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66 lines
2.0 KiB
66 lines
2.0 KiB
/*
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* Copyright (C) 2018 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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#include "idmap2/FileUtils.h"
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#include <string>
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#include "android-base/file.h"
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#include "android-base/macros.h"
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#include "android-base/stringprintf.h"
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#include "private/android_filesystem_config.h"
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namespace android::idmap2::utils {
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#ifdef __ANDROID__
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bool UidHasWriteAccessToPath(uid_t uid, const std::string& path) {
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// resolve symlinks and relative paths; the directories must exist
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std::string canonical_path;
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if (!base::Realpath(base::Dirname(path), &canonical_path)) {
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return false;
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}
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const std::string cache_subdir = base::StringPrintf("%s/", kIdmapCacheDir);
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if (canonical_path == kIdmapCacheDir ||
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canonical_path.compare(0, cache_subdir.size(), cache_subdir) == 0) {
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// limit access to /data/resource-cache to root and system
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return uid == AID_ROOT || uid == AID_SYSTEM;
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}
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return true;
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}
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#else
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bool UidHasWriteAccessToPath(uid_t uid ATTRIBUTE_UNUSED, const std::string& path ATTRIBUTE_UNUSED) {
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return true;
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}
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#endif
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std::string RandomStringForPath(const size_t length) {
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constexpr char kChars[] = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
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constexpr size_t kCharLastIndex = sizeof(kChars) - 1;
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std::string out_rand;
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out_rand.reserve(length);
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std::random_device rd;
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std::uniform_int_distribution<int> dist(0, kCharLastIndex);
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for (size_t i = 0; i < length; i++) {
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out_rand[i] = kChars[dist(rd) % (kCharLastIndex)];
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}
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return out_rand;
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}
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} // namespace android::idmap2::utils
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