timeout, sm_conn); 326 btstack_run_loop_add_timer(&setup->sm_timeout); 327 } 328 static void sm_timeout_stop(void){ 329 btstack_run_loop_remove_timer(&setup->sm_timeout); 330 } 331 static void sm_timeout_reset(sm_connection_t * sm_conn){ 332 sm_timeout_stop(); 333 sm_timeout_start(sm_conn); 334 } 335 336 // end of sm timeout 337 338 // GAP Random Address updates 339 static gap_random_address_type_t gap_random_adress_type; 340 static btstack_timer_source_t gap_random_address_update_timer; 341 static uint32_t gap_random_adress_update_period; 342 343 static void gap_random_address_trigger(void){ 344 if (rau_state != RAU_IDLE) return; 345 log_info("gap_random_address_trigger"); 346 rau_state = RAU_GET_RANDOM; 347 sm_run(); 348 } 349 350 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 351 log_info("GAP Random Address Update due"); 352 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 353 btstack_run_loop_add_timer(&gap_random_address_update_timer); 354 gap_random_address_trigger(); 355 } 356 357 static void gap_random_address_update_start(void){ 358 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 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 } 362 363 static void gap_random_address_update_stop(void){ 364 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 365 } 366 367 368 static void sm_random_start(void * context){ 369 sm_random_context = context; 370 hci_send_cmd(&hci_le_rand); 371 } 372 373 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 374 // context is made availabe to aes128 result handler by this 375 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 376 sm_aes128_state = SM_AES128_ACTIVE; 377 sm_key_t key_flipped, plaintext_flipped; 378 swap128(key, key_flipped); 379 swap128(plaintext, plaintext_flipped); 380 sm_aes128_context = context; 381 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 382 } 383 384 // ah(k,r) helper 385 // r = padding || r 386 // r - 24 bit value 387 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 388 // r'= padding || r 389 memset(r_prime, 0, 16); 390 memcpy(&r_prime[13], r, 3); 391 } 392 393 // d1 helper 394 // d' = padding || r || d 395 // d,r - 16 bit values 396 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 397 // d'= padding || r || d 398 memset(d1_prime, 0, 16); 399 net_store_16(d1_prime, 12, r); 400 net_store_16(d1_prime, 14, d); 401 } 402 403 // dm helper 404 // r’ = padding || r 405 // r - 64 bit value 406 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 407 memset(r_prime, 0, 16); 408 memcpy(&r_prime[8], r, 8); 409 } 410 411 // calculate arguments for first AES128 operation in C1 function 412 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){ 413 414 // p1 = pres || preq || rat’ || iat’ 415 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 416 // cant octet of pres becomes the most significant octet of p1. 417 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 418 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 419 // p1 is 0x05000800000302070710000001010001." 420 421 sm_key_t p1; 422 swap56(pres, &p1[0]); 423 swap56(preq, &p1[7]); 424 p1[14] = rat; 425 p1[15] = iat; 426 log_key("p1", p1); 427 log_key("r", r); 428 429 // t1 = r xor p1 430 int i; 431 for (i=0;i<16;i++){ 432 t1[i] = r[i] ^ p1[i]; 433 } 434 log_key("t1", t1); 435 } 436 437 // calculate arguments for second AES128 operation in C1 function 438 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 439 // p2 = padding || ia || ra 440 // "The least significant octet of ra becomes the least significant octet of p2 and 441 // the most significant octet of padding becomes the most significant octet of p2. 442 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 443 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 444 445 sm_key_t p2; 446 memset(p2, 0, 16); 447 memcpy(&p2[4], ia, 6); 448 memcpy(&p2[10], ra, 6); 449 log_key("p2", p2); 450 451 // c1 = e(k, t2_xor_p2) 452 int i; 453 for (i=0;i<16;i++){ 454 t3[i] = t2[i] ^ p2[i]; 455 } 456 log_key("t3", t3); 457 } 458 459 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 460 log_key("r1", r1); 461 log_key("r2", r2); 462 memcpy(&r_prime[8], &r2[8], 8); 463 memcpy(&r_prime[0], &r1[8], 8); 464 } 465 466 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, uint16_t handle, uint8_t addr_type, bd_addr_t address){ 467 event[0] = type; 468 event[1] = event_size - 2; 469 bt_store_16(event, 2, handle); 470 event[4] = addr_type; 471 bt_flip_addr(&event[5], address); 472 } 473 474 static void sm_notify_client_base(uint8_t type, uint16_t handle, uint8_t addr_type, bd_addr_t address){ 475 uint8_t event[11]; 476 sm_setup_event_base(event, sizeof(event), type, handle, addr_type, address); 477 478 if (!sm_client_packet_handler) return; 479 sm_client_packet_handler(HCI_EVENT_PACKET, 0, event, sizeof(event)); 480 } 481 482 static void sm_notify_client_passkey(uint8_t type, uint16_t handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 483 uint8_t event[15]; 484 sm_setup_event_base(event, sizeof(event), type, handle, addr_type, address); 485 bt_store_32(event, 11, passkey); 486 487 if (!sm_client_packet_handler) return; 488 sm_client_packet_handler(HCI_EVENT_PACKET, 0, event, sizeof(event)); 489 } 490 491 static void sm_notify_client_index(uint8_t type, uint16_t handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 492 uint8_t event[13]; 493 sm_setup_event_base(event, sizeof(event), type, handle, addr_type, address); 494 bt_store_16(event, 11, index); 495 496 if (!sm_client_packet_handler) return; 497 sm_client_packet_handler(HCI_EVENT_PACKET, 0, event, sizeof(event)); 498 } 499 500 static void sm_notify_client_authorization(uint8_t type, uint16_t handle, uint8_t addr_type, bd_addr_t address, uint8_t result){ 501 502 uint8_t event[18]; 503 sm_setup_event_base(event, sizeof(event), type, handle, addr_type, address); 504 event[11] = result; 505 506 if (!sm_client_packet_handler) return; 507 sm_client_packet_handler(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 508 } 509 510 // decide on stk generation based on 511 // - pairing request 512 // - io capabilities 513 // - OOB data availability 514 static void sm_setup_tk(void){ 515 516 // default: just works 517 setup->sm_stk_generation_method = JUST_WORKS; 518 519 // If both devices have out of band authentication data, then the Authentication 520 // Requirements Flags shall be ignored when selecting the pairing method and the 521 // Out of Band pairing method shall be used. 522 if (setup->sm_m_preq.oob_data_flag && setup->sm_s_pres.oob_data_flag){ 523 log_info("SM: have OOB data"); 524 log_key("OOB", setup->sm_tk); 525 setup->sm_stk_generation_method = OOB; 526 return; 527 } 528 529 // Reset TK as it has been setup in sm_init_setup 530 sm_reset_tk(); 531 532 // If both devices have not set the MITM option in the Authentication Requirements 533 // Flags, then the IO capabilities shall be ignored and the Just Works association 534 // model shall be used. 535 if ( ((setup->sm_m_preq.auth_req & SM_AUTHREQ_MITM_PROTECTION) == 0x00) && ((setup->sm_s_pres.auth_req & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 536 return; 537 } 538 539 // Also use just works if unknown io capabilites 540 if ((setup->sm_m_preq.io_capability > IO_CAPABILITY_KEYBOARD_DISPLAY) || (setup->sm_m_preq.io_capability > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 541 return; 542 } 543 544 // Otherwise the IO capabilities of the devices shall be used to determine the 545 // pairing method as defined in Table 2.4. 546 setup->sm_stk_generation_method = stk_generation_method[setup->sm_s_pres.io_capability][setup->sm_m_preq.io_capability]; 547 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 548 setup->sm_m_preq.io_capability, setup->sm_s_pres.io_capability, setup->sm_stk_generation_method); 549 } 550 551 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 552 int flags = 0; 553 if (key_set & SM_KEYDIST_ENC_KEY){ 554 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 555 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 556 } 557 if (key_set & SM_KEYDIST_ID_KEY){ 558 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 559 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 560 } 561 if (key_set & SM_KEYDIST_SIGN){ 562 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 563 } 564 return flags; 565 } 566 567 static void sm_setup_key_distribution(uint8_t key_set){ 568 setup->sm_key_distribution_received_set = 0; 569 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 570 } 571 572 // CSRK Key Lookup 573 574 575 static int sm_address_resolution_idle(void){ 576 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 577 } 578 579 static void sm_address_resolution_start_lookup(uint8_t addr_type, uint16_t handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 580 memcpy(sm_address_resolution_address, addr, 6); 581 sm_address_resolution_addr_type = addr_type; 582 sm_address_resolution_test = 0; 583 sm_address_resolution_mode = mode; 584 sm_address_resolution_context = context; 585 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, handle, addr_type, addr); 586 } 587 588 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 589 // check if already in list 590 btstack_linked_list_iterator_t it; 591 sm_lookup_entry_t * entry; 592 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 593 while(btstack_linked_list_iterator_has_next(&it)){ 594 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 595 if (entry->address_type != address_type) continue; 596 if (memcmp(entry->address, address, 6)) continue; 597 // already in list 598 return BTSTACK_BUSY; 599 } 600 entry = btstack_memory_sm_lookup_entry_get(); 601 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 602 entry->address_type = (bd_addr_type_t) address_type; 603 memcpy(entry->address, address, 6); 604 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 605 sm_run(); 606 return 0; 607 } 608 609 // CMAC Implementation using AES128 engine 610 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 611 int i; 612 int carry = 0; 613 for (i=len-1; i >= 0 ; i--){ 614 int new_carry = data[i] >> 7; 615 data[i] = data[i] << 1 | carry; 616 carry = new_carry; 617 } 618 } 619 620 // 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 621 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 622 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 623 } 624 static inline void dkg_next_state(void){ 625 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 626 } 627 static inline void rau_next_state(void){ 628 rau_state = (random_address_update_t) (((int)rau_state) + 1); 629 } 630 static inline void sm_cmac_next_state(void){ 631 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 632 } 633 static int sm_cmac_last_block_complete(void){ 634 if (sm_cmac_message_len == 0) return 0; 635 return (sm_cmac_message_len & 0x0f) == 0; 636 } 637 static inline uint8_t sm_cmac_message_get_byte(int offset){ 638 if (offset >= sm_cmac_message_len) { 639 log_error("sm_cmac_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 640 return 0; 641 } 642 643 offset = sm_cmac_message_len - 1 - offset; 644 645 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 646 if (offset < 3){ 647 return sm_cmac_header[offset]; 648 } 649 int actual_message_len_incl_header = sm_cmac_message_len - 4; 650 if (offset < actual_message_len_incl_header){ 651 return sm_cmac_message[offset - 3]; 652 } 653 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 654 } 655 656 void sm_cmac_start(sm_key_t k, uint8_t opcode, uint16_t handle, uint16_t message_len, uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t hash[8])){ 657 memcpy(sm_cmac_k, k, 16); 658 sm_cmac_header[0] = opcode; 659 bt_store_16(sm_cmac_header, 1, handle); 660 bt_store_32(sm_cmac_sign_counter, 0, sign_counter); 661 sm_cmac_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 662 sm_cmac_message = message; 663 sm_cmac_done_handler = done_handler; 664 sm_cmac_block_current = 0; 665 memset(sm_cmac_x, 0, 16); 666 667 // step 2: n := ceil(len/const_Bsize); 668 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 669 670 // step 3: .. 671 if (sm_cmac_block_count==0){ 672 sm_cmac_block_count = 1; 673 } 674 675 log_info("sm_cmac_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 676 677 // first, we need to compute l for k1, k2, and m_last 678 sm_cmac_state = CMAC_CALC_SUBKEYS; 679 680 // let's go 681 sm_run(); 682 } 683 684 int sm_cmac_ready(void){ 685 return sm_cmac_state == CMAC_IDLE; 686 } 687 688 static void sm_cmac_handle_aes_engine_ready(void){ 689 switch (sm_cmac_state){ 690 case CMAC_CALC_SUBKEYS: { 691 sm_key_t const_zero; 692 memset(const_zero, 0, 16); 693 sm_cmac_next_state(); 694 sm_aes128_start(sm_cmac_k, const_zero, NULL); 695 break; 696 } 697 case CMAC_CALC_MI: { 698 int j; 699 sm_key_t y; 700 for (j=0;j<16;j++){ 701 y[j] = sm_cmac_x[j] ^ sm_cmac_message_get_byte(sm_cmac_block_current*16 + j); 702 } 703 sm_cmac_block_current++; 704 sm_cmac_next_state(); 705 sm_aes128_start(sm_cmac_k, y, NULL); 706 break; 707 } 708 case CMAC_CALC_MLAST: { 709 int i; 710 sm_key_t y; 711 for (i=0;i<16;i++){ 712 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 713 } 714 log_key("Y", y); 715 sm_cmac_block_current++; 716 sm_cmac_next_state(); 717 sm_aes128_start(sm_cmac_k, y, NULL); 718 break; 719 } 720 default: 721 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 722 break; 723 } 724 } 725 726 static void sm_cmac_handle_encryption_result(sm_key_t data){ 727 switch (sm_cmac_state){ 728 case CMAC_W4_SUBKEYS: { 729 sm_key_t k1; 730 memcpy(k1, data, 16); 731 sm_shift_left_by_one_bit_inplace(16, k1); 732 if (data[0] & 0x80){ 733 k1[15] ^= 0x87; 734 } 735 sm_key_t k2; 736 memcpy(k2, k1, 16); 737 sm_shift_left_by_one_bit_inplace(16, k2); 738 if (k1[0] & 0x80){ 739 k2[15] ^= 0x87; 740 } 741 742 log_key("k", sm_cmac_k); 743 log_key("k1", k1); 744 log_key("k2", k2); 745 746 // step 4: set m_last 747 int i; 748 if (sm_cmac_last_block_complete()){ 749 for (i=0;i<16;i++){ 750 sm_cmac_m_last[i] = sm_cmac_message_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 751 } 752 } else { 753 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 754 for (i=0;i<16;i++){ 755 if (i < valid_octets_in_last_block){ 756 sm_cmac_m_last[i] = sm_cmac_message_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 757 continue; 758 } 759 if (i == valid_octets_in_last_block){ 760 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 761 continue; 762 } 763 sm_cmac_m_last[i] = k2[i]; 764 } 765 } 766 767 // next 768 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 769 break; 770 } 771 case CMAC_W4_MI: 772 memcpy(sm_cmac_x, data, 16); 773 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 774 break; 775 case CMAC_W4_MLAST: 776 // done 777 log_key("CMAC", data); 778 sm_cmac_done_handler(data); 779 sm_cmac_state = CMAC_IDLE; 780 break; 781 default: 782 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 783 break; 784 } 785 } 786 787 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 788 // notify client for: JUST WORKS confirm, PASSKEY display or input 789 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 790 switch (setup->sm_stk_generation_method){ 791 case PK_RESP_INPUT: 792 if (sm_conn->sm_role){ 793 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 794 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 795 } else { 796 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, READ_NET_32(setup->sm_tk, 12)); 797 } 798 break; 799 case PK_INIT_INPUT: 800 if (sm_conn->sm_role){ 801 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, READ_NET_32(setup->sm_tk, 12)); 802 } else { 803 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 804 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 805 } 806 break; 807 case OK_BOTH_INPUT: 808 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 809 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 810 break; 811 case JUST_WORKS: 812 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 813 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 814 break; 815 case OOB: 816 // client already provided OOB data, let's skip notification. 817 break; 818 } 819 } 820 821 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 822 int recv_flags; 823 if (sm_conn->sm_role){ 824 // slave / responser 825 recv_flags = sm_key_distribution_flags_for_set(setup->sm_s_pres.initiator_key_distribution); 826 } else { 827 // master / initiator 828 recv_flags = sm_key_distribution_flags_for_set(setup->sm_s_pres.responder_key_distribution); 829 } 830 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 831 return recv_flags == setup->sm_key_distribution_received_set; 832 } 833 834 static void sm_done_for_handle(uint16_t handle){ 835 if (sm_active_connection == handle){ 836 sm_timeout_stop(); 837 sm_active_connection = 0; 838 log_info("sm: connection 0x%x released setup context", handle); 839 } 840 } 841 842 static int sm_key_distribution_flags_for_auth_req(void){ 843 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 844 if (sm_auth_req & SM_AUTHREQ_BONDING){ 845 // encryption information only if bonding requested 846 flags |= SM_KEYDIST_ENC_KEY; 847 } 848 return flags; 849 } 850 851 static void sm_init_setup(sm_connection_t * sm_conn){ 852 853 // fill in sm setup 854 sm_reset_tk(); 855 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 856 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 857 858 // query client for OOB data 859 int have_oob_data = 0; 860 if (sm_get_oob_data) { 861 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 862 } 863 864 sm_pairing_packet_t * local_packet; 865 if (sm_conn->sm_role){ 866 // slave 867 local_packet = &setup->sm_s_pres; 868 hci_le_advertisement_address(&setup->sm_s_addr_type, setup->sm_s_address); 869 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 870 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 871 } else { 872 // master 873 local_packet = &setup->sm_m_preq; 874 hci_le_advertisement_address(&setup->sm_m_addr_type, setup->sm_m_address); 875 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 876 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 877 878 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 879 setup->sm_m_preq.initiator_key_distribution = key_distribution_flags; 880 setup->sm_m_preq.responder_key_distribution = key_distribution_flags; 881 } 882 883 local_packet->io_capability = sm_io_capabilities; 884 local_packet->oob_data_flag = have_oob_data; 885 local_packet->auth_req = sm_auth_req; 886 local_packet->max_encryption_key_size = sm_max_encryption_key_size; 887 } 888 889 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 890 891 sm_pairing_packet_t * remote_packet; 892 int remote_key_request; 893 if (sm_conn->sm_role){ 894 // slave / responser 895 remote_packet = &setup->sm_m_preq; 896 remote_key_request = setup->sm_m_preq.responder_key_distribution; 897 } else { 898 // master / initiator 899 remote_packet = &setup->sm_s_pres; 900 remote_key_request = setup->sm_s_pres.initiator_key_distribution; 901 } 902 903 // check key size 904 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(remote_packet->max_encryption_key_size); 905 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 906 907 // setup key distribution 908 sm_setup_key_distribution(remote_key_request); 909 910 // identical to responder 911 912 // decide on STK generation method 913 sm_setup_tk(); 914 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 915 916 // check if STK generation method is acceptable by client 917 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 918 919 // JUST WORKS doens't provide authentication 920 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 921 922 return 0; 923 } 924 925 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 926 927 // cache and reset context 928 int matched_device_id = sm_address_resolution_test; 929 address_resolution_mode_t mode = sm_address_resolution_mode; 930 void * context = sm_address_resolution_context; 931 932 // reset context 933 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 934 sm_address_resolution_context = NULL; 935 sm_address_resolution_test = -1; 936 uint16_t handle = 0; 937 938 sm_connection_t * sm_connection; 939 uint16_t ediv; 940 switch (mode){ 941 case ADDRESS_RESOLUTION_GENERAL: 942 break; 943 case ADDRESS_RESOLUTION_FOR_CONNECTION: 944 sm_connection = (sm_connection_t *) context; 945 handle = sm_connection->sm_handle; 946 switch (event){ 947 case ADDRESS_RESOLUTION_SUCEEDED: 948 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 949 sm_connection->sm_le_db_index = matched_device_id; 950 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 951 if (sm_connection->sm_role) break; 952 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 953 sm_connection->sm_security_request_received = 0; 954 sm_connection->sm_bonding_requested = 0; 955 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 956 if (ediv){ 957 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 958 } else { 959 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 960 } 961 break; 962 case ADDRESS_RESOLUTION_FAILED: 963 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 964 if (sm_connection->sm_role) break; 965 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 966 sm_connection->sm_security_request_received = 0; 967 sm_connection->sm_bonding_requested = 0; 968 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 969 break; 970 } 971 break; 972 default: 973 break; 974 } 975 976 switch (event){ 977 case ADDRESS_RESOLUTION_SUCEEDED: 978 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 979 break; 980 case ADDRESS_RESOLUTION_FAILED: 981 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, handle, sm_address_resolution_addr_type, sm_address_resolution_address); 982 break; 983 } 984 } 985 986 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 987 988 int le_db_index = -1; 989 990 // lookup device based on IRK 991 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 992 int i; 993 for (i=0; i < le_device_db_count(); i++){ 994 sm_key_t irk; 995 bd_addr_t address; 996 int address_type; 997 le_device_db_info(i, &address_type, address, irk); 998 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 999 log_info("sm: device found for IRK, updating"); 1000 le_db_index = i; 1001 break; 1002 } 1003 } 1004 } 1005 1006 // if not found, lookup via public address if possible 1007 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1008 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1009 int i; 1010 for (i=0; i < le_device_db_count(); i++){ 1011 bd_addr_t address; 1012 int address_type; 1013 le_device_db_info(i, &address_type, address, NULL); 1014 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1015 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1016 log_info("sm: device found for public address, updating"); 1017 le_db_index = i; 1018 break; 1019 } 1020 } 1021 } 1022 1023 // if not found, add to db 1024 if (le_db_index < 0) { 1025 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1026 } 1027 1028 if (le_db_index >= 0){ 1029 le_device_db_local_counter_set(le_db_index, 0); 1030 1031 // store local CSRK 1032 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1033 log_info("sm: store local CSRK"); 1034 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1035 le_device_db_local_counter_set(le_db_index, 0); 1036 } 1037 1038 // store remote CSRK 1039 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1040 log_info("sm: store remote CSRK"); 1041 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1042 le_device_db_remote_counter_set(le_db_index, 0); 1043 } 1044 1045 // store encryption information 1046 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION 1047 && setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1048 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1049 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1050 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1051 } 1052 } 1053 1054 // keep le_db_index 1055 sm_conn->sm_le_db_index = le_db_index; 1056 } 1057 1058 static void sm_run(void){ 1059 1060 btstack_linked_list_iterator_t it; 1061 1062 // assert that we can send at least commands 1063 if (!hci_can_send_command_packet_now()) return; 1064 1065 // 1066 // non-connection related behaviour 1067 // 1068 1069 // distributed key generation 1070 switch (dkg_state){ 1071 case DKG_CALC_IRK: 1072 // already busy? 1073 if (sm_aes128_state == SM_AES128_IDLE) { 1074 // IRK = d1(IR, 1, 0) 1075 sm_key_t d1_prime; 1076 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1077 dkg_next_state(); 1078 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1079 return; 1080 } 1081 break; 1082 case DKG_CALC_DHK: 1083 // already busy? 1084 if (sm_aes128_state == SM_AES128_IDLE) { 1085 // DHK = d1(IR, 3, 0) 1086 sm_key_t d1_prime; 1087 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1088 dkg_next_state(); 1089 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1090 return; 1091 } 1092 break; 1093 default: 1094 break; 1095 } 1096 1097 // random address updates 1098 switch (rau_state){ 1099 case RAU_GET_RANDOM: 1100 rau_next_state(); 1101 sm_random_start(NULL); 1102 return; 1103 case RAU_GET_ENC: 1104 // already busy? 1105 if (sm_aes128_state == SM_AES128_IDLE) { 1106 sm_key_t r_prime; 1107 sm_ah_r_prime(sm_random_address, r_prime); 1108 rau_next_state(); 1109 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1110 return; 1111 } 1112 break; 1113 case RAU_SET_ADDRESS: 1114 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1115 rau_state = RAU_IDLE; 1116 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1117 return; 1118 default: 1119 break; 1120 } 1121 1122 // CMAC 1123 switch (sm_cmac_state){ 1124 case CMAC_CALC_SUBKEYS: 1125 case CMAC_CALC_MI: 1126 case CMAC_CALC_MLAST: 1127 // already busy? 1128 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1129 sm_cmac_handle_aes_engine_ready(); 1130 return; 1131 default: 1132 break; 1133 } 1134 1135 // CSRK Lookup 1136 // -- if csrk lookup ready, find connection that require csrk lookup 1137 if (sm_address_resolution_idle()){ 1138 hci_connections_get_iterator(&it); 1139 while(btstack_linked_list_iterator_has_next(&it)){ 1140 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1141 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1142 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1143 // and start lookup 1144 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); 1145 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1146 break; 1147 } 1148 } 1149 } 1150 1151 // -- if csrk lookup ready, resolved addresses for received addresses 1152 if (sm_address_resolution_idle()) { 1153 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1154 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1155 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1156 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1157 btstack_memory_sm_lookup_entry_free(entry); 1158 } 1159 } 1160 1161 // -- Continue with CSRK device lookup by public or resolvable private address 1162 if (!sm_address_resolution_idle()){ 1163 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1164 while (sm_address_resolution_test < le_device_db_count()){ 1165 int addr_type; 1166 bd_addr_t addr; 1167 sm_key_t irk; 1168 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1169 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1170 1171 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1172 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1173 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1174 break; 1175 } 1176 1177 if (sm_address_resolution_addr_type == 0){ 1178 sm_address_resolution_test++; 1179 continue; 1180 } 1181 1182 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1183 1184 log_info("LE Device Lookup: calculate AH"); 1185 log_key("IRK", irk); 1186 1187 sm_key_t r_prime; 1188 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1189 sm_address_resolution_ah_calculation_active = 1; 1190 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1191 return; 1192 } 1193 1194 if (sm_address_resolution_test >= le_device_db_count()){ 1195 log_info("LE Device Lookup: not found"); 1196 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1197 } 1198 } 1199 1200 1201 // 1202 // active connection handling 1203 // -- use loop to handle next connection if lock on setup context is released 1204 1205 while (1) { 1206 1207 // Find connections that requires setup context and make active if no other is locked 1208 hci_connections_get_iterator(&it); 1209 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1210 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1211 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1212 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1213 int done = 1; 1214 int err; 1215 int encryption_key_size; 1216 int authenticated; 1217 int authorized; 1218 switch (sm_connection->sm_engine_state) { 1219 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1220 // send packet if possible, 1221 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle)){ 1222 uint8_t buffer[2]; 1223 buffer[0] = SM_CODE_SECURITY_REQUEST; 1224 buffer[1] = SM_AUTHREQ_BONDING; 1225 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1226 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1227 } 1228 // don't lock setup context yet 1229 done = 0; 1230 break; 1231 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1232 sm_init_setup(sm_connection); 1233 // recover pairing request 1234 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1235 err = sm_stk_generation_init(sm_connection); 1236 if (err){ 1237 setup->sm_pairing_failed_reason = err; 1238 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1239 break; 1240 } 1241 sm_timeout_start(sm_connection); 1242 // generate random number first, if we need to show passkey 1243 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1244 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1245 break; 1246 } 1247 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1248 break; 1249 case SM_INITIATOR_PH0_HAS_LTK: 1250 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1251 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1252 &encryption_key_size, &authenticated, &authorized); 1253 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1254 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1255 sm_connection->sm_connection_authenticated = authenticated; 1256 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1257 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1258 break; 1259 case SM_RESPONDER_PH0_RECEIVED_LTK: 1260 // re-establish previously used LTK using Rand and EDIV 1261 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1262 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1263 // re-establish used key encryption size 1264 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1265 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1266 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1267 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1268 log_info("sm: received ltk request with key size %u, authenticated %u", 1269 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1270 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1271 break; 1272 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1273 sm_init_setup(sm_connection); 1274 sm_timeout_start(sm_connection); 1275 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1276 break; 1277 default: 1278 done = 0; 1279 break; 1280 } 1281 if (done){ 1282 sm_active_connection = sm_connection->sm_handle; 1283 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1284 } 1285 } 1286 1287 // 1288 // active connection handling 1289 // 1290 1291 if (sm_active_connection == 0) return; 1292 1293 // assert that we could send a SM PDU - not needed for all of the following 1294 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection)) return; 1295 1296 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1297 if (!connection) return; 1298 1299 sm_key_t plaintext; 1300 int key_distribution_flags; 1301 1302 log_info("sm_run: state %u", connection->sm_engine_state); 1303 1304 // responding state 1305 switch (connection->sm_engine_state){ 1306 1307 // general 1308 case SM_GENERAL_SEND_PAIRING_FAILED: { 1309 uint8_t buffer[2]; 1310 buffer[0] = SM_CODE_PAIRING_FAILED; 1311 buffer[1] = setup->sm_pairing_failed_reason; 1312 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1313 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1314 sm_done_for_handle(connection->sm_handle); 1315 break; 1316 } 1317 1318 // initiator side 1319 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1320 sm_key_t peer_ltk_flipped; 1321 swap128(setup->sm_peer_ltk, peer_ltk_flipped); 1322 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1323 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1324 uint32_t rand_high = READ_NET_32(setup->sm_peer_rand, 0); 1325 uint32_t rand_low = READ_NET_32(setup->sm_peer_rand, 4); 1326 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1327 return; 1328 } 1329 1330 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1331 setup->sm_m_preq.code = SM_CODE_PAIRING_REQUEST; 1332 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1333 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1334 sm_timeout_reset(connection); 1335 break; 1336 1337 // responder side 1338 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1339 connection->sm_engine_state = SM_RESPONDER_IDLE; 1340 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1341 return; 1342 1343 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 1344 // echo initiator for now 1345 setup->sm_s_pres.code = SM_CODE_PAIRING_RESPONSE; 1346 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1347 setup->sm_s_pres.initiator_key_distribution = setup->sm_m_preq.initiator_key_distribution & key_distribution_flags; 1348 setup->sm_s_pres.responder_key_distribution = setup->sm_m_preq.responder_key_distribution & key_distribution_flags; 1349 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 1350 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 1351 sm_timeout_reset(connection); 1352 sm_trigger_user_response(connection); 1353 return; 1354 1355 case SM_PH2_SEND_PAIRING_RANDOM: { 1356 uint8_t buffer[17]; 1357 buffer[0] = SM_CODE_PAIRING_RANDOM; 1358 swap128(setup->sm_local_random, &buffer[1]); 1359 if (connection->sm_role){ 1360 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 1361 } else { 1362 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 1363 } 1364 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1365 sm_timeout_reset(connection); 1366 break; 1367 } 1368 1369 case SM_PH2_GET_RANDOM_TK: 1370 case SM_PH2_C1_GET_RANDOM_A: 1371 case SM_PH2_C1_GET_RANDOM_B: 1372 case SM_PH3_GET_RANDOM: 1373 case SM_PH3_GET_DIV: 1374 sm_next_responding_state(connection); 1375 sm_random_start(connection); 1376 return; 1377 1378 case SM_PH2_C1_GET_ENC_B: 1379 case SM_PH2_C1_GET_ENC_D: 1380 // already busy? 1381 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1382 sm_next_responding_state(connection); 1383 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 1384 return; 1385 1386 case SM_PH3_LTK_GET_ENC: 1387 case SM_RESPONDER_PH4_LTK_GET_ENC: 1388 // already busy? 1389 if (sm_aes128_state == SM_AES128_IDLE) { 1390 sm_key_t d_prime; 1391 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 1392 sm_next_responding_state(connection); 1393 sm_aes128_start(sm_persistent_er, d_prime, connection); 1394 return; 1395 } 1396 break; 1397 1398 case SM_PH3_CSRK_GET_ENC: 1399 // already busy? 1400 if (sm_aes128_state == SM_AES128_IDLE) { 1401 sm_key_t d_prime; 1402 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 1403 sm_next_responding_state(connection); 1404 sm_aes128_start(sm_persistent_er, d_prime, connection); 1405 return; 1406 } 1407 break; 1408 1409 case SM_PH2_C1_GET_ENC_C: 1410 // already busy? 1411 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1412 // calculate m_confirm using aes128 engine - step 1 1413 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); 1414 sm_next_responding_state(connection); 1415 sm_aes128_start(setup->sm_tk, plaintext, connection); 1416 break; 1417 case SM_PH2_C1_GET_ENC_A: 1418 // already busy? 1419 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1420 // calculate confirm using aes128 engine - step 1 1421 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); 1422 sm_next_responding_state(connection); 1423 sm_aes128_start(setup->sm_tk, plaintext, connection); 1424 break; 1425 case SM_PH2_CALC_STK: 1426 // already busy? 1427 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1428 // calculate STK 1429 if (connection->sm_role){ 1430 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 1431 } else { 1432 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 1433 } 1434 sm_next_responding_state(connection); 1435 sm_aes128_start(setup->sm_tk, plaintext, connection); 1436 break; 1437 case SM_PH3_Y_GET_ENC: 1438 // already busy? 1439 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1440 // PH3B2 - calculate Y from - enc 1441 // Y = dm(DHK, Rand) 1442 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1443 sm_next_responding_state(connection); 1444 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1445 return; 1446 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 1447 uint8_t buffer[17]; 1448 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1449 swap128(setup->sm_local_confirm, &buffer[1]); 1450 if (connection->sm_role){ 1451 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 1452 } else { 1453 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 1454 } 1455 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1456 sm_timeout_reset(connection); 1457 return; 1458 } 1459 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 1460 sm_key_t stk_flipped; 1461 swap128(setup->sm_ltk, stk_flipped); 1462 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1463 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 1464 return; 1465 } 1466 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 1467 sm_key_t stk_flipped; 1468 swap128(setup->sm_ltk, stk_flipped); 1469 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1470 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 1471 return; 1472 } 1473 case SM_RESPONDER_PH4_SEND_LTK: { 1474 sm_key_t ltk_flipped; 1475 swap128(setup->sm_ltk, ltk_flipped); 1476 connection->sm_engine_state = SM_RESPONDER_IDLE; 1477 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 1478 return; 1479 } 1480 case SM_RESPONDER_PH4_Y_GET_ENC: 1481 // already busy? 1482 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1483 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 1484 // Y = dm(DHK, Rand) 1485 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1486 sm_next_responding_state(connection); 1487 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1488 return; 1489 1490 case SM_PH3_DISTRIBUTE_KEYS: 1491 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 1492 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 1493 uint8_t buffer[17]; 1494 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 1495 swap128(setup->sm_ltk, &buffer[1]); 1496 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1497 sm_timeout_reset(connection); 1498 return; 1499 } 1500 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1501 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 1502 uint8_t buffer[11]; 1503 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 1504 bt_store_16(buffer, 1, setup->sm_local_ediv); 1505 swap64(setup->sm_local_rand, &buffer[3]); 1506 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1507 sm_timeout_reset(connection); 1508 return; 1509 } 1510 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1511 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 1512 uint8_t buffer[17]; 1513 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 1514 swap128(sm_persistent_irk, &buffer[1]); 1515 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1516 sm_timeout_reset(connection); 1517 return; 1518 } 1519 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 1520 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 1521 bd_addr_t local_address; 1522 uint8_t buffer[8]; 1523 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 1524 hci_le_advertisement_address(&buffer[1], local_address); 1525 bt_flip_addr(&buffer[2], local_address); 1526 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1527 sm_timeout_reset(connection); 1528 return; 1529 } 1530 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1531 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 1532 1533 // hack to reproduce test runs 1534 if (test_use_fixed_local_csrk){ 1535 memset(setup->sm_local_csrk, 0xcc, 16); 1536 } 1537 1538 uint8_t buffer[17]; 1539 buffer[0] = SM_CODE_SIGNING_INFORMATION; 1540 swap128(setup->sm_local_csrk, &buffer[1]); 1541 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1542 sm_timeout_reset(connection); 1543 return; 1544 } 1545 1546 // keys are sent 1547 if (connection->sm_role){ 1548 // slave -> receive master keys if any 1549 if (sm_key_distribution_all_received(connection)){ 1550 sm_key_distribution_handle_all_received(connection); 1551 connection->sm_engine_state = SM_RESPONDER_IDLE; 1552 sm_done_for_handle(connection->sm_handle); 1553 } else { 1554 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1555 } 1556 } else { 1557 // master -> all done 1558 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1559 sm_done_for_handle(connection->sm_handle); 1560 } 1561 break; 1562 1563 default: 1564 break; 1565 } 1566 1567 // check again if active connection was released 1568 if (sm_active_connection) break; 1569 } 1570 } 1571 1572 // note: aes engine is ready as we just got the aes result 1573 static void sm_handle_encryption_result(uint8_t * data){ 1574 1575 sm_aes128_state = SM_AES128_IDLE; 1576 1577 if (sm_address_resolution_ah_calculation_active){ 1578 sm_address_resolution_ah_calculation_active = 0; 1579 // compare calulated address against connecting device 1580 uint8_t hash[3]; 1581 swap24(data, hash); 1582 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 1583 log_info("LE Device Lookup: matched resolvable private address"); 1584 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1585 return; 1586 } 1587 // no match, try next 1588 sm_address_resolution_test++; 1589 return; 1590 } 1591 1592 switch (dkg_state){ 1593 case DKG_W4_IRK: 1594 swap128(data, sm_persistent_irk); 1595 log_key("irk", sm_persistent_irk); 1596 dkg_next_state(); 1597 return; 1598 case DKG_W4_DHK: 1599 swap128(data, sm_persistent_dhk); 1600 log_key("dhk", sm_persistent_dhk); 1601 dkg_next_state(); 1602 1603 // SM INIT FINISHED, start application code - TODO untangle that 1604 if (sm_client_packet_handler) 1605 { 1606 uint8_t event[] = { BTSTACK_EVENT_STATE, 1, HCI_STATE_WORKING }; 1607 sm_client_packet_handler(HCI_EVENT_PACKET, 0, (uint8_t*) event, sizeof(event)); 1608 } 1609 return; 1610 default: 1611 break; 1612 } 1613 1614 switch (rau_state){ 1615 case RAU_W4_ENC: 1616 swap24(data, &sm_random_address[3]); 1617 rau_next_state(); 1618 return; 1619 default: 1620 break; 1621 } 1622 1623 switch (sm_cmac_state){ 1624 case CMAC_W4_SUBKEYS: 1625 case CMAC_W4_MI: 1626 case CMAC_W4_MLAST: 1627 { 1628 sm_key_t t; 1629 swap128(data, t); 1630 sm_cmac_handle_encryption_result(t); 1631 } 1632 return; 1633 default: 1634 break; 1635 } 1636 1637 // retrieve sm_connection provided to sm_aes128_start_encryption 1638 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 1639 if (!connection) return; 1640 switch (connection->sm_engine_state){ 1641 case SM_PH2_C1_W4_ENC_A: 1642 case SM_PH2_C1_W4_ENC_C: 1643 { 1644 sm_key_t t2; 1645 swap128(data, t2); 1646 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 1647 } 1648 sm_next_responding_state(connection); 1649 return; 1650 case SM_PH2_C1_W4_ENC_B: 1651 swap128(data, setup->sm_local_confirm); 1652 log_key("c1!", setup->sm_local_confirm); 1653 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 1654 return; 1655 case SM_PH2_C1_W4_ENC_D: 1656 { 1657 sm_key_t peer_confirm_test; 1658 swap128(data, peer_confirm_test); 1659 log_key("c1!", peer_confirm_test); 1660 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 1661 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 1662 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1663 return; 1664 } 1665 if (connection->sm_role){ 1666 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 1667 } else { 1668 connection->sm_engine_state = SM_PH2_CALC_STK; 1669 } 1670 } 1671 return; 1672 case SM_PH2_W4_STK: 1673 swap128(data, setup->sm_ltk); 1674 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 1675 log_key("stk", setup->sm_ltk); 1676 if (connection->sm_role){ 1677 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 1678 } else { 1679 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1680 } 1681 return; 1682 case SM_PH3_Y_W4_ENC:{ 1683 sm_key_t y128; 1684 swap128(data, y128); 1685 setup->sm_local_y = READ_NET_16(y128, 14); 1686 log_info_hex16("y", setup->sm_local_y); 1687 // PH3B3 - calculate EDIV 1688 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 1689 log_info_hex16("ediv", setup->sm_local_ediv); 1690 // PH3B4 - calculate LTK - enc 1691 // LTK = d1(ER, DIV, 0)) 1692 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 1693 return; 1694 } 1695 case SM_RESPONDER_PH4_Y_W4_ENC:{ 1696 sm_key_t y128; 1697 swap128(data, y128); 1698 setup->sm_local_y = READ_NET_16(y128, 14); 1699 log_info_hex16("y", setup->sm_local_y); 1700 1701 // PH3B3 - calculate DIV 1702 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 1703 log_info_hex16("ediv", setup->sm_local_ediv); 1704 // PH3B4 - calculate LTK - enc 1705 // LTK = d1(ER, DIV, 0)) 1706 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 1707 return; 1708 } 1709 case SM_PH3_LTK_W4_ENC: 1710 swap128(data, setup->sm_ltk); 1711 log_key("ltk", setup->sm_ltk); 1712 // calc CSRK next 1713 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 1714 return; 1715 case SM_PH3_CSRK_W4_ENC: 1716 swap128(data, setup->sm_local_csrk); 1717 log_key("csrk", setup->sm_local_csrk); 1718 if (setup->sm_key_distribution_send_set){ 1719 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 1720 } else { 1721 // no keys to send, just continue 1722 if (connection->sm_role){ 1723 // slave -> receive master keys 1724 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1725 } else { 1726 // master -> all done 1727 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1728 sm_done_for_handle(connection->sm_handle); 1729 } 1730 } 1731 return; 1732 case SM_RESPONDER_PH4_LTK_W4_ENC: 1733 swap128(data, setup->sm_ltk); 1734 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 1735 log_key("ltk", setup->sm_ltk); 1736 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 1737 return; 1738 default: 1739 break; 1740 } 1741 } 1742 1743 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 1744 static void sm_handle_random_result(uint8_t * data){ 1745 1746 switch (rau_state){ 1747 case RAU_W4_RANDOM: 1748 // non-resolvable vs. resolvable 1749 switch (gap_random_adress_type){ 1750 case GAP_RANDOM_ADDRESS_RESOLVABLE: 1751 // resolvable: use random as prand and calc address hash 1752 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 1753 memcpy(sm_random_address, data, 3); 1754 sm_random_address[0] &= 0x3f; 1755 sm_random_address[0] |= 0x40; 1756 rau_state = RAU_GET_ENC; 1757 break; 1758 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 1759 default: 1760 // "The two most significant bits of the address shall be equal to ‘0’"" 1761 memcpy(sm_random_address, data, 6); 1762 sm_random_address[0] &= 0x3f; 1763 rau_state = RAU_SET_ADDRESS; 1764 break; 1765 } 1766 return; 1767 default: 1768 break; 1769 } 1770 1771 // retrieve sm_connection provided to sm_random_start 1772 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 1773 if (!connection) return; 1774 switch (connection->sm_engine_state){ 1775 case SM_PH2_W4_RANDOM_TK: 1776 { 1777 // map random to 0-999999 without speding much cycles on a modulus operation 1778 uint32_t tk = READ_BT_32(data,0); 1779 tk = tk & 0xfffff; // 1048575 1780 if (tk >= 999999){ 1781 tk = tk - 999999; 1782 } 1783 sm_reset_tk(); 1784 net_store_32(setup->sm_tk, 12, tk); 1785 if (connection->sm_role){ 1786 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1787 } else { 1788 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 1789 sm_trigger_user_response(connection); 1790 // response_idle == nothing <--> sm_trigger_user_response() did not require response 1791 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 1792 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 1793 } 1794 } 1795 return; 1796 } 1797 case SM_PH2_C1_W4_RANDOM_A: 1798 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 1799 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 1800 return; 1801 case SM_PH2_C1_W4_RANDOM_B: 1802 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 1803 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 1804 return; 1805 case SM_PH3_W4_RANDOM: 1806 swap64(data, setup->sm_local_rand); 1807 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1808 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 1809 // no db for authenticated flag hack: store flag in bit 4 of LSB 1810 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 1811 connection->sm_engine_state = SM_PH3_GET_DIV; 1812 return; 1813 case SM_PH3_W4_DIV: 1814 // use 16 bit from random value as div 1815 setup->sm_local_div = READ_NET_16(data, 0); 1816 log_info_hex16("div", setup->sm_local_div); 1817 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 1818 return; 1819 default: 1820 break; 1821 } 1822 } 1823 1824 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 1825 1826 sm_connection_t * sm_conn; 1827 uint16_t handle; 1828 1829 switch (packet_type) { 1830 1831 case HCI_EVENT_PACKET: 1832 switch (packet[0]) { 1833 1834 case BTSTACK_EVENT_STATE: 1835 // bt stack activated, get started 1836 if (packet[2] == HCI_STATE_WORKING) { 1837 log_info("HCI Working!"); 1838 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 1839 rau_state = RAU_IDLE; 1840 1841 sm_run(); 1842 return; // don't notify app packet handler just yet 1843 } 1844 break; 1845 1846 case HCI_EVENT_LE_META: 1847 switch (packet[2]) { 1848 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 1849 1850 log_info("sm: connected"); 1851 1852 if (packet[3]) return; // connection failed 1853 1854 handle = READ_BT_16(packet, 4); 1855 sm_conn = sm_get_connection_for_handle(handle); 1856 if (!sm_conn) break; 1857 1858 sm_conn->sm_handle = handle; 1859 sm_conn->sm_role = packet[6]; 1860 sm_conn->sm_peer_addr_type = packet[7]; 1861 bt_flip_addr(sm_conn->sm_peer_address, &packet[8]); 1862 1863 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 1864 1865 // reset security properties 1866 sm_conn->sm_connection_encrypted = 0; 1867 sm_conn->sm_connection_authenticated = 0; 1868 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 1869 sm_conn->sm_le_db_index = -1; 1870 1871 // prepare CSRK lookup (does not involve setup) 1872 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 1873 1874 // just connected -> everything else happens in sm_run() 1875 if (sm_conn->sm_role){ 1876 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 1877 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 1878 if (sm_slave_request_security) { 1879 // request security if requested by app 1880 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1881 } else { 1882 // otherwise, wait for pairing request 1883 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1884 } 1885 } 1886 break; 1887 } else { 1888 // master 1889 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1890 } 1891 break; 1892 1893 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 1894 handle = READ_BT_16(packet, 3); 1895 sm_conn = sm_get_connection_for_handle(handle); 1896 if (!sm_conn) break; 1897 1898 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 1899 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 1900 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 1901 break; 1902 } 1903 1904 // assume that we don't have a LTK for ediv == 0 and random == null 1905 if (READ_BT_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 1906 log_info("LTK Request: ediv & random are empty"); 1907 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1908 break; 1909 } 1910 1911 // store rand and ediv 1912 swap64(&packet[5], sm_conn->sm_local_rand); 1913 sm_conn->sm_local_ediv = READ_BT_16(packet, 13); 1914 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 1915 break; 1916 1917 default: 1918 break; 1919 } 1920 break; 1921 1922 case HCI_EVENT_ENCRYPTION_CHANGE: 1923 handle = READ_BT_16(packet, 3); 1924 sm_conn = sm_get_connection_for_handle(handle); 1925 if (!sm_conn) break; 1926 1927 sm_conn->sm_connection_encrypted = packet[5]; 1928 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 1929 sm_conn->sm_actual_encryption_key_size); 1930 log_info("event handler, state %u", sm_conn->sm_engine_state); 1931 if (!sm_conn->sm_connection_encrypted) break; 1932 // continue if part of initial pairing 1933 switch (sm_conn->sm_engine_state){ 1934 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 1935 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1936 sm_done_for_handle(sm_conn->sm_handle); 1937 break; 1938 case SM_PH2_W4_CONNECTION_ENCRYPTED: 1939 if (sm_conn->sm_role){ 1940 // slave 1941 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1942 } else { 1943 // master 1944 if (sm_key_distribution_all_received(sm_conn)){ 1945 // skip receiving keys as there are none 1946 sm_key_distribution_handle_all_received(sm_conn); 1947 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1948 } else { 1949 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1950 } 1951 } 1952 break; 1953 default: 1954 break; 1955 } 1956 break; 1957 1958 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 1959 handle = READ_BT_16(packet, 3); 1960 sm_conn = sm_get_connection_for_handle(handle); 1961 if (!sm_conn) break; 1962 1963 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 1964 log_info("event handler, state %u", sm_conn->sm_engine_state); 1965 // continue if part of initial pairing 1966 switch (sm_conn->sm_engine_state){ 1967 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 1968 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1969 sm_done_for_handle(sm_conn->sm_handle); 1970 break; 1971 case SM_PH2_W4_CONNECTION_ENCRYPTED: 1972 if (sm_conn->sm_role){ 1973 // slave 1974 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1975 } else { 1976 // master 1977 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1978 } 1979 break; 1980 default: 1981 break; 1982 } 1983 break; 1984 1985 1986 case HCI_EVENT_DISCONNECTION_COMPLETE: 1987 handle = READ_BT_16(packet, 3); 1988 sm_done_for_handle(handle); 1989 sm_conn = sm_get_connection_for_handle(handle); 1990 if (!sm_conn) break; 1991 1992 // delete stored bonding on disconnect with authentication failure in ph0 1993 if (sm_conn->sm_role == 0 1994 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 1995 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 1996 le_device_db_remove(sm_conn->sm_le_db_index); 1997 } 1998 1999 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2000 sm_conn->sm_handle = 0; 2001 break; 2002 2003 case HCI_EVENT_COMMAND_COMPLETE: 2004 if (COMMAND_COMPLETE_EVENT(packet, hci_le_encrypt)){ 2005 sm_handle_encryption_result(&packet[6]); 2006 break; 2007 } 2008 if (COMMAND_COMPLETE_EVENT(packet, hci_le_rand)){ 2009 sm_handle_random_result(&packet[6]); 2010 break; 2011 } 2012 } 2013 2014 // forward packet to higher layer 2015 if (sm_client_packet_handler){ 2016 sm_client_packet_handler(packet_type, 0, packet, size); 2017 } 2018 } 2019 2020 sm_run(); 2021 } 2022 2023 static inline int sm_calc_actual_encryption_key_size(int other){ 2024 if (other < sm_min_encryption_key_size) return 0; 2025 if (other < sm_max_encryption_key_size) return other; 2026 return sm_max_encryption_key_size; 2027 } 2028 2029 /** 2030 * @return ok 2031 */ 2032 static int sm_validate_stk_generation_method(void){ 2033 // check if STK generation method is acceptable by client 2034 switch (setup->sm_stk_generation_method){ 2035 case JUST_WORKS: 2036 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2037 case PK_RESP_INPUT: 2038 case PK_INIT_INPUT: 2039 case OK_BOTH_INPUT: 2040 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2041 case OOB: 2042 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2043 default: 2044 return 0; 2045 } 2046 } 2047 2048 // helper for sm_packet_handler, calls sm_run on exit 2049 static void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 2050 setup->sm_pairing_failed_reason = SM_REASON_UNSPECIFIED_REASON; 2051 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2052 sm_done_for_handle(sm_conn->sm_handle); 2053 } 2054 2055 static void sm_packet_handler(uint8_t packet_type, uint16_t handle, uint8_t *packet, uint16_t size){ 2056 2057 if (packet_type == HCI_EVENT_PACKET) { 2058 sm_event_packet_handler(packet_type, handle, packet, size); 2059 return; 2060 } 2061 2062 if (packet_type != SM_DATA_PACKET) return; 2063 2064 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2065 if (!sm_conn) return; 2066 2067 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2068 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2069 return; 2070 } 2071 2072 log_debug("sm_packet_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2073 2074 int err; 2075 2076 switch (sm_conn->sm_engine_state){ 2077 2078 // a sm timeout requries a new physical connection 2079 case SM_GENERAL_TIMEOUT: 2080 return; 2081 2082 // Initiator 2083 case SM_INITIATOR_CONNECTED: 2084 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2085 sm_pdu_received_in_wrong_state(sm_conn); 2086 break; 2087 } 2088 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2089 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2090 break; 2091 } 2092 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2093 uint16_t ediv; 2094 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2095 if (ediv){ 2096 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2097 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2098 } else { 2099 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2100 } 2101 break; 2102 } 2103 // otherwise, store security request 2104 sm_conn->sm_security_request_received = 1; 2105 break; 2106 2107 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2108 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2109 sm_pdu_received_in_wrong_state(sm_conn); 2110 break; 2111 } 2112 // store pairing request 2113 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2114 err = sm_stk_generation_init(sm_conn); 2115 if (err){ 2116 setup->sm_pairing_failed_reason = err; 2117 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2118 break; 2119 } 2120 // generate random number first, if we need to show passkey 2121 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2122 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2123 break; 2124 } 2125 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2126 sm_trigger_user_response(sm_conn); 2127 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2128 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2129 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2130 } 2131 break; 2132 2133 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2134 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2135 sm_pdu_received_in_wrong_state(sm_conn); 2136 break; 2137 } 2138 2139 // store s_confirm 2140 swap128(&packet[1], setup->sm_peer_confirm); 2141 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2142 break; 2143 2144 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2145 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2146 sm_pdu_received_in_wrong_state(sm_conn); 2147 break;; 2148 } 2149 2150 // received random value 2151 swap128(&packet[1], setup->sm_peer_random); 2152 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2153 break; 2154 2155 // Responder 2156 case SM_RESPONDER_IDLE: 2157 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2158 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2159 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2160 sm_pdu_received_in_wrong_state(sm_conn); 2161 break;; 2162 } 2163 2164 // store pairing request 2165 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2166 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2167 break; 2168 2169 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 2170 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2171 sm_pdu_received_in_wrong_state(sm_conn); 2172 break;; 2173 } 2174 2175 // received confirm value 2176 swap128(&packet[1], setup->sm_peer_confirm); 2177 2178 // notify client to hide shown passkey 2179 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2180 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 2181 } 2182 2183 // handle user cancel pairing? 2184 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 2185 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2186 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2187 break; 2188 } 2189 2190 // wait for user action? 2191 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 2192 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2193 break; 2194 } 2195 2196 // calculate and send local_confirm 2197 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2198 break; 2199 2200 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 2201 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2202 sm_pdu_received_in_wrong_state(sm_conn); 2203 break;; 2204 } 2205 2206 // received random value 2207 swap128(&packet[1], setup->sm_peer_random); 2208 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2209 break; 2210 2211 case SM_PH3_RECEIVE_KEYS: 2212 switch(packet[0]){ 2213 case SM_CODE_ENCRYPTION_INFORMATION: 2214 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2215 swap128(&packet[1], setup->sm_peer_ltk); 2216 break; 2217 2218 case SM_CODE_MASTER_IDENTIFICATION: 2219 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2220 setup->sm_peer_ediv = READ_BT_16(packet, 1); 2221 swap64(&packet[3], setup->sm_peer_rand); 2222 break; 2223 2224 case SM_CODE_IDENTITY_INFORMATION: 2225 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2226 swap128(&packet[1], setup->sm_peer_irk); 2227 break; 2228 2229 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 2230 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2231 setup->sm_peer_addr_type = packet[1]; 2232 bt_flip_addr(setup->sm_peer_address, &packet[2]); 2233 break; 2234 2235 case SM_CODE_SIGNING_INFORMATION: 2236 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2237 swap128(&packet[1], setup->sm_peer_csrk); 2238 break; 2239 default: 2240 // Unexpected PDU 2241 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 2242 break; 2243 } 2244 // done with key distribution? 2245 if (sm_key_distribution_all_received(sm_conn)){ 2246 2247 sm_key_distribution_handle_all_received(sm_conn); 2248 2249 if (sm_conn->sm_role){ 2250 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2251 sm_done_for_handle(sm_conn->sm_handle); 2252 } else { 2253 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2254 } 2255 } 2256 break; 2257 default: 2258 // Unexpected PDU 2259 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 2260 break; 2261 } 2262 2263 // try to send preparared packet 2264 sm_run(); 2265 } 2266 2267 // Security Manager Client API 2268 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 2269 sm_get_oob_data = get_oob_data_callback; 2270 } 2271 2272 void sm_register_packet_handler(btstack_packet_handler_t handler){ 2273 sm_client_packet_handler = handler; 2274 } 2275 2276 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 2277 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 2278 } 2279 2280 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 2281 sm_min_encryption_key_size = min_size; 2282 sm_max_encryption_key_size = max_size; 2283 } 2284 2285 void sm_set_authentication_requirements(uint8_t auth_req){ 2286 sm_auth_req = auth_req; 2287 } 2288 2289 void sm_set_io_capabilities(io_capability_t io_capability){ 2290 sm_io_capabilities = io_capability; 2291 } 2292 2293 void sm_set_request_security(int enable){ 2294 sm_slave_request_security = enable; 2295 } 2296 2297 void sm_set_er(sm_key_t er){ 2298 memcpy(sm_persistent_er, er, 16); 2299 } 2300 2301 void sm_set_ir(sm_key_t ir){ 2302 memcpy(sm_persistent_ir, ir, 16); 2303 } 2304 2305 // Testing support only 2306 void sm_test_set_irk(sm_key_t irk){ 2307 memcpy(sm_persistent_irk, irk, 16); 2308 sm_persistent_irk_ready = 1; 2309 } 2310 2311 void sm_test_use_fixed_local_csrk(void){ 2312 test_use_fixed_local_csrk = 1; 2313 } 2314 2315 void sm_init(void){ 2316 // set some (BTstack default) ER and IR 2317 int i; 2318 sm_key_t er; 2319 sm_key_t ir; 2320 for (i=0;i<16;i++){ 2321 er[i] = 0x30 + i; 2322 ir[i] = 0x90 + i; 2323 } 2324 sm_set_er(er); 2325 sm_set_ir(ir); 2326 // defaults 2327 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 2328 | SM_STK_GENERATION_METHOD_OOB 2329 | SM_STK_GENERATION_METHOD_PASSKEY; 2330 sm_max_encryption_key_size = 16; 2331 sm_min_encryption_key_size = 7; 2332 2333 sm_cmac_state = CMAC_IDLE; 2334 dkg_state = DKG_W4_WORKING; 2335 rau_state = RAU_W4_WORKING; 2336 sm_aes128_state = SM_AES128_IDLE; 2337 sm_address_resolution_test = -1; // no private address to resolve yet 2338 sm_address_resolution_ah_calculation_active = 0; 2339 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 2340 sm_address_resolution_general_queue = NULL; 2341 2342 gap_random_adress_update_period = 15 * 60 * 1000L; 2343 2344 sm_active_connection = 0; 2345 2346 test_use_fixed_local_csrk = 0; 2347 2348 // attach to lower layers 2349 l2cap_register_fixed_channel(sm_packet_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2350 } 2351 2352 static sm_connection_t * sm_get_connection_for_handle(uint16_t con_handle){ 2353 hci_connection_t * hci_con = hci_connection_for_handle((hci_con_handle_t) con_handle); 2354 if (!hci_con) return NULL; 2355 return &hci_con->sm_connection; 2356 } 2357 2358 // @returns 0 if not encrypted, 7-16 otherwise 2359 int sm_encryption_key_size(uint16_t handle){ 2360 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2361 if (!sm_conn) return 0; // wrong connection 2362 if (!sm_conn->sm_connection_encrypted) return 0; 2363 return sm_conn->sm_actual_encryption_key_size; 2364 } 2365 2366 int sm_authenticated(uint16_t handle){ 2367 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2368 if (!sm_conn) return 0; // wrong connection 2369 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 2370 return sm_conn->sm_connection_authenticated; 2371 } 2372 2373 authorization_state_t sm_authorization_state(uint16_t handle){ 2374 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2375 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 2376 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 2377 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 2378 return sm_conn->sm_connection_authorization_state; 2379 } 2380 2381 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 2382 switch (sm_conn->sm_engine_state){ 2383 case SM_GENERAL_IDLE: 2384 case SM_RESPONDER_IDLE: 2385 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2386 sm_run(); 2387 break; 2388 default: 2389 break; 2390 } 2391 } 2392 2393 /** 2394 * @brief Trigger Security Request 2395 */ 2396 void sm_send_security_request(uint16_t handle){ 2397 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2398 if (!sm_conn) return; 2399 sm_send_security_request_for_connection(sm_conn); 2400 } 2401 2402 // request pairing 2403 void sm_request_pairing(uint16_t handle){ 2404 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2405 if (!sm_conn) return; // wrong connection 2406 2407 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 2408 if (sm_conn->sm_role){ 2409 sm_send_security_request_for_connection(sm_conn); 2410 } else { 2411 // used as a trigger to start central/master/initiator security procedures 2412 uint16_t ediv; 2413 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 2414 switch (sm_conn->sm_irk_lookup_state){ 2415 case IRK_LOOKUP_FAILED: 2416 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2417 break; 2418 case IRK_LOOKUP_SUCCEEDED: 2419 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2420 if (ediv){ 2421 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2422 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2423 } else { 2424 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2425 } 2426 break; 2427 default: 2428 sm_conn->sm_bonding_requested = 1; 2429 break; 2430 } 2431 } 2432 } 2433 sm_run(); 2434 } 2435 2436 // called by client app on authorization request 2437 void sm_authorization_decline(uint16_t handle){ 2438 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2439 if (!sm_conn) return; // wrong connection 2440 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 2441 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 2442 } 2443 2444 void sm_authorization_grant(uint16_t handle){ 2445 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2446 if (!sm_conn) return; // wrong connection 2447 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 2448 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 2449 } 2450 2451 // GAP Bonding API 2452 2453 void sm_bonding_decline(uint16_t handle){ 2454 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2455 if (!sm_conn) return; // wrong connection 2456 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 2457 2458 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2459 sm_done_for_handle(sm_conn->sm_handle); 2460 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2461 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2462 } 2463 sm_run(); 2464 } 2465 2466 void sm_just_works_confirm(uint16_t handle){ 2467 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2468 if (!sm_conn) return; // wrong connection 2469 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 2470 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2471 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2472 } 2473 sm_run(); 2474 } 2475 2476 void sm_passkey_input(uint16_t handle, uint32_t passkey){ 2477 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2478 if (!sm_conn) return; // wrong connection 2479 sm_reset_tk(); 2480 net_store_32(setup->sm_tk, 12, passkey); 2481 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 2482 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2483 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2484 } 2485 sm_run(); 2486 } 2487 2488 /** 2489 * @brief Identify device in LE Device DB 2490 * @param handle 2491 * @returns index from le_device_db or -1 if not found/identified 2492 */ 2493 int sm_le_device_index(uint16_t handle ){ 2494 sm_connection_t * sm_conn = sm_get_connection_for_handle(handle); 2495 if (!sm_conn) return -1; 2496 return sm_conn->sm_le_db_index; 2497 } 2498 2499 // GAP LE API 2500 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 2501 gap_random_address_update_stop(); 2502 gap_random_adress_type = random_address_type; 2503 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 2504 gap_random_address_update_start(); 2505 gap_random_address_trigger(); 2506 } 2507 2508 gap_random_address_type_t gap_random_address_get_mode(void){ 2509 return gap_random_adress_type; 2510 } 2511 2512 void gap_random_address_set_update_period(int period_ms){ 2513 gap_random_adress_update_period = period_ms; 2514 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 2515 gap_random_address_update_stop(); 2516 gap_random_address_update_start(); 2517 } 2518 2519 void gap_random_address_set(bd_addr_t addr){ 2520 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 2521 memcpy(sm_random_address, addr, 6); 2522 rau_state = RAU_SET_ADDRESS; 2523 sm_run(); 2524 } 2525 2526 /* 2527 * @brief Set Advertisement Paramters 2528 * @param adv_int_min 2529 * @param adv_int_max 2530 * @param adv_type 2531 * @param direct_address_type 2532 * @param direct_address 2533 * @param channel_map 2534 * @param filter_policy 2535 * 2536 * @note own_address_type is used from gap_random_address_set_mode 2537 */ 2538 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 2539 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 2540 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 2541 direct_address_typ, direct_address, channel_map, filter_policy); 2542 } 2543 2544