/* * 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 MATTHIAS * RINGWALD 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 #include "ble/le_device_db.h" #include "ble/core.h" #include "ble/sm.h" #include "bluetooth_company_id.h" #include "btstack_debug.h" #include "btstack_event.h" #include "btstack_linked_list.h" #include "btstack_memory.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_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) #define IS_RESPONDER(role) (role) #else #ifdef ENABLE_LE_CENTRAL // only central - never responder (avoid 'unused variable' warnings) #define IS_RESPONDER(role) (0 && role) #else // only peripheral - always responder (avoid 'unused variable' warnings) #define IS_RESPONDER(role) (1 || role) #endif #endif #ifdef ENABLE_LE_SECURE_CONNECTIONS // assert SM Public Key can be sent/received #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 #ifdef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT #error "Support for DHKEY Support in HCI Controller not implemented yet. Please use software implementation" #else // #define USE_MBEDTLS_FOR_ECDH #define USE_MICROECC_FOR_ECDH #endif #endif // Software ECDH implementation provided by mbedtls #ifdef USE_MBEDTLS_FOR_ECDH #include "mbedtls/config.h" #include "mbedtls/platform.h" #include "mbedtls/ecp.h" #include "sm_mbedtls_allocator.h" #endif // Software ECDH implementation provided by micro-ecc #ifdef USE_MICROECC_FOR_ECDH #include "uECC.h" #endif #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) #define ENABLE_CMAC_ENGINE #endif // // SM internal types and globals // typedef enum { DKG_W4_WORKING, DKG_CALC_IRK, DKG_W4_IRK, DKG_CALC_DHK, DKG_W4_DHK, DKG_READY } derived_key_generation_t; typedef enum { RAU_W4_WORKING, RAU_IDLE, RAU_GET_RANDOM, RAU_W4_RANDOM, RAU_GET_ENC, RAU_W4_ENC, RAU_SET_ADDRESS, } 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 OK_BOTH_INPUT, // Only input on both, both input PK NK_BOTH_INPUT, // Only numerical compparison (yes/no) on on both sides OOB // OOB available on both sides } 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_SUCEEDED, ADDRESS_RESOLUTION_FAILED, } address_resolution_event_t; typedef enum { EC_KEY_GENERATION_IDLE, EC_KEY_GENERATION_ACTIVE, EC_KEY_GENERATION_W4_KEY, EC_KEY_GENERATION_DONE, } ec_key_generation_state_t; typedef enum { SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 0 } sm_state_var_t; // // GLOBAL DATA // static uint8_t test_use_fixed_local_csrk; // 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 uint8_t sm_slave_request_security; #ifdef ENABLE_LE_SECURE_CONNECTIONS static uint8_t sm_have_ec_keypair; #endif // 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 uint8_t sm_persistent_irk_ready = 0; // used for testing 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; // CMAC Calculation: General #ifdef ENABLE_CMAC_ENGINE static cmac_state_t sm_cmac_state; static uint16_t sm_cmac_message_len; static sm_key_t sm_cmac_k; static sm_key_t sm_cmac_x; static sm_key_t sm_cmac_m_last; static uint8_t sm_cmac_block_current; static uint8_t sm_cmac_block_count; static uint8_t (*sm_cmac_get_byte)(uint16_t offset); static void (*sm_cmac_done_handler)(uint8_t * hash); #endif // CMAC for ATT Signed Writes #ifdef ENABLE_LE_SIGNED_WRITE static uint8_t sm_cmac_header[3]; static const uint8_t * sm_cmac_message; static uint8_t sm_cmac_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 int sm_address_resolution_ah_calculation_active; 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. store current sm_connection_t in sm_aes128_context static sm_aes128_state_t sm_aes128_state; static void * sm_aes128_context; // use aes128 provided by MCU - not needed usually #ifdef HAVE_AES128 static uint8_t aes128_result_flipped[16]; static btstack_timer_source_t aes128_timer; void btstack_aes128_calc(uint8_t * key, uint8_t * plaintext, uint8_t * result); #endif // random engine. store context (ususally sm_connection_t) static void * sm_random_context; // to receive hci events static btstack_packet_callback_registration_t hci_event_callback_registration; /* to dispatch sm event */ static btstack_linked_list_t sm_event_handlers; // LE Secure Connections #ifdef ENABLE_LE_SECURE_CONNECTIONS static ec_key_generation_state_t ec_key_generation_state; static uint8_t ec_d[32]; static uint8_t ec_q[64]; #endif // Software ECDH implementation provided by mbedtls #ifdef USE_MBEDTLS_FOR_ECDH // group is always valid static mbedtls_ecp_group mbedtls_ec_group; #ifndef HAVE_MALLOC // COMP Method with Window 2 // 1300 bytes with 23 allocations // #define MBEDTLS_ALLOC_BUFFER_SIZE (1300+23*sizeof(void *)) // NAIVE Method with safe cond assignments (without safe cond, order changes and allocations fail) #define MBEDTLS_ALLOC_BUFFER_SIZE (700+18*sizeof(void *)) static uint8_t mbedtls_memory_buffer[MBEDTLS_ALLOC_BUFFER_SIZE]; #endif #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; // used in all phases uint8_t sm_pairing_failed_reason; // user response, (Phase 1 and/or 2) uint8_t sm_user_response; uint8_t sm_keypress_notification; // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 int sm_key_distribution_send_set; int 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_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 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; } 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; // @returns 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; // 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, OK_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, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, { PK_RESP_INPUT, NK_BOTH_INPUT, PK_INIT_INPUT, JUST_WORKS, NK_BOTH_INPUT }, }; #endif static void sm_run(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 inline int sm_calc_actual_encryption_key_size(int other); static int sm_validate_stk_generation_method(void); static void sm_handle_encryption_result(uint8_t * data); static void log_info_hex16(const char * name, uint16_t value){ log_info("%-6s 0x%04x", name, value); } // @returns 1 if all bytes are 0 static int sm_is_null(uint8_t * data, int size){ int i; for (i=0; i < size ; i++){ if (data[i]) return 0; } return 1; } static int sm_is_null_random(uint8_t random[8]){ return sm_is_null(random, 8); } static int sm_is_null_key(uint8_t * key){ return sm_is_null(key, 16); } // 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; } } // 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_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){ if (rau_state != RAU_IDLE) return; log_info("gap_random_address_trigger"); rau_state = RAU_GET_RANDOM; sm_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); } static void sm_random_start(void * context){ sm_random_context = context; hci_send_cmd(&hci_le_rand); } #ifdef HAVE_AES128 static void aes128_completed(btstack_timer_source_t * ts){ UNUSED(ts); sm_handle_encryption_result(&aes128_result_flipped[0]); sm_run(); } #endif // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 // context is made availabe to aes128 result handler by this static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ sm_aes128_state = SM_AES128_ACTIVE; sm_aes128_context = context; #ifdef HAVE_AES128 // calc result directly sm_key_t result; btstack_aes128_calc(key, plaintext, result); // log log_info_key("key", key); log_info_key("txt", plaintext); log_info_key("res", result); // flip reverse_128(&result[0], &aes128_result_flipped[0]); // deliver via timer btstack_run_loop_set_timer_handler(&aes128_timer, &aes128_completed); btstack_run_loop_set_timer(&aes128_timer, 0); // no delay btstack_run_loop_add_timer(&aes128_timer); #else sm_key_t key_flipped, plaintext_flipped; reverse_128(key, key_flipped); reverse_128(plaintext, plaintext_flipped); hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); #endif } // 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); 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); } // dm helper // r’ = padding || r // r - 64 bit value static void sm_dm_r_prime(uint8_t r[8], uint8_t * r_prime){ memset(r_prime, 0, 16); memcpy(&r_prime[8], r, 8); } // 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; memset(p2, 0, 16); memcpy(&p2[4], ia, 6); 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); memcpy(&r_prime[8], &r2[8], 8); memcpy(&r_prime[0], &r1[8], 8); } #ifdef ENABLE_LE_SECURE_CONNECTIONS // Software implementations of crypto toolbox for LE Secure Connection // TODO: replace with code to use AES Engine of HCI Controller typedef uint8_t sm_key24_t[3]; typedef uint8_t sm_key56_t[7]; typedef uint8_t sm_key256_t[32]; #if 0 static void aes128_calc_cyphertext(const uint8_t key[16], const uint8_t plaintext[16], uint8_t cyphertext[16]){ uint32_t rk[RKLENGTH(KEYBITS)]; int nrounds = rijndaelSetupEncrypt(rk, &key[0], KEYBITS); rijndaelEncrypt(rk, nrounds, plaintext, cyphertext); } static void calc_subkeys(sm_key_t k0, sm_key_t k1, sm_key_t k2){ memcpy(k1, k0, 16); sm_shift_left_by_one_bit_inplace(16, k1); if (k0[0] & 0x80){ k1[15] ^= 0x87; } memcpy(k2, k1, 16); sm_shift_left_by_one_bit_inplace(16, k2); if (k1[0] & 0x80){ k2[15] ^= 0x87; } } static void aes_cmac(sm_key_t aes_cmac, const sm_key_t key, const uint8_t * data, int cmac_message_len){ sm_key_t k0, k1, k2, zero; memset(zero, 0, 16); aes128_calc_cyphertext(key, zero, k0); calc_subkeys(k0, k1, k2); int cmac_block_count = (cmac_message_len + 15) / 16; // step 3: .. if (cmac_block_count==0){ cmac_block_count = 1; } // step 4: set m_last sm_key_t cmac_m_last; int sm_cmac_last_block_complete = cmac_message_len != 0 && (cmac_message_len & 0x0f) == 0; int i; if (sm_cmac_last_block_complete){ for (i=0;i<16;i++){ cmac_m_last[i] = data[cmac_message_len - 16 + i] ^ k1[i]; } } else { int valid_octets_in_last_block = cmac_message_len & 0x0f; for (i=0;i<16;i++){ if (i < valid_octets_in_last_block){ cmac_m_last[i] = data[(cmac_message_len & 0xfff0) + i] ^ k2[i]; continue; } if (i == valid_octets_in_last_block){ cmac_m_last[i] = 0x80 ^ k2[i]; continue; } cmac_m_last[i] = k2[i]; } } // printf("sm_cmac_start: len %u, block count %u\n", cmac_message_len, cmac_block_count); // LOG_KEY(cmac_m_last); // Step 5 sm_key_t cmac_x; memset(cmac_x, 0, 16); // Step 6 sm_key_t sm_cmac_y; for (int block = 0 ; block < cmac_block_count-1 ; block++){ for (i=0;i<16;i++){ sm_cmac_y[i] = cmac_x[i] ^ data[block * 16 + i]; } aes128_calc_cyphertext(key, sm_cmac_y, cmac_x); } for (i=0;i<16;i++){ sm_cmac_y[i] = cmac_x[i] ^ cmac_m_last[i]; } // Step 7 aes128_calc_cyphertext(key, sm_cmac_y, aes_cmac); } #endif #endif 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_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ UNUSED(channel); // log event hci_dump_packet(packet_type, 1, 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_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_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ uint8_t event[15]; sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); little_endian_store_32(event, 11, passkey); 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 bd_addr_t identity_address; int identity_address_type; le_device_db_info(index, &identity_address_type, identity_address, NULL); uint8_t event[19]; 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]); event[18] = index; sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); } static void sm_notify_client_authorization(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t result){ uint8_t event[18]; sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); event[11] = result; sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); } // decide on stk generation based on // - pairing request // - io capabilities // - OOB data availability static void sm_setup_tk(void){ // 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 ) != 0; memset(setup->sm_ra, 0, 16); memset(setup->sm_rb, 0, 16); #else setup->sm_use_secure_connections = 0; #endif // 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) == 0) && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ log_info("SM: MITM not required by both -> JUST WORKS"); return; } // TODO: with LE SC, OOB is used to transfer data OOB during pairing, single device with OOB is sufficient // If both devices have out of band authentication data, then the Authentication // Requirements Flags shall be ignored when selecting the pairing method and the // Out of Band pairing method shall be used. if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ log_info("SM: have OOB data"); log_info_key("OOB", setup->sm_tk); setup->sm_stk_generation_method = OOB; 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){ flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; } if (key_set & SM_KEYDIST_ID_KEY){ flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; } if (key_set & SM_KEYDIST_SIGN){ flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; } return flags; } static void sm_setup_key_distribution(uint8_t key_set){ setup->sm_key_distribution_received_set = 0; setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); } // CSRK Key Lookup static int 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){ 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)) 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; memcpy(entry->address, address, 6); btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); sm_run(); return 0; } // while x_state++ for an enum is possible in C, it isn't in C++. we use this helpers to avoid compile errors for now static inline void sm_next_responding_state(sm_connection_t * sm_conn){ sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); } static inline void dkg_next_state(void){ dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); } static inline void rau_next_state(void){ rau_state = (random_address_update_t) (((int)rau_state) + 1); } // CMAC calculation using AES Engine #ifdef ENABLE_CMAC_ENGINE static inline void sm_cmac_next_state(void){ sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); } static int sm_cmac_last_block_complete(void){ if (sm_cmac_message_len == 0) return 0; return (sm_cmac_message_len & 0x0f) == 0; } int sm_cmac_ready(void){ return sm_cmac_state == CMAC_IDLE; } // generic cmac calculation void sm_cmac_general_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t hash[8])){ // Generalized CMAC memcpy(sm_cmac_k, key, 16); memset(sm_cmac_x, 0, 16); sm_cmac_block_current = 0; sm_cmac_message_len = message_len; sm_cmac_done_handler = done_callback; sm_cmac_get_byte = get_byte_callback; // step 2: n := ceil(len/const_Bsize); sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; // step 3: .. if (sm_cmac_block_count==0){ sm_cmac_block_count = 1; } log_info("sm_cmac_general_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); // first, we need to compute l for k1, k2, and m_last sm_cmac_state = CMAC_CALC_SUBKEYS; // let's go sm_run(); } #endif // cmac for ATT Message signing #ifdef ENABLE_LE_SIGNED_WRITE static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ if (offset >= sm_cmac_message_len) { log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); return 0; } offset = sm_cmac_message_len - 1 - offset; // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] if (offset < 3){ return sm_cmac_header[offset]; } int actual_message_len_incl_header = sm_cmac_message_len - 4; if (offset < actual_message_len_incl_header){ return sm_cmac_message[offset - 3]; } return sm_cmac_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_header[0] = opcode; little_endian_store_16(sm_cmac_header, 1, con_handle); little_endian_store_32(sm_cmac_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_message = message; sm_cmac_general_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); } #endif #ifdef ENABLE_CMAC_ENGINE static void sm_cmac_handle_aes_engine_ready(void){ switch (sm_cmac_state){ case CMAC_CALC_SUBKEYS: { sm_key_t const_zero; memset(const_zero, 0, 16); sm_cmac_next_state(); sm_aes128_start(sm_cmac_k, const_zero, NULL); break; } case CMAC_CALC_MI: { int j; sm_key_t y; for (j=0;j<16;j++){ y[j] = sm_cmac_x[j] ^ sm_cmac_get_byte(sm_cmac_block_current*16 + j); } sm_cmac_block_current++; sm_cmac_next_state(); sm_aes128_start(sm_cmac_k, y, NULL); break; } case CMAC_CALC_MLAST: { int i; sm_key_t y; for (i=0;i<16;i++){ y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; } log_info_key("Y", y); sm_cmac_block_current++; sm_cmac_next_state(); sm_aes128_start(sm_cmac_k, y, NULL); break; } default: log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); break; } } // CMAC Implementation using AES128 engine static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ int i; int carry = 0; for (i=len-1; i >= 0 ; i--){ int new_carry = data[i] >> 7; data[i] = data[i] << 1 | carry; carry = new_carry; } } static void sm_cmac_handle_encryption_result(sm_key_t data){ switch (sm_cmac_state){ case CMAC_W4_SUBKEYS: { sm_key_t k1; memcpy(k1, data, 16); sm_shift_left_by_one_bit_inplace(16, k1); if (data[0] & 0x80){ k1[15] ^= 0x87; } sm_key_t k2; memcpy(k2, k1, 16); sm_shift_left_by_one_bit_inplace(16, k2); if (k1[0] & 0x80){ k2[15] ^= 0x87; } log_info_key("k", sm_cmac_k); log_info_key("k1", k1); log_info_key("k2", k2); // step 4: set m_last int i; if (sm_cmac_last_block_complete()){ for (i=0;i<16;i++){ sm_cmac_m_last[i] = sm_cmac_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; } } else { int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; for (i=0;i<16;i++){ if (i < valid_octets_in_last_block){ sm_cmac_m_last[i] = sm_cmac_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; continue; } if (i == valid_octets_in_last_block){ sm_cmac_m_last[i] = 0x80 ^ k2[i]; continue; } sm_cmac_m_last[i] = k2[i]; } } // next sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; break; } case CMAC_W4_MI: memcpy(sm_cmac_x, data, 16); sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; break; case CMAC_W4_MLAST: // done log_info("Setting CMAC Engine to IDLE"); sm_cmac_state = CMAC_IDLE; log_info_key("CMAC", data); sm_cmac_done_handler(data); break; default: log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); break; } } #endif 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; switch (setup->sm_stk_generation_method){ case PK_RESP_INPUT: if (IS_RESPONDER(sm_conn->sm_role)){ setup->sm_user_response = SM_USER_RESPONSE_PENDING; sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); } else { sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); } break; case PK_INIT_INPUT: if (IS_RESPONDER(sm_conn->sm_role)){ sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); } else { setup->sm_user_response = SM_USER_RESPONSE_PENDING; sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); } break; case OK_BOTH_INPUT: setup->sm_user_response = SM_USER_RESPONSE_PENDING; sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); break; case NK_BOTH_INPUT: setup->sm_user_response = SM_USER_RESPONSE_PENDING; sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); break; case JUST_WORKS: setup->sm_user_response = SM_USER_RESPONSE_PENDING; sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); break; case OOB: // client already provided OOB data, let's skip notification. break; } } static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ int recv_flags; if (IS_RESPONDER(sm_conn->sm_role)){ // slave / responder recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); } else { // master / initiator recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); } log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); return recv_flags == setup->sm_key_distribution_received_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); } } static int sm_key_distribution_flags_for_auth_req(void){ int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; if (sm_auth_req & SM_AUTHREQ_BONDING){ // encryption information only if bonding requested flags |= SM_KEYDIST_ENC_KEY; } return flags; } static void sm_reset_setup(void){ // fill in sm setup setup->sm_state_vars = 0; setup->sm_keypress_notification = 0xff; 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; memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); // query client for OOB data int have_oob_data = 0; if (sm_get_oob_data) { have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); } sm_pairing_packet_t * local_packet; if (IS_RESPONDER(sm_conn->sm_role)){ // slave local_packet = &setup->sm_s_pres; gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); } else { // master local_packet = &setup->sm_m_preq; gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); int 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); } uint8_t auth_req = sm_auth_req; sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); sm_pairing_packet_set_auth_req(*local_packet, auth_req); sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); } static int sm_stk_generation_init(sm_connection_t * sm_conn){ sm_pairing_packet_t * remote_packet; int remote_key_request; if (IS_RESPONDER(sm_conn->sm_role)){ // slave / responder remote_packet = &setup->sm_m_preq; remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); } else { // master / initiator remote_packet = &setup->sm_s_pres; remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); } // check key size 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 == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; // decide on STK generation method 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; // identical to responder sm_setup_key_distribution(remote_key_request); // 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 = 0; sm_connection_t * sm_connection; #ifdef ENABLE_LE_CENTRAL sm_key_t ltk; #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; switch (event){ case ADDRESS_RESOLUTION_SUCEEDED: sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; sm_connection->sm_le_db_index = matched_device_id; log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); #ifdef ENABLE_LE_CENTRAL if (sm_connection->sm_role) break; if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; sm_connection->sm_security_request_received = 0; sm_connection->sm_bonding_requested = 0; le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); if (!sm_is_null_key(ltk)){ sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; } else { sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; } #endif break; case ADDRESS_RESOLUTION_FAILED: sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; #ifdef ENABLE_LE_CENTRAL if (sm_connection->sm_role) break; if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; sm_connection->sm_security_request_received = 0; sm_connection->sm_bonding_requested = 0; sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; #endif break; } break; default: break; } switch (event){ case ADDRESS_RESOLUTION_SUCEEDED: 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; } } static void sm_key_distribution_handle_all_received(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){ int i; for (i=0; i < le_device_db_count(); i++){ sm_key_t irk; bd_addr_t address; int address_type; le_device_db_info(i, &address_type, address, irk); if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ log_info("sm: device found for IRK, updating"); le_db_index = i; break; } } } // 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_count(); i++){ bd_addr_t address; int address_type; le_device_db_info(i, &address_type, address, NULL); 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 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); } sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); if (le_db_index >= 0){ #ifdef ENABLE_LE_SIGNED_WRITE // store local CSRK if (setup->sm_key_distribution_send_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, authenticatd %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); } // store encryption infromation 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, authenticatd %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); } } // keep le_db_index sm_conn->sm_le_db_index = le_db_index; } static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ setup->sm_pairing_failed_reason = reason; sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; } 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 int sm_passkey_used(stk_generation_method_t method); static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); static void sm_log_ec_keypair(void){ log_info("Elliptic curve: X"); log_info_hexdump(&ec_q[0],32); log_info("Elliptic curve: Y"); log_info_hexdump(&ec_q[32],32); } static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ if (sm_passkey_used(setup->sm_stk_generation_method)){ sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; } else { sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; } } static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ if (IS_RESPONDER(sm_conn->sm_role)){ // Responder 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 NK_BOTH_INPUT: sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; break; case PK_INIT_INPUT: case PK_RESP_INPUT: case OK_BOTH_INPUT: if (setup->sm_passkey_bit < 20) { sm_sc_start_calculating_local_confirm(sm_conn); } else { sm_sc_prepare_dhkey_check(sm_conn); } break; case OOB: // TODO: implement SC OOB break; } } } static uint8_t sm_sc_cmac_get_byte(uint16_t offset){ return sm_cmac_sc_buffer[offset]; } static void sm_sc_cmac_done(uint8_t * hash){ log_info("sm_sc_cmac_done: "); log_info_hexdump(hash, 16); sm_connection_t * sm_conn = sm_cmac_connection; sm_cmac_connection = NULL; link_key_type_t link_key_type; switch (sm_conn->sm_engine_state){ case SM_SC_W4_CMAC_FOR_CONFIRMATION: 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; } 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: 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: 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." memcpy(setup->sm_ltk, hash, 16); 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: 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){ 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; case SM_SC_W4_CALCULATE_H6_ILK: memcpy(setup->sm_t, hash, 16); sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; break; case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: #ifdef ENABLE_CLASSIC 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); if (IS_RESPONDER(sm_conn->sm_role)){ gap_store_link_key_for_bd_addr(setup->sm_m_address, setup->sm_t, link_key_type); } else { gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); } #endif if (IS_RESPONDER(sm_conn->sm_role)){ sm_conn->sm_engine_state = SM_RESPONDER_IDLE; } else { gap_store_link_key_for_bd_addr(setup->sm_s_address, setup->sm_t, link_key_type); sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; } sm_done_for_handle(sm_conn->sm_handle); break; default: log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); break; } sm_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; memcpy(sm_cmac_sc_buffer, u, 32); 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_general_start(x, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); } static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; static const uint8_t f5_length[] = { 0x01, 0x00}; static void sm_sc_calculate_dhkey(sm_key256_t dhkey){ memset(dhkey, 0, 32); #ifdef USE_MBEDTLS_FOR_ECDH // da * Pb mbedtls_mpi d; mbedtls_ecp_point Q; mbedtls_ecp_point DH; mbedtls_mpi_init(&d); mbedtls_ecp_point_init(&Q); mbedtls_ecp_point_init(&DH); mbedtls_mpi_read_binary(&d, ec_d, 32); mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0] , 32); mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); mbedtls_mpi_lset(&Q.Z, 1); mbedtls_ecp_mul(&mbedtls_ec_group, &DH, &d, &Q, NULL, NULL); mbedtls_mpi_write_binary(&DH.X, dhkey, 32); mbedtls_ecp_point_free(&DH); mbedtls_mpi_free(&d); mbedtls_ecp_point_free(&Q); #endif #ifdef USE_MICROECC_FOR_ECDH #if uECC_SUPPORTS_secp256r1 // standard version uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey, uECC_secp256r1()); #else // static version uECC_shared_secret(setup->sm_peer_q, ec_d, dhkey); #endif #endif log_info("dhkey"); log_info_hexdump(dhkey, 32); } static void f5_calculate_salt(sm_connection_t * sm_conn){ // calculate DHKEY sm_key256_t dhkey; sm_sc_calculate_dhkey(dhkey); // calculate salt for f5 const uint16_t message_len = 32; sm_cmac_connection = sm_conn; memcpy(sm_cmac_sc_buffer, dhkey, message_len); sm_cmac_general_start(f5_salt, message_len, &sm_sc_cmac_get_byte, &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; memcpy(sm_cmac_sc_buffer+01, f5_key_id, 4); memcpy(sm_cmac_sc_buffer+05, n1, 16); memcpy(sm_cmac_sc_buffer+21, n2, 16); memcpy(sm_cmac_sc_buffer+37, a1, 7); memcpy(sm_cmac_sc_buffer+44, a2, 7); 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_general_start(t, message_len, &sm_sc_cmac_get_byte, &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; memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 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_general_start(t, message_len, &sm_sc_cmac_get_byte, &sm_sc_cmac_done); } static void f5_calculate_ltk(sm_connection_t * sm_conn){ f5_ltk(sm_conn, setup->sm_t); } static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w, 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){ const uint16_t message_len = 65; sm_cmac_connection = sm_conn; memcpy(sm_cmac_sc_buffer, n1, 16); memcpy(sm_cmac_sc_buffer+16, n2, 16); memcpy(sm_cmac_sc_buffer+32, r, 16); memcpy(sm_cmac_sc_buffer+48, io_cap, 3); memcpy(sm_cmac_sc_buffer+51, a1, 7); memcpy(sm_cmac_sc_buffer+58, a2, 7); log_info("f6 key"); log_info_hexdump(w, 16); log_info("f6 message"); log_info_hexdump(sm_cmac_sc_buffer, message_len); sm_cmac_general_start(w, 65, &sm_sc_cmac_get_byte, &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; memcpy(sm_cmac_sc_buffer, u, 32); memcpy(sm_cmac_sc_buffer+32, v, 32); 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_general_start(x, message_len, &sm_sc_cmac_get_byte, &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 (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ // some form of passkey uint32_t pk = big_endian_read_32(setup->sm_tk, 12); z = 0x80 | ((pk >> setup->sm_passkey_bit) & 1); 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){ uint8_t z = 0; if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT){ // 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 = 0x80 | ((pk >> (setup->sm_passkey_bit-1)) & 1); } 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){ sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; } 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; memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 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_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); } else { // initiator f6_engine(sm_conn, setup->sm_mackey, setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); } } 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; memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 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_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); } else { // initiator f6_engine(sm_conn, setup->sm_mackey, setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); } } // // Link Key Conversion Function h6 // // h6(W, keyID) = AES-CMACW(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_general_start(w, message_len, &sm_sc_cmac_get_byte, &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(sm_connection_t * sm_conn){ h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" } static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" } #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; // 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); log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 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; } #endif #ifdef ENABLE_LE_PERIPHERAL static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 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[7] & 0x0f) + 1; // no db for authenticated flag hack: flag is stored in bit 4 of LSB sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; log_info("sm: received ltk request with key size %u, authenticated %u", sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; } #endif static void sm_run(void){ btstack_linked_list_iterator_t it; // assert that stack has already bootet if (hci_get_state() != HCI_STATE_WORKING) return; // assert that we can send at least commands if (!hci_can_send_command_packet_now()) return; // // non-connection related behaviour // // distributed key generation switch (dkg_state){ case DKG_CALC_IRK: // already busy? if (sm_aes128_state == SM_AES128_IDLE) { // IRK = d1(IR, 1, 0) sm_key_t d1_prime; sm_d1_d_prime(1, 0, d1_prime); // plaintext dkg_next_state(); sm_aes128_start(sm_persistent_ir, d1_prime, NULL); return; } break; case DKG_CALC_DHK: // already busy? if (sm_aes128_state == SM_AES128_IDLE) { // DHK = d1(IR, 3, 0) sm_key_t d1_prime; sm_d1_d_prime(3, 0, d1_prime); // plaintext dkg_next_state(); sm_aes128_start(sm_persistent_ir, d1_prime, NULL); return; } break; default: break; } #ifdef ENABLE_LE_SECURE_CONNECTIONS if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ #ifndef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT sm_random_start(NULL); #else ec_key_generation_state = EC_KEY_GENERATION_W4_KEY; hci_send_cmd(&hci_le_read_local_p256_public_key); #endif return; } #endif // random address updates switch (rau_state){ case RAU_GET_RANDOM: rau_next_state(); sm_random_start(NULL); return; case RAU_GET_ENC: // already busy? if (sm_aes128_state == SM_AES128_IDLE) { sm_key_t r_prime; sm_ah_r_prime(sm_random_address, r_prime); rau_next_state(); sm_aes128_start(sm_persistent_irk, r_prime, NULL); return; } break; case RAU_SET_ADDRESS: log_info("New random address: %s", bd_addr_to_str(sm_random_address)); rau_state = RAU_IDLE; hci_send_cmd(&hci_le_set_random_address, sm_random_address); return; default: break; } #ifdef ENABLE_CMAC_ENGINE // CMAC switch (sm_cmac_state){ case CMAC_CALC_SUBKEYS: case CMAC_CALC_MI: case CMAC_CALC_MLAST: // already busy? if (sm_aes128_state == SM_AES128_ACTIVE) break; sm_cmac_handle_aes_engine_ready(); return; default: break; } #endif // CSRK Lookup // -- if csrk 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 CSRK device lookup by public or resolvable private address if (!sm_address_resolution_idle()){ log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); while (sm_address_resolution_test < le_device_db_count()){ int addr_type; bd_addr_t addr; sm_key_t irk; le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ log_info("LE Device Lookup: found CSRK by { addr_type, address} "); sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); break; } if (sm_address_resolution_addr_type == 0){ 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); sm_key_t r_prime; sm_ah_r_prime(sm_address_resolution_address, r_prime); sm_address_resolution_ah_calculation_active = 1; sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context return; } if (sm_address_resolution_test >= le_device_db_count()){ log_info("LE Device Lookup: not found"); sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); } } // handle basic actions that don't requires the full context 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; switch(sm_connection->sm_engine_state){ // 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; #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: ediv & random are empty, but no stored LTK (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; default: break; } break; #endif default: break; } } // // active connection handling // -- use loop to handle next connection if lock on setup context is released while (1) { // Find connections that requires setup context and make active if no other is locked 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 int done = 1; int err; UNUSED(err); switch (sm_connection->sm_engine_state) { #ifdef ENABLE_LE_PERIPHERAL case SM_RESPONDER_SEND_SECURITY_REQUEST: // send packet if possible, if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); } else { l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); } // don't lock sxetup context yet done = 0; break; case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: sm_reset_setup(); sm_init_setup(sm_connection); // recover pairing request memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); err = sm_stk_generation_init(sm_connection); if (err){ setup->sm_pairing_failed_reason = err; sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; break; } sm_timeout_start(sm_connection); // generate random number first, if we need to show passkey if (setup->sm_stk_generation_method == PK_INIT_INPUT){ sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; break; } sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; break; case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: sm_reset_setup(); sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); break; #endif #ifdef ENABLE_LE_CENTRAL case SM_INITIATOR_PH0_HAS_LTK: sm_reset_setup(); sm_load_security_info(sm_connection); sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; break; case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: sm_reset_setup(); sm_init_setup(sm_connection); sm_timeout_start(sm_connection); sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; break; #endif #ifdef ENABLE_LE_SECURE_CONNECTIONS case SM_SC_RECEIVED_LTK_REQUEST: switch (sm_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(sm_connection); if (setup->sm_peer_ediv == 0 && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; break; } log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); sm_connection->sm_engine_state = SM_RESPONDER_IDLE; hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); // don't lock setup context yet return; default: // just wait until IRK lookup is completed // don't lock setup context yet done = 0; break; } break; #endif default: done = 0; 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); } } // // active connection handling // if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) 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, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { log_info("cannot send now, requesting can send now event"); l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); return; } 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; } // send keypress notifications if (setup->sm_keypress_notification != 0xff){ uint8_t buffer[2]; buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; buffer[1] = setup->sm_keypress_notification; setup->sm_keypress_notification = 0xff; l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); return; } sm_key_t plaintext; int key_distribution_flags; UNUSED(key_distribution_flags); log_info("sm_run: state %u", connection->sm_engine_state); switch (connection->sm_engine_state){ // general case SM_GENERAL_SEND_PAIRING_FAILED: { uint8_t buffer[2]; buffer[0] = SM_CODE_PAIRING_FAILED; buffer[1] = setup->sm_pairing_failed_reason; connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); sm_done_for_handle(connection->sm_handle); break; } // responding state #ifdef ENABLE_LE_SECURE_CONNECTIONS case SM_SC_W2_GET_RANDOM_A: sm_random_start(connection); connection->sm_engine_state = SM_SC_W4_GET_RANDOM_A; break; case SM_SC_W2_GET_RANDOM_B: sm_random_start(connection); connection->sm_engine_state = SM_SC_W4_GET_RANDOM_B; break; case SM_SC_W2_CMAC_FOR_CONFIRMATION: if (!sm_cmac_ready()) break; 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: if (!sm_cmac_ready()) break; 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: if (!sm_cmac_ready()) break; 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: if (!sm_cmac_ready()) break; 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: if (!sm_cmac_ready()) break; connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; f5_calculate_salt(connection); break; case SM_SC_W2_CALCULATE_F5_MACKEY: if (!sm_cmac_ready()) break; connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; f5_calculate_mackey(connection); break; case SM_SC_W2_CALCULATE_F5_LTK: if (!sm_cmac_ready()) break; connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; f5_calculate_ltk(connection); break; case SM_SC_W2_CALCULATE_G2: if (!sm_cmac_ready()) break; connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; g2_calculate(connection); break; case SM_SC_W2_CALCULATE_H6_ILK: if (!sm_cmac_ready()) break; connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; h6_calculate_ilk(connection); break; case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: if (!sm_cmac_ready()) break; connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; h6_calculate_br_edr_link_key(connection); break; #endif #ifdef ENABLE_LE_CENTRAL // initiator side case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { sm_key_t peer_ltk_flipped; reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); connection->sm_engine_state = SM_INITIATOR_PH0_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); return; } case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); sm_timeout_reset(connection); break; #endif #ifdef ENABLE_LE_SECURE_CONNECTIONS case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 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]); // stk generation method // passkey entry: notify app to show passkey or to request passkey switch (setup->sm_stk_generation_method){ case JUST_WORKS: case NK_BOTH_INPUT: if (IS_RESPONDER(connection->sm_role)){ // responder sm_sc_start_calculating_local_confirm(connection); } else { // initiator connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; } break; case PK_INIT_INPUT: case PK_RESP_INPUT: case OK_BOTH_INPUT: // use random TK for display memcpy(setup->sm_ra, setup->sm_tk, 16); 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; } sm_trigger_user_response(connection); break; case OOB: // TODO: implement SC OOB break; } l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); break; } case SM_SC_SEND_CONFIRMATION: { 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; } l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); break; } case SM_SC_SEND_PAIRING_RANDOM: { uint8_t buffer[17]; buffer[0] = SM_CODE_PAIRING_RANDOM; reverse_128(setup->sm_local_nonce, &buffer[1]); if (setup->sm_stk_generation_method != JUST_WORKS && setup->sm_stk_generation_method != NK_BOTH_INPUT && setup->sm_passkey_bit < 20){ 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 { if (IS_RESPONDER(connection->sm_role)){ // responder if (setup->sm_stk_generation_method == NK_BOTH_INPUT){ connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; } else { sm_sc_prepare_dhkey_check(connection); } } else { // initiator connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; } } l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); break; } case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 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; } l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); break; } #endif #ifdef ENABLE_LE_PERIPHERAL case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: // echo initiator for now sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); key_distribution_flags = sm_key_distribution_flags_for_auth_req(); if (setup->sm_use_secure_connections){ connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; // skip LTK/EDIV for SC log_info("sm: dropping encryption information flag"); key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; } else { connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; } 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)); l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); sm_timeout_reset(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; } l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); break; } case SM_PH2_GET_RANDOM_TK: case SM_PH2_C1_GET_RANDOM_A: case SM_PH2_C1_GET_RANDOM_B: case SM_PH3_GET_RANDOM: case SM_PH3_GET_DIV: sm_next_responding_state(connection); sm_random_start(connection); return; case SM_PH2_C1_GET_ENC_B: case SM_PH2_C1_GET_ENC_D: // already busy? if (sm_aes128_state == SM_AES128_ACTIVE) break; sm_next_responding_state(connection); sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); return; case SM_PH3_LTK_GET_ENC: case SM_RESPONDER_PH4_LTK_GET_ENC: // already busy? if (sm_aes128_state == SM_AES128_IDLE) { sm_key_t d_prime; sm_d1_d_prime(setup->sm_local_div, 0, d_prime); sm_next_responding_state(connection); sm_aes128_start(sm_persistent_er, d_prime, connection); return; } break; case SM_PH3_CSRK_GET_ENC: // already busy? if (sm_aes128_state == SM_AES128_IDLE) { sm_key_t d_prime; sm_d1_d_prime(setup->sm_local_div, 1, d_prime); sm_next_responding_state(connection); sm_aes128_start(sm_persistent_er, d_prime, connection); return; } 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, plaintext); sm_next_responding_state(connection); sm_aes128_start(setup->sm_tk, plaintext, 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, plaintext); sm_next_responding_state(connection); sm_aes128_start(setup->sm_tk, plaintext, connection); 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, plaintext); } else { sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); } sm_next_responding_state(connection); sm_aes128_start(setup->sm_tk, plaintext, connection); break; case SM_PH3_Y_GET_ENC: // already busy? if (sm_aes128_state == SM_AES128_ACTIVE) break; // PH3B2 - calculate Y from - enc // Y = dm(DHK, Rand) sm_dm_r_prime(setup->sm_local_rand, plaintext); sm_next_responding_state(connection); sm_aes128_start(sm_persistent_dhk, plaintext, connection); return; 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; } l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); return; } #ifdef ENABLE_LE_PERIPHERAL case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 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: { sm_key_t ltk_flipped; reverse_128(setup->sm_ltk, ltk_flipped); connection->sm_engine_state = SM_RESPONDER_IDLE; hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); return; } case SM_RESPONDER_PH4_Y_GET_ENC: // already busy? if (sm_aes128_state == SM_AES128_ACTIVE) break; log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); // Y = dm(DHK, Rand) sm_dm_r_prime(setup->sm_local_rand, plaintext); sm_next_responding_state(connection); sm_aes128_start(sm_persistent_dhk, plaintext, connection); return; #endif #ifdef ENABLE_LE_CENTRAL case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 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: if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; uint8_t buffer[17]; buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; reverse_128(setup->sm_ltk, &buffer[1]); l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); return; } if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ setup->sm_key_distribution_send_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]); l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); return; } if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; uint8_t buffer[17]; buffer[0] = SM_CODE_IDENTITY_INFORMATION; reverse_128(sm_persistent_irk, &buffer[1]); l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); return; } if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; bd_addr_t local_address; uint8_t buffer[8]; buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; gap_le_get_own_address(&buffer[1], local_address); reverse_bd_addr(local_address, &buffer[2]); l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); return; } if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; // hack to reproduce test runs if (test_use_fixed_local_csrk){ memset(setup->sm_local_csrk, 0xcc, 16); } uint8_t buffer[17]; buffer[0] = SM_CODE_SIGNING_INFORMATION; reverse_128(setup->sm_local_csrk, &buffer[1]); l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); sm_timeout_reset(connection); return; } // keys are sent if (IS_RESPONDER(connection->sm_role)){ // slave -> receive master keys if any if (sm_key_distribution_all_received(connection)){ sm_key_distribution_handle_all_received(connection); connection->sm_engine_state = SM_RESPONDER_IDLE; sm_done_for_handle(connection->sm_handle); } else { connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; } } else { // master -> all done connection->sm_engine_state = SM_INITIATOR_CONNECTED; sm_done_for_handle(connection->sm_handle); } break; default: break; } // check again if active connection was released if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; } } // note: aes engine is ready as we just got the aes result static void sm_handle_encryption_result(uint8_t * data){ sm_aes128_state = SM_AES128_IDLE; if (sm_address_resolution_ah_calculation_active){ sm_address_resolution_ah_calculation_active = 0; // compare calulated address against connecting device uint8_t hash[3]; reverse_24(data, hash); 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_SUCEEDED); return; } // no match, try next sm_address_resolution_test++; return; } switch (dkg_state){ case DKG_W4_IRK: reverse_128(data, sm_persistent_irk); log_info_key("irk", sm_persistent_irk); dkg_next_state(); return; case DKG_W4_DHK: reverse_128(data, sm_persistent_dhk); log_info_key("dhk", sm_persistent_dhk); dkg_next_state(); // SM Init Finished return; default: break; } switch (rau_state){ case RAU_W4_ENC: reverse_24(data, &sm_random_address[3]); rau_next_state(); return; default: break; } #ifdef ENABLE_CMAC_ENGINE switch (sm_cmac_state){ case CMAC_W4_SUBKEYS: case CMAC_W4_MI: case CMAC_W4_MLAST: { sm_key_t t; reverse_128(data, t); sm_cmac_handle_encryption_result(t); } return; default: break; } #endif // retrieve sm_connection provided to sm_aes128_start_encryption sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; if (!connection) return; switch (connection->sm_engine_state){ case SM_PH2_C1_W4_ENC_A: case SM_PH2_C1_W4_ENC_C: { sm_key_t t2; reverse_128(data, t2); sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); } sm_next_responding_state(connection); return; case SM_PH2_C1_W4_ENC_B: reverse_128(data, setup->sm_local_confirm); log_info_key("c1!", setup->sm_local_confirm); connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; return; case SM_PH2_C1_W4_ENC_D: { sm_key_t peer_confirm_test; reverse_128(data, peer_confirm_test); log_info_key("c1!", peer_confirm_test); if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; return; } if (IS_RESPONDER(connection->sm_role)){ connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; } else { connection->sm_engine_state = SM_PH2_CALC_STK; } } return; case SM_PH2_W4_STK: reverse_128(data, setup->sm_ltk); 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; } return; case SM_PH3_Y_W4_ENC:{ sm_key_t y128; reverse_128(data, y128); setup->sm_local_y = big_endian_read_16(y128, 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)) connection->sm_engine_state = SM_PH3_LTK_GET_ENC; return; } case SM_RESPONDER_PH4_Y_W4_ENC:{ sm_key_t y128; reverse_128(data, y128); setup->sm_local_y = big_endian_read_16(y128, 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)) connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; return; } case SM_PH3_LTK_W4_ENC: reverse_128(data, setup->sm_ltk); log_info_key("ltk", setup->sm_ltk); // calc CSRK next connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; return; case SM_PH3_CSRK_W4_ENC: reverse_128(data, setup->sm_local_csrk); log_info_key("csrk", setup->sm_local_csrk); if (setup->sm_key_distribution_send_set){ connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; } else { // no keys to send, just continue if (IS_RESPONDER(connection->sm_role)){ // slave -> receive master keys connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; } else { if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; } else { // master -> all done connection->sm_engine_state = SM_INITIATOR_CONNECTED; sm_done_for_handle(connection->sm_handle); } } } return; #ifdef ENABLE_LE_PERIPHERAL case SM_RESPONDER_PH4_LTK_W4_ENC: reverse_128(data, setup->sm_ltk); 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; return; #endif default: break; } } #ifdef ENABLE_LE_SECURE_CONNECTIONS #ifndef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT #if !defined(WICED_VERSION) || defined(USE_MBEDTLS_FOR_ECDH) // @return OK static int sm_generate_f_rng(unsigned char * buffer, unsigned size){ if (ec_key_generation_state != EC_KEY_GENERATION_ACTIVE) return 0; int offset = setup->sm_passkey_bit; log_info("sm_generate_f_rng: size %u - offset %u", (int) size, offset); while (size) { *buffer++ = setup->sm_peer_q[offset++]; size--; } setup->sm_passkey_bit = offset; return 1; } #endif #ifdef USE_MBEDTLS_FOR_ECDH // @return error static int sm_generate_f_rng_mbedtls(void * context, unsigned char * buffer, size_t size){ UNUSED(context); return sm_generate_f_rng(buffer, size) == 1; } #endif #endif #endif // note: random generator is ready. this doesn NOT imply that aes engine is unused! static void sm_handle_random_result(uint8_t * data){ #ifdef ENABLE_LE_SECURE_CONNECTIONS #ifndef HAVE_HCI_CONTROLLER_DHKEY_SUPPORT if (ec_key_generation_state == EC_KEY_GENERATION_ACTIVE){ int num_bytes = setup->sm_passkey_bit; memcpy(&setup->sm_peer_q[num_bytes], data, 8); num_bytes += 8; setup->sm_passkey_bit = num_bytes; if (num_bytes >= 64){ // init pre-generated random data from sm_peer_q setup->sm_passkey_bit = 0; // generate EC key #ifdef USE_MBEDTLS_FOR_ECDH mbedtls_mpi d; mbedtls_ecp_point P; mbedtls_mpi_init(&d); mbedtls_ecp_point_init(&P); int res = mbedtls_ecp_gen_keypair(&mbedtls_ec_group, &d, &P, &sm_generate_f_rng_mbedtls, NULL); log_info("gen keypair %x", res); mbedtls_mpi_write_binary(&P.X, &ec_q[0], 32); mbedtls_mpi_write_binary(&P.Y, &ec_q[32], 32); mbedtls_mpi_write_binary(&d, ec_d, 32); mbedtls_ecp_point_free(&P); mbedtls_mpi_free(&d); #endif #ifdef USE_MICROECC_FOR_ECDH #ifndef WICED_VERSION log_info("set uECC RNG for initial key generation with 64 random bytes"); // micro-ecc from WICED SDK uses its wiced_crypto_get_random by default - no need to set it uECC_set_rng(&sm_generate_f_rng); #endif /* WICED_VERSION */ #if uECC_SUPPORTS_secp256r1 // standard version uECC_make_key(ec_q, ec_d, uECC_secp256r1()); #else // static version uECC_make_key(ec_q, ec_d); #endif /* USE_MICROECC_FOR_ECDH */ #endif /* USE_MICROECC_FOR_ECDH */ ec_key_generation_state = EC_KEY_GENERATION_DONE; log_info("Elliptic curve: d"); log_info_hexdump(ec_d,32); sm_log_ec_keypair(); } } #endif #endif switch (rau_state){ case RAU_W4_RANDOM: // 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" memcpy(sm_random_address, data, 3); sm_random_address[0] &= 0x3f; sm_random_address[0] |= 0x40; 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’"" memcpy(sm_random_address, data, 6); sm_random_address[0] &= 0x3f; rau_state = RAU_SET_ADDRESS; break; } return; default: break; } // retrieve sm_connection provided to sm_random_start sm_connection_t * connection = (sm_connection_t *) sm_random_context; if (!connection) return; switch (connection->sm_engine_state){ #ifdef ENABLE_LE_SECURE_CONNECTIONS case SM_SC_W4_GET_RANDOM_A: memcpy(&setup->sm_local_nonce[0], data, 8); connection->sm_engine_state = SM_SC_W2_GET_RANDOM_B; break; case SM_SC_W4_GET_RANDOM_B: memcpy(&setup->sm_local_nonce[8], data, 8); // initiator & jw/nc -> send pairing random if (connection->sm_role == 0 && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; break; } else { connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; } break; #endif case SM_PH2_W4_RANDOM_TK: { // map random to 0-999999 without speding much cycles on a modulus operation uint32_t tk = little_endian_read_32(data,0); tk = tk & 0xfffff; // 1048575 if (tk >= 999999){ tk = tk - 999999; } sm_reset_tk(); 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){ connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; } } } return; } case SM_PH2_C1_W4_RANDOM_A: memcpy(&setup->sm_local_random[0], data, 8); // random endinaness connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; return; case SM_PH2_C1_W4_RANDOM_B: memcpy(&setup->sm_local_random[8], data, 8); // random endinaness connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; return; case SM_PH3_W4_RANDOM: reverse_64(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[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); // no db for authenticated flag hack: store flag in bit 4 of LSB setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); connection->sm_engine_state = SM_PH3_GET_DIV; return; case SM_PH3_W4_DIV: // use 16 bit from random value as div setup->sm_local_div = big_endian_read_16(data, 0); log_info_hex16("div", setup->sm_local_div); connection->sm_engine_state = SM_PH3_Y_GET_ENC; return; default: break; } } static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ UNUSED(channel); UNUSED(size); sm_connection_t * sm_conn; hci_con_handle_t con_handle; switch (packet_type) { case HCI_EVENT_PACKET: switch (hci_event_packet_get_type(packet)) { case BTSTACK_EVENT_STATE: // bt stack activated, get started if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ log_info("HCI Working!"); // set local addr for le device db bd_addr_t local_bd_addr; gap_local_bd_addr(local_bd_addr); le_device_db_set_local_bd_addr(local_bd_addr); dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; #ifdef ENABLE_LE_SECURE_CONNECTIONS if (!sm_have_ec_keypair){ setup->sm_passkey_bit = 0; ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; } #endif // trigger Random Address generation if requested before switch (gap_random_adress_type){ case GAP_RANDOM_ADDRESS_TYPE_OFF: rau_state = RAU_IDLE; break; case GAP_RANDOM_ADDRESS_TYPE_STATIC: rau_state = RAU_SET_ADDRESS; break; default: rau_state = RAU_GET_RANDOM; break; } sm_run(); } break; case HCI_EVENT_LE_META: switch (packet[2]) { case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: log_info("sm: connected"); if (packet[3]) return; // connection failed con_handle = little_endian_read_16(packet, 4); sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) break; sm_conn->sm_handle = con_handle; sm_conn->sm_role = packet[6]; sm_conn->sm_peer_addr_type = packet[7]; reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); // reset 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; // prepare CSRK lookup (does not involve setup) sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; // just connected -> everything else happens in sm_run() if (IS_RESPONDER(sm_conn->sm_role)){ // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ if (sm_slave_request_security) { // request security if requested by app sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; } else { // otherwise, wait for pairing request sm_conn->sm_engine_state = SM_RESPONDER_IDLE; } } break; } else { // master sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; } break; case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: con_handle = little_endian_read_16(packet, 3); 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 = little_endian_read_16(packet, 13); // 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 != 0 || !sm_is_null_random(sm_conn->sm_local_rand)){ sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 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; #ifdef ENABLE_LE_SECURE_CONNECTIONS case HCI_SUBEVENT_LE_READ_LOCAL_P256_PUBLIC_KEY_COMPLETE: if (hci_subevent_le_read_local_p256_public_key_complete_get_status(packet)){ log_error("Read Local P256 Public Key failed"); break; } hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_x(packet, &ec_q[0]); hci_subevent_le_read_local_p256_public_key_complete_get_dhkey_y(packet, &ec_q[32]); ec_key_generation_state = EC_KEY_GENERATION_DONE; sm_log_ec_keypair(); break; #endif default: break; } break; case HCI_EVENT_ENCRYPTION_CHANGE: con_handle = little_endian_read_16(packet, 3); sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) break; sm_conn->sm_connection_encrypted = packet[5]; 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); if (!sm_conn->sm_connection_encrypted) break; // continue if part of initial pairing switch (sm_conn->sm_engine_state){ case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; sm_done_for_handle(sm_conn->sm_handle); break; case SM_PH2_W4_CONNECTION_ENCRYPTED: if (IS_RESPONDER(sm_conn->sm_role)){ // slave if (setup->sm_use_secure_connections){ sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; } else { sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; } } else { // master if (sm_key_distribution_all_received(sm_conn)){ // skip receiving keys as there are none sm_key_distribution_handle_all_received(sm_conn); sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; } else { sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; } } break; 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_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; sm_done_for_handle(sm_conn->sm_handle); break; case SM_PH2_W4_CONNECTION_ENCRYPTED: if (IS_RESPONDER(sm_conn->sm_role)){ // slave sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; } else { // master sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; } break; 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; // delete stored bonding on disconnect with authentication failure in ph0 if (sm_conn->sm_role == 0 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ le_device_db_remove(sm_conn->sm_le_db_index); } sm_conn->sm_engine_state = SM_GENERAL_IDLE; sm_conn->sm_handle = 0; break; case HCI_EVENT_COMMAND_COMPLETE: if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ sm_handle_encryption_result(&packet[6]); break; } if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ sm_handle_random_result(&packet[6]); break; } if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ // Hack for Nordic nRF5 series that doesn't have public address: // - with patches from port/nrf5-zephyr, hci_read_bd_addr returns random static address // - we use this as default for advertisements/connections if (hci_get_manufacturer() == BLUETOOTH_COMPANY_ID_NORDIC_SEMICONDUCTOR_ASA){ log_info("nRF5: using (fake) public address as random static address"); bd_addr_t addr; reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); gap_random_address_set(addr); } } break; 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 int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ switch (method){ case JUST_WORKS: case NK_BOTH_INPUT: return 1; default: return 0; } } // responder static int sm_passkey_used(stk_generation_method_t method){ switch (method){ case PK_RESP_INPUT: return 1; default: return 0; } } #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) != 0; case PK_RESP_INPUT: case PK_INIT_INPUT: case OK_BOTH_INPUT: return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; case OOB: return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; case NK_BOTH_INPUT: return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0; return 1; default: return 0; } } static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ UNUSED(size); if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ sm_run(); } if (packet_type != SM_DATA_PACKET) return; sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return; if (packet[0] == SM_CODE_PAIRING_FAILED){ sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; return; } log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); int err; UNUSED(err); if (packet[0] == 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; } switch (sm_conn->sm_engine_state){ // a sm timeout requries a new physical connection case SM_GENERAL_TIMEOUT: return; #ifdef ENABLE_LE_CENTRAL // Initiator case SM_INITIATOR_CONNECTED: if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ sm_pdu_received_in_wrong_state(sm_conn); break; } if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; break; } if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ sm_key_t ltk; le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL); if (!sm_is_null_key(ltk)){ log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; } else { sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; } break; } // otherwise, store security request sm_conn->sm_security_request_received = 1; break; case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: if (packet[0] != SM_CODE_PAIRING_RESPONSE){ sm_pdu_received_in_wrong_state(sm_conn); break; } // store pairing request memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); err = sm_stk_generation_init(sm_conn); if (err){ setup->sm_pairing_failed_reason = err; sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; break; } // generate random number first, if we need to show passkey if (setup->sm_stk_generation_method == PK_RESP_INPUT){ sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 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){ sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; } break; case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: if (packet[0] != SM_CODE_PAIRING_CONFIRM){ sm_pdu_received_in_wrong_state(sm_conn); break; } // store s_confirm reverse_128(&packet[1], setup->sm_peer_confirm); sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; break; case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: if (packet[0] != 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 #ifdef ENABLE_LE_PERIPHERAL // Responder case SM_RESPONDER_IDLE: case SM_RESPONDER_SEND_SECURITY_REQUEST: case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: if (packet[0] != SM_CODE_PAIRING_REQUEST){ sm_pdu_received_in_wrong_state(sm_conn); break;; } // store pairing request memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; break; #endif #ifdef ENABLE_LE_SECURE_CONNECTIONS case SM_SC_W4_PUBLIC_KEY_COMMAND: if (packet[0] != SM_CODE_PAIRING_PUBLIC_KEY){ sm_pdu_received_in_wrong_state(sm_conn); break; } // 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]); // validate public key err = 0; #ifdef USE_MBEDTLS_FOR_ECDH mbedtls_ecp_point Q; mbedtls_ecp_point_init( &Q ); mbedtls_mpi_read_binary(&Q.X, &setup->sm_peer_q[0], 32); mbedtls_mpi_read_binary(&Q.Y, &setup->sm_peer_q[32], 32); mbedtls_mpi_lset(&Q.Z, 1); err = mbedtls_ecp_check_pubkey(&mbedtls_ec_group, &Q); mbedtls_ecp_point_free( & Q); #endif #ifdef USE_MICROECC_FOR_ECDH #if uECC_SUPPORTS_secp256r1 // standard version err = uECC_valid_public_key(setup->sm_peer_q, uECC_secp256r1()) == 0; #else // static version err = uECC_valid_public_key(setup->sm_peer_q) == 0; #endif #endif if (err){ log_error("sm: peer public key invalid %x", err); // uses "unspecified reason", there is no "public key invalid" error code sm_pdu_received_in_wrong_state(sm_conn); break; } 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 NK_BOTH_INPUT: 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 OK_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: // TODO: implement SC OOB break; } } break; case SM_SC_W4_CONFIRMATION: if (packet[0] != SM_CODE_PAIRING_CONFIRM){ sm_pdu_received_in_wrong_state(sm_conn); break; } // received confirm value reverse_128(&packet[1], setup->sm_peer_confirm); 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)){ sm_conn->sm_engine_state = SM_SC_W2_GET_RANDOM_A; } else { sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; } } break; case SM_SC_W4_PAIRING_RANDOM: if (packet[0] != 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 AND passkey entry if (sm_conn->sm_role || sm_passkey_used(setup->sm_stk_generation_method)) { sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; } sm_sc_state_after_receiving_random(sm_conn); break; case SM_SC_W2_CALCULATE_G2: case SM_SC_W4_CALCULATE_G2: 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: if (packet[0] != 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 (packet[0] != SM_CODE_PAIRING_CONFIRM){ sm_pdu_received_in_wrong_state(sm_conn); break; } // received confirm value reverse_128(&packet[1], setup->sm_peer_confirm); // 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){ setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_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 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; break; case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: if (packet[0] != 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_PH3_RECEIVE_KEYS: switch(packet[0]){ 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_conn)){ sm_key_distribution_handle_all_received(sm_conn); if (IS_RESPONDER(sm_conn->sm_role)){ if (setup->sm_use_secure_connections && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION)){ sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; } else { sm_conn->sm_engine_state = SM_RESPONDER_IDLE; sm_done_for_handle(sm_conn->sm_handle); } } else { if (setup->sm_use_secure_connections){ sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; } else { sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; } } } break; default: // Unexpected PDU log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); break; } // try to send preparared packet sm_run(); } // Security Manager Client API void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ sm_get_oob_data = get_oob_data_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_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){ 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(int enable){ sm_slave_request_security = enable; } #endif void sm_set_er(sm_key_t er){ memcpy(sm_persistent_er, er, 16); } void sm_set_ir(sm_key_t ir){ memcpy(sm_persistent_ir, ir, 16); } // Testing support only void sm_test_set_irk(sm_key_t irk){ memcpy(sm_persistent_irk, irk, 16); sm_persistent_irk_ready = 1; } void sm_test_use_fixed_local_csrk(void){ test_use_fixed_local_csrk = 1; } void sm_init(void){ // set some (BTstack default) ER and IR int i; sm_key_t er; sm_key_t ir; for (i=0;i<16;i++){ er[i] = 0x30 + i; ir[i] = 0x90 + i; } sm_set_er(er); sm_set_ir(ir); // 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; #ifdef ENABLE_CMAC_ENGINE sm_cmac_state = CMAC_IDLE; #endif dkg_state = DKG_W4_WORKING; rau_state = RAU_W4_WORKING; sm_aes128_state = SM_AES128_IDLE; sm_address_resolution_test = -1; // no private address to resolve yet sm_address_resolution_ah_calculation_active = 0; sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; sm_address_resolution_general_queue = NULL; gap_random_adress_update_period = 15 * 60 * 1000L; sm_active_connection_handle = HCI_CON_HANDLE_INVALID; test_use_fixed_local_csrk = 0; // register for HCI Events from HCI hci_event_callback_registration.callback = &sm_event_packet_handler; hci_add_event_handler(&hci_event_callback_registration); // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); #ifdef ENABLE_LE_SECURE_CONNECTIONS ec_key_generation_state = EC_KEY_GENERATION_IDLE; #endif #ifdef USE_MBEDTLS_FOR_ECDH #ifndef HAVE_MALLOC sm_mbedtls_allocator_init(mbedtls_memory_buffer, sizeof(mbedtls_memory_buffer)); #endif mbedtls_ecp_group_init(&mbedtls_ec_group); mbedtls_ecp_group_load(&mbedtls_ec_group, MBEDTLS_ECP_DP_SECP256R1); #endif } void sm_use_fixed_ec_keypair(uint8_t * qx, uint8_t * qy, uint8_t * d){ #ifdef ENABLE_LE_SECURE_CONNECTIONS memcpy(&ec_q[0], qx, 32); memcpy(&ec_q[32], qy, 32); memcpy(ec_d, d, 32); sm_have_ec_keypair = 1; ec_key_generation_state = EC_KEY_GENERATION_DONE; #else UNUSED(qx); UNUSED(qy); UNUSED(d); #endif } #ifdef ENABLE_LE_SECURE_CONNECTIONS #ifndef USE_MBEDTLS_FOR_ECDH static void parse_hex(uint8_t * buffer, const char * hex_string){ while (*hex_string){ int high_nibble = nibble_for_char(*hex_string++); int low_nibble = nibble_for_char(*hex_string++); *buffer++ = (high_nibble << 4) | low_nibble; } } #endif #endif void sm_test_use_fixed_ec_keypair(void){ #ifdef ENABLE_LE_SECURE_CONNECTIONS const char * ec_d_string = "3f49f6d4a3c55f3874c9b3e3d2103f504aff607beb40b7995899b8a6cd3c1abd"; const char * ec_qx_string = "20b003d2f297be2c5e2c83a7e9f9a5b9eff49111acf4fddbcc0301480e359de6"; const char * ec_qy_string = "dc809c49652aeb6d63329abf5a52155c766345c28fed3024741c8ed01589d28b"; #ifdef USE_MBEDTLS_FOR_ECDH // use test keypair from spec mbedtls_mpi x; mbedtls_mpi_init(&x); mbedtls_mpi_read_string( &x, 16, ec_d_string); mbedtls_mpi_write_binary(&x, ec_d, 32); mbedtls_mpi_read_string( &x, 16, ec_qx_string); mbedtls_mpi_write_binary(&x, &ec_q[0], 32); mbedtls_mpi_read_string( &x, 16, ec_qy_string); mbedtls_mpi_write_binary(&x, &ec_q[32], 32); mbedtls_mpi_free(&x); #else parse_hex(ec_d, ec_d_string); parse_hex(&ec_q[0], ec_qx_string); parse_hex(&ec_q[32], ec_qy_string); #endif sm_have_ec_keypair = 1; ec_key_generation_state = EC_KEY_GENERATION_DONE; #endif } 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; } // @returns 0 if not encrypted, 7-16 otherwise int sm_encryption_key_size(hci_con_handle_t con_handle){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return 0; // wrong connection if (!sm_conn->sm_connection_encrypted) return 0; return sm_conn->sm_actual_encryption_key_size; } int sm_authenticated(hci_con_handle_t con_handle){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return 0; // wrong connection if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated return sm_conn->sm_connection_authenticated; } authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized return sm_conn->sm_connection_authorization_state; } static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ switch (sm_conn->sm_engine_state){ case SM_GENERAL_IDLE: case SM_RESPONDER_IDLE: sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; sm_run(); break; default: break; } } /** * @brief Trigger Security Request */ 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; sm_send_security_request_for_connection(sm_conn); } // 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 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)){ sm_send_security_request_for_connection(sm_conn); } else { // used as a trigger to start central/master/initiator security procedures uint16_t ediv; sm_key_t ltk; if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ switch (sm_conn->sm_irk_lookup_state){ case IRK_LOOKUP_FAILED: 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, &ediv, NULL, ltk, NULL, NULL, NULL); if (!sm_is_null_key(ltk) || ediv){ log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; } else { sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; } break; default: sm_conn->sm_bonding_requested = 1; break; } } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ sm_conn->sm_bonding_requested = 1; } } sm_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_authorization(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_authorization(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; if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ switch (setup->sm_stk_generation_method){ case PK_RESP_INPUT: case PK_INIT_INPUT: case OK_BOTH_INPUT: sm_pairing_error(sm_conn, SM_GENERAL_SEND_PAIRING_FAILED); break; case NK_BOTH_INPUT: 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; } } sm_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 { sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; } } #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_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){ sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; } #ifdef ENABLE_LE_SECURE_CONNECTIONS memcpy(setup->sm_ra, setup->sm_tk, 16); 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_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; setup->sm_keypress_notification = action; sm_run(); } /** * @brief Identify device in LE Device DB * @param handle * @returns 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; } static int gap_random_address_type_requires_updates(void){ if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return 0; 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(bd_addr_t addr){ gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); memcpy(sm_random_address, addr, 6); if (rau_state == RAU_W4_WORKING) return; rau_state = RAU_SET_ADDRESS; sm_run(); } #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