ec0f7ac36f
The library provides an init function and an API for DNS resolver to query whether the application is allowed to send DNS query based on BPF maps settings. Bug: 288340533 Test: atest dns_helper_unit_test (with test CL) Change-Id: Ibfb383bfb074da2104a25aa4f04ebc32b22d11da
77 lines
2.4 KiB
C++
77 lines
2.4 KiB
C++
/*
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* Copyright (C) 2023 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define LOG_TAG "DnsBpfHelper"
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#include "DnsBpfHelper.h"
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#include <android-base/logging.h>
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#include <android-modules-utils/sdk_level.h>
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namespace android {
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namespace net {
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base::Result<void> DnsBpfHelper::init() {
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if (!android::modules::sdklevel::IsAtLeastT()) {
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LOG(ERROR) << __func__ << ": Unsupported before Android T.";
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return base::Error(EOPNOTSUPP);
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}
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auto result = mConfigurationMap.init(CONFIGURATION_MAP_PATH);
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if (!result.ok()) {
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LOG(ERROR) << __func__ << ": Failed to init configuration_map: "
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<< strerror(result.error().code());
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return result;
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}
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result = mUidOwnerMap.init(UID_OWNER_MAP_PATH);
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if (!result.ok()) {
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LOG(ERROR) << __func__ << ": Failed to init uid_owner_map: "
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<< strerror(result.error().code());
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}
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return result;
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}
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base::Result<bool> DnsBpfHelper::isUidNetworkingBlocked(uid_t uid, bool) {
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if (is_system_uid(uid)) return false;
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if (!mConfigurationMap.isValid() || !mUidOwnerMap.isValid()) {
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LOG(ERROR) << __func__
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<< ": BPF maps are not ready. Forgot to call ADnsHelper_init?";
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return base::Error(EUNATCH);
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}
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auto enabledRules = mConfigurationMap.readValue(UID_RULES_CONFIGURATION_KEY);
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if (!enabledRules.ok()) {
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LOG(ERROR) << __func__
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<< ": Failed to read enabled rules from configuration_map: "
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<< strerror(enabledRules.error().code());
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return enabledRules.error();
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}
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auto value = mUidOwnerMap.readValue(uid);
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uint32_t uidRules = value.ok() ? value.value().rule : 0;
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if (isBlockedByUidRules(enabledRules.value(), uidRules)) return true;
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// TODO: Read data saver settings from bpf maps. For metered network, check penalty box, happy box
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// and data saver settings.
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return false;
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}
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} // namespace net
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} // namespace android
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