/** * Copyright (c) 2018, Nordic Semiconductor ASA * * All rights reserved. * * 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, except as embedded into a Nordic * Semiconductor ASA integrated circuit in a product or a software update for * such product, 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 Nordic Semiconductor ASA nor the names of its * contributors may be used to endorse or promote products derived from this * software without specific prior written permission. * * 4. This software, with or without modification, must only be used with a * Nordic Semiconductor ASA integrated circuit. * * 5. Any software provided in binary form under this license must not be reverse * engineered, decompiled, modified and/or disassembled. * * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA 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. * */ #include "sdk_common.h" #if NRF_MODULE_ENABLED(PEER_MANAGER) && NRF_MODULE_ENABLED(PM_RA_PROTECTION) #include "auth_status_tracker.h" #include "app_timer.h" #include "id_manager.h" #define NRF_LOG_MODULE_NAME peer_manager_ast #if PM_LOG_ENABLED #define NRF_LOG_LEVEL PM_LOG_LEVEL #define NRF_LOG_INFO_COLOR PM_LOG_INFO_COLOR #define NRF_LOG_DEBUG_COLOR PM_LOG_DEBUG_COLOR #else #define NRF_LOG_LEVEL 0 #endif // PM_LOG_ENABLED #include "nrf_log.h" NRF_LOG_MODULE_REGISTER(); #include "nrf_strerror.h" // Assume that waiting interval doubles with each failed authentication. //lint --emacro((647),PENALITY_LVL_TO_PENALITY_MS) #define PAIR_REWARD_TICKS APP_TIMER_TICKS(PM_RA_PROTECTION_REWARD_PERIOD) #define PENALITY_LVL_TO_PENALITY_MS(_lvl) (PM_RA_PROTECTION_MIN_WAIT_INTERVAL * (1 << _lvl)) #define PENALITY_LVL_TO_PENALITY_TICKS(_lvl) APP_TIMER_TICKS(PENALITY_LVL_TO_PENALITY_MS(_lvl)) #define PENALITY_LVL_NEXT_SET(_lvl) \ _lvl = (PENALITY_LVL_TO_PENALITY_MS(_lvl) >= (PM_RA_PROTECTION_MAX_WAIT_INTERVAL)) ? \ (_lvl) : (_lvl + 1) /**@brief Tracked peer state. */ typedef struct { ble_gap_addr_t peer_addr; /**< BLE address, used to identify peer. */ uint32_t reward_ticks; /**< Accumulated reward ticks, used to decrease penality level after achieving certain threshold. */ uint32_t penality_ticks; /**< Accumulated penality ticks, used to determine remaining time in which pairing attempts should be rejected. */ uint8_t penality_lvl; /**< Accumulated penality level, used to determine waiting interval after failed authorization attempt. */ bool is_active; /**< Flag indicating that the waiting interval for this peer has not passed yet. */ bool is_valid; /**< Flag indicating that this entry is valid in the peer blacklist. */ } blacklisted_peer_t; APP_TIMER_DEF(m_pairing_attempt_timer); static blacklisted_peer_t m_blacklisted_peers[PM_RA_PROTECTION_TRACKED_PEERS_NUM]; static uint32_t m_ticks_cnt; /**@brief Function for updating the state of blacklisted peers after timer has been stopped or * timed out. * * @param[in] ticks_passed The number of ticks since the timer has started. */ static uint32_t blacklisted_peers_state_update(uint32_t ticks_passed) { uint32_t minimal_ticks = UINT32_MAX; for (uint32_t id = 0; id < ARRAY_SIZE(m_blacklisted_peers); id++) { blacklisted_peer_t * p_bl_peer = &m_blacklisted_peers[id]; if (p_bl_peer->is_valid) { if (p_bl_peer->is_active) { if (p_bl_peer->penality_ticks > ticks_passed) { p_bl_peer->penality_ticks -= ticks_passed; minimal_ticks = MIN(minimal_ticks, p_bl_peer->penality_ticks); } else { p_bl_peer->is_active = false; if (p_bl_peer->penality_lvl == 0) { p_bl_peer->is_valid = false; NRF_LOG_DEBUG("Peer has been removed from the blacklist, its address:"); NRF_LOG_HEXDUMP_DEBUG(p_bl_peer->peer_addr.addr, sizeof(p_bl_peer->peer_addr.addr)); } else { minimal_ticks = MIN(minimal_ticks, PAIR_REWARD_TICKS); } NRF_LOG_DEBUG("Pairing waiting interval has expired for:"); NRF_LOG_HEXDUMP_DEBUG(p_bl_peer->peer_addr.addr, sizeof(p_bl_peer->peer_addr.addr)); } } else { if (p_bl_peer->penality_lvl == 0) { p_bl_peer->is_valid = false; NRF_LOG_DEBUG("Peer has been removed from the blacklist, its address:"); NRF_LOG_HEXDUMP_DEBUG(p_bl_peer->peer_addr.addr, sizeof(p_bl_peer->peer_addr.addr)); } else { p_bl_peer->reward_ticks += ticks_passed; if (p_bl_peer->reward_ticks >= PAIR_REWARD_TICKS) { p_bl_peer->penality_lvl--; p_bl_peer->reward_ticks -= PAIR_REWARD_TICKS; NRF_LOG_DEBUG("Peer penality level has decreased to %d for device:", p_bl_peer->penality_lvl); NRF_LOG_HEXDUMP_DEBUG(p_bl_peer->peer_addr.addr, sizeof(p_bl_peer->peer_addr.addr)); } minimal_ticks = MIN(minimal_ticks, (PAIR_REWARD_TICKS - p_bl_peer->reward_ticks)); } } } } return minimal_ticks; } /**@brief Function for handling state transition of blacklisted peers. * * @param[in] context Context containing the number of ticks since the timer has started. */ static void blacklisted_peers_state_transition_handle(void * context) { ret_code_t err_code; uint32_t minimal_ticks; uint32_t ticks_passed = (uint32_t) context; minimal_ticks = blacklisted_peers_state_update(ticks_passed); m_ticks_cnt = app_timer_cnt_get(); if (minimal_ticks != UINT32_MAX) { err_code = app_timer_start(m_pairing_attempt_timer, minimal_ticks, (void *) minimal_ticks); if (err_code != NRF_SUCCESS) { NRF_LOG_WARNING("app_timer_start() returned %s", nrf_strerror_get(err_code)); } NRF_LOG_DEBUG("Restarting the timer"); } } ret_code_t ast_init(void) { ret_code_t err_code = app_timer_create(&m_pairing_attempt_timer, APP_TIMER_MODE_SINGLE_SHOT, blacklisted_peers_state_transition_handle); return err_code; } void ast_auth_error_notify(uint16_t conn_handle) { ret_code_t err_code; ble_gap_addr_t peer_addr; uint32_t new_timeout; uint32_t free_id = ARRAY_SIZE(m_blacklisted_peers); bool new_bl_entry = true; // Get the peer address associated with connection handle. err_code = im_ble_addr_get(conn_handle, &peer_addr); if (err_code != NRF_SUCCESS) { NRF_LOG_WARNING("im_ble_addr_get() returned %s. conn_handle: %d. " "Link was likely disconnected.", nrf_strerror_get(err_code), conn_handle); return; } // Stop the timer and update the state of all blacklisted peers. err_code = app_timer_stop(m_pairing_attempt_timer); if (err_code != NRF_SUCCESS) { NRF_LOG_WARNING("app_timer_stop() returned %s", nrf_strerror_get(err_code)); return; } new_timeout = blacklisted_peers_state_update(app_timer_cnt_diff_compute(app_timer_cnt_get(), m_ticks_cnt)); m_ticks_cnt = app_timer_cnt_get(); // Check if authorization has failed for already blacklisted peer. for (uint32_t id = 0; id < ARRAY_SIZE(m_blacklisted_peers); id++) { blacklisted_peer_t * p_bl_peer = &m_blacklisted_peers[id]; if (p_bl_peer->is_valid) { if (memcmp(peer_addr.addr, p_bl_peer->peer_addr.addr, BLE_GAP_ADDR_LEN) == 0) { uint8_t lvl = p_bl_peer->penality_lvl; PENALITY_LVL_NEXT_SET(lvl); p_bl_peer->penality_lvl = lvl; p_bl_peer->reward_ticks = 0; p_bl_peer->penality_ticks = PENALITY_LVL_TO_PENALITY_TICKS(lvl); new_timeout = MIN(new_timeout, p_bl_peer->penality_ticks); p_bl_peer->is_active = true; new_bl_entry = false; NRF_LOG_DEBUG("Pairing waiting interval has been renewed. " "Penality level: %d for device:", lvl); NRF_LOG_HEXDUMP_DEBUG(p_bl_peer->peer_addr.addr, sizeof(p_bl_peer->peer_addr.addr)); } } else { free_id = id; } } // Add a new peer to the blacklist. if (new_bl_entry) { if (free_id < ARRAY_SIZE(m_blacklisted_peers)) { blacklisted_peer_t * p_bl_peer = &m_blacklisted_peers[free_id]; memcpy(&p_bl_peer->peer_addr, &peer_addr, sizeof(peer_addr)); p_bl_peer->penality_lvl = 0; p_bl_peer->reward_ticks = 0; p_bl_peer->penality_ticks = PENALITY_LVL_TO_PENALITY_TICKS(p_bl_peer->penality_lvl); new_timeout = MIN(new_timeout, p_bl_peer->penality_ticks); p_bl_peer->is_active = true; p_bl_peer->is_valid = true; NRF_LOG_DEBUG("New peer has been added to the blacklist:"); NRF_LOG_HEXDUMP_DEBUG(p_bl_peer->peer_addr.addr, sizeof(p_bl_peer->peer_addr.addr)); } else { NRF_LOG_WARNING("No space to blacklist another peer ID"); } } // Restart the timer. if (new_timeout != UINT32_MAX) { err_code = app_timer_start(m_pairing_attempt_timer, new_timeout, (void *) new_timeout); if (err_code != NRF_SUCCESS) { NRF_LOG_WARNING("app_timer_start() returned %s", nrf_strerror_get(err_code)); } } } bool ast_peer_blacklisted(uint16_t conn_handle) { ret_code_t err_code; ble_gap_addr_t peer_addr; err_code = im_ble_addr_get(conn_handle, &peer_addr); if (err_code != NRF_SUCCESS) { NRF_LOG_WARNING("im_ble_addr_get() returned %s. conn_handle: %d. " "Link was likely disconnected.", nrf_strerror_get(err_code), conn_handle); return true; } for (uint32_t id = 0; id < ARRAY_SIZE(m_blacklisted_peers); id++) { blacklisted_peer_t * p_bl_peer = &m_blacklisted_peers[id]; if (p_bl_peer->is_valid) { if ((memcmp(peer_addr.addr, p_bl_peer->peer_addr.addr, BLE_GAP_ADDR_LEN) == 0) && (p_bl_peer->is_active)) { return true; } } } return false; } #endif // NRF_MODULE_ENABLED(PEER_MANAGER) && NRF_MODULE_ENABLED(PM_RA_PROTECTION)