1bd078fa7b
We have a bunch of magic that mounts the correct view of storage access based on the runtime permissions of an app, but we forgot to protect the real underlying data sources; oops. This series of changes just bumps the directory heirarchy one level to give us /mnt/runtime which we can mask off as 0700 to prevent people from jumping to the exposed internals. Also add CTS tests to verify that we're protecting access to internal mount points like this. Bug: 22964288 Change-Id: I83f09f0423f4993e766273c50389dd29b1c50589
132 lines
3.6 KiB
C++
132 lines
3.6 KiB
C++
/*
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* Copyright (C) 2015 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 "EmulatedVolume.h"
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#include "Utils.h"
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#include <base/stringprintf.h>
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#include <base/logging.h>
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#include <cutils/fs.h>
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#include <private/android_filesystem_config.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <sys/mount.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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using android::base::StringPrintf;
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namespace android {
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namespace vold {
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static const char* kFusePath = "/system/bin/sdcard";
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EmulatedVolume::EmulatedVolume(const std::string& rawPath) :
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VolumeBase(Type::kEmulated), mFusePid(0) {
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setId("emulated");
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mRawPath = rawPath;
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mLabel = "emulated";
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}
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EmulatedVolume::EmulatedVolume(const std::string& rawPath, dev_t device,
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const std::string& fsUuid) : VolumeBase(Type::kEmulated), mFusePid(0) {
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setId(StringPrintf("emulated:%u,%u", major(device), minor(device)));
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mRawPath = rawPath;
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mLabel = fsUuid;
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}
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EmulatedVolume::~EmulatedVolume() {
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}
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status_t EmulatedVolume::doMount() {
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// We could have migrated storage to an adopted private volume, so always
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// call primary storage "emulated" to avoid media rescans.
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std::string label = mLabel;
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if (getMountFlags() & MountFlags::kPrimary) {
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label = "emulated";
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}
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mFuseDefault = StringPrintf("/mnt/runtime/default/%s", label.c_str());
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mFuseRead = StringPrintf("/mnt/runtime/read/%s", label.c_str());
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mFuseWrite = StringPrintf("/mnt/runtime/write/%s", label.c_str());
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setInternalPath(mRawPath);
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setPath(StringPrintf("/storage/%s", label.c_str()));
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if (fs_prepare_dir(mFuseDefault.c_str(), 0700, AID_ROOT, AID_ROOT) ||
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fs_prepare_dir(mFuseRead.c_str(), 0700, AID_ROOT, AID_ROOT) ||
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fs_prepare_dir(mFuseWrite.c_str(), 0700, AID_ROOT, AID_ROOT)) {
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PLOG(ERROR) << getId() << " failed to create mount points";
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return -errno;
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}
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dev_t before = GetDevice(mFuseWrite);
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if (!(mFusePid = fork())) {
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if (execl(kFusePath, kFusePath,
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"-u", "1023", // AID_MEDIA_RW
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"-g", "1023", // AID_MEDIA_RW
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"-m",
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"-w",
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mRawPath.c_str(),
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label.c_str(),
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NULL)) {
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PLOG(ERROR) << "Failed to exec";
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}
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LOG(ERROR) << "FUSE exiting";
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_exit(1);
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}
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if (mFusePid == -1) {
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PLOG(ERROR) << getId() << " failed to fork";
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return -errno;
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}
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while (before == GetDevice(mFuseWrite)) {
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LOG(VERBOSE) << "Waiting for FUSE to spin up...";
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usleep(50000); // 50ms
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}
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return OK;
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}
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status_t EmulatedVolume::doUnmount() {
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if (mFusePid > 0) {
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kill(mFusePid, SIGTERM);
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TEMP_FAILURE_RETRY(waitpid(mFusePid, nullptr, 0));
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mFusePid = 0;
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}
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ForceUnmount(mFuseDefault);
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ForceUnmount(mFuseRead);
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ForceUnmount(mFuseWrite);
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rmdir(mFuseDefault.c_str());
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rmdir(mFuseRead.c_str());
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rmdir(mFuseWrite.c_str());
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mFuseDefault.clear();
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mFuseRead.clear();
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mFuseWrite.clear();
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return OK;
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}
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} // namespace vold
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} // namespace android
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