/* * Copyright (C) 2014 BlueKitchen GmbH * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the copyright holders nor the names of * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * 4. Any redistribution, use, or modification is done solely for * personal benefit and not for any commercial purpose or for * monetary gain. * * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BLUEKITCHEN * GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * Please inquire about commercial licensing options at * contact@bluekitchen-gmbh.com * */ #define BTSTACK_FILE__ "sm.c" #include #include #include "ble/le_device_db.h" #include "ble/core.h" #include "ble/sm.h" #include "bluetooth_company_id.h" #include "btstack_bool.h" #include "btstack_crypto.h" #include "btstack_debug.h" #include "btstack_event.h" #include "btstack_linked_list.h" #include "btstack_memory.h" #include "btstack_tlv.h" #include "gap.h" #include "hci.h" #include "hci_dump.h" #include "l2cap.h" #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." #endif #if defined(ENABLE_CROSS_TRANSPORT_KEY_DERIVATION) && (!defined(ENABLE_CLASSIC) || !defined(ENABLE_LE_SECURE_CONNECTIONS)) #error "Cross Transport Key Derivation requires support for LE Secure Connections and BR/EDR (Classic)" #endif // assert SM Public Key can be sent/received #ifdef ENABLE_LE_SECURE_CONNECTIONS #if HCI_ACL_PAYLOAD_SIZE < 69 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" #endif #endif #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) #define IS_RESPONDER(role) ((role) == HCI_ROLE_SLAVE) #else #ifdef ENABLE_LE_CENTRAL // only central - never responder (avoid 'unused variable' warnings) #define IS_RESPONDER(role) (0 && ((role) == HCI_ROLE_SLAVE)) #else // only peripheral - always responder (avoid 'unused variable' warnings) #define IS_RESPONDER(role) (1 || ((role) == HCI_ROLE_SLAVE)) #endif #endif #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) #define USE_CMAC_ENGINE #endif #define BTSTACK_TAG32(A,B,C,D) (((A) << 24) | ((B) << 16) | ((C) << 8) | (D)) // // SM internal types and globals // typedef enum { DKG_W4_WORKING, DKG_CALC_IRK, DKG_CALC_DHK, DKG_READY } derived_key_generation_t; typedef enum { RAU_IDLE, RAU_GET_RANDOM, RAU_W4_RANDOM, RAU_GET_ENC, RAU_W4_ENC, } random_address_update_t; typedef enum { CMAC_IDLE, CMAC_CALC_SUBKEYS, CMAC_W4_SUBKEYS, CMAC_CALC_MI, CMAC_W4_MI, CMAC_CALC_MLAST, CMAC_W4_MLAST } cmac_state_t; typedef enum { JUST_WORKS, PK_RESP_INPUT, // Initiator displays PK, responder inputs PK PK_INIT_INPUT, // Responder displays PK, initiator inputs PK PK_BOTH_INPUT, // Only input on both, both input PK NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides OOB // OOB available on one (SC) or both sides (legacy) } stk_generation_method_t; typedef enum { SM_USER_RESPONSE_IDLE, SM_USER_RESPONSE_PENDING, SM_USER_RESPONSE_CONFIRM, SM_USER_RESPONSE_PASSKEY, SM_USER_RESPONSE_DECLINE } sm_user_response_t; typedef enum { SM_AES128_IDLE, SM_AES128_ACTIVE } sm_aes128_state_t; typedef enum { ADDRESS_RESOLUTION_IDLE, ADDRESS_RESOLUTION_GENERAL, ADDRESS_RESOLUTION_FOR_CONNECTION, } address_resolution_mode_t; typedef enum { ADDRESS_RESOLUTION_SUCCEEDED, ADDRESS_RESOLUTION_FAILED, } address_resolution_event_t; typedef enum { EC_KEY_GENERATION_IDLE, EC_KEY_GENERATION_ACTIVE, EC_KEY_GENERATION_DONE, } ec_key_generation_state_t; typedef enum { SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, } sm_state_var_t; typedef enum { SM_SC_OOB_IDLE, SM_SC_OOB_W4_RANDOM, SM_SC_OOB_W2_CALC_CONFIRM, SM_SC_OOB_W4_CONFIRM, } sm_sc_oob_state_t; typedef uint8_t sm_key24_t[3]; typedef uint8_t sm_key56_t[7]; typedef uint8_t sm_key256_t[32]; // // GLOBAL DATA // static bool sm_initialized; static bool test_use_fixed_local_csrk; static bool test_use_fixed_local_irk; #ifdef ENABLE_TESTING_SUPPORT static uint8_t test_pairing_failure; #endif // configuration static uint8_t sm_accepted_stk_generation_methods; static uint8_t sm_max_encryption_key_size; static uint8_t sm_min_encryption_key_size; static uint8_t sm_auth_req = 0; static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; static uint32_t sm_fixed_passkey_in_display_role; static bool sm_reconstruct_ltk_without_le_device_db_entry; #ifdef ENABLE_LE_PERIPHERAL static bool sm_slave_request_security; #endif #ifdef ENABLE_LE_SECURE_CONNECTIONS static bool sm_sc_only_mode; static uint8_t sm_sc_oob_random[16]; static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); static sm_sc_oob_state_t sm_sc_oob_state; #ifdef ENABLE_LE_SECURE_CONNECTIONS_DEBUG_KEY static bool sm_sc_debug_keys_enabled; #endif #endif static bool sm_persistent_keys_random_active; static const btstack_tlv_t * sm_tlv_impl; static void * sm_tlv_context; // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values static sm_key_t sm_persistent_er; static sm_key_t sm_persistent_ir; // derived from sm_persistent_ir static sm_key_t sm_persistent_dhk; static sm_key_t sm_persistent_irk; static derived_key_generation_t dkg_state; // derived from sm_persistent_er // .. // random address update static random_address_update_t rau_state; static bd_addr_t sm_random_address; #ifdef USE_CMAC_ENGINE // CMAC Calculation: General static btstack_crypto_aes128_cmac_t sm_cmac_request; static void (*sm_cmac_done_callback)(uint8_t hash[8]); static uint8_t sm_cmac_active; static uint8_t sm_cmac_hash[16]; #endif // CMAC for ATT Signed Writes #ifdef ENABLE_LE_SIGNED_WRITE static uint16_t sm_cmac_signed_write_message_len; static uint8_t sm_cmac_signed_write_header[3]; static const uint8_t * sm_cmac_signed_write_message; static uint8_t sm_cmac_signed_write_sign_counter[4]; #endif // CMAC for Secure Connection functions #ifdef ENABLE_LE_SECURE_CONNECTIONS static sm_connection_t * sm_cmac_connection; static uint8_t sm_cmac_sc_buffer[80]; #endif // resolvable private address lookup / CSRK calculation static int sm_address_resolution_test; static uint8_t sm_address_resolution_addr_type; static bd_addr_t sm_address_resolution_address; static void * sm_address_resolution_context; static address_resolution_mode_t sm_address_resolution_mode; static btstack_linked_list_t sm_address_resolution_general_queue; // aes128 crypto engine. static sm_aes128_state_t sm_aes128_state; // crypto static btstack_crypto_random_t sm_crypto_random_request; static btstack_crypto_aes128_t sm_crypto_aes128_request; #ifdef ENABLE_LE_SECURE_CONNECTIONS static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; #endif // temp storage for random data static uint8_t sm_random_data[8]; static uint8_t sm_aes128_key[16]; static uint8_t sm_aes128_plaintext[16]; static uint8_t sm_aes128_ciphertext[16]; // to receive events static btstack_packet_callback_registration_t hci_event_callback_registration; #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION static btstack_packet_callback_registration_t l2cap_event_callback_registration; #endif /* to dispatch sm event */ static btstack_linked_list_t sm_event_handlers; /* to schedule calls to sm_run */ static btstack_timer_source_t sm_run_timer; // LE Secure Connections #ifdef ENABLE_LE_SECURE_CONNECTIONS static ec_key_generation_state_t ec_key_generation_state; static uint8_t ec_q[64]; #endif // // Volume 3, Part H, Chapter 24 // "Security shall be initiated by the Security Manager in the device in the master role. // The device in the slave role shall be the responding device." // -> master := initiator, slave := responder // // data needed for security setup typedef struct sm_setup_context { btstack_timer_source_t sm_timeout; // user response, (Phase 1 and/or 2) uint8_t sm_user_response; uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 uint8_t sm_key_distribution_send_set; uint8_t sm_key_distribution_sent_set; uint8_t sm_key_distribution_expected_set; uint8_t sm_key_distribution_received_set; // Phase 2 (Pairing over SMP) stk_generation_method_t sm_stk_generation_method; sm_key_t sm_tk; uint8_t sm_have_oob_data; bool sm_use_secure_connections; sm_key_t sm_c1_t3_value; // c1 calculation sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 sm_key_t sm_local_random; sm_key_t sm_local_confirm; sm_key_t sm_peer_random; sm_key_t sm_peer_confirm; uint8_t sm_m_addr_type; // address and type can be removed uint8_t sm_s_addr_type; // '' bd_addr_t sm_m_address; // '' bd_addr_t sm_s_address; // '' sm_key_t sm_ltk; uint8_t sm_state_vars; #ifdef ENABLE_LE_SECURE_CONNECTIONS uint8_t sm_peer_q[64]; // also stores random for EC key generation during init sm_key_t sm_peer_nonce; // might be combined with sm_peer_random sm_key_t sm_local_nonce; // might be combined with sm_local_random uint8_t sm_dhkey[32]; sm_key_t sm_peer_dhkey_check; sm_key_t sm_local_dhkey_check; sm_key_t sm_ra; sm_key_t sm_rb; sm_key_t sm_t; // used for f5 and h6 sm_key_t sm_mackey; uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation #endif // Phase 3 // key distribution, we generate uint16_t sm_local_y; uint16_t sm_local_div; uint16_t sm_local_ediv; uint8_t sm_local_rand[8]; sm_key_t sm_local_ltk; sm_key_t sm_local_csrk; sm_key_t sm_local_irk; // sm_local_address/addr_type not needed // key distribution, received from peer uint16_t sm_peer_y; uint16_t sm_peer_div; uint16_t sm_peer_ediv; uint8_t sm_peer_rand[8]; sm_key_t sm_peer_ltk; sm_key_t sm_peer_irk; sm_key_t sm_peer_csrk; uint8_t sm_peer_addr_type; bd_addr_t sm_peer_address; #ifdef ENABLE_LE_SIGNED_WRITE int sm_le_device_index; #endif #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION link_key_t sm_link_key; link_key_type_t sm_link_key_type; #endif } sm_setup_context_t; // static sm_setup_context_t the_setup; static sm_setup_context_t * setup = &the_setup; // active connection - the one for which the_setup is used for static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; // @return 1 if oob data is available // stores oob data in provided 16 byte buffer if not null static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; static int (*sm_get_sc_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random); static bool (*sm_get_ltk_callback)(hci_con_handle_t con_handle, uint8_t addres_type, bd_addr_t addr, uint8_t * ltk); static void sm_run(void); static void sm_state_reset(void); static void sm_done_for_handle(hci_con_handle_t con_handle); static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); static void sm_cache_ltk(sm_connection_t * connection, const sm_key_t ltk); #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type); #endif static inline int sm_calc_actual_encryption_key_size(int other); static int sm_validate_stk_generation_method(void); static void sm_handle_encryption_result_address_resolution(void *arg); static void sm_handle_encryption_result_dkg_dhk(void *arg); static void sm_handle_encryption_result_dkg_irk(void *arg); static void sm_handle_encryption_result_enc_a(void *arg); static void sm_handle_encryption_result_enc_b(void *arg); static void sm_handle_encryption_result_enc_c(void *arg); static void sm_handle_encryption_result_enc_csrk(void *arg); static void sm_handle_encryption_result_enc_d(void * arg); static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); static void sm_handle_encryption_result_enc_ph3_y(void *arg); #ifdef ENABLE_LE_PERIPHERAL static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); static void sm_handle_encryption_result_enc_ph4_y(void *arg); #endif static void sm_handle_encryption_result_enc_stk(void *arg); static void sm_handle_encryption_result_rau(void *arg); static void sm_handle_random_result_ph2_tk(void * arg); static void sm_handle_random_result_rau(void * arg); #ifdef ENABLE_LE_SECURE_CONNECTIONS static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)); static void sm_ec_generate_new_key(void); static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); static bool sm_passkey_entry(stk_generation_method_t method); #endif static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); static void log_info_hex16(const char * name, uint16_t value){ UNUSED(name); UNUSED(value); log_info("%-6s 0x%04x", name, value); } // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ // return packet[0]; // } static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ return packet[1]; } static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ return packet[2]; } static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ return packet[3]; } static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ return packet[4]; } static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ return packet[5]; } static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ return packet[6]; } static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ packet[0] = code; } static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ packet[1] = io_capability; } static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ packet[2] = oob_data_flag; } static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ packet[3] = auth_req; } static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ packet[4] = max_encryption_key_size; } static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ packet[5] = initiator_key_distribution; } static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ packet[6] = responder_key_distribution; } static bool sm_is_null_random(uint8_t random[8]){ return btstack_is_null(random, 8); } static bool sm_is_null_key(uint8_t * key){ return btstack_is_null(key, 16); } #ifdef ENABLE_LE_SECURE_CONNECTIONS static bool sm_is_ff(const uint8_t * buffer, uint16_t size){ uint16_t i; for (i=0; i < size ; i++){ if (buffer[i] != 0xff) { return false; } } return true; } #endif // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth static void sm_run_timer_handler(btstack_timer_source_t * ts){ UNUSED(ts); sm_run(); } static void sm_trigger_run(void){ if (!sm_initialized) return; (void)btstack_run_loop_remove_timer(&sm_run_timer); btstack_run_loop_set_timer(&sm_run_timer, 0); btstack_run_loop_add_timer(&sm_run_timer); } // Key utils static void sm_reset_tk(void){ int i; for (i=0;i<16;i++){ setup->sm_tk[i] = 0; } } // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" static void sm_truncate_key(sm_key_t key, int max_encryption_size){ int i; for (i = max_encryption_size ; i < 16 ; i++){ key[15-i] = 0; } } // ER / IR checks static void sm_er_ir_set_default(void){ int i; for (i=0;i<16;i++){ sm_persistent_er[i] = 0x30 + i; sm_persistent_ir[i] = 0x90 + i; } } static bool sm_er_is_default(void){ int i; for (i=0;i<16;i++){ if (sm_persistent_er[i] != (0x30+i)) return true; } return false; } static bool sm_ir_is_default(void){ int i; for (i=0;i<16;i++){ if (sm_persistent_ir[i] != (0x90+i)) return true; } return false; } static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ UNUSED(channel); // log event hci_dump_btstack_event(packet, size); // dispatch to all event handlers btstack_linked_list_iterator_t it; btstack_linked_list_iterator_init(&it, &sm_event_handlers); while (btstack_linked_list_iterator_has_next(&it)){ btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); entry->callback(packet_type, 0, packet, size); } } 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){ event[0] = type; event[1] = event_size - 2; little_endian_store_16(event, 2, con_handle); event[4] = addr_type; reverse_bd_addr(address, &event[5]); } static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ uint8_t event[11]; sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); } 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){ // fetch addr and addr type from db, only called for valid entries bd_addr_t identity_address; int identity_address_type; le_device_db_info(index, &identity_address_type, identity_address, NULL); uint8_t event[20]; sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); event[11] = identity_address_type; reverse_bd_addr(identity_address, &event[12]); little_endian_store_16(event, 18, index); sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); } static void sm_notify_client_status(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t status){ uint8_t event[12]; sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); event[11] = status; sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); } static void sm_reencryption_started(sm_connection_t * sm_conn){ if (sm_conn->sm_reencryption_active) return; sm_conn->sm_reencryption_active = true; int identity_addr_type; bd_addr_t identity_addr; if (sm_conn->sm_le_db_index >= 0){ // fetch addr and addr type from db, only called for valid entries le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); } else { // for legacy pairing with LTK re-construction, use current peer addr identity_addr_type = sm_conn->sm_peer_addr_type; // cppcheck-suppress uninitvar ; identity_addr is reported as uninitialized although it's the destination of the memcpy memcpy(identity_addr, sm_conn->sm_peer_address, 6); } sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); } static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ if (!sm_conn->sm_reencryption_active) return; sm_conn->sm_reencryption_active = false; int identity_addr_type; bd_addr_t identity_addr; if (sm_conn->sm_le_db_index >= 0){ // fetch addr and addr type from db, only called for valid entries le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); } else { // for legacy pairing with LTK re-construction, use current peer addr identity_addr_type = sm_conn->sm_peer_addr_type; // cppcheck-suppress uninitvar ; identity_addr is reported as uninitialized although it's the destination of the memcpy memcpy(identity_addr, sm_conn->sm_peer_address, 6); } sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); } static void sm_pairing_started(sm_connection_t * sm_conn){ if (sm_conn->sm_pairing_active) return; sm_conn->sm_pairing_active = true; uint8_t event[11]; sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_STARTED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); } static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ if (!sm_conn->sm_pairing_active) return; sm_conn->sm_pairing_active = false; uint8_t event[13]; sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); event[11] = status; event[12] = reason; sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); } // SMP Timeout implementation // Upon transmission of the Pairing Request command or reception of the Pairing Request command, // the Security Manager Timer shall be reset and started. // // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. // // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been // established. static void sm_timeout_handler(btstack_timer_source_t * timer){ log_info("SM timeout"); sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; sm_reencryption_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT); sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); sm_done_for_handle(sm_conn->sm_handle); // trigger handling of next ready connection sm_run(); } static void sm_timeout_start(sm_connection_t * sm_conn){ btstack_run_loop_remove_timer(&setup->sm_timeout); btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout btstack_run_loop_add_timer(&setup->sm_timeout); } static void sm_timeout_stop(void){ btstack_run_loop_remove_timer(&setup->sm_timeout); } static void sm_timeout_reset(sm_connection_t * sm_conn){ sm_timeout_stop(); sm_timeout_start(sm_conn); } // end of sm timeout // GAP Random Address updates static gap_random_address_type_t gap_random_adress_type; static btstack_timer_source_t gap_random_address_update_timer; static uint32_t gap_random_adress_update_period; static void gap_random_address_trigger(void){ log_info("gap_random_address_trigger, state %u", rau_state); if (rau_state != RAU_IDLE) return; rau_state = RAU_GET_RANDOM; sm_trigger_run(); } static void gap_random_address_update_handler(btstack_timer_source_t * timer){ UNUSED(timer); log_info("GAP Random Address Update due"); btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); btstack_run_loop_add_timer(&gap_random_address_update_timer); gap_random_address_trigger(); } static void gap_random_address_update_start(void){ btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); btstack_run_loop_add_timer(&gap_random_address_update_timer); } static void gap_random_address_update_stop(void){ btstack_run_loop_remove_timer(&gap_random_address_update_timer); } // ah(k,r) helper // r = padding || r // r - 24 bit value static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ // r'= padding || r memset(r_prime, 0, 16); (void)memcpy(&r_prime[13], r, 3); } // d1 helper // d' = padding || r || d // d,r - 16 bit values static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ // d'= padding || r || d memset(d1_prime, 0, 16); big_endian_store_16(d1_prime, 12, r); big_endian_store_16(d1_prime, 14, d); } // calculate arguments for first AES128 operation in C1 function static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, uint8_t * t1){ // p1 = pres || preq || rat’ || iat’ // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- // cant octet of pres becomes the most significant octet of p1. // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then // p1 is 0x05000800000302070710000001010001." sm_key_t p1; reverse_56(pres, &p1[0]); reverse_56(preq, &p1[7]); p1[14] = rat; p1[15] = iat; log_info_key("p1", p1); log_info_key("r", r); // t1 = r xor p1 int i; for (i=0;i<16;i++){ t1[i] = r[i] ^ p1[i]; } log_info_key("t1", t1); } // calculate arguments for second AES128 operation in C1 function static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ // p2 = padding || ia || ra // "The least significant octet of ra becomes the least significant octet of p2 and // the most significant octet of padding becomes the most significant octet of p2. // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. sm_key_t p2; // cppcheck-suppress uninitvar ; p2 is reported as uninitialized memset(p2, 0, 16); (void)memcpy(&p2[4], ia, 6); (void)memcpy(&p2[10], ra, 6); log_info_key("p2", p2); // c1 = e(k, t2_xor_p2) int i; for (i=0;i<16;i++){ t3[i] = t2[i] ^ p2[i]; } log_info_key("t3", t3); } static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ log_info_key("r1", r1); log_info_key("r2", r2); (void)memcpy(&r_prime[8], &r2[8], 8); (void)memcpy(&r_prime[0], &r1[8], 8); } // decide on stk generation based on // - pairing request // - io capabilities // - OOB data availability static void sm_setup_tk(void){ // horizontal: initiator capabilities // vertial: responder capabilities static const stk_generation_method_t stk_generation_method [5] [5] = { { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, }; // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations #ifdef ENABLE_LE_SECURE_CONNECTIONS static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, }; #endif // default: just works setup->sm_stk_generation_method = JUST_WORKS; #ifdef ENABLE_LE_SECURE_CONNECTIONS setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; #else setup->sm_use_secure_connections = false; #endif log_info("Secure pairing: %u", setup->sm_use_secure_connections); // decide if OOB will be used based on SC vs. Legacy and oob flags bool use_oob; if (setup->sm_use_secure_connections){ // In LE Secure Connections pairing, the out of band method is used if at least // one device has the peer device's out of band authentication data available. use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; } else { // In LE legacy pairing, the out of band method is used if both the devices have // the other device's out of band authentication data available. use_oob = (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)) != 0; } if (use_oob){ log_info("SM: have OOB data"); log_info_key("OOB", setup->sm_tk); setup->sm_stk_generation_method = OOB; return; } // If both devices have not set the MITM option in the Authentication Requirements // Flags, then the IO capabilities shall be ignored and the Just Works association // model shall be used. if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ log_info("SM: MITM not required by both -> JUST WORKS"); return; } // Reset TK as it has been setup in sm_init_setup sm_reset_tk(); // Also use just works if unknown io capabilites if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ return; } // Otherwise the IO capabilities of the devices shall be used to determine the // pairing method as defined in Table 2.4. // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array const stk_generation_method_t (*generation_method)[5] = stk_generation_method; #ifdef ENABLE_LE_SECURE_CONNECTIONS // table not define by default if (setup->sm_use_secure_connections){ generation_method = stk_generation_method_with_secure_connection; } #endif setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); } static int sm_key_distribution_flags_for_set(uint8_t key_set){ int flags = 0; if ((key_set & SM_KEYDIST_ENC_KEY) != 0u){ flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; } if ((key_set & SM_KEYDIST_ID_KEY) != 0u){ flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; } if ((key_set & SM_KEYDIST_SIGN) != 0u){ flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; } return flags; } static void sm_setup_key_distribution(uint8_t keys_to_send, uint8_t keys_to_receive){ setup->sm_key_distribution_received_set = 0; setup->sm_key_distribution_expected_set = sm_key_distribution_flags_for_set(keys_to_receive); setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(keys_to_send); setup->sm_key_distribution_sent_set = 0; #ifdef ENABLE_LE_SIGNED_WRITE setup->sm_le_device_index = -1; #endif } // CSRK Key Lookup static bool sm_address_resolution_idle(void){ return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; } 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){ (void)memcpy(sm_address_resolution_address, addr, 6); sm_address_resolution_addr_type = addr_type; sm_address_resolution_test = 0; sm_address_resolution_mode = mode; sm_address_resolution_context = context; sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); } int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ // check if already in list btstack_linked_list_iterator_t it; sm_lookup_entry_t * entry; btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); while(btstack_linked_list_iterator_has_next(&it)){ entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); if (entry->address_type != address_type) continue; if (memcmp(entry->address, address, 6) != 0) continue; // already in list return BTSTACK_BUSY; } entry = btstack_memory_sm_lookup_entry_get(); if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; entry->address_type = (bd_addr_type_t) address_type; (void)memcpy(entry->address, address, 6); btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); sm_trigger_run(); return 0; } // CMAC calculation using AES Engineq #ifdef USE_CMAC_ENGINE static void sm_cmac_done_trampoline(void * arg){ UNUSED(arg); sm_cmac_active = 0; (*sm_cmac_done_callback)(sm_cmac_hash); sm_trigger_run(); } int sm_cmac_ready(void){ return sm_cmac_active == 0u; } #endif #ifdef ENABLE_LE_SECURE_CONNECTIONS // generic cmac calculation static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)){ sm_cmac_active = 1; sm_cmac_done_callback = done_callback; btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); } #endif // cmac for ATT Message signing #ifdef ENABLE_LE_SIGNED_WRITE static void sm_cmac_generator_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t * hash)){ sm_cmac_active = 1; sm_cmac_done_callback = done_callback; btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); } static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ if (offset >= sm_cmac_signed_write_message_len) { log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); return 0; } offset = sm_cmac_signed_write_message_len - 1 - offset; // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] if (offset < 3){ return sm_cmac_signed_write_header[offset]; } int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; if (offset < actual_message_len_incl_header){ return sm_cmac_signed_write_message[offset - 3]; } return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; } void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ // ATT Message Signing sm_cmac_signed_write_header[0] = opcode; little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE sm_cmac_signed_write_message = message; sm_cmac_signed_write_message_len = total_message_len; sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); } #endif static void sm_trigger_user_response_basic(sm_connection_t * sm_conn, uint8_t event_type){ setup->sm_user_response = SM_USER_RESPONSE_PENDING; uint8_t event[12]; sm_setup_event_base(event, sizeof(event), event_type, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); event[11] = setup->sm_use_secure_connections ? 1 : 0; sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); } static void sm_trigger_user_response_passkey(sm_connection_t * sm_conn, uint8_t event_type){ uint8_t event[16]; uint32_t passkey = big_endian_read_32(setup->sm_tk, 12); sm_setup_event_base(event, sizeof(event), event_type, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); event[11] = setup->sm_use_secure_connections ? 1 : 0; little_endian_store_32(event, 12, passkey); sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); } static void sm_trigger_user_response(sm_connection_t * sm_conn){ // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input setup->sm_user_response = SM_USER_RESPONSE_IDLE; sm_conn->sm_pairing_active = true; switch (setup->sm_stk_generation_method){ case PK_RESP_INPUT: if (IS_RESPONDER(sm_conn->sm_role)){ sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); } else { sm_trigger_user_response_passkey(sm_conn, SM_EVENT_PASSKEY_DISPLAY_NUMBER); } break; case PK_INIT_INPUT: if (IS_RESPONDER(sm_conn->sm_role)){ sm_trigger_user_response_passkey(sm_conn, SM_EVENT_PASSKEY_DISPLAY_NUMBER); } else { sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); } break; case PK_BOTH_INPUT: sm_trigger_user_response_basic(sm_conn, SM_EVENT_PASSKEY_INPUT_NUMBER); break; case NUMERIC_COMPARISON: sm_trigger_user_response_passkey(sm_conn, SM_EVENT_NUMERIC_COMPARISON_REQUEST); break; case JUST_WORKS: sm_trigger_user_response_basic(sm_conn, SM_EVENT_JUST_WORKS_REQUEST); break; case OOB: // client already provided OOB data, let's skip notification. break; default: btstack_assert(false); break; } } static bool sm_key_distribution_all_received(void) { log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, setup->sm_key_distribution_expected_set); return (setup->sm_key_distribution_expected_set & setup->sm_key_distribution_received_set) == setup->sm_key_distribution_expected_set; } static void sm_done_for_handle(hci_con_handle_t con_handle){ if (sm_active_connection_handle == con_handle){ sm_timeout_stop(); sm_active_connection_handle = HCI_CON_HANDLE_INVALID; log_info("sm: connection 0x%x released setup context", con_handle); #ifdef ENABLE_LE_SECURE_CONNECTIONS // generate new ec key after each pairing (that used it) if (setup->sm_use_secure_connections){ sm_ec_generate_new_key(); } #endif } } static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done connection->sm_engine_state = SM_INITIATOR_CONNECTED; sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); sm_done_for_handle(connection->sm_handle); } static int sm_key_distribution_flags_for_auth_req(void){ int flags = SM_KEYDIST_ID_KEY; if ((sm_auth_req & SM_AUTHREQ_BONDING) != 0u){ // encryption and signing information only if bonding requested flags |= SM_KEYDIST_ENC_KEY; #ifdef ENABLE_LE_SIGNED_WRITE flags |= SM_KEYDIST_SIGN; #endif #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION // LinkKey for CTKD requires SC and BR/EDR Support if (hci_classic_supported() && ((sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION) != 0)){ flags |= SM_KEYDIST_LINK_KEY; } #endif } return flags; } static void sm_reset_setup(void){ // fill in sm setup setup->sm_state_vars = 0; setup->sm_keypress_notification = 0; setup->sm_have_oob_data = 0; sm_reset_tk(); } static void sm_init_setup(sm_connection_t * sm_conn){ // fill in sm setup setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); // query client for Legacy Pairing OOB data if (sm_get_oob_data != NULL) { setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); } // if available and SC supported, also ask for SC OOB Data #ifdef ENABLE_LE_SECURE_CONNECTIONS memset(setup->sm_ra, 0, 16); memset(setup->sm_rb, 0, 16); if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ if (sm_get_sc_oob_data != NULL){ if (IS_RESPONDER(sm_conn->sm_role)){ setup->sm_have_oob_data = (*sm_get_sc_oob_data)( sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_peer_confirm, setup->sm_ra); } else { setup->sm_have_oob_data = (*sm_get_sc_oob_data)( sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_peer_confirm, setup->sm_rb); } } else { setup->sm_have_oob_data = 0; } } #endif sm_pairing_packet_t * local_packet; if (IS_RESPONDER(sm_conn->sm_role)){ // slave local_packet = &setup->sm_s_pres; setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; setup->sm_s_addr_type = sm_conn->sm_own_addr_type; (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); (void)memcpy(setup->sm_s_address, sm_conn->sm_own_address, 6); } else { // master local_packet = &setup->sm_m_preq; setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; setup->sm_m_addr_type = sm_conn->sm_own_addr_type; (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); (void)memcpy(setup->sm_m_address, sm_conn->sm_own_address, 6); uint8_t key_distribution_flags = sm_key_distribution_flags_for_auth_req(); sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); } log_info("our address %s type %u", bd_addr_to_str(sm_conn->sm_own_address), sm_conn->sm_own_addr_type); log_info("peer address %s type %u", bd_addr_to_str(sm_conn->sm_peer_address), sm_conn->sm_peer_addr_type); uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; uint8_t max_encryption_key_size = sm_max_encryption_key_size; #ifdef ENABLE_LE_SECURE_CONNECTIONS // enable SC for SC only mode if (sm_sc_only_mode){ auth_req |= SM_AUTHREQ_SECURE_CONNECTION; max_encryption_key_size = 16; } #endif #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION // set CT2 if SC + Bonding + CTKD const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ auth_req |= SM_AUTHREQ_CT2; } #endif sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); sm_pairing_packet_set_auth_req(*local_packet, auth_req); sm_pairing_packet_set_max_encryption_key_size(*local_packet, max_encryption_key_size); } static int sm_stk_generation_init(sm_connection_t * sm_conn){ sm_pairing_packet_t * remote_packet; uint8_t keys_to_send; uint8_t keys_to_receive; if (IS_RESPONDER(sm_conn->sm_role)){ // slave / responder remote_packet = &setup->sm_m_preq; keys_to_send = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); keys_to_receive = sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq); } else { // master / initiator remote_packet = &setup->sm_s_pres; keys_to_send = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); keys_to_receive = sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres); } // check key size #ifdef ENABLE_LE_SECURE_CONNECTIONS // SC Only mandates 128 bit key size if (sm_sc_only_mode && (sm_pairing_packet_get_max_encryption_key_size(*remote_packet) < 16)) { return SM_REASON_ENCRYPTION_KEY_SIZE; } #endif sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; // decide on STK generation method / SC sm_setup_tk(); log_info("SMP: generation method %u", setup->sm_stk_generation_method); // check if STK generation method is acceptable by client if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; #ifdef ENABLE_LE_SECURE_CONNECTIONS // Check LE SC Only mode if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ log_info("SC Only mode active but SC not possible"); return SM_REASON_AUTHENTHICATION_REQUIREMENTS; } // LTK (= encryption information & master identification) only used exchanged for LE Legacy Connection if (setup->sm_use_secure_connections){ keys_to_send &= ~SM_KEYDIST_ENC_KEY; keys_to_receive &= ~SM_KEYDIST_ENC_KEY; } #endif // identical to responder sm_setup_key_distribution(keys_to_send, keys_to_receive); // JUST WORKS doens't provide authentication sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; return 0; } static void sm_address_resolution_handle_event(address_resolution_event_t event){ // cache and reset context int matched_device_id = sm_address_resolution_test; address_resolution_mode_t mode = sm_address_resolution_mode; void * context = sm_address_resolution_context; // reset context sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; sm_address_resolution_context = NULL; sm_address_resolution_test = -1; hci_con_handle_t con_handle = HCI_CON_HANDLE_INVALID; sm_connection_t * sm_connection; sm_key_t ltk; bool have_ltk; int authenticated; #ifdef ENABLE_LE_CENTRAL bool trigger_pairing; #endif switch (mode){ case ADDRESS_RESOLUTION_GENERAL: break; case ADDRESS_RESOLUTION_FOR_CONNECTION: sm_connection = (sm_connection_t *) context; con_handle = sm_connection->sm_handle; // have ltk -> start encryption / send security request // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request // "When a bond has been created between two devices, any reconnection should result in the local device // enabling or requesting encryption with the remote device before initiating any service request." switch (event){ case ADDRESS_RESOLUTION_SUCCEEDED: sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; sm_connection->sm_le_db_index = matched_device_id; log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, &authenticated, NULL, NULL); have_ltk = !sm_is_null_key(ltk); if (IS_RESPONDER(sm_connection->sm_role)) { #ifdef ENABLE_LE_PERIPHERAL // IRK required before, continue if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; break; } // Pairing request before, continue if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; break; } bool trigger_security_request = sm_connection->sm_pairing_requested || sm_slave_request_security; sm_connection->sm_pairing_requested = false; #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION // trigger security request for Proactive Authentication if LTK available trigger_security_request = trigger_security_request || have_ltk; #endif log_info("peripheral: pairing request local %u, have_ltk %u => trigger_security_request %u", (int) sm_connection->sm_pairing_requested, (int) have_ltk, trigger_security_request); if (trigger_security_request){ sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; if (have_ltk){ sm_reencryption_started(sm_connection); } else { sm_pairing_started(sm_connection); } sm_trigger_run(); } #endif } else { #ifdef ENABLE_LE_CENTRAL // check if pairing already requested and reset requests trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; bool auth_required = sm_auth_req & SM_AUTHREQ_MITM_PROTECTION; log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", (int) sm_connection->sm_pairing_requested, (int) sm_connection->sm_security_request_received, (int) trigger_pairing, (int) have_ltk); sm_connection->sm_security_request_received = false; sm_connection->sm_pairing_requested = false; bool trigger_reencryption = false; if (have_ltk){ if (trigger_pairing){ // if pairing is requested, re-encryption is sufficient, if ltk is already authenticated or we don't require authentication trigger_reencryption = (authenticated != 0) || (auth_required == false); } else { #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION trigger_reencryption = true; #else log_info("central: defer enabling encryption for bonded device"); #endif } } if (trigger_reencryption){ log_info("central: enable encryption for bonded device"); sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; break; } // pairing_request -> send pairing request if (trigger_pairing){ sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; break; } #endif } break; case ADDRESS_RESOLUTION_FAILED: sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; if (IS_RESPONDER(sm_connection->sm_role)) { #ifdef ENABLE_LE_PERIPHERAL // LTK request received before, IRK required -> negative LTK reply if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; } // Pairing request before, continue if (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK){ sm_connection->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; break; } // send security request if requested bool trigger_security_request = sm_connection->sm_pairing_requested || sm_slave_request_security; sm_connection->sm_pairing_requested = false; if (trigger_security_request){ sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; sm_pairing_started(sm_connection); } break; #endif } #ifdef ENABLE_LE_CENTRAL if ((sm_connection->sm_pairing_requested == false) && (sm_connection->sm_security_request_received == false)) break; sm_connection->sm_security_request_received = false; sm_connection->sm_pairing_requested = false; sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; #endif break; default: btstack_assert(false); break; } break; default: break; } switch (event){ case ADDRESS_RESOLUTION_SUCCEEDED: sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); break; case ADDRESS_RESOLUTION_FAILED: sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); break; default: btstack_assert(false); break; } } static void sm_store_bonding_information(sm_connection_t * sm_conn){ int le_db_index = -1; // lookup device based on IRK if ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION) != 0u){ int i; for (i=0; i < le_device_db_max_count(); i++){ sm_key_t irk; bd_addr_t address; int address_type = BD_ADDR_TYPE_UNKNOWN; le_device_db_info(i, &address_type, address, irk); // skip unused entries if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; // compare Identity Address if (memcmp(address, setup->sm_peer_address, 6) != 0) continue; // compare Identity Resolving Key if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; log_info("sm: device found for IRK, updating"); le_db_index = i; break; } } else { // assert IRK is set to zero memset(setup->sm_peer_irk, 0, 16); } // if not found, lookup via public address if possible log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ int i; for (i=0; i < le_device_db_max_count(); i++){ bd_addr_t address; int address_type = BD_ADDR_TYPE_UNKNOWN; le_device_db_info(i, &address_type, address, NULL); // skip unused entries if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ log_info("sm: device found for public address, updating"); le_db_index = i; break; } } } // if not found, add to db bool new_to_le_device_db = false; if (le_db_index < 0) { le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); new_to_le_device_db = true; } if (le_db_index >= 0){ #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION if (!new_to_le_device_db){ hci_remove_le_device_db_entry_from_resolving_list(le_db_index); } hci_load_le_device_db_entry_into_resolving_list(le_db_index); #else UNUSED(new_to_le_device_db); #endif sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; sm_conn->sm_le_db_index = le_db_index; #ifdef ENABLE_LE_SIGNED_WRITE // store local CSRK setup->sm_le_device_index = le_db_index; if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ log_info("sm: store local CSRK"); le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); le_device_db_local_counter_set(le_db_index, 0); } // store remote CSRK if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ log_info("sm: store remote CSRK"); le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); le_device_db_remote_counter_set(le_db_index, 0); } #endif // store encryption information for secure connections: LTK generated by ECDH if (setup->sm_use_secure_connections){ log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); uint8_t zero_rand[8]; memset(zero_rand, 0, 8); le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); } // store encryption information for legacy pairing: peer LTK, EDIV, RAND else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); } } } static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ sm_conn->sm_pairing_failed_reason = reason; sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; } static int sm_le_device_db_index_lookup(bd_addr_type_t address_type, bd_addr_t address){ int i; for (i=0; i < le_device_db_max_count(); i++){ bd_addr_t db_address; int db_address_type = BD_ADDR_TYPE_UNKNOWN; le_device_db_info(i, &db_address_type, db_address, NULL); // skip unused entries if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; if ((address_type == (unsigned int)db_address_type) && (memcmp(address, db_address, 6) == 0)){ return i; } } return -1; } static void sm_remove_le_device_db_entry(uint16_t i) { le_device_db_remove(i); #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION // to remove an entry from the resolving list requires its identity address, which was already deleted // fully reload resolving list instead gap_load_resolving_list_from_le_device_db(); #endif } static uint8_t sm_key_distribution_validate_received(sm_connection_t * sm_conn){ UNUSED(sm_conn); // if identity is provided, abort if we have bonding with same address but different irk if ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION) != 0u){ int index = sm_le_device_db_index_lookup(BD_ADDR_TYPE_LE_PUBLIC, setup->sm_peer_address); if (index >= 0){ sm_key_t irk; le_device_db_info(index, NULL, NULL, irk); if (memcmp(irk, setup->sm_peer_irk, 16) != 0){ // IRK doesn't match, delete bonding information log_info("New IRK for %s (type %u) does not match stored IRK -> delete bonding information", bd_addr_to_str(sm_conn->sm_peer_address), sm_conn->sm_peer_addr_type); sm_remove_le_device_db_entry(index); } } } return 0; } static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ // abort pairing if received keys are not valid uint8_t reason = sm_key_distribution_validate_received(sm_conn); if (reason != 0){ sm_pairing_error(sm_conn, reason); return; } // only store pairing information if both sides are bondable, i.e., the bonadble flag is set bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_BONDING ) != 0u; if (bonding_enabled){ sm_store_bonding_information(sm_conn); } else { log_info("Ignoring received keys, bonding not enabled"); } } static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); } #ifdef ENABLE_LE_SECURE_CONNECTIONS static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); static bool sm_passkey_used(stk_generation_method_t method); static bool sm_just_works_or_numeric_comparison(stk_generation_method_t method); static void sm_sc_generate_nx_for_send_random(sm_connection_t * sm_conn); static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ if (setup->sm_stk_generation_method == OOB){ sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; } else { btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_w2_cmac_for_confirmation, (void *)(uintptr_t) sm_conn->sm_handle); } } static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ if (IS_RESPONDER(sm_conn->sm_role)){ // Responder if (setup->sm_stk_generation_method == OOB){ sm_sc_generate_nx_for_send_random(sm_conn); } else { sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; } } else { // Initiator role switch (setup->sm_stk_generation_method){ case JUST_WORKS: sm_sc_prepare_dhkey_check(sm_conn); break; case NUMERIC_COMPARISON: sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; break; case PK_INIT_INPUT: case PK_RESP_INPUT: case PK_BOTH_INPUT: if (setup->sm_passkey_bit < 20u) { sm_sc_start_calculating_local_confirm(sm_conn); } else { sm_sc_prepare_dhkey_check(sm_conn); } break; case OOB: sm_sc_prepare_dhkey_check(sm_conn); break; default: btstack_assert(false); break; } } } static void sm_sc_cmac_done(uint8_t * hash){ log_info("sm_sc_cmac_done: "); log_info_hexdump(hash, 16); if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ sm_sc_oob_state = SM_SC_OOB_IDLE; (*sm_sc_oob_callback)(hash, sm_sc_oob_random); return; } sm_connection_t * sm_conn = sm_cmac_connection; sm_cmac_connection = NULL; #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION link_key_type_t link_key_type; #endif switch (sm_conn->sm_engine_state){ case SM_SC_W4_CMAC_FOR_CONFIRMATION: (void)memcpy(setup->sm_local_confirm, hash, 16); sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; break; case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: // check if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); break; } // for OOB, C is verified before generating and sending random Nonce if (setup->sm_stk_generation_method == OOB){ sm_sc_generate_nx_for_send_random(sm_conn); } else { sm_sc_state_after_receiving_random(sm_conn); } break; case SM_SC_W4_CALCULATE_G2: { uint32_t vab = big_endian_read_32(hash, 12) % 1000000; big_endian_store_32(setup->sm_tk, 12, vab); sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; sm_trigger_user_response(sm_conn); break; } case SM_SC_W4_CALCULATE_F5_SALT: (void)memcpy(setup->sm_t, hash, 16); sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; break; case SM_SC_W4_CALCULATE_F5_MACKEY: (void)memcpy(setup->sm_mackey, hash, 16); sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; break; case SM_SC_W4_CALCULATE_F5_LTK: // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk // Errata Service Release to the Bluetooth Specification: ESR09 // E6405 – Cross transport key derivation from a key of size less than 128 bits // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." (void)memcpy(setup->sm_ltk, hash, 16); (void)memcpy(setup->sm_local_ltk, hash, 16); sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; break; case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: (void)memcpy(setup->sm_local_dhkey_check, hash, 16); if (IS_RESPONDER(sm_conn->sm_role)){ // responder if ((setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED) != 0u){ sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; } else { sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; } } else { sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; } break; case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); break; } if (IS_RESPONDER(sm_conn->sm_role)){ // responder sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; } else { // initiator sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; } break; #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION case SM_SC_W4_CALCULATE_ILK: (void)memcpy(setup->sm_t, hash, 16); sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; break; case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: reverse_128(hash, setup->sm_t); link_key_type = sm_conn->sm_connection_authenticated ? AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); if (IS_RESPONDER(sm_conn->sm_role)){ sm_conn->sm_engine_state = SM_RESPONDER_IDLE; } else { sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; } sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); sm_done_for_handle(sm_conn->sm_handle); break; case SM_BR_EDR_W4_CALCULATE_ILK: (void)memcpy(setup->sm_t, hash, 16); sm_conn->sm_engine_state = SM_BR_EDR_W2_CALCULATE_LE_LTK; break; case SM_BR_EDR_W4_CALCULATE_LE_LTK: log_info("Derived LE LTK from BR/EDR Link Key"); log_info_key("Link Key", hash); (void)memcpy(setup->sm_ltk, hash, 16); sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); sm_conn->sm_connection_authenticated = setup->sm_link_key_type == AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; sm_store_bonding_information(sm_conn); sm_done_for_handle(sm_conn->sm_handle); break; #endif default: log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); break; } sm_trigger_run(); } static void f4_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, uint8_t z){ const uint16_t message_len = 65; sm_cmac_connection = sm_conn; (void)memcpy(sm_cmac_sc_buffer, u, 32); (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); sm_cmac_sc_buffer[64] = z; log_info("f4 key"); log_info_hexdump(x, 16); log_info("f4 message"); log_info_hexdump(sm_cmac_sc_buffer, message_len); sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); } static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; static const uint8_t f5_length[] = { 0x01, 0x00}; static void f5_calculate_salt(sm_connection_t * sm_conn){ static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; log_info("f5_calculate_salt"); // calculate salt for f5 const uint16_t message_len = 32; sm_cmac_connection = sm_conn; (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); } static inline void f5_mackkey(sm_connection_t * sm_conn, sm_key_t t, const sm_key_t n1, const sm_key_t n2, const sm_key56_t a1, const sm_key56_t a2){ const uint16_t message_len = 53; sm_cmac_connection = sm_conn; // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey sm_cmac_sc_buffer[0] = 0; (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); log_info("f5 key"); log_info_hexdump(t, 16); log_info("f5 message for MacKey"); log_info_hexdump(sm_cmac_sc_buffer, message_len); sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); } static void f5_calculate_mackey(sm_connection_t * sm_conn){ sm_key56_t bd_addr_master, bd_addr_slave; bd_addr_master[0] = setup->sm_m_addr_type; bd_addr_slave[0] = setup->sm_s_addr_type; (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); if (IS_RESPONDER(sm_conn->sm_role)){ // responder f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); } else { // initiator f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); } } // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ const uint16_t message_len = 53; sm_cmac_connection = sm_conn; sm_cmac_sc_buffer[0] = 1; // 1..52 setup before log_info("f5 key"); log_info_hexdump(t, 16); log_info("f5 message for LTK"); log_info_hexdump(sm_cmac_sc_buffer, message_len); sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); } static void f5_calculate_ltk(sm_connection_t * sm_conn){ f5_ltk(sm_conn, setup->sm_t); } static void f6_setup(const sm_key_t n1, const sm_key_t n2, const sm_key_t r, const sm_key24_t io_cap, const sm_key56_t a1, const sm_key56_t a2){ (void)memcpy(sm_cmac_sc_buffer, n1, 16); (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); } static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ const uint16_t message_len = 65; sm_cmac_connection = sm_conn; log_info("f6 key"); log_info_hexdump(w, 16); log_info("f6 message"); log_info_hexdump(sm_cmac_sc_buffer, message_len); sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); } // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 // - U is 256 bits // - V is 256 bits // - X is 128 bits // - Y is 128 bits static void g2_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ const uint16_t message_len = 80; sm_cmac_connection = sm_conn; (void)memcpy(sm_cmac_sc_buffer, u, 32); (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); log_info("g2 key"); log_info_hexdump(x, 16); log_info("g2 message"); log_info_hexdump(sm_cmac_sc_buffer, message_len); sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); } static void g2_calculate(sm_connection_t * sm_conn) { // calc Va if numeric comparison if (IS_RESPONDER(sm_conn->sm_role)){ // responder g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; } else { // initiator g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); } } static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ uint8_t z = 0; if (sm_passkey_entry(setup->sm_stk_generation_method)){ // some form of passkey uint32_t pk = big_endian_read_32(setup->sm_tk, 12); z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); setup->sm_passkey_bit++; } f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); } static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ // OOB if (setup->sm_stk_generation_method == OOB){ if (IS_RESPONDER(sm_conn->sm_role)){ f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); } else { f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); } return; } uint8_t z = 0; if (sm_passkey_entry(setup->sm_stk_generation_method)){ // some form of passkey uint32_t pk = big_endian_read_32(setup->sm_tk, 12); // sm_passkey_bit was increased before sending confirm value z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); } f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); } static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) != 0 ? 1 : 0); if ((setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) != 0u){ sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; } else { sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; } } static void sm_sc_dhkey_calculated(void * arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (sm_conn == NULL) return; // check for invalid public key detected by Controller if (sm_is_ff(setup->sm_dhkey, 32)){ log_info("sm: peer public key invalid"); sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); return; } log_info("dhkey"); log_info_hexdump(&setup->sm_dhkey[0], 32); setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; // trigger next step if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; } sm_trigger_run(); } static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ // calculate DHKCheck sm_key56_t bd_addr_master, bd_addr_slave; bd_addr_master[0] = setup->sm_m_addr_type; bd_addr_slave[0] = setup->sm_s_addr_type; (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); uint8_t iocap_a[3]; iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); uint8_t iocap_b[3]; iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); if (IS_RESPONDER(sm_conn->sm_role)){ // responder f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); f6_engine(sm_conn, setup->sm_mackey); } else { // initiator f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); f6_engine(sm_conn, setup->sm_mackey); } } static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ // validate E = f6() sm_key56_t bd_addr_master, bd_addr_slave; bd_addr_master[0] = setup->sm_m_addr_type; bd_addr_slave[0] = setup->sm_s_addr_type; (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); uint8_t iocap_a[3]; iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); uint8_t iocap_b[3]; iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); if (IS_RESPONDER(sm_conn->sm_role)){ // responder f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); f6_engine(sm_conn, setup->sm_mackey); } else { // initiator f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); f6_engine(sm_conn, setup->sm_mackey); } } static void sm_sc_generate_nx_for_send_random(sm_connection_t * sm_conn){ // generate Nx log_info("Generate N%c", IS_RESPONDER(sm_conn->sm_role) ? 'b' : 'a'); btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void*)(uintptr_t) sm_conn->sm_handle); } #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION // // Link Key Conversion Function h6 // // h6(W, keyID) = AES-CMAC_W(keyID) // - W is 128 bits // - keyID is 32 bits static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ const uint16_t message_len = 4; sm_cmac_connection = sm_conn; big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); log_info("h6 key"); log_info_hexdump(w, 16); log_info("h6 message"); log_info_hexdump(sm_cmac_sc_buffer, message_len); sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); } // // Link Key Conversion Function h7 // // h7(SALT, W) = AES-CMAC_SALT(W) // - SALT is 128 bits // - W is 128 bits static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { const uint16_t message_len = 16; sm_cmac_connection = sm_conn; log_info("h7 key"); log_info_hexdump(salt, 16); log_info("h7 message"); log_info_hexdump(w, 16); sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); } // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) // Errata Service Release to the Bluetooth Specification: ESR09 // E6405 – Cross transport key derivation from a key of size less than 128 bits // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." static void h6_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" } static void h6_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ h6_engine(sm_conn, setup->sm_link_key, 0x746D7032); // "tmp2" } static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" } static void h6_calculate_le_ltk(sm_connection_t * sm_conn){ h6_engine(sm_conn, setup->sm_t, 0x62726C65); // "brle" } static void h7_calculate_ilk_from_le_ltk(sm_connection_t * sm_conn){ const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" h7_engine(sm_conn, salt, setup->sm_local_ltk); } static void h7_calculate_ilk_from_br_edr(sm_connection_t * sm_conn){ const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x32}; // "tmp2" h7_engine(sm_conn, salt, setup->sm_link_key); } static void sm_ctkd_fetch_br_edr_link_key(sm_connection_t * sm_conn){ hci_connection_t * hci_connection = hci_connection_for_handle(sm_conn->sm_handle); btstack_assert(hci_connection != NULL); reverse_128(hci_connection->link_key, setup->sm_link_key); setup->sm_link_key_type = hci_connection->link_key_type; } static void sm_ctkd_start_from_br_edr(sm_connection_t * sm_conn){ // only derive LTK if EncKey is set by both bool derive_ltk = (sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & SM_KEYDIST_ENC_KEY) != 0; if (derive_ltk){ bool use_h7 = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_CT2) != 0; sm_conn->sm_engine_state = use_h7 ? SM_BR_EDR_W2_CALCULATE_ILK_USING_H7 : SM_BR_EDR_W2_CALCULATE_ILK_USING_H6; } else { sm_done_for_handle(sm_conn->sm_handle); } } #endif #endif // key management legacy connections: // - potentially two different LTKs based on direction. each device stores LTK provided by peer // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder // - responder reconnects: responder uses LTK receveived from master // key management secure connections: // - both devices store same LTK from ECDH key exchange. #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) static void sm_load_security_info(sm_connection_t * sm_connection){ int encryption_key_size; int authenticated; int authorized; int secure_connection; // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, &encryption_key_size, &authenticated, &authorized, &secure_connection); log_info("db index %u, key size %u, authenticated %u, authorized %u, secure connetion %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized, secure_connection); sm_connection->sm_actual_encryption_key_size = encryption_key_size; sm_connection->sm_connection_authenticated = authenticated; sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; sm_connection->sm_connection_sc = secure_connection != 0; } #endif #ifdef ENABLE_LE_PERIPHERAL static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); setup->sm_local_ediv = sm_connection->sm_local_ediv; // re-establish used key encryption size // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; // no db for authenticated flag hack: flag is stored in bit 4 of LSB sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; // Legacy paring -> not SC sm_connection->sm_connection_sc = false; log_info("sm: received ltk request with key size %u, authenticated %u", sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); } #endif // distributed key generation static bool sm_run_dpkg(void){ switch (dkg_state){ case DKG_CALC_IRK: // already busy? if (sm_aes128_state == SM_AES128_IDLE) { log_info("DKG_CALC_IRK started"); // IRK = d1(IR, 1, 0) sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); return true; } break; case DKG_CALC_DHK: // already busy? if (sm_aes128_state == SM_AES128_IDLE) { log_info("DKG_CALC_DHK started"); // DHK = d1(IR, 3, 0) sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); return true; } break; default: break; } return false; } // random address updates static bool sm_run_rau(void){ switch (rau_state){ case RAU_GET_RANDOM: rau_state = RAU_W4_RANDOM; btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); return true; case RAU_GET_ENC: // already busy? if (sm_aes128_state == SM_AES128_IDLE) { sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); return true; } break; default: break; } return false; } // device lookup with IRK static bool sm_run_irk_lookup(void){ btstack_linked_list_iterator_t it; // -- if IRK lookup ready, find connection that require csrk lookup if (sm_address_resolution_idle()){ hci_connections_get_iterator(&it); while(btstack_linked_list_iterator_has_next(&it)){ hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); sm_connection_t * sm_connection = &hci_connection->sm_connection; if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ // and start lookup 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); sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; break; } } } // -- if csrk lookup ready, resolved addresses for received addresses if (sm_address_resolution_idle()) { if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); btstack_memory_sm_lookup_entry_free(entry); } } // -- Continue with device lookup by public or resolvable private address if (!sm_address_resolution_idle()){ bool started_aes128 = false; while (sm_address_resolution_test < le_device_db_max_count()){ int addr_type = BD_ADDR_TYPE_UNKNOWN; bd_addr_t addr; sm_key_t irk; le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); // skip unused entries if (addr_type == BD_ADDR_TYPE_UNKNOWN){ sm_address_resolution_test++; continue; } log_info("LE Device Lookup: device %u of %u - type %u, %s", sm_address_resolution_test, le_device_db_max_count(), addr_type, bd_addr_to_str(addr)); // map resolved identity addresses to regular addresses int regular_addr_type = sm_address_resolution_addr_type & 1; if ((regular_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ log_info("LE Device Lookup: found by { addr_type, address} "); sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); break; } // if connection type is not random (i.e. public or resolved identity), it must be a different entry if (sm_address_resolution_addr_type != BD_ADDR_TYPE_LE_RANDOM){ sm_address_resolution_test++; continue; } // skip AH if no IRK if (sm_is_null_key(irk)){ sm_address_resolution_test++; continue; } if (sm_aes128_state == SM_AES128_ACTIVE) break; log_info("LE Device Lookup: calculate AH"); log_info_key("IRK", irk); (void)memcpy(sm_aes128_key, irk, 16); sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); started_aes128 = true; break; } if (started_aes128){ return true; } if (sm_address_resolution_test >= le_device_db_max_count()){ log_info("LE Device Lookup: not found"); sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); } } return false; } // SC OOB static bool sm_run_oob(void){ #ifdef ENABLE_LE_SECURE_CONNECTIONS switch (sm_sc_oob_state){ case SM_SC_OOB_W2_CALC_CONFIRM: if (!sm_cmac_ready()) break; sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); return true; default: break; } #endif return false; } static void sm_send_connectionless(sm_connection_t * sm_connection, const uint8_t * buffer, uint16_t size){ l2cap_send_connectionless(sm_connection->sm_handle, sm_connection->sm_cid, (uint8_t*) buffer, size); } // handle basic actions that don't requires the full context static bool sm_run_basic(void){ btstack_linked_list_iterator_t it; hci_connections_get_iterator(&it); while(btstack_linked_list_iterator_has_next(&it)){ hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); sm_connection_t * sm_connection = &hci_connection->sm_connection; switch(sm_connection->sm_engine_state){ // general case SM_GENERAL_SEND_PAIRING_FAILED: { uint8_t buffer[2]; buffer[0] = SM_CODE_PAIRING_FAILED; buffer[1] = sm_connection->sm_pairing_failed_reason; sm_connection->sm_engine_state = sm_connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; sm_send_connectionless(sm_connection, (uint8_t*) buffer, sizeof(buffer)); sm_pairing_complete(sm_connection, ERROR_CODE_AUTHENTICATION_FAILURE, sm_connection->sm_pairing_failed_reason); sm_done_for_handle(sm_connection->sm_handle); break; } // responder side case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: sm_connection->sm_engine_state = SM_RESPONDER_IDLE; hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); return true; #ifdef ENABLE_LE_SECURE_CONNECTIONS case SM_SC_RECEIVED_LTK_REQUEST: switch (sm_connection->sm_irk_lookup_state){ case IRK_LOOKUP_FAILED: log_info("LTK Request: IRK Lookup Failed)"); sm_connection->sm_engine_state = SM_RESPONDER_IDLE; hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); return true; default: break; } break; #endif default: break; } } return false; } static void sm_run_activate_connection(void){ // Find connections that requires setup context and make active if no other is locked btstack_linked_list_iterator_t it; hci_connections_get_iterator(&it); while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); sm_connection_t * sm_connection = &hci_connection->sm_connection; // - if no connection locked and we're ready/waiting for setup context, fetch it and start bool done = true; #ifdef ENABLE_LE_SECURE_CONNECTIONS // assert ec key is ready if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ sm_ec_generate_new_key(); } if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ continue; } } #endif switch (sm_connection->sm_engine_state) { #ifdef ENABLE_LE_PERIPHERAL case SM_RESPONDER_SEND_SECURITY_REQUEST: case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: #ifdef ENABLE_LE_SECURE_CONNECTIONS case SM_SC_RECEIVED_LTK_REQUEST: #endif #endif #ifdef ENABLE_LE_CENTRAL case SM_INITIATOR_PH4_HAS_LTK: case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: #endif #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: #endif // just lock context break; default: done = false; break; } if (done){ sm_active_connection_handle = sm_connection->sm_handle; log_info("sm: connection 0x%04x locked setup context as %s, state %u", sm_active_connection_handle, sm_connection->sm_role ? "responder" : "initiator", sm_connection->sm_engine_state); } } } static void sm_run_send_keypress_notification(sm_connection_t * connection){ int i; uint8_t flags = setup->sm_keypress_notification & 0x1fu; uint8_t num_actions = setup->sm_keypress_notification >> 5; uint8_t action = 0; for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ if ((flags & (1u<sm_keypress_notification = (num_actions << 5) | flags; // send keypress notification uint8_t buffer[2]; buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; buffer[1] = action; sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); // try l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); } static void sm_run_distribute_keys(sm_connection_t * connection){ if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) != 0u){ setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; uint8_t buffer[17]; buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; reverse_128(setup->sm_ltk, &buffer[1]); sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); return; } if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION) != 0u){ setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; uint8_t buffer[11]; buffer[0] = SM_CODE_MASTER_IDENTIFICATION; little_endian_store_16(buffer, 1, setup->sm_local_ediv); reverse_64(setup->sm_local_rand, &buffer[3]); sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); return; } if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION) != 0u){ setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; uint8_t buffer[17]; buffer[0] = SM_CODE_IDENTITY_INFORMATION; reverse_128(sm_persistent_irk, &buffer[1]); sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); return; } if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0u){ setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; bd_addr_t local_address; uint8_t buffer[8]; buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; switch (gap_random_address_get_mode()){ case GAP_RANDOM_ADDRESS_TYPE_OFF: case GAP_RANDOM_ADDRESS_TYPE_STATIC: // public or static random gap_le_get_own_address(&buffer[1], local_address); break; case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: case GAP_RANDOM_ADDRESS_RESOLVABLE: // fallback to public gap_local_bd_addr(local_address); buffer[1] = 0; break; default: btstack_assert(false); break; } reverse_bd_addr(local_address, &buffer[2]); sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); return; } if ((setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION) != 0u){ setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; #ifdef ENABLE_LE_SIGNED_WRITE // hack to reproduce test runs if (test_use_fixed_local_csrk){ memset(setup->sm_local_csrk, 0xcc, 16); } // store local CSRK if (setup->sm_le_device_index >= 0){ log_info("sm: store local CSRK"); le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); le_device_db_local_counter_set(setup->sm_le_device_index, 0); } #endif uint8_t buffer[17]; buffer[0] = SM_CODE_SIGNING_INFORMATION; reverse_128(setup->sm_local_csrk, &buffer[1]); sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); return; } btstack_assert(false); } static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION // requirements to derive link key from LE: // - use secure connections if (setup->sm_use_secure_connections == 0) return false; // - bonding needs to be enabled: bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_BONDING ) != 0u; if (!bonding_enabled) return false; // - need identity address / public addr bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0) || (setup->sm_peer_addr_type == 0); if (!have_identity_address_info) return false; // - there is no stored BR/EDR link key or the derived key has at least the same level of authentication (bail if stored key has higher authentication) // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. // If SC is authenticated, we consider it safe to overwrite a stored key. // If stored link key is not authenticated, it could already be compromised by a MITM attack. Allowing overwrite by unauthenticated derived key does not make it worse. uint8_t link_key[16]; link_key_type_t link_key_type; bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type); bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; if (have_link_key && link_key_authenticated && !derived_key_authenticated) { return false; } // get started (all of the above are true) return true; #else UNUSED(sm_connection); return false; #endif } #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION static bool sm_ctkd_from_classic(sm_connection_t * sm_connection){ hci_connection_t * hci_connection = hci_connection_for_handle(sm_connection->sm_handle); btstack_assert(hci_connection != NULL); // requirements to derive ltk from BR/EDR: // - BR/EDR uses secure connections if (gap_secure_connection_for_link_key_type(hci_connection->link_key_type) == false) return false; // - there is no stored LTK or the derived key has at least the same level of authentication (bail if LTK is authenticated but Link Key isn't) bool link_key_authenticated = gap_authenticated_for_link_key_type(hci_connection->link_key_type); if (link_key_authenticated) return true; int index = sm_le_device_db_index_lookup(BD_ADDR_TYPE_LE_PUBLIC, hci_connection->address); if (index >= 0){ int ltk_authenticated; sm_key_t ltk; le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, <k_authenticated, NULL, NULL); bool have_ltk = !sm_is_null_key(ltk); if (have_ltk && ltk_authenticated) return false; } return true; } #endif static void sm_key_distribution_complete_responder(sm_connection_t * connection){ if (sm_ctkd_from_le(connection)){ bool use_h7 = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_CT2) != 0; connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; } else { connection->sm_engine_state = SM_RESPONDER_IDLE; sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); sm_done_for_handle(connection->sm_handle); } } static void sm_key_distribution_complete_initiator(sm_connection_t * connection){ if (sm_ctkd_from_le(connection)){ bool use_h7 = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_CT2) != 0; connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; } else { sm_master_pairing_success(connection); } } #ifdef ENABLE_LE_SECURE_CONNECTIONS static void sm_run_state_sc_send_confirmation(sm_connection_t *connection) { uint8_t buffer[17]; buffer[0] = SM_CODE_PAIRING_CONFIRM; reverse_128(setup->sm_local_confirm, &buffer[1]); if (IS_RESPONDER(connection->sm_role)){ connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; } else { connection->sm_engine_state = SM_SC_W4_CONFIRMATION; } sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); } static void sm_run_state_sc_send_pairing_random(sm_connection_t *connection) { uint8_t buffer[17]; buffer[0] = SM_CODE_PAIRING_RANDOM; reverse_128(setup->sm_local_nonce, &buffer[1]); log_info("stk method %u, bit num: %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ log_info("SM_SC_SEND_PAIRING_RANDOM A"); if (IS_RESPONDER(connection->sm_role)){ // responder connection->sm_engine_state = SM_SC_W4_CONFIRMATION; } else { // initiator connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; } } else { log_info("SM_SC_SEND_PAIRING_RANDOM B"); if (IS_RESPONDER(connection->sm_role)){ // responder if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ log_info("SM_SC_SEND_PAIRING_RANDOM B1"); connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; } else { log_info("SM_SC_SEND_PAIRING_RANDOM B2"); sm_sc_prepare_dhkey_check(connection); } } else { // initiator connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; } } sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); } static void sm_run_state_sc_send_dhkey_check_command(sm_connection_t *connection) { uint8_t buffer[17]; buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; reverse_128(setup->sm_local_dhkey_check, &buffer[1]); if (IS_RESPONDER(connection->sm_role)){ connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; } else { connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; } sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); } static void sm_run_state_sc_send_public_key_command(sm_connection_t *connection) { bool trigger_user_response = false; bool trigger_start_calculating_local_confirm = false; uint8_t buffer[65]; buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; // reverse_256(&ec_q[0], &buffer[1]); reverse_256(&ec_q[32], &buffer[33]); #ifdef ENABLE_TESTING_SUPPORT if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ log_info("testing_support: invalidating public key"); // flip single bit of public key coordinate buffer[1] ^= 1; } #endif // stk generation method // passkey entry: notify app to show passkey or to request passkey switch (setup->sm_stk_generation_method){ case JUST_WORKS: case NUMERIC_COMPARISON: if (IS_RESPONDER(connection->sm_role)){ // responder trigger_start_calculating_local_confirm = true; connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; } else { // initiator connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; } break; case PK_INIT_INPUT: case PK_RESP_INPUT: case PK_BOTH_INPUT: // use random TK for display (void)memcpy(setup->sm_ra, setup->sm_tk, 16); (void)memcpy(setup->sm_rb, setup->sm_tk, 16); setup->sm_passkey_bit = 0; if (IS_RESPONDER(connection->sm_role)){ // responder connection->sm_engine_state = SM_SC_W4_CONFIRMATION; } else { // initiator connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; } trigger_user_response = true; break; case OOB: if (IS_RESPONDER(connection->sm_role)){ // responder connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; } else { // initiator connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; } break; default: btstack_assert(false); break; } sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); // trigger user response and calc confirm after sending pdu if (trigger_user_response){ sm_trigger_user_response(connection); } if (trigger_start_calculating_local_confirm){ sm_sc_start_calculating_local_confirm(connection); } } #endif static bool sm_run_non_connection_logic(void){ bool done;; done = sm_run_dpkg(); if (done) return true; done = sm_run_rau(); if (done) return true; done = sm_run_irk_lookup(); if (done) return true; done = sm_run_oob(); return done; } static bool sm_run_ready(void) { // assert that stack has already booted if (hci_get_state() != HCI_STATE_WORKING) return false; // assert that we can send at least commands if (!hci_can_send_command_packet_now()) return false; // pause until IR/ER are ready if (sm_persistent_keys_random_active) return false; return true; } static void sm_run(void){ // ready if (sm_run_ready() == false) return; // non-connection related behaviour bool done = sm_run_non_connection_logic(); if (done) return; // assert that we can send at least commands - cmd might have been sent by crypto engine if (!hci_can_send_command_packet_now()) return; // handle basic actions that don't requires the full context done = sm_run_basic(); if (done) return; // // active connection handling // -- use loop to handle next connection if lock on setup context is released while (true) { sm_run_activate_connection(); if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; // // active connection handling // sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); if (!connection) { log_info("no connection for handle 0x%04x", sm_active_connection_handle); return; } // assert that we could send a SM PDU - not needed for all of the following if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, connection->sm_cid)) { log_info("cannot send now, requesting can send now event"); l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, connection->sm_cid); return; } // send keypress notifications if (setup->sm_keypress_notification != 0u){ sm_run_send_keypress_notification(connection); return; } #ifdef ENABLE_LE_SECURE_CONNECTIONS // assert that sm cmac engine is ready if (sm_cmac_ready() == false){ break; } #endif // initialize to avoid 'maybe used uninitialized' error int key_distribution_flags = 0; UNUSED(key_distribution_flags); #ifdef ENABLE_LE_PERIPHERAL int err; bool have_ltk; uint8_t ltk[16]; #endif log_info("sm_run: state %u", connection->sm_engine_state); switch (connection->sm_engine_state){ // secure connections, initiator + responding states #ifdef ENABLE_LE_SECURE_CONNECTIONS case SM_SC_W2_CMAC_FOR_CONFIRMATION: connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; sm_sc_calculate_local_confirm(connection); break; case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; sm_sc_calculate_remote_confirm(connection); break; case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; sm_sc_calculate_f6_for_dhkey_check(connection); break; case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; sm_sc_calculate_f6_to_verify_dhkey_check(connection); break; case SM_SC_W2_CALCULATE_F5_SALT: connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; f5_calculate_salt(connection); break; case SM_SC_W2_CALCULATE_F5_MACKEY: connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; f5_calculate_mackey(connection); break; case SM_SC_W2_CALCULATE_F5_LTK: connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; f5_calculate_ltk(connection); break; case SM_SC_W2_CALCULATE_G2: connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; g2_calculate(connection); break; #endif #ifdef ENABLE_LE_CENTRAL // initiator side case SM_INITIATOR_PH4_HAS_LTK: { sm_reset_setup(); sm_load_security_info(connection); // cache key before using sm_cache_ltk(connection, setup->sm_peer_ltk); sm_key_t peer_ltk_flipped; reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); // notify after sending sm_reencryption_started(connection); return; } case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: sm_reset_setup(); sm_init_setup(connection); sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; sm_send_connectionless(connection, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); sm_timeout_reset(connection); // notify after sending sm_pairing_started(connection); break; #endif #ifdef ENABLE_LE_SECURE_CONNECTIONS case SM_SC_SEND_PUBLIC_KEY_COMMAND: sm_run_state_sc_send_public_key_command(connection); break; case SM_SC_SEND_CONFIRMATION: sm_run_state_sc_send_confirmation(connection); break; case SM_SC_SEND_PAIRING_RANDOM: sm_run_state_sc_send_pairing_random(connection); break; case SM_SC_SEND_DHKEY_CHECK_COMMAND: sm_run_state_sc_send_dhkey_check_command(connection); break; #endif #ifdef ENABLE_LE_PERIPHERAL case SM_RESPONDER_SEND_SECURITY_REQUEST: { const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; sm_send_connectionless(connection, (uint8_t *) buffer, sizeof(buffer)); sm_timeout_start(connection); break; } #ifdef ENABLE_LE_SECURE_CONNECTIONS case SM_SC_RECEIVED_LTK_REQUEST: switch (connection->sm_irk_lookup_state){ case IRK_LOOKUP_SUCCEEDED: // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null // start using context by loading security info sm_reset_setup(); sm_load_security_info(connection); if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; sm_reencryption_started(connection); sm_trigger_run(); break; } log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); connection->sm_engine_state = SM_RESPONDER_IDLE; hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); return; default: // just wait until IRK lookup is completed break; } break; #endif /* ENABLE_LE_SECURE_CONNECTIONS */ case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: sm_reset_setup(); // handle Pairing Request with LTK available switch (connection->sm_irk_lookup_state) { case IRK_LOOKUP_SUCCEEDED: le_device_db_encryption_get(connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); have_ltk = !sm_is_null_key(ltk); if (have_ltk){ log_info("pairing request but LTK available"); // emit re-encryption start/fail sequence sm_reencryption_started(connection); sm_reencryption_complete(connection, ERROR_CODE_PIN_OR_KEY_MISSING); } break; default: break; } sm_init_setup(connection); // recover pairing request (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); err = sm_stk_generation_init(connection); #ifdef ENABLE_TESTING_SUPPORT if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ log_info("testing_support: respond with pairing failure %u", test_pairing_failure); err = test_pairing_failure; } #endif if (err != 0){ // emit pairing started/failed sequence sm_pairing_started(connection); sm_pairing_error(connection, err); sm_trigger_run(); break; } sm_timeout_start(connection); // generate random number first, if we need to show passkey, otherwise send response if (setup->sm_stk_generation_method == PK_INIT_INPUT){ btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); break; } /* fall through */ case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); // start with initiator key dist flags key_distribution_flags = sm_key_distribution_flags_for_auth_req(); #ifdef ENABLE_LE_SECURE_CONNECTIONS // LTK (= encryption information & master identification) only exchanged for LE Legacy Connection if (setup->sm_use_secure_connections){ key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; } #endif // setup in response sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq) & key_distribution_flags); sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq) & key_distribution_flags); // update key distribution after ENC was dropped sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres), sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); if (setup->sm_use_secure_connections){ connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; } else { connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; } sm_send_connectionless(connection, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); sm_timeout_reset(connection); // notify after sending sm_pairing_started(connection); // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ sm_trigger_user_response(connection); } return; #endif case SM_PH2_SEND_PAIRING_RANDOM: { uint8_t buffer[17]; buffer[0] = SM_CODE_PAIRING_RANDOM; reverse_128(setup->sm_local_random, &buffer[1]); if (IS_RESPONDER(connection->sm_role)){ connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; } else { connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; } sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); break; } case SM_PH2_C1_GET_ENC_A: // already busy? if (sm_aes128_state == SM_AES128_ACTIVE) break; // calculate confirm using aes128 engine - step 1 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, sm_aes128_plaintext); connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, (void *)(uintptr_t) connection->sm_handle); break; case SM_PH2_C1_GET_ENC_C: // already busy? if (sm_aes128_state == SM_AES128_ACTIVE) break; // calculate m_confirm using aes128 engine - step 1 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, sm_aes128_plaintext); connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, (void *)(uintptr_t) connection->sm_handle); break; case SM_PH2_CALC_STK: // already busy? if (sm_aes128_state == SM_AES128_ACTIVE) break; // calculate STK if (IS_RESPONDER(connection->sm_role)){ sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); } else { sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); } connection->sm_engine_state = SM_PH2_W4_STK; sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); break; case SM_PH3_Y_GET_ENC: // already busy? if (sm_aes128_state == SM_AES128_ACTIVE) break; // PH3B2 - calculate Y from - enc // dm helper (was sm_dm_r_prime) // r' = padding || r // r - 64 bit value memset(&sm_aes128_plaintext[0], 0, 8); (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); // Y = dm(DHK, Rand) connection->sm_engine_state = SM_PH3_Y_W4_ENC; sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph3_y, (void *)(uintptr_t) connection->sm_handle); break; case SM_PH2_C1_SEND_PAIRING_CONFIRM: { uint8_t buffer[17]; buffer[0] = SM_CODE_PAIRING_CONFIRM; reverse_128(setup->sm_local_confirm, &buffer[1]); if (IS_RESPONDER(connection->sm_role)){ connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; } else { connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; } sm_send_connectionless(connection, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); return; } #ifdef ENABLE_LE_PERIPHERAL case SM_RESPONDER_PH2_SEND_LTK_REPLY: { // cache key before using sm_cache_ltk(connection, setup->sm_ltk); sm_key_t stk_flipped; reverse_128(setup->sm_ltk, stk_flipped); connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); return; } case SM_RESPONDER_PH4_SEND_LTK_REPLY: { // allow to override LTK if (sm_get_ltk_callback != NULL){ (void)(*sm_get_ltk_callback)(connection->sm_handle, connection->sm_peer_addr_type, connection->sm_peer_address, setup->sm_ltk); } // cache key before using sm_cache_ltk(connection, setup->sm_ltk); sm_key_t ltk_flipped; reverse_128(setup->sm_ltk, ltk_flipped); connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); return; } case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: // already busy? if (sm_aes128_state == SM_AES128_ACTIVE) break; log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); sm_reset_setup(); sm_start_calculating_ltk_from_ediv_and_rand(connection); sm_reencryption_started(connection); // dm helper (was sm_dm_r_prime) // r' = padding || r // r - 64 bit value memset(&sm_aes128_plaintext[0], 0, 8); (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); // Y = dm(DHK, Rand) connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph4_y, (void *)(uintptr_t) connection->sm_handle); return; #endif #ifdef ENABLE_LE_CENTRAL case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { // cache key before using sm_cache_ltk(connection, setup->sm_ltk); sm_key_t stk_flipped; reverse_128(setup->sm_ltk, stk_flipped); connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); return; } #endif case SM_PH3_DISTRIBUTE_KEYS: // send next key if (setup->sm_key_distribution_send_set != 0){ sm_run_distribute_keys(connection); } // more to send? if (setup->sm_key_distribution_send_set != 0){ return; } // keys are sent if (IS_RESPONDER(connection->sm_role)){ // slave -> receive master keys if any if (sm_key_distribution_all_received()){ sm_key_distribution_handle_all_received(connection); sm_key_distribution_complete_responder(connection); // start CTKD right away continue; } else { connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; } } else { sm_master_pairing_success(connection); } break; #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION case SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST: // fill in sm setup (lite version of sm_init_setup) sm_reset_setup(); setup->sm_peer_addr_type = connection->sm_peer_addr_type; setup->sm_m_addr_type = connection->sm_peer_addr_type; setup->sm_s_addr_type = connection->sm_own_addr_type; (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); setup->sm_use_secure_connections = true; sm_ctkd_fetch_br_edr_link_key(connection); // Enc Key and IRK if requested key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; #ifdef ENABLE_LE_SIGNED_WRITE // Plus signing key if supported key_distribution_flags |= SM_KEYDIST_ID_KEY; #endif sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); sm_pairing_packet_set_io_capability(setup->sm_m_preq, 0); sm_pairing_packet_set_oob_data_flag(setup->sm_m_preq, 0); sm_pairing_packet_set_auth_req(setup->sm_m_preq, SM_AUTHREQ_CT2); sm_pairing_packet_set_max_encryption_key_size(setup->sm_m_preq, sm_max_encryption_key_size); sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); // set state and send pairing response sm_timeout_start(connection); connection->sm_engine_state = SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE; sm_send_connectionless(connection, (uint8_t *) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); break; case SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED: // fill in sm setup (lite version of sm_init_setup) sm_reset_setup(); setup->sm_peer_addr_type = connection->sm_peer_addr_type; setup->sm_m_addr_type = connection->sm_peer_addr_type; setup->sm_s_addr_type = connection->sm_own_addr_type; (void) memcpy(setup->sm_peer_address, connection->sm_peer_address, 6); (void) memcpy(setup->sm_m_address, connection->sm_peer_address, 6); (void) memcpy(setup->sm_s_address, connection->sm_own_address, 6); setup->sm_use_secure_connections = true; sm_ctkd_fetch_br_edr_link_key(connection); (void) memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); // Enc Key and IRK if requested key_distribution_flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_ENC_KEY; #ifdef ENABLE_LE_SIGNED_WRITE // Plus signing key if supported key_distribution_flags |= SM_KEYDIST_ID_KEY; #endif // drop flags not requested by initiator key_distribution_flags &= sm_pairing_packet_get_initiator_key_distribution(connection->sm_m_preq); // If Secure Connections pairing has been initiated over BR/EDR, the following fields of the SM Pairing Request PDU are reserved for future use: // - the IO Capability field, // - the OOB data flag field, and // - all bits in the Auth Req field except the CT2 bit. sm_pairing_packet_set_code(setup->sm_s_pres, SM_CODE_PAIRING_RESPONSE); sm_pairing_packet_set_io_capability(setup->sm_s_pres, 0); sm_pairing_packet_set_oob_data_flag(setup->sm_s_pres, 0); sm_pairing_packet_set_auth_req(setup->sm_s_pres, SM_AUTHREQ_CT2); sm_pairing_packet_set_max_encryption_key_size(setup->sm_s_pres, connection->sm_actual_encryption_key_size); sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, key_distribution_flags); sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, key_distribution_flags); // configure key distribution, LTK is derived locally key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; sm_setup_key_distribution(key_distribution_flags, key_distribution_flags); // set state and send pairing response sm_timeout_start(connection); connection->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; sm_send_connectionless(connection, (uint8_t *) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); break; case SM_BR_EDR_DISTRIBUTE_KEYS: // send next key if (setup->sm_key_distribution_send_set != 0) { sm_run_distribute_keys(connection); } // more to send? if (setup->sm_key_distribution_send_set != 0){ return; } // keys are sent if (IS_RESPONDER(connection->sm_role)) { // responder -> receive master keys if there are any if (!sm_key_distribution_all_received()){ connection->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; break; } } // otherwise start CTKD right away (responder and no keys to receive / initiator) sm_ctkd_start_from_br_edr(connection); continue; case SM_SC_W2_CALCULATE_ILK_USING_H6: connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; h6_calculate_ilk_from_le_ltk(connection); break; case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; h6_calculate_br_edr_link_key(connection); break; case SM_SC_W2_CALCULATE_ILK_USING_H7: connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; h7_calculate_ilk_from_le_ltk(connection); break; case SM_BR_EDR_W2_CALCULATE_ILK_USING_H6: connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; h6_calculate_ilk_from_br_edr(connection); break; case SM_BR_EDR_W2_CALCULATE_LE_LTK: connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_LE_LTK; h6_calculate_le_ltk(connection); break; case SM_BR_EDR_W2_CALCULATE_ILK_USING_H7: connection->sm_engine_state = SM_BR_EDR_W4_CALCULATE_ILK; h7_calculate_ilk_from_br_edr(connection); break; #endif default: break; } // check again if active connection was released if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; } } // sm_aes128_state stays active static void sm_handle_encryption_result_enc_a(void *arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_aes128_state = SM_AES128_IDLE; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, setup->sm_local_confirm, sm_handle_encryption_result_enc_b, (void *)(uintptr_t) connection->sm_handle); } static void sm_handle_encryption_result_enc_b(void *arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_aes128_state = SM_AES128_IDLE; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; log_info_key("c1!", setup->sm_local_confirm); connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; sm_trigger_run(); } // sm_aes128_state stays active static void sm_handle_encryption_result_enc_c(void *arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_aes128_state = SM_AES128_IDLE; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, sm_aes128_ciphertext, sm_handle_encryption_result_enc_d, (void *)(uintptr_t) connection->sm_handle); } static void sm_handle_encryption_result_enc_d(void * arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_aes128_state = SM_AES128_IDLE; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; log_info_key("c1!", sm_aes128_ciphertext); if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ sm_pairing_error(connection, SM_REASON_CONFIRM_VALUE_FAILED); sm_trigger_run(); return; } if (IS_RESPONDER(connection->sm_role)){ connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; sm_trigger_run(); } else { sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); } } static void sm_handle_encryption_result_enc_stk(void *arg){ sm_aes128_state = SM_AES128_IDLE; hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); log_info_key("stk", setup->sm_ltk); if (IS_RESPONDER(connection->sm_role)){ connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; } else { connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; } sm_trigger_run(); } // sm_aes128_state stays active static void sm_handle_encryption_result_enc_ph3_y(void *arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_aes128_state = SM_AES128_IDLE; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); log_info_hex16("y", setup->sm_local_y); // PH3B3 - calculate EDIV setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; log_info_hex16("ediv", setup->sm_local_ediv); // PH3B4 - calculate LTK - enc // LTK = d1(ER, DIV, 0)) sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph3_ltk, (void *)(uintptr_t) connection->sm_handle); } #ifdef ENABLE_LE_PERIPHERAL // sm_aes128_state stays active static void sm_handle_encryption_result_enc_ph4_y(void *arg){ sm_aes128_state = SM_AES128_IDLE; hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); log_info_hex16("y", setup->sm_local_y); // PH3B3 - calculate DIV setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; log_info_hex16("ediv", setup->sm_local_ediv); // PH3B4 - calculate LTK - enc // LTK = d1(ER, DIV, 0)) sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph4_ltk, (void *)(uintptr_t) connection->sm_handle); } #endif // sm_aes128_state stays active static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_aes128_state = SM_AES128_IDLE; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; log_info_key("ltk", setup->sm_ltk); // calc CSRK next sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); sm_aes128_state = SM_AES128_ACTIVE; btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_local_csrk, sm_handle_encryption_result_enc_csrk, (void *)(uintptr_t) connection->sm_handle); } static void sm_handle_encryption_result_enc_csrk(void *arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_aes128_state = SM_AES128_IDLE; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; sm_aes128_state = SM_AES128_IDLE; log_info_key("csrk", setup->sm_local_csrk); if (setup->sm_key_distribution_send_set != 0u){ connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; } else { // no keys to send, just continue if (IS_RESPONDER(connection->sm_role)){ if (sm_key_distribution_all_received()){ sm_key_distribution_handle_all_received(connection); sm_key_distribution_complete_responder(connection); } else { // slave -> receive master keys connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; } } else { sm_key_distribution_complete_initiator(connection); } } sm_trigger_run(); } #ifdef ENABLE_LE_PERIPHERAL static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_aes128_state = SM_AES128_IDLE; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); log_info_key("ltk", setup->sm_ltk); connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; sm_trigger_run(); } #endif static void sm_handle_encryption_result_address_resolution(void *arg){ UNUSED(arg); sm_aes128_state = SM_AES128_IDLE; // compare calulated address against connecting device uint8_t * hash = &sm_aes128_ciphertext[13]; if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ log_info("LE Device Lookup: matched resolvable private address"); sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); sm_trigger_run(); return; } // no match, try next sm_address_resolution_test++; sm_trigger_run(); } static void sm_handle_encryption_result_dkg_irk(void *arg){ UNUSED(arg); sm_aes128_state = SM_AES128_IDLE; log_info_key("irk", sm_persistent_irk); dkg_state = DKG_CALC_DHK; sm_trigger_run(); } static void sm_handle_encryption_result_dkg_dhk(void *arg){ UNUSED(arg); sm_aes128_state = SM_AES128_IDLE; log_info_key("dhk", sm_persistent_dhk); dkg_state = DKG_READY; sm_trigger_run(); } static void sm_handle_encryption_result_rau(void *arg){ UNUSED(arg); sm_aes128_state = SM_AES128_IDLE; (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); rau_state = RAU_IDLE; hci_le_random_address_set(sm_random_address); sm_trigger_run(); } static void sm_handle_random_result_rau(void * arg){ UNUSED(arg); // non-resolvable vs. resolvable switch (gap_random_adress_type){ case GAP_RANDOM_ADDRESS_RESOLVABLE: // resolvable: use random as prand and calc address hash // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" sm_random_address[0u] &= 0x3fu; sm_random_address[0u] |= 0x40u; rau_state = RAU_GET_ENC; break; case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: default: // "The two most significant bits of the address shall be equal to ‘0’"" sm_random_address[0u] &= 0x3fu; rau_state = RAU_IDLE; hci_le_random_address_set(sm_random_address); break; } sm_trigger_run(); } #ifdef ENABLE_LE_SECURE_CONNECTIONS static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; sm_trigger_run(); } static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; sm_trigger_run(); } #endif static void sm_handle_random_result_ph2_random(void * arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; sm_trigger_run(); } static void sm_handle_random_result_ph2_tk(void * arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; sm_reset_tk(); uint32_t tk; if (sm_fixed_passkey_in_display_role == 0xffffffffU){ // map random to 0-999999 without speding much cycles on a modulus operation tk = little_endian_read_32(sm_random_data,0); tk = tk & 0xfffff; // 1048575 if (tk >= 999999u){ tk = tk - 999999u; } } else { // override with pre-defined passkey tk = sm_fixed_passkey_in_display_role; } big_endian_store_32(setup->sm_tk, 12, tk); if (IS_RESPONDER(connection->sm_role)){ connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; } else { if (setup->sm_use_secure_connections){ connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; } else { connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; sm_trigger_user_response(connection); // response_idle == nothing <--> sm_trigger_user_response() did not require response if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) connection->sm_handle); } } } sm_trigger_run(); } static void sm_handle_random_result_ph3_div(void * arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; // use 16 bit from random value as div setup->sm_local_div = big_endian_read_16(sm_random_data, 0); log_info_hex16("div", setup->sm_local_div); connection->sm_engine_state = SM_PH3_Y_GET_ENC; sm_trigger_run(); } static void sm_handle_random_result_ph3_random(void * arg){ hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; sm_connection_t * connection = sm_get_connection_for_handle(con_handle); if (connection == NULL) return; reverse_64(sm_random_data, setup->sm_local_rand); // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); // no db for authenticated flag hack: store flag in bit 4 of LSB setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); } static void sm_validate_er_ir(void){ // warn about default ER/IR bool warning = false; if (sm_ir_is_default()){ warning = true; log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); } if (sm_er_is_default()){ warning = true; log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); } if (warning) { log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); } } static void sm_handle_random_result_ir(void *arg){ sm_persistent_keys_random_active = false; if (arg != NULL){ // key generated, store in tlv int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); log_info("Generated IR key. Store in TLV status: %d", status); UNUSED(status); } log_info_key("IR", sm_persistent_ir); dkg_state = DKG_CALC_IRK; if (test_use_fixed_local_irk){ log_info_key("IRK", sm_persistent_irk); dkg_state = DKG_CALC_DHK; } sm_trigger_run(); } static void sm_handle_random_result_er(void *arg){ sm_persistent_keys_random_active = false; if (arg != NULL){ // key generated, store in tlv int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); log_info("Generated ER key. Store in TLV status: %d", status); UNUSED(status); } log_info_key("ER", sm_persistent_er); // try load ir int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); if (key_size == 16){ // ok, let's continue log_info("IR from TLV"); sm_handle_random_result_ir( NULL ); } else { // invalid, generate new random one sm_persistent_keys_random_active = true; btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); } } static void sm_connection_init(sm_connection_t * sm_conn, hci_con_handle_t con_handle, uint8_t role, uint8_t peer_addr_type, bd_addr_t peer_address){ // connection info sm_conn->sm_handle = con_handle; sm_conn->sm_role = role; sm_conn->sm_peer_addr_type = peer_addr_type; memcpy(sm_conn->sm_peer_address, peer_address, 6); // security properties sm_conn->sm_connection_encrypted = 0; sm_conn->sm_connection_authenticated = 0; sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; sm_conn->sm_le_db_index = -1; sm_conn->sm_reencryption_active = false; // prepare CSRK lookup (does not involve setup) sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; sm_conn->sm_engine_state = SM_GENERAL_IDLE; } #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION static void sm_event_handle_classic_encryption_event(sm_connection_t * sm_conn, hci_con_handle_t con_handle){ // CTKD requires BR/EDR Secure Connection if (sm_conn->sm_connection_encrypted != 2) return; // prepare for pairing request if (IS_RESPONDER(sm_conn->sm_role)){ log_info("CTKD: SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST"); sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST; } else if (sm_conn->sm_pairing_requested){ // check if remote supports fixed channels bool defer = true; const hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); if (hci_connection->l2cap_state.information_state == L2CAP_INFORMATION_STATE_DONE){ // check if remote supports SMP over BR/EDR if ((hci_connection->l2cap_state.fixed_channels_supported & (1 << L2CAP_CID_BR_EDR_SECURITY_MANAGER)) != 0){ log_info("CTKD: SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST"); sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; } else { defer = false; } } else { // wait for fixed channel info log_info("CTKD: SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK"); sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK; } if (defer){ hci_dedicated_bonding_defer_disconnect(con_handle, true); } } } #endif static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ UNUSED(channel); // ok: there is no channel UNUSED(size); // ok: fixed format HCI events sm_connection_t * sm_conn; hci_con_handle_t con_handle; uint8_t status; bd_addr_t addr; bd_addr_type_t addr_type; switch (packet_type) { case HCI_EVENT_PACKET: switch (hci_event_packet_get_type(packet)) { case BTSTACK_EVENT_STATE: switch (btstack_event_state_get_state(packet)){ case HCI_STATE_WORKING: log_info("HCI Working!"); // setup IR/ER with TLV btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); if (sm_tlv_impl != NULL){ int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); if (key_size == 16){ // ok, let's continue log_info("ER from TLV"); sm_handle_random_result_er( NULL ); } else { // invalid, generate random one sm_persistent_keys_random_active = true; btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); } } else { sm_validate_er_ir(); dkg_state = DKG_CALC_IRK; if (test_use_fixed_local_irk){ log_info_key("IRK", sm_persistent_irk); dkg_state = DKG_CALC_DHK; } } #ifdef ENABLE_LE_SECURE_CONNECTIONS // trigger ECC key generation if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ sm_ec_generate_new_key(); } #endif // restart random address updates after power cycle if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_STATIC){ gap_random_address_set(sm_random_address); } else { gap_random_address_set_mode(gap_random_adress_type); } break; case HCI_STATE_OFF: case HCI_STATE_HALTING: log_info("SM: reset state"); // stop random address update gap_random_address_update_stop(); // reset state sm_state_reset(); break; default: break; } break; #ifdef ENABLE_CLASSIC case HCI_EVENT_CONNECTION_COMPLETE: // ignore if connection failed if (hci_event_connection_complete_get_status(packet)) return; con_handle = hci_event_connection_complete_get_connection_handle(packet); sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) break; hci_event_connection_complete_get_bd_addr(packet, addr); sm_connection_init(sm_conn, con_handle, (uint8_t) gap_get_role(con_handle), BD_ADDR_TYPE_LE_PUBLIC, addr); // classic connection corresponds to public le address sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_PUBLIC; gap_local_bd_addr(sm_conn->sm_own_address); sm_conn->sm_cid = L2CAP_CID_BR_EDR_SECURITY_MANAGER; sm_conn->sm_engine_state = SM_BR_EDR_W4_ENCRYPTION_COMPLETE; break; #endif #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION case HCI_EVENT_ROLE_CHANGE: hci_event_role_change_get_bd_addr(packet, addr); sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); if (sm_conn == NULL) break; sm_conn->sm_role = hci_event_role_change_get_role(packet); break; case HCI_EVENT_SIMPLE_PAIRING_COMPLETE: if (hci_event_simple_pairing_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; hci_event_simple_pairing_complete_get_bd_addr(packet, addr); sm_conn = sm_get_connection_for_bd_addr_and_type(addr, BD_ADDR_TYPE_ACL); if (sm_conn == NULL) break; sm_conn->sm_pairing_requested = true; break; #endif case HCI_EVENT_META_GAP: switch (hci_event_gap_meta_get_subevent_code(packet)) { case GAP_SUBEVENT_LE_CONNECTION_COMPLETE: // ignore if connection failed if (gap_subevent_le_connection_complete_get_status(packet) != ERROR_CODE_SUCCESS) break; con_handle = gap_subevent_le_connection_complete_get_connection_handle(packet); sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) break; // Get current peer address addr_type = gap_subevent_le_connection_complete_get_peer_address_type(packet); if (hci_is_le_identity_address_type(addr_type)){ addr_type = BD_ADDR_TYPE_LE_RANDOM; gap_subevent_le_connection_complete_get_peer_resolvable_private_address(packet, addr); } else { gap_subevent_le_connection_complete_get_peer_address(packet, addr); } sm_connection_init(sm_conn, con_handle, gap_subevent_le_connection_complete_get_role(packet), addr_type, addr); sm_conn->sm_cid = L2CAP_CID_SECURITY_MANAGER_PROTOCOL; // track our addr used for this connection and set state #ifdef ENABLE_LE_PERIPHERAL if (gap_subevent_le_connection_complete_get_role(packet) != 0){ // responder - use own address from advertisements #ifdef ENABLE_LE_EXTENDED_ADVERTISING if (hci_le_extended_advertising_supported()){ // cache local resolvable address // note: will be overwritten if random or private address was used in adv set by HCI_SUBEVENT_LE_ADVERTISING_SET_TERMINATED sm_conn->sm_own_addr_type = BD_ADDR_TYPE_LE_RANDOM; gap_subevent_le_connection_complete_get_local_resolvable_private_address(packet,sm_conn->sm_own_address); } else #endif { gap_le_get_own_advertisements_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); } sm_conn->sm_engine_state = SM_RESPONDER_IDLE; } #endif #ifdef ENABLE_LE_CENTRAL if (gap_subevent_le_connection_complete_get_role(packet) == 0){ // initiator - use own address from create connection gap_le_get_own_connection_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address); sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; } #endif break; default: break; } break; case HCI_EVENT_LE_META: switch (hci_event_le_meta_get_subevent_code(packet)) { #ifdef ENABLE_LE_PERIPHERAL #ifdef ENABLE_LE_EXTENDED_ADVERTISING case HCI_SUBEVENT_LE_ADVERTISING_SET_TERMINATED: if (hci_subevent_le_advertising_set_terminated_get_status(packet) == ERROR_CODE_SUCCESS){ uint8_t advertising_handle = hci_subevent_le_advertising_set_terminated_get_advertising_handle(packet); con_handle = hci_subevent_le_advertising_set_terminated_get_connection_handle(packet); sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) break; gap_le_get_own_advertising_set_address(&sm_conn->sm_own_addr_type, sm_conn->sm_own_address, advertising_handle); log_info("Adv set %u terminated -> use addr type %u, addr %s for con handle 0x%04x", advertising_handle, sm_conn->sm_own_addr_type, bd_addr_to_str(sm_conn->sm_own_address), con_handle); } break; #endif #endif case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: con_handle = hci_subevent_le_long_term_key_request_get_connection_handle(packet); sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) break; log_info("LTK Request: state %u", sm_conn->sm_engine_state); if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ sm_conn->sm_engine_state = SM_PH2_CALC_STK; break; } if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ // PH2 SEND LTK as we need to exchange keys in PH3 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; break; } // store rand and ediv reverse_64(&packet[5], sm_conn->sm_local_rand); sm_conn->sm_local_ediv = hci_subevent_le_long_term_key_request_get_encryption_diversifier(packet); // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a // potentially stored LTK is from the master if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ if (sm_reconstruct_ltk_without_le_device_db_entry){ sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; break; } // additionally check if remote is in LE Device DB if requested switch(sm_conn->sm_irk_lookup_state){ case IRK_LOOKUP_FAILED: log_info("LTK Request: device not in device db"); sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; break; case IRK_LOOKUP_SUCCEEDED: sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; break; default: // wait for irk look doen sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; break; } break; } #ifdef ENABLE_LE_SECURE_CONNECTIONS sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; #else log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; #endif break; default: break; } break; case HCI_EVENT_ENCRYPTION_CHANGE: case HCI_EVENT_ENCRYPTION_CHANGE_V2: con_handle = hci_event_encryption_change_get_connection_handle(packet); sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) break; sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, sm_conn->sm_actual_encryption_key_size); log_info("event handler, state %u", sm_conn->sm_engine_state); switch (sm_conn->sm_engine_state){ case SM_PH4_W4_CONNECTION_ENCRYPTED: // encryption change event concludes re-encryption for bonded devices (even if it fails) if (sm_conn->sm_connection_encrypted != 0u) { status = ERROR_CODE_SUCCESS; if (IS_RESPONDER(sm_conn->sm_role)){ sm_conn->sm_engine_state = SM_RESPONDER_IDLE; } else { sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; } } else { status = hci_event_encryption_change_get_status(packet); // set state to 'RE-ENCRYPTION FAILED' to allow pairing but prevent other interactions // also, gap_reconnect_security_setup_active will return true sm_conn->sm_engine_state = SM_GENERAL_REENCRYPTION_FAILED; } // emit re-encryption complete sm_reencryption_complete(sm_conn, status); // notify client, if pairing was requested before if (sm_conn->sm_pairing_requested){ sm_conn->sm_pairing_requested = false; sm_pairing_complete(sm_conn, status, 0); } sm_done_for_handle(sm_conn->sm_handle); break; case SM_PH2_W4_CONNECTION_ENCRYPTED: if (!sm_conn->sm_connection_encrypted) break; // handler for HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE // contains the same code for this state sm_conn->sm_connection_sc = setup->sm_use_secure_connections; if (IS_RESPONDER(sm_conn->sm_role)){ // slave if (sm_conn->sm_connection_sc){ sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; } else { btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); } } else { // master if (sm_key_distribution_all_received()){ // skip receiving keys as there are none sm_key_distribution_handle_all_received(sm_conn); btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); } else { sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; } } break; #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: sm_event_handle_classic_encryption_event(sm_conn, con_handle); break; #endif default: break; } break; case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: con_handle = little_endian_read_16(packet, 3); sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) break; log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); log_info("event handler, state %u", sm_conn->sm_engine_state); // continue if part of initial pairing switch (sm_conn->sm_engine_state){ case SM_PH4_W4_CONNECTION_ENCRYPTED: if (IS_RESPONDER(sm_conn->sm_role)){ sm_conn->sm_engine_state = SM_RESPONDER_IDLE; } else { sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; } sm_done_for_handle(sm_conn->sm_handle); break; case SM_PH2_W4_CONNECTION_ENCRYPTED: // handler for HCI_EVENT_ENCRYPTION_CHANGE // contains the same code for this state sm_conn->sm_connection_sc = setup->sm_use_secure_connections; if (IS_RESPONDER(sm_conn->sm_role)){ // slave if (sm_conn->sm_connection_sc){ sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; } else { btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); } } else { // master if (sm_key_distribution_all_received()){ // skip receiving keys as there are none sm_key_distribution_handle_all_received(sm_conn); btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); } else { sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; } } break; #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: sm_event_handle_classic_encryption_event(sm_conn, con_handle); break; #endif default: break; } break; case HCI_EVENT_DISCONNECTION_COMPLETE: con_handle = little_endian_read_16(packet, 3); sm_done_for_handle(con_handle); sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) break; // pairing failed, if it was ongoing switch (sm_conn->sm_engine_state){ case SM_GENERAL_IDLE: case SM_INITIATOR_CONNECTED: case SM_RESPONDER_IDLE: break; default: sm_reencryption_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION); sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); break; } sm_conn->sm_engine_state = SM_GENERAL_IDLE; sm_conn->sm_handle = 0; break; case HCI_EVENT_COMMAND_COMPLETE: if (hci_event_command_complete_get_command_opcode(packet) == HCI_OPCODE_HCI_READ_BD_ADDR) { // set local addr for le device db reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); le_device_db_set_local_bd_addr(addr); } break; #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION case L2CAP_EVENT_INFORMATION_RESPONSE: con_handle = l2cap_event_information_response_get_con_handle(packet); sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) break; if (sm_conn->sm_engine_state == SM_BR_EDR_INITIATOR_W4_FIXED_CHANNEL_MASK){ // check if remote supports SMP over BR/EDR const hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); if ((hci_connection->l2cap_state.fixed_channels_supported & (1 << L2CAP_CID_BR_EDR_SECURITY_MANAGER)) != 0){ sm_conn->sm_engine_state = SM_BR_EDR_INITIATOR_SEND_PAIRING_REQUEST; } else { sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; hci_dedicated_bonding_defer_disconnect(con_handle, false); } } break; #endif default: break; } break; default: break; } sm_run(); } static inline int sm_calc_actual_encryption_key_size(int other){ if (other < sm_min_encryption_key_size) return 0; if (other < sm_max_encryption_key_size) return other; return sm_max_encryption_key_size; } #ifdef ENABLE_LE_SECURE_CONNECTIONS static bool sm_just_works_or_numeric_comparison(stk_generation_method_t method){ switch (method){ case JUST_WORKS: case NUMERIC_COMPARISON: return true; default: return false; } } // responder static bool sm_passkey_used(stk_generation_method_t method){ switch (method){ case PK_RESP_INPUT: return true; default: return 0; } } static bool sm_passkey_entry(stk_generation_method_t method){ switch (method){ case PK_RESP_INPUT: case PK_INIT_INPUT: case PK_BOTH_INPUT: return true; default: return false; } } #endif /** * @return ok */ static int sm_validate_stk_generation_method(void){ // check if STK generation method is acceptable by client switch (setup->sm_stk_generation_method){ case JUST_WORKS: return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; case PK_RESP_INPUT: case PK_INIT_INPUT: case PK_BOTH_INPUT: return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; case OOB: return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; case NUMERIC_COMPARISON: return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; default: return 0; } } #ifdef ENABLE_LE_CENTRAL static void sm_initiator_connected_handle_security_request(sm_connection_t * sm_conn, const uint8_t *packet){ #ifdef ENABLE_LE_SECURE_CONNECTIONS if (sm_sc_only_mode){ uint8_t auth_req = packet[1]; if ((auth_req & SM_AUTHREQ_SECURE_CONNECTION) == 0){ sm_pairing_error(sm_conn, SM_REASON_AUTHENTHICATION_REQUIREMENTS); return; } } #else UNUSED(packet); #endif int have_ltk; uint8_t ltk[16]; // IRK complete? switch (sm_conn->sm_irk_lookup_state){ case IRK_LOOKUP_FAILED: // start pairing sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; break; case IRK_LOOKUP_SUCCEEDED: le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); have_ltk = !sm_is_null_key(ltk); log_info("central: security request - have_ltk %u, encryption %u", have_ltk, sm_conn->sm_connection_encrypted); if (have_ltk && (sm_conn->sm_connection_encrypted == 0)){ // start re-encrypt if we have LTK and the connection is not already encrypted sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; } else { // start pairing sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; } break; default: // otherwise, store security request sm_conn->sm_security_request_received = true; break; } } #endif static uint8_t sm_pdu_validate_and_get_opcode(uint8_t packet_type, const uint8_t *packet, uint16_t size){ // size of complete sm_pdu used to validate input static const uint8_t sm_pdu_size[] = { 0, // 0x00 invalid opcode 7, // 0x01 pairing request 7, // 0x02 pairing response 17, // 0x03 pairing confirm 17, // 0x04 pairing random 2, // 0x05 pairing failed 17, // 0x06 encryption information 11, // 0x07 master identification 17, // 0x08 identification information 8, // 0x09 identify address information 17, // 0x0a signing information 2, // 0x0b security request 65, // 0x0c pairing public key 17, // 0x0d pairing dhk check 2, // 0x0e keypress notification }; if (packet_type != SM_DATA_PACKET) return 0; if (size == 0u) return 0; uint8_t sm_pdu_code = packet[0]; // validate pdu size if (sm_pdu_code >= sizeof(sm_pdu_size)) return 0; if (sm_pdu_size[sm_pdu_code] != size) return 0; return sm_pdu_code; } #ifdef ENABLE_LE_SECURE_CONNECTIONS static void sm_pdu_handler_pairing_public_key(sm_connection_t * sm_conn, const uint8_t * packet) { // store public key for DH Key calculation reverse_256(&packet[01], &setup->sm_peer_q[0]); reverse_256(&packet[33], &setup->sm_peer_q[32]); // CVE-2020-26558: abort pairing if remote uses the same public key if (memcmp(&setup->sm_peer_q, ec_q, 64) == 0){ log_info("Remote PK matches ours"); sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); return; } // validate public key int err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); if (err != 0){ log_info("sm: peer public key invalid %x", err); sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); return; } // start calculating dhkey btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, (void*)(uintptr_t) sm_conn->sm_handle); log_info("public key received, generation method %u", setup->sm_stk_generation_method); if (IS_RESPONDER(sm_conn->sm_role)){ // responder sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; } else { // initiator // stk generation method // passkey entry: notify app to show passkey or to request passkey switch (setup->sm_stk_generation_method){ case JUST_WORKS: case NUMERIC_COMPARISON: sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; break; case PK_RESP_INPUT: sm_sc_start_calculating_local_confirm(sm_conn); break; case PK_INIT_INPUT: case PK_BOTH_INPUT: if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; break; } sm_sc_start_calculating_local_confirm(sm_conn); break; case OOB: if (setup->sm_have_oob_data){ // if we have received rb & cb, verify Cb = f4(PKb, PKb, rb, 0) sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; } else { // otherwise, generate our nonce sm_sc_generate_nx_for_send_random(sm_conn); } break; default: btstack_assert(false); break; } } } #endif static void sm_pdu_handler(sm_connection_t *sm_conn, uint8_t sm_pdu_code, const uint8_t *packet) { log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); #ifdef ENABLE_LE_CENTRAL int err; #endif uint8_t max_encryption_key_size; switch (sm_conn->sm_engine_state){ // a sm timeout requires a new physical connection case SM_GENERAL_TIMEOUT: return; #ifdef ENABLE_LE_CENTRAL // Initiator case SM_INITIATOR_CONNECTED: if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ sm_pdu_received_in_wrong_state(sm_conn); break; } sm_initiator_connected_handle_security_request(sm_conn, packet); break; case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: // Core 5, Vol 3, Part H, 2.4.6: // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ log_info("Ignoring Security Request"); break; } // all other pdus are incorrect if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ sm_pdu_received_in_wrong_state(sm_conn); break; } // store pairing request (void)memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); // validate encryption key size max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres); if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); break; } err = sm_stk_generation_init(sm_conn); #ifdef ENABLE_TESTING_SUPPORT if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ log_info("testing_support: abort with pairing failure %u", test_pairing_failure); err = test_pairing_failure; } #endif if (err != 0){ sm_pairing_error(sm_conn, err); break; } // generate random number first, if we need to show passkey if (setup->sm_stk_generation_method == PK_RESP_INPUT){ btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) sm_conn->sm_handle); break; } #ifdef ENABLE_LE_SECURE_CONNECTIONS if (setup->sm_use_secure_connections){ // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged if (setup->sm_stk_generation_method == JUST_WORKS){ sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; sm_trigger_user_response(sm_conn); if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; } } else { sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; } break; } #endif sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; sm_trigger_user_response(sm_conn); // response_idle == nothing <--> sm_trigger_user_response() did not require response if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); } break; case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ sm_pdu_received_in_wrong_state(sm_conn); break; } // store s_confirm reverse_128(&packet[1], setup->sm_peer_confirm); // abort if s_confirm matches m_confirm if (memcmp(setup->sm_local_confirm, setup->sm_peer_confirm, 16) == 0){ sm_pdu_received_in_wrong_state(sm_conn); break; } #ifdef ENABLE_TESTING_SUPPORT if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ log_info("testing_support: reset confirm value"); memset(setup->sm_peer_confirm, 0, 16); } #endif sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; break; case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ sm_pdu_received_in_wrong_state(sm_conn); break;; } // received random value reverse_128(&packet[1], setup->sm_peer_random); sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; break; case SM_INITIATOR_PH4_HAS_LTK: case SM_PH4_W4_CONNECTION_ENCRYPTED: // ignore Security Request, see SM_INITIATOR_PH1_W4_PAIRING_RESPONSE above if (sm_pdu_code != SM_CODE_SECURITY_REQUEST){ sm_pdu_received_in_wrong_state(sm_conn); } break; #endif #ifdef ENABLE_LE_PERIPHERAL // Responder case SM_RESPONDER_IDLE: case SM_RESPONDER_SEND_SECURITY_REQUEST: case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ sm_pdu_received_in_wrong_state(sm_conn); break;; } // store pairing request (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); // validation encryption key size max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(sm_conn->sm_m_preq); if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); break; } // check if IRK completed switch (sm_conn->sm_irk_lookup_state){ case IRK_LOOKUP_SUCCEEDED: case IRK_LOOKUP_FAILED: sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; break; default: sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED_W4_IRK; break; } break; #endif #ifdef ENABLE_LE_SECURE_CONNECTIONS case SM_SC_W4_PUBLIC_KEY_COMMAND: if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ sm_pdu_received_in_wrong_state(sm_conn); break; } sm_pdu_handler_pairing_public_key(sm_conn, packet); break; case SM_SC_W4_CONFIRMATION: if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ sm_pdu_received_in_wrong_state(sm_conn); break; } // received confirm value reverse_128(&packet[1], setup->sm_peer_confirm); #ifdef ENABLE_TESTING_SUPPORT if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ log_info("testing_support: reset confirm value"); memset(setup->sm_peer_confirm, 0, 16); } #endif if (IS_RESPONDER(sm_conn->sm_role)){ // responder if (sm_passkey_used(setup->sm_stk_generation_method)){ if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ // still waiting for passkey sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; break; } } sm_sc_start_calculating_local_confirm(sm_conn); } else { // initiator if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void*)(uintptr_t) sm_conn->sm_handle); } else { sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; } } break; case SM_SC_W4_PAIRING_RANDOM: if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ sm_pdu_received_in_wrong_state(sm_conn); break; } // received random value reverse_128(&packet[1], setup->sm_peer_nonce); // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) // only check for JUST WORK/NC in initiator role OR passkey entry log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; break; } // OOB if (setup->sm_stk_generation_method == OOB){ // setup local random, set to zero if remote did not receive our data log_info("Received nonce, setup local random ra/rb for dhkey check"); if (IS_RESPONDER(sm_conn->sm_role)) { if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u) { log_info("Reset rb as A does not have OOB data"); memset(setup->sm_rb, 0, 16); } else { (void) memcpy(setup->sm_rb, sm_sc_oob_random, 16); log_info("Use stored rb"); log_info_hexdump(setup->sm_rb, 16); } } else { if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ log_info("Reset ra as B does not have OOB data"); memset(setup->sm_ra, 0, 16); } else { (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); log_info("Use stored ra"); log_info_hexdump(setup->sm_ra, 16); } } if (IS_RESPONDER(sm_conn->sm_role)){ if (setup->sm_have_oob_data){ // if we have received ra & ca, verify Ca = f4(PKa, PKa, ra, 0) sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; } else { // otherwise, generate our nonce sm_sc_generate_nx_for_send_random(sm_conn); } } else { // Confirm value already validated if received before, // move on to DHKey check sm_sc_prepare_dhkey_check(sm_conn); } break; } // TODO: we only get here for Responder role with JW/NC sm_sc_state_after_receiving_random(sm_conn); break; case SM_SC_W2_CALCULATE_G2: case SM_SC_W4_CALCULATE_G2: case SM_SC_W4_CALCULATE_DHKEY: case SM_SC_W2_CALCULATE_F5_SALT: case SM_SC_W4_CALCULATE_F5_SALT: case SM_SC_W2_CALCULATE_F5_MACKEY: case SM_SC_W4_CALCULATE_F5_MACKEY: case SM_SC_W2_CALCULATE_F5_LTK: case SM_SC_W4_CALCULATE_F5_LTK: case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: case SM_SC_W4_DHKEY_CHECK_COMMAND: case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: case SM_SC_W4_USER_RESPONSE: if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ sm_pdu_received_in_wrong_state(sm_conn); break; } // store DHKey Check setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; reverse_128(&packet[01], setup->sm_peer_dhkey_check); // have we been only waiting for dhkey check command? if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; } break; #endif #ifdef ENABLE_LE_PERIPHERAL case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ sm_pdu_received_in_wrong_state(sm_conn); break; } // received confirm value reverse_128(&packet[1], setup->sm_peer_confirm); #ifdef ENABLE_TESTING_SUPPORT if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ log_info("testing_support: reset confirm value"); memset(setup->sm_peer_confirm, 0, 16); } #endif // notify client to hide shown passkey if (setup->sm_stk_generation_method == PK_INIT_INPUT){ sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); } // handle user cancel pairing? if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); break; } // wait for user action? if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; break; } // calculate and send local_confirm btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); break; case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ sm_pdu_received_in_wrong_state(sm_conn); break;; } // received random value reverse_128(&packet[1], setup->sm_peer_random); sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; break; #endif case SM_PH2_W4_CONNECTION_ENCRYPTED: case SM_PH3_RECEIVE_KEYS: switch(sm_pdu_code){ case SM_CODE_ENCRYPTION_INFORMATION: setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; reverse_128(&packet[1], setup->sm_peer_ltk); break; case SM_CODE_MASTER_IDENTIFICATION: setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; setup->sm_peer_ediv = little_endian_read_16(packet, 1); reverse_64(&packet[3], setup->sm_peer_rand); break; case SM_CODE_IDENTITY_INFORMATION: setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; reverse_128(&packet[1], setup->sm_peer_irk); break; case SM_CODE_IDENTITY_ADDRESS_INFORMATION: setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; setup->sm_peer_addr_type = packet[1]; reverse_bd_addr(&packet[2], setup->sm_peer_address); break; case SM_CODE_SIGNING_INFORMATION: setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; reverse_128(&packet[1], setup->sm_peer_csrk); break; default: // Unexpected PDU log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); break; } // done with key distribution? if (sm_key_distribution_all_received()){ sm_key_distribution_handle_all_received(sm_conn); if (IS_RESPONDER(sm_conn->sm_role)){ sm_key_distribution_complete_responder(sm_conn); } else { if (setup->sm_use_secure_connections){ sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; } else { btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); } } } break; #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION case SM_BR_EDR_W4_ENCRYPTION_COMPLETE: // GAP/DM/LEP/BI-02-C - reject CTKD if P-192 encryption is used if (sm_pdu_code == SM_CODE_PAIRING_REQUEST){ sm_pairing_error(sm_conn, SM_REASON_CROSS_TRANSPORT_KEY_DERIVATION_NOT_ALLOWED); } break; case SM_BR_EDR_INITIATOR_W4_PAIRING_RESPONSE: // dedicated bonding complete hci_dedicated_bonding_defer_disconnect(sm_conn->sm_handle, false); if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ sm_pdu_received_in_wrong_state(sm_conn); break; } // store pairing response (void)memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); // validate encryption key size max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(setup->sm_s_pres); if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); break; } sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(max_encryption_key_size); // SC Only mandates 128 bit key size if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { sm_conn->sm_actual_encryption_key_size = 0; } if (sm_conn->sm_actual_encryption_key_size == 0){ sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); break; } // prepare key exchange, LTK is derived locally sm_setup_key_distribution(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY, sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres) & ~SM_KEYDIST_ENC_KEY); // skip receive if there are none if (sm_key_distribution_all_received()){ // distribute keys in run handles 'no keys to send' sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; } else { sm_conn->sm_engine_state = SM_BR_EDR_RECEIVE_KEYS; } break; case SM_BR_EDR_RESPONDER_W4_PAIRING_REQUEST: if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ sm_pdu_received_in_wrong_state(sm_conn); break; } // store pairing request (void)memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); // validate encryption key size max_encryption_key_size = sm_pairing_packet_get_max_encryption_key_size(sm_conn->sm_m_preq); if ((max_encryption_key_size < 7) || (max_encryption_key_size > 16)){ sm_pairing_error(sm_conn, SM_REASON_INVALID_PARAMETERS); break; } sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(max_encryption_key_size); // SC Only mandates 128 bit key size if (sm_sc_only_mode && (sm_conn->sm_actual_encryption_key_size < 16)) { sm_conn->sm_actual_encryption_key_size = 0; } if (sm_conn->sm_actual_encryption_key_size == 0){ sm_pairing_error(sm_conn, SM_REASON_ENCRYPTION_KEY_SIZE); break; } // trigger response if (sm_ctkd_from_classic(sm_conn)){ sm_conn->sm_engine_state = SM_BR_EDR_RESPONDER_PAIRING_REQUEST_RECEIVED; } else { sm_pairing_error(sm_conn, SM_REASON_CROSS_TRANSPORT_KEY_DERIVATION_NOT_ALLOWED); } break; case SM_BR_EDR_RECEIVE_KEYS: switch(sm_pdu_code){ case SM_CODE_IDENTITY_INFORMATION: setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; reverse_128(&packet[1], setup->sm_peer_irk); break; case SM_CODE_IDENTITY_ADDRESS_INFORMATION: setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; setup->sm_peer_addr_type = packet[1]; reverse_bd_addr(&packet[2], setup->sm_peer_address); break; case SM_CODE_SIGNING_INFORMATION: setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; reverse_128(&packet[1], setup->sm_peer_csrk); break; default: // Unexpected PDU log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); break; } // all keys received if (sm_key_distribution_all_received()){ if (IS_RESPONDER(sm_conn->sm_role)){ // responder -> keys exchanged, derive LE LTK sm_ctkd_start_from_br_edr(sm_conn); } else { // initiator -> send our keys if any sm_conn->sm_engine_state = SM_BR_EDR_DISTRIBUTE_KEYS; } } break; #endif default: // Unexpected PDU log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); sm_pdu_received_in_wrong_state(sm_conn); break; } // try to send next pdu sm_trigger_run(); } static void sm_channel_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ sm_run(); } uint8_t sm_pdu_code = sm_pdu_validate_and_get_opcode(packet_type, packet, size); if (sm_pdu_code == 0) return; sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return; if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ sm_reencryption_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE); sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); sm_done_for_handle(con_handle); sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; return; } if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ uint8_t buffer[5]; buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; buffer[1] = 3; little_endian_store_16(buffer, 2, con_handle); buffer[4] = packet[1]; sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); return; } sm_pdu_handler(sm_conn, sm_pdu_code, packet); } // Security Manager Client API void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ sm_get_oob_data = get_oob_data_callback; } void sm_register_sc_oob_data_callback( int (*get_sc_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random)){ sm_get_sc_oob_data = get_sc_oob_data_callback; } void sm_register_ltk_callback( bool (*get_ltk_callback)(hci_con_handle_t con_handle, uint8_t address_type, bd_addr_t addr, uint8_t * ltk)){ sm_get_ltk_callback = get_ltk_callback; } void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); } void sm_remove_event_handler(btstack_packet_callback_registration_t * callback_handler){ btstack_linked_list_remove(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); } void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ sm_accepted_stk_generation_methods = accepted_stk_generation_methods; } void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ sm_min_encryption_key_size = min_size; sm_max_encryption_key_size = max_size; } void sm_set_authentication_requirements(uint8_t auth_req){ #ifndef ENABLE_LE_SECURE_CONNECTIONS if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; } #endif sm_auth_req = auth_req; } void sm_set_io_capabilities(io_capability_t io_capability){ sm_io_capabilities = io_capability; } #ifdef ENABLE_LE_PERIPHERAL void sm_set_request_security(bool enable){ sm_slave_request_security = enable; } #endif void sm_set_er(sm_key_t er){ (void)memcpy(sm_persistent_er, er, 16); } void sm_set_ir(sm_key_t ir){ (void)memcpy(sm_persistent_ir, ir, 16); } // Testing support only void sm_test_set_irk(sm_key_t irk){ (void)memcpy(sm_persistent_irk, irk, 16); dkg_state = DKG_CALC_DHK; test_use_fixed_local_irk = true; } void sm_test_use_fixed_local_csrk(void){ test_use_fixed_local_csrk = true; } #ifdef ENABLE_LE_SECURE_CONNECTIONS static void sm_ec_generated(void * arg){ UNUSED(arg); ec_key_generation_state = EC_KEY_GENERATION_DONE; // trigger pairing if pending for ec key sm_trigger_run(); } static void sm_ec_generate_new_key(void) { log_info("sm: generate new ec key"); #ifdef ENABLE_LE_SECURE_CONNECTIONS_DEBUG_KEY // LE Secure Connections Debug Key const uint8_t debug_key_public[64] = { 0x20, 0xb0, 0x03, 0xd2, 0xf2, 0x97, 0xbe, 0x2c, 0x5e, 0x2c, 0x83, 0xa7, 0xe9, 0xf9, 0xa5, 0xb9, 0xef, 0xf4, 0x91, 0x11, 0xac, 0xf4, 0xfd, 0xdb, 0xcc, 0x03, 0x01, 0x48, 0x0e, 0x35, 0x9d, 0xe6, 0xdc, 0x80, 0x9c, 0x49, 0x65, 0x2a, 0xeb, 0x6d, 0x63, 0x32, 0x9a, 0xbf, 0x5a, 0x52, 0x15, 0x5c, 0x76, 0x63, 0x45, 0xc2, 0x8f, 0xed, 0x30, 0x24, 0x74, 0x1c, 0x8e, 0xd0, 0x15, 0x89, 0xd2, 0x8b }; const uint8_t debug_key_private[32] = { 0x3f, 0x49, 0xf6, 0xd4, 0xa3, 0xc5, 0x5f, 0x38, 0x74, 0xc9, 0xb3, 0xe3, 0xd2, 0x10, 0x3f, 0x50, 0x4a, 0xff, 0x60, 0x7b, 0xeb, 0x40, 0xb7, 0x99, 0x58, 0x99, 0xb8, 0xa6, 0xcd, 0x3c, 0x1a, 0xbd }; if (sm_sc_debug_keys_enabled) { memcpy(ec_q, debug_key_public, 64); btstack_crypto_ecc_p256_set_key(debug_key_public, debug_key_private); ec_key_generation_state = EC_KEY_GENERATION_DONE; } else #endif { ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); } } #endif #ifdef ENABLE_TESTING_SUPPORT void sm_test_set_pairing_failure(int reason){ test_pairing_failure = reason; } #endif static void sm_state_reset(void) { #ifdef USE_CMAC_ENGINE sm_cmac_active = 0; #endif dkg_state = DKG_W4_WORKING; rau_state = RAU_IDLE; sm_aes128_state = SM_AES128_IDLE; sm_address_resolution_test = -1; // no private address to resolve yet sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; sm_address_resolution_general_queue = NULL; sm_active_connection_handle = HCI_CON_HANDLE_INVALID; sm_persistent_keys_random_active = false; #ifdef ENABLE_LE_SECURE_CONNECTIONS ec_key_generation_state = EC_KEY_GENERATION_IDLE; #endif } void sm_init(void){ if (sm_initialized) return; // set default ER and IR values (should be unique - set by app or sm later using TLV) sm_er_ir_set_default(); // defaults sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS | SM_STK_GENERATION_METHOD_OOB | SM_STK_GENERATION_METHOD_PASSKEY | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; sm_max_encryption_key_size = 16; sm_min_encryption_key_size = 7; sm_fixed_passkey_in_display_role = 0xffffffffU; sm_reconstruct_ltk_without_le_device_db_entry = true; gap_random_adress_update_period = 15 * 60 * 1000L; test_use_fixed_local_csrk = false; // other btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); // register for HCI Events hci_event_callback_registration.callback = &sm_event_packet_handler; hci_add_event_handler(&hci_event_callback_registration); #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION // register for L2CAP events l2cap_event_callback_registration.callback = &sm_event_packet_handler; l2cap_add_event_handler(&l2cap_event_callback_registration); #endif // btstack_crypto_init(); // init le_device_db le_device_db_init(); // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW l2cap_register_fixed_channel(sm_channel_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); #ifdef ENABLE_CLASSIC l2cap_register_fixed_channel(sm_channel_handler, L2CAP_CID_BR_EDR_SECURITY_MANAGER); #endif // state sm_state_reset(); sm_initialized = true; } void sm_deinit(void){ sm_initialized = false; btstack_run_loop_remove_timer(&sm_run_timer); #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined (ENABLE_LE_SECURE_CONNECTION_DEBUG_KEY) sm_sc_debug_keys_enabled = false; #endif } void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ sm_fixed_passkey_in_display_role = passkey; } void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ sm_reconstruct_ltk_without_le_device_db_entry = allow != 0; } static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ hci_connection_t * hci_con = hci_connection_for_handle(con_handle); if (!hci_con) return NULL; return &hci_con->sm_connection; } static void sm_cache_ltk(sm_connection_t * connection, const sm_key_t ltk){ hci_connection_t * hci_con = hci_connection_for_handle(connection->sm_handle); btstack_assert(hci_con != NULL); memcpy(hci_con->link_key, ltk, 16); hci_con->link_key_type = COMBINATION_KEY; } #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION static sm_connection_t * sm_get_connection_for_bd_addr_and_type(bd_addr_t address, bd_addr_type_t addr_type){ hci_connection_t * hci_con = hci_connection_for_bd_addr_and_type(address, addr_type); if (!hci_con) return NULL; return &hci_con->sm_connection; } #endif // @deprecated: map onto sm_request_pairing void sm_send_security_request(hci_con_handle_t con_handle){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return; if (!IS_RESPONDER(sm_conn->sm_role)) return; sm_request_pairing(con_handle); } // request pairing void sm_request_pairing(hci_con_handle_t con_handle){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return; // wrong connection bool have_ltk; uint8_t ltk[16]; bool auth_required; int authenticated; bool trigger_reencryption; log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); if (IS_RESPONDER(sm_conn->sm_role)){ switch (sm_conn->sm_engine_state){ case SM_GENERAL_IDLE: case SM_RESPONDER_IDLE: switch (sm_conn->sm_irk_lookup_state){ case IRK_LOOKUP_SUCCEEDED: le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); have_ltk = !sm_is_null_key(ltk); log_info("have ltk %u", have_ltk); if (have_ltk){ sm_conn->sm_pairing_requested = true; sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; sm_reencryption_started(sm_conn); break; } /* fall through */ case IRK_LOOKUP_FAILED: sm_conn->sm_pairing_requested = true; sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; sm_pairing_started(sm_conn); break; default: log_info("irk lookup pending"); sm_conn->sm_pairing_requested = true; break; } break; default: break; } } else { // used as a trigger to start central/master/initiator security procedures switch (sm_conn->sm_engine_state){ case SM_INITIATOR_CONNECTED: switch (sm_conn->sm_irk_lookup_state){ case IRK_LOOKUP_SUCCEEDED: le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, &authenticated, NULL, NULL); have_ltk = !sm_is_null_key(ltk); auth_required = sm_auth_req & SM_AUTHREQ_MITM_PROTECTION; // re-encrypt is sufficient if we have ltk and that is either already authenticated or we don't require authentication trigger_reencryption = have_ltk && ((authenticated != 0) || (auth_required == false)); log_info("have ltk %u, authenticated %u, auth required %u => reencrypt %u", have_ltk, authenticated, auth_required, trigger_reencryption); if (trigger_reencryption){ sm_conn->sm_pairing_requested = true; sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; break; } /* fall through */ case IRK_LOOKUP_FAILED: sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; break; default: log_info("irk lookup pending"); sm_conn->sm_pairing_requested = true; break; } break; case SM_GENERAL_REENCRYPTION_FAILED: sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; break; case SM_GENERAL_IDLE: sm_conn->sm_pairing_requested = true; break; default: break; } } sm_trigger_run(); } // called by client app on authorization request void sm_authorization_decline(hci_con_handle_t con_handle){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return; // wrong connection sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); } void sm_authorization_grant(hci_con_handle_t con_handle){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return; // wrong connection sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); } // GAP Bonding API void sm_bonding_decline(hci_con_handle_t con_handle){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return; // wrong connection setup->sm_user_response = SM_USER_RESPONSE_DECLINE; log_info("decline, state %u", sm_conn->sm_engine_state); switch(sm_conn->sm_engine_state){ #ifdef ENABLE_LE_SECURE_CONNECTIONS case SM_SC_W4_USER_RESPONSE: case SM_SC_W4_CONFIRMATION: case SM_SC_W4_PUBLIC_KEY_COMMAND: #endif case SM_PH1_W4_USER_RESPONSE: switch (setup->sm_stk_generation_method){ case PK_RESP_INPUT: case PK_INIT_INPUT: case PK_BOTH_INPUT: sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); break; case NUMERIC_COMPARISON: sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); break; case JUST_WORKS: case OOB: sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); break; default: btstack_assert(false); break; } break; default: break; } sm_trigger_run(); } void sm_just_works_confirm(hci_con_handle_t con_handle){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return; // wrong connection setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ if (setup->sm_use_secure_connections){ sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; } else { btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); } } #ifdef ENABLE_LE_SECURE_CONNECTIONS if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ sm_sc_prepare_dhkey_check(sm_conn); } #endif sm_trigger_run(); } void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ // for now, it's the same sm_just_works_confirm(con_handle); } void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return; // wrong connection sm_reset_tk(); big_endian_store_32(setup->sm_tk, 12, passkey); setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); } #ifdef ENABLE_LE_SECURE_CONNECTIONS (void)memcpy(setup->sm_ra, setup->sm_tk, 16); (void)memcpy(setup->sm_rb, setup->sm_tk, 16); if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ sm_sc_start_calculating_local_confirm(sm_conn); } #endif sm_trigger_run(); } void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return; // wrong connection if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; uint8_t num_actions = setup->sm_keypress_notification >> 5; uint8_t flags = setup->sm_keypress_notification & 0x1fu; switch (action){ case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: flags |= (1u << action); break; case SM_KEYPRESS_PASSKEY_CLEARED: // clear counter, keypress & erased flags + set passkey cleared flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); break; case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: if ((flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)) != 0u){ // erase actions queued num_actions--; if (num_actions == 0u){ // clear counter, keypress & erased flags flags &= 0x19u; } break; } num_actions++; flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); break; case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: if ((flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)) != 0u){ // enter actions queued num_actions--; if (num_actions == 0u){ // clear counter, keypress & erased flags flags &= 0x19u; } break; } num_actions++; flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); break; default: break; } setup->sm_keypress_notification = (num_actions << 5) | flags; sm_trigger_run(); } #ifdef ENABLE_LE_SECURE_CONNECTIONS static void sm_handle_random_result_oob(void * arg){ UNUSED(arg); sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; sm_trigger_run(); } uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ static btstack_crypto_random_t sm_crypto_random_oob_request; if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; sm_sc_oob_callback = callback; sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); return 0; } #endif /** * @brief Get Identity Resolving state * @param con_handle * @return irk_lookup_state_t */ irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return IRK_LOOKUP_IDLE; return sm_conn->sm_irk_lookup_state; } /** * @brief Identify device in LE Device DB * @param handle * @return index from le_device_db or -1 if not found/identified */ int sm_le_device_index(hci_con_handle_t con_handle ){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return -1; return sm_conn->sm_le_db_index; } uint8_t sm_get_ltk(hci_con_handle_t con_handle, sm_key_t ltk){ hci_connection_t * hci_connection = hci_connection_for_handle(con_handle); if (hci_connection == NULL){ return ERROR_CODE_UNKNOWN_CONNECTION_IDENTIFIER; } if (hci_connection->link_key_type == INVALID_LINK_KEY){ return ERROR_CODE_PIN_OR_KEY_MISSING; } memcpy(ltk, hci_connection->link_key, 16); return ERROR_CODE_SUCCESS; } static int gap_random_address_type_requires_updates(void){ switch (gap_random_adress_type){ case GAP_RANDOM_ADDRESS_TYPE_OFF: case GAP_RANDOM_ADDRESS_TYPE_STATIC: return 0; default: return 1; } } static uint8_t own_address_type(void){ switch (gap_random_adress_type){ case GAP_RANDOM_ADDRESS_TYPE_OFF: return BD_ADDR_TYPE_LE_PUBLIC; default: return BD_ADDR_TYPE_LE_RANDOM; } } // GAP LE API void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ gap_random_address_update_stop(); gap_random_adress_type = random_address_type; hci_le_set_own_address_type(own_address_type()); if (!gap_random_address_type_requires_updates()) return; gap_random_address_update_start(); gap_random_address_trigger(); } gap_random_address_type_t gap_random_address_get_mode(void){ return gap_random_adress_type; } void gap_random_address_set_update_period(int period_ms){ gap_random_adress_update_period = period_ms; if (!gap_random_address_type_requires_updates()) return; gap_random_address_update_stop(); gap_random_address_update_start(); } void gap_random_address_set(const bd_addr_t addr){ gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); (void)memcpy(sm_random_address, addr, 6); // assert msb bits are set to '11' sm_random_address[0] |= 0xc0; hci_le_random_address_set(sm_random_address); } #ifdef ENABLE_LE_PERIPHERAL /* * @brief Set Advertisement Paramters * @param adv_int_min * @param adv_int_max * @param adv_type * @param direct_address_type * @param direct_address * @param channel_map * @param filter_policy * * @note own_address_type is used from gap_random_address_set_mode */ void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, direct_address_typ, direct_address, channel_map, filter_policy); } #endif bool gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); // wrong connection if (!sm_conn) return false; // already encrypted if (sm_conn->sm_connection_encrypted) return false; // irk status? switch(sm_conn->sm_irk_lookup_state){ case IRK_LOOKUP_FAILED: // done, cannot setup encryption return false; case IRK_LOOKUP_SUCCEEDED: break; default: // IR Lookup pending return true; } // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset or indicates failure if (sm_conn->sm_engine_state == SM_GENERAL_REENCRYPTION_FAILED) return false; if (sm_conn->sm_role != 0){ return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; } else { return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; } } void sm_set_secure_connections_only_mode(bool enable){ #ifdef ENABLE_LE_SECURE_CONNECTIONS sm_sc_only_mode = enable; #else // SC Only mode not possible without support for SC btstack_assert(enable == false); #endif } #if defined(ENABLE_LE_SECURE_CONNECTIONS) && defined (ENABLE_LE_SECURE_CONNECTION_DEBUG_KEY) void sm_test_enable_secure_connections_debug_keys(void) { log_info("Enable LE Secure Connection Debug Keys for testing"); sm_sc_debug_keys_enabled = true; // set debug key sm_ec_generate_new_key(); } #endif const uint8_t * gap_get_persistent_irk(void){ return sm_persistent_irk; } void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ int index = sm_le_device_db_index_lookup(address_type, address); if (index >= 0){ sm_remove_le_device_db_entry(index); } }