platform_system_vold/VolumeManager.cpp
Sudheer Shanka 144e7cc25a Merge "Add unmountTree to utils." am: a64572431e am: f5b24f1015
am: e9c88c4c6c

Change-Id: Iae8f7c972272807f87b2ce9c4ba536cf6458d3cb
2018-09-27 13:35:28 -07:00

1106 lines
37 KiB
C++

/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define ATRACE_TAG ATRACE_TAG_PACKAGE_MANAGER
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <mntent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <linux/kdev_t.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <cutils/fs.h>
#include <utils/Trace.h>
#include <selinux/android.h>
#include <sysutils/NetlinkEvent.h>
#include <private/android_filesystem_config.h>
#include <ext4_utils/ext4_crypt.h>
#include "Devmapper.h"
#include "Ext4Crypt.h"
#include "Loop.h"
#include "NetlinkManager.h"
#include "Process.h"
#include "Utils.h"
#include "VoldUtil.h"
#include "VolumeManager.h"
#include "cryptfs.h"
#include "fs/Ext4.h"
#include "fs/Vfat.h"
#include "model/EmulatedVolume.h"
#include "model/ObbVolume.h"
using android::base::GetBoolProperty;
using android::base::StringAppendF;
using android::base::StringPrintf;
using android::base::unique_fd;
static const char* kPathUserMount = "/mnt/user";
static const char* kPathVirtualDisk = "/data/misc/vold/virtual_disk";
static const char* kIsolatedStorage = "persist.sys.isolated_storage";
static const char* kPropVirtualDisk = "persist.sys.virtual_disk";
static const std::string kEmptyString("");
/* 512MiB is large enough for testing purposes */
static const unsigned int kSizeVirtualDisk = 536870912;
static const unsigned int kMajorBlockMmc = 179;
static const unsigned int kMajorBlockExperimentalMin = 240;
static const unsigned int kMajorBlockExperimentalMax = 254;
VolumeManager* VolumeManager::sInstance = NULL;
VolumeManager* VolumeManager::Instance() {
if (!sInstance) sInstance = new VolumeManager();
return sInstance;
}
VolumeManager::VolumeManager() {
mDebug = false;
mNextObbId = 0;
// For security reasons, assume that a secure keyguard is
// showing until we hear otherwise
mSecureKeyguardShowing = true;
mMntStorageCreated = false;
}
VolumeManager::~VolumeManager() {}
int VolumeManager::updateVirtualDisk() {
ATRACE_NAME("VolumeManager::updateVirtualDisk");
if (android::base::GetBoolProperty(kPropVirtualDisk, false)) {
if (access(kPathVirtualDisk, F_OK) != 0) {
Loop::createImageFile(kPathVirtualDisk, kSizeVirtualDisk / 512);
}
if (mVirtualDisk == nullptr) {
if (Loop::create(kPathVirtualDisk, mVirtualDiskPath) != 0) {
LOG(ERROR) << "Failed to create virtual disk";
return -1;
}
struct stat buf;
if (stat(mVirtualDiskPath.c_str(), &buf) < 0) {
PLOG(ERROR) << "Failed to stat " << mVirtualDiskPath;
return -1;
}
auto disk = new android::vold::Disk(
"virtual", buf.st_rdev, "virtual",
android::vold::Disk::Flags::kAdoptable | android::vold::Disk::Flags::kSd);
mVirtualDisk = std::shared_ptr<android::vold::Disk>(disk);
handleDiskAdded(mVirtualDisk);
}
} else {
if (mVirtualDisk != nullptr) {
dev_t device = mVirtualDisk->getDevice();
handleDiskRemoved(device);
Loop::destroyByDevice(mVirtualDiskPath.c_str());
mVirtualDisk = nullptr;
}
if (access(kPathVirtualDisk, F_OK) == 0) {
unlink(kPathVirtualDisk);
}
}
return 0;
}
int VolumeManager::setDebug(bool enable) {
mDebug = enable;
return 0;
}
int VolumeManager::start() {
ATRACE_NAME("VolumeManager::start");
// Always start from a clean slate by unmounting everything in
// directories that we own, in case we crashed.
unmountAll();
Devmapper::destroyAll();
Loop::destroyAll();
// Assume that we always have an emulated volume on internal
// storage; the framework will decide if it should be mounted.
CHECK(mInternalEmulated == nullptr);
mInternalEmulated = std::shared_ptr<android::vold::VolumeBase>(
new android::vold::EmulatedVolume("/data/media"));
mInternalEmulated->create();
// Consider creating a virtual disk
updateVirtualDisk();
return 0;
}
int VolumeManager::stop() {
CHECK(mInternalEmulated != nullptr);
mInternalEmulated->destroy();
mInternalEmulated = nullptr;
return 0;
}
void VolumeManager::handleBlockEvent(NetlinkEvent* evt) {
std::lock_guard<std::mutex> lock(mLock);
if (mDebug) {
LOG(DEBUG) << "----------------";
LOG(DEBUG) << "handleBlockEvent with action " << (int)evt->getAction();
evt->dump();
}
std::string eventPath(evt->findParam("DEVPATH") ? evt->findParam("DEVPATH") : "");
std::string devType(evt->findParam("DEVTYPE") ? evt->findParam("DEVTYPE") : "");
if (devType != "disk") return;
int major = std::stoi(evt->findParam("MAJOR"));
int minor = std::stoi(evt->findParam("MINOR"));
dev_t device = makedev(major, minor);
switch (evt->getAction()) {
case NetlinkEvent::Action::kAdd: {
for (const auto& source : mDiskSources) {
if (source->matches(eventPath)) {
// For now, assume that MMC and virtio-blk (the latter is
// emulator-specific; see Disk.cpp for details) devices are SD,
// and that everything else is USB
int flags = source->getFlags();
if (major == kMajorBlockMmc || (android::vold::IsRunningInEmulator() &&
major >= (int)kMajorBlockExperimentalMin &&
major <= (int)kMajorBlockExperimentalMax)) {
flags |= android::vold::Disk::Flags::kSd;
} else {
flags |= android::vold::Disk::Flags::kUsb;
}
auto disk =
new android::vold::Disk(eventPath, device, source->getNickname(), flags);
handleDiskAdded(std::shared_ptr<android::vold::Disk>(disk));
break;
}
}
break;
}
case NetlinkEvent::Action::kChange: {
LOG(DEBUG) << "Disk at " << major << ":" << minor << " changed";
handleDiskChanged(device);
break;
}
case NetlinkEvent::Action::kRemove: {
handleDiskRemoved(device);
break;
}
default: {
LOG(WARNING) << "Unexpected block event action " << (int)evt->getAction();
break;
}
}
}
void VolumeManager::handleDiskAdded(const std::shared_ptr<android::vold::Disk>& disk) {
// For security reasons, if secure keyguard is showing, wait
// until the user unlocks the device to actually touch it
if (mSecureKeyguardShowing) {
LOG(INFO) << "Found disk at " << disk->getEventPath()
<< " but delaying scan due to secure keyguard";
mPendingDisks.push_back(disk);
} else {
disk->create();
mDisks.push_back(disk);
}
}
void VolumeManager::handleDiskChanged(dev_t device) {
for (const auto& disk : mDisks) {
if (disk->getDevice() == device) {
disk->readMetadata();
disk->readPartitions();
}
}
// For security reasons, we ignore all pending disks, since
// we'll scan them once the device is unlocked
}
void VolumeManager::handleDiskRemoved(dev_t device) {
auto i = mDisks.begin();
while (i != mDisks.end()) {
if ((*i)->getDevice() == device) {
(*i)->destroy();
i = mDisks.erase(i);
} else {
++i;
}
}
auto j = mPendingDisks.begin();
while (j != mPendingDisks.end()) {
if ((*j)->getDevice() == device) {
j = mPendingDisks.erase(j);
} else {
++j;
}
}
}
void VolumeManager::addDiskSource(const std::shared_ptr<DiskSource>& diskSource) {
std::lock_guard<std::mutex> lock(mLock);
mDiskSources.push_back(diskSource);
}
std::shared_ptr<android::vold::Disk> VolumeManager::findDisk(const std::string& id) {
for (auto disk : mDisks) {
if (disk->getId() == id) {
return disk;
}
}
return nullptr;
}
std::shared_ptr<android::vold::VolumeBase> VolumeManager::findVolume(const std::string& id) {
// Vold could receive "mount" after "shutdown" command in the extreme case.
// If this happens, mInternalEmulated will equal nullptr and
// we need to deal with it in order to avoid null pointer crash.
if (mInternalEmulated != nullptr && mInternalEmulated->getId() == id) {
return mInternalEmulated;
}
for (const auto& disk : mDisks) {
auto vol = disk->findVolume(id);
if (vol != nullptr) {
return vol;
}
}
for (const auto& vol : mObbVolumes) {
if (vol->getId() == id) {
return vol;
}
}
return nullptr;
}
void VolumeManager::listVolumes(android::vold::VolumeBase::Type type, std::list<std::string>& list) {
list.clear();
for (const auto& disk : mDisks) {
disk->listVolumes(type, list);
}
}
int VolumeManager::forgetPartition(const std::string& partGuid, const std::string& fsUuid) {
std::string normalizedGuid;
if (android::vold::NormalizeHex(partGuid, normalizedGuid)) {
LOG(WARNING) << "Invalid GUID " << partGuid;
return -1;
}
bool success = true;
std::string keyPath = android::vold::BuildKeyPath(normalizedGuid);
if (unlink(keyPath.c_str()) != 0) {
LOG(ERROR) << "Failed to unlink " << keyPath;
success = false;
}
if (e4crypt_is_native()) {
if (!e4crypt_destroy_volume_keys(fsUuid)) {
success = false;
}
}
return success ? 0 : -1;
}
static int prepareMntStorageDir() {
std::string mntTarget("/mnt/storage");
if (fs_prepare_dir(mntTarget.c_str(), 0755, AID_ROOT, AID_ROOT) != 0) {
PLOG(ERROR) << "fs_prepare_dir failed on " << mntTarget;
return -errno;
}
if (TEMP_FAILURE_RETRY(mount("/mnt/runtime/write", mntTarget.c_str(), nullptr, MS_BIND | MS_REC,
nullptr)) == -1) {
PLOG(ERROR) << "Failed to mount /mnt/runtime/write at " << mntTarget;
return -errno;
}
if (TEMP_FAILURE_RETRY(
mount(nullptr, mntTarget.c_str(), nullptr, MS_REC | MS_SLAVE, nullptr)) == -1) {
PLOG(ERROR) << "Failed to set MS_SLAVE at " << mntTarget;
return -errno;
}
return 0;
}
int VolumeManager::linkPrimary(userid_t userId, const std::vector<std::string>& packageNames) {
if (GetBoolProperty(kIsolatedStorage, false)) {
// This should ideally go into start() but it's possible that system properties are not
// loaded at that point.
if (!mMntStorageCreated) {
prepareMntStorageDir();
mMntStorageCreated = true;
}
if (mountSandboxesForPrimaryVol(userId, packageNames) != 0) {
return -errno;
}
// Keep /sdcard working for shell process
std::string primarySource(mPrimary->getPath());
if (mPrimary->getType() == android::vold::VolumeBase::Type::kEmulated) {
StringAppendF(&primarySource, "/%d", userId);
}
std::string target(StringPrintf("/mnt/user/%d/primary", userId));
if (TEMP_FAILURE_RETRY(unlink(target.c_str()))) {
if (errno != ENOENT) {
PLOG(WARNING) << "Failed to unlink " << target;
}
}
if (TEMP_FAILURE_RETRY(symlink(primarySource.c_str(), target.c_str()))) {
PLOG(WARNING) << "Failed to link " << primarySource << " at " << target;
return -errno;
}
} else {
std::string source(mPrimary->getPath());
if (mPrimary->getType() == android::vold::VolumeBase::Type::kEmulated) {
source = StringPrintf("%s/%d", source.c_str(), userId);
fs_prepare_dir(source.c_str(), 0755, AID_ROOT, AID_ROOT);
}
std::string target(StringPrintf("/mnt/user/%d/primary", userId));
if (TEMP_FAILURE_RETRY(unlink(target.c_str()))) {
if (errno != ENOENT) {
PLOG(WARNING) << "Failed to unlink " << target;
}
}
LOG(DEBUG) << "Linking " << source << " to " << target;
if (TEMP_FAILURE_RETRY(symlink(source.c_str(), target.c_str()))) {
PLOG(WARNING) << "Failed to link";
return -errno;
}
}
return 0;
}
int VolumeManager::mountSandboxesForPrimaryVol(userid_t userId,
const std::vector<std::string>& packageNames) {
std::string primaryRoot(StringPrintf("/mnt/storage/%s", mPrimary->getLabel().c_str()));
bool isPrimaryEmulated = (mPrimary->getType() == android::vold::VolumeBase::Type::kEmulated);
if (isPrimaryEmulated) {
StringAppendF(&primaryRoot, "/%d", userId);
if (fs_prepare_dir(primaryRoot.c_str(), 0755, AID_ROOT, AID_ROOT) != 0) {
PLOG(ERROR) << "fs_prepare_dir failed on " << primaryRoot;
return -errno;
}
}
std::string sandboxRoot =
prepareSubDirs(primaryRoot, "Android/sandbox/", 0700, AID_ROOT, AID_ROOT);
if (sandboxRoot.empty()) {
return -errno;
}
std::string sharedSandboxRoot;
StringAppendF(&sharedSandboxRoot, "%s/shared", sandboxRoot.c_str());
// Create shared sandbox base dir for apps with sharedUserIds
if (fs_prepare_dir(sharedSandboxRoot.c_str(), 0700, AID_ROOT, AID_ROOT) != 0) {
PLOG(ERROR) << "fs_prepare_dir failed on " << sharedSandboxRoot;
return -errno;
}
std::string dataRoot = prepareSubDirs(primaryRoot, "Android/data/", 0700, AID_ROOT, AID_ROOT);
if (dataRoot.empty()) {
return -errno;
}
std::string mntTargetRoot = StringPrintf("/mnt/user/%d", userId);
if (fs_prepare_dir(mntTargetRoot.c_str(), 0751, AID_ROOT, AID_ROOT) != 0) {
PLOG(ERROR) << "fs_prepare_dir failed on " << mntTargetRoot;
return -errno;
}
mntTargetRoot.append("/package");
if (fs_prepare_dir(mntTargetRoot.c_str(), 0700, AID_ROOT, AID_ROOT) != 0) {
PLOG(ERROR) << "fs_prepare_dir failed on " << mntTargetRoot;
return -errno;
}
for (auto& packageName : packageNames) {
const auto& it = mAppIds.find(packageName);
if (it == mAppIds.end()) {
PLOG(ERROR) << "appId is not available for " << packageName;
continue;
}
appid_t appId = it->second;
std::string sandboxId = mSandboxIds[appId];
uid_t uid = multiuser_get_uid(userId, appId);
// Create /mnt/storage/emulated/0/Android/sandbox/<sandboxId>
std::string pkgSandboxSourceDir = prepareSandboxSource(uid, sandboxId, sandboxRoot);
if (pkgSandboxSourceDir.empty()) {
return -errno;
}
// Create [1] /mnt/storage/emulated/0/Android/data/<packageName>
// Create [2] /mnt/storage/emulated/0/Android/sandbox/<sandboxId>/Android/data/<packageName>
// Mount [1] at [2]
std::string pkgDataSourceDir = preparePkgDataSource(packageName, uid, dataRoot);
if (pkgDataSourceDir.empty()) {
return -errno;
}
std::string pkgDataTargetDir = preparePkgDataTarget(packageName, uid, pkgSandboxSourceDir);
if (pkgDataTargetDir.empty()) {
return -errno;
}
if (TEMP_FAILURE_RETRY(mount(pkgDataSourceDir.c_str(), pkgDataTargetDir.c_str(), nullptr,
MS_BIND | MS_REC, nullptr)) == -1) {
PLOG(ERROR) << "Failed to mount " << pkgDataSourceDir << " at " << pkgDataTargetDir;
return -errno;
}
// Already created [1] /mnt/storage/emulated/0/Android/sandbox/<sandboxId>
// Create [2] /mnt/user/0/package/<packageName>/emulated/0
// Mount [1] at [2]
std::string pkgSandboxTargetDir = prepareSandboxTarget(
packageName, uid, mPrimary->getLabel(), mntTargetRoot, isPrimaryEmulated);
if (pkgSandboxTargetDir.empty()) {
return -errno;
}
if (TEMP_FAILURE_RETRY(mount(pkgSandboxSourceDir.c_str(), pkgSandboxTargetDir.c_str(),
nullptr, MS_BIND | MS_REC, nullptr)) == -1) {
PLOG(ERROR) << "Failed to mount " << pkgSandboxSourceDir << " at "
<< pkgSandboxTargetDir;
return -errno;
}
// Create [1] /mnt/user/0/package/<packageName>/self/primary
// Already created [2] /mnt/user/0/package/<packageName>/emulated/0
// Mount [2] at [1]
std::string pkgPrimaryTargetDir =
prepareSubDirs(StringPrintf("%s/%s", mntTargetRoot.c_str(), packageName.c_str()),
"self/primary/", 0755, uid, uid);
if (pkgPrimaryTargetDir.empty()) {
return -errno;
}
if (TEMP_FAILURE_RETRY(mount(pkgSandboxTargetDir.c_str(), pkgPrimaryTargetDir.c_str(),
nullptr, MS_BIND | MS_REC, nullptr)) == -1) {
PLOG(ERROR) << "Failed to mount " << pkgSandboxTargetDir << " at "
<< pkgPrimaryTargetDir;
return -errno;
}
}
return 0;
}
std::string VolumeManager::prepareSubDirs(const std::string& pathPrefix, const std::string& subDirs,
mode_t mode, uid_t uid, gid_t gid) {
std::string path(pathPrefix);
std::vector<std::string> subDirList = android::base::Split(subDirs, "/");
for (size_t i = 0; i < subDirList.size(); ++i) {
std::string subDir = subDirList[i];
if (subDir.empty()) {
continue;
}
StringAppendF(&path, "/%s", subDir.c_str());
if (fs_prepare_dir(path.c_str(), mode, uid, gid) != 0) {
PLOG(ERROR) << "fs_prepare_dir failed on " << path;
return kEmptyString;
}
}
return path;
}
std::string VolumeManager::prepareSandboxSource(uid_t uid, const std::string& sandboxId,
const std::string& sandboxRootDir) {
std::string sandboxSourceDir(sandboxRootDir);
if (android::base::StartsWith(sandboxId, "shared:")) {
StringAppendF(&sandboxSourceDir, "/shared/%s", sandboxId.substr(7).c_str());
} else {
StringAppendF(&sandboxSourceDir, "/%s", sandboxId.c_str());
}
if (fs_prepare_dir(sandboxSourceDir.c_str(), 0755, uid, uid) != 0) {
PLOG(ERROR) << "fs_prepare_dir failed on " << sandboxSourceDir;
return kEmptyString;
}
return sandboxSourceDir;
}
std::string VolumeManager::prepareSandboxTarget(const std::string& packageName, uid_t uid,
const std::string& volumeLabel,
const std::string& mntTargetRootDir,
bool isUserDependent) {
std::string segment;
if (isUserDependent) {
segment = StringPrintf("%s/%s/%d/", packageName.c_str(), volumeLabel.c_str(),
multiuser_get_user_id(uid));
} else {
segment = StringPrintf("%s/%s/", packageName.c_str(), volumeLabel.c_str());
}
return prepareSubDirs(mntTargetRootDir, segment.c_str(), 0755, uid, uid);
}
std::string VolumeManager::preparePkgDataSource(const std::string& packageName, uid_t uid,
const std::string& dataRootDir) {
std::string dataSourceDir = StringPrintf("%s/%s", dataRootDir.c_str(), packageName.c_str());
if (fs_prepare_dir(dataSourceDir.c_str(), 0755, uid, uid) != 0) {
PLOG(ERROR) << "fs_prepare_dir failed on " << dataSourceDir;
return kEmptyString;
}
return dataSourceDir;
}
std::string VolumeManager::preparePkgDataTarget(const std::string& packageName, uid_t uid,
const std::string& pkgSandboxDir) {
std::string segment = StringPrintf("Android/data/%s/", packageName.c_str());
return prepareSubDirs(pkgSandboxDir, segment.c_str(), 0755, uid, uid);
}
int VolumeManager::onUserAdded(userid_t userId, int userSerialNumber) {
mAddedUsers[userId] = userSerialNumber;
return 0;
}
int VolumeManager::onUserRemoved(userid_t userId) {
mAddedUsers.erase(userId);
return 0;
}
int VolumeManager::onUserStarted(userid_t userId, const std::vector<std::string>& packageNames) {
// Note that sometimes the system will spin up processes from Zygote
// before actually starting the user, so we're okay if Zygote
// already created this directory.
std::string path(StringPrintf("%s/%d", kPathUserMount, userId));
fs_prepare_dir(path.c_str(), 0755, AID_ROOT, AID_ROOT);
mStartedUsers.insert(userId);
mUserPackages[userId] = packageNames;
if (mPrimary) {
linkPrimary(userId, packageNames);
}
return 0;
}
int VolumeManager::onUserStopped(userid_t userId) {
mStartedUsers.erase(userId);
return 0;
}
int VolumeManager::addAppIds(const std::vector<std::string>& packageNames,
const std::vector<int32_t>& appIds) {
for (size_t i = 0; i < packageNames.size(); ++i) {
mAppIds[packageNames[i]] = appIds[i];
}
return 0;
}
int VolumeManager::addSandboxIds(const std::vector<int32_t>& appIds,
const std::vector<std::string>& sandboxIds) {
for (size_t i = 0; i < appIds.size(); ++i) {
mSandboxIds[appIds[i]] = sandboxIds[i];
}
return 0;
}
int VolumeManager::mountExternalStorageForApp(const std::string& packageName, appid_t appId,
const std::string& sandboxId, userid_t userId) {
if (!GetBoolProperty(kIsolatedStorage, false)) {
return 0;
} else if (mStartedUsers.find(userId) == mStartedUsers.end()) {
// User not started, no need to do anything now. Required bind mounts for the package will
// be created when the user starts.
return 0;
}
mUserPackages[userId].push_back(packageName);
mAppIds[packageName] = appId;
mSandboxIds[appId] = sandboxId;
if (mPrimary) {
return mountSandboxesForPrimaryVol(userId, {packageName});
}
return 0;
}
int VolumeManager::onSecureKeyguardStateChanged(bool isShowing) {
mSecureKeyguardShowing = isShowing;
if (!mSecureKeyguardShowing) {
// Now that secure keyguard has been dismissed, process
// any pending disks
for (const auto& disk : mPendingDisks) {
disk->create();
mDisks.push_back(disk);
}
mPendingDisks.clear();
}
return 0;
}
int VolumeManager::setPrimary(const std::shared_ptr<android::vold::VolumeBase>& vol) {
mPrimary = vol;
for (userid_t userId : mStartedUsers) {
linkPrimary(userId, mUserPackages[userId]);
}
return 0;
}
static int unmount_tree(const std::string& prefix) {
return android::vold::UnmountTree(prefix);
}
int VolumeManager::remountUid(uid_t uid, const std::string& mode) {
// If the isolated storage is enabled, return -1 since in the isolated storage world, there
// are no longer any runtime storage permissions, so this shouldn't be called anymore.
if (GetBoolProperty(kIsolatedStorage, false)) {
return -1;
}
LOG(DEBUG) << "Remounting " << uid << " as mode " << mode;
DIR* dir;
struct dirent* de;
std::string rootName;
std::string pidName;
int pidFd;
int nsFd;
struct stat sb;
pid_t child;
if (!(dir = opendir("/proc"))) {
PLOG(ERROR) << "Failed to opendir";
return -1;
}
// Figure out root namespace to compare against below
if (!android::vold::Readlinkat(dirfd(dir), "1/ns/mnt", &rootName)) {
PLOG(ERROR) << "Failed to read root namespace";
closedir(dir);
return -1;
}
// Poke through all running PIDs look for apps running as UID
while ((de = readdir(dir))) {
pid_t pid;
if (de->d_type != DT_DIR) continue;
if (!android::base::ParseInt(de->d_name, &pid)) continue;
pidFd = -1;
nsFd = -1;
pidFd = openat(dirfd(dir), de->d_name, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
if (pidFd < 0) {
goto next;
}
if (fstat(pidFd, &sb) != 0) {
PLOG(WARNING) << "Failed to stat " << de->d_name;
goto next;
}
if (sb.st_uid != uid) {
goto next;
}
// Matches so far, but refuse to touch if in root namespace
LOG(DEBUG) << "Found matching PID " << de->d_name;
if (!android::vold::Readlinkat(pidFd, "ns/mnt", &pidName)) {
PLOG(WARNING) << "Failed to read namespace for " << de->d_name;
goto next;
}
if (rootName == pidName) {
LOG(WARNING) << "Skipping due to root namespace";
goto next;
}
// We purposefully leave the namespace open across the fork
nsFd = openat(pidFd, "ns/mnt", O_RDONLY); // not O_CLOEXEC
if (nsFd < 0) {
PLOG(WARNING) << "Failed to open namespace for " << de->d_name;
goto next;
}
if (!(child = fork())) {
if (setns(nsFd, CLONE_NEWNS) != 0) {
PLOG(ERROR) << "Failed to setns for " << de->d_name;
_exit(1);
}
unmount_tree("/storage/");
std::string storageSource;
if (mode == "default") {
storageSource = "/mnt/runtime/default";
} else if (mode == "read") {
storageSource = "/mnt/runtime/read";
} else if (mode == "write") {
storageSource = "/mnt/runtime/write";
} else {
// Sane default of no storage visible
_exit(0);
}
if (TEMP_FAILURE_RETRY(
mount(storageSource.c_str(), "/storage", NULL, MS_BIND | MS_REC, NULL)) == -1) {
PLOG(ERROR) << "Failed to mount " << storageSource << " for " << de->d_name;
_exit(1);
}
if (TEMP_FAILURE_RETRY(mount(NULL, "/storage", NULL, MS_REC | MS_SLAVE, NULL)) == -1) {
PLOG(ERROR) << "Failed to set MS_SLAVE to /storage for " << de->d_name;
_exit(1);
}
// Mount user-specific symlink helper into place
userid_t user_id = multiuser_get_user_id(uid);
std::string userSource(StringPrintf("/mnt/user/%d", user_id));
if (TEMP_FAILURE_RETRY(
mount(userSource.c_str(), "/storage/self", NULL, MS_BIND, NULL)) == -1) {
PLOG(ERROR) << "Failed to mount " << userSource << " for " << de->d_name;
_exit(1);
}
_exit(0);
}
if (child == -1) {
PLOG(ERROR) << "Failed to fork";
goto next;
} else {
TEMP_FAILURE_RETRY(waitpid(child, nullptr, 0));
}
next:
close(nsFd);
close(pidFd);
}
closedir(dir);
return 0;
}
int VolumeManager::reset() {
// Tear down all existing disks/volumes and start from a blank slate so
// newly connected framework hears all events.
if (mInternalEmulated != nullptr) {
mInternalEmulated->destroy();
mInternalEmulated->create();
}
for (const auto& disk : mDisks) {
disk->destroy();
disk->create();
}
updateVirtualDisk();
mAddedUsers.clear();
mStartedUsers.clear();
mUserPackages.clear();
mAppIds.clear();
mSandboxIds.clear();
// For unmounting dirs under /mnt/user/<user-id>/package/<package-name>
unmount_tree("/mnt/user/");
// For unmounting dirs under /mnt/storage including the bind mount at /mnt/storage, that's
// why no trailing '/'
unmount_tree("/mnt/storage");
mMntStorageCreated = false;
return 0;
}
// Can be called twice (sequentially) during shutdown. should be safe for that.
int VolumeManager::shutdown() {
if (mInternalEmulated == nullptr) {
return 0; // already shutdown
}
android::vold::sSleepOnUnmount = false;
mInternalEmulated->destroy();
mInternalEmulated = nullptr;
for (const auto& disk : mDisks) {
disk->destroy();
}
mDisks.clear();
mPendingDisks.clear();
android::vold::sSleepOnUnmount = true;
return 0;
}
int VolumeManager::unmountAll() {
std::lock_guard<std::mutex> lock(mLock);
ATRACE_NAME("VolumeManager::unmountAll()");
// First, try gracefully unmounting all known devices
if (mInternalEmulated != nullptr) {
mInternalEmulated->unmount();
}
for (const auto& disk : mDisks) {
disk->unmountAll();
}
// Worst case we might have some stale mounts lurking around, so
// force unmount those just to be safe.
FILE* fp = setmntent("/proc/mounts", "r");
if (fp == NULL) {
PLOG(ERROR) << "Failed to open /proc/mounts";
return -errno;
}
// Some volumes can be stacked on each other, so force unmount in
// reverse order to give us the best chance of success.
std::list<std::string> toUnmount;
mntent* mentry;
while ((mentry = getmntent(fp)) != NULL) {
auto test = std::string(mentry->mnt_dir);
if ((android::base::StartsWith(test, "/mnt/") &&
!android::base::StartsWith(test, "/mnt/vendor") &&
!android::base::StartsWith(test, "/mnt/product") &&
!android::base::StartsWith(test, "/mnt/storage")) ||
android::base::StartsWith(test, "/storage/")) {
toUnmount.push_front(test);
}
}
endmntent(fp);
for (const auto& path : toUnmount) {
LOG(DEBUG) << "Tearing down stale mount " << path;
android::vold::ForceUnmount(path);
}
return 0;
}
int VolumeManager::mkdirs(const std::string& path) {
// Only offer to create directories for paths managed by vold
if (android::base::StartsWith(path, "/storage/")) {
// fs_mkdirs() does symlink checking and relative path enforcement
return fs_mkdirs(path.c_str(), 0700);
} else {
LOG(ERROR) << "Failed to find mounted volume for " << path;
return -EINVAL;
}
}
static size_t kAppFuseMaxMountPointName = 32;
static android::status_t getMountPath(uid_t uid, const std::string& name, std::string* path) {
if (name.size() > kAppFuseMaxMountPointName) {
LOG(ERROR) << "AppFuse mount name is too long.";
return -EINVAL;
}
for (size_t i = 0; i < name.size(); i++) {
if (!isalnum(name[i])) {
LOG(ERROR) << "AppFuse mount name contains invalid character.";
return -EINVAL;
}
}
*path = android::base::StringPrintf("/mnt/appfuse/%d_%s", uid, name.c_str());
return android::OK;
}
static android::status_t mountInNamespace(uid_t uid, int device_fd, const std::string& path) {
// Remove existing mount.
android::vold::ForceUnmount(path);
const auto opts = android::base::StringPrintf(
"fd=%i,"
"rootmode=40000,"
"default_permissions,"
"allow_other,"
"user_id=%d,group_id=%d,"
"context=\"u:object_r:app_fuse_file:s0\","
"fscontext=u:object_r:app_fusefs:s0",
device_fd, uid, uid);
const int result =
TEMP_FAILURE_RETRY(mount("/dev/fuse", path.c_str(), "fuse",
MS_NOSUID | MS_NODEV | MS_NOEXEC | MS_NOATIME, opts.c_str()));
if (result != 0) {
PLOG(ERROR) << "Failed to mount " << path;
return -errno;
}
return android::OK;
}
static android::status_t runCommandInNamespace(const std::string& command, uid_t uid, pid_t pid,
const std::string& path, int device_fd) {
if (DEBUG_APPFUSE) {
LOG(DEBUG) << "Run app fuse command " << command << " for the path " << path
<< " in namespace " << uid;
}
unique_fd dir(open("/proc", O_RDONLY | O_DIRECTORY | O_CLOEXEC));
if (dir.get() == -1) {
PLOG(ERROR) << "Failed to open /proc";
return -errno;
}
// Obtains process file descriptor.
const std::string pid_str = android::base::StringPrintf("%d", pid);
const unique_fd pid_fd(openat(dir.get(), pid_str.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC));
if (pid_fd.get() == -1) {
PLOG(ERROR) << "Failed to open /proc/" << pid;
return -errno;
}
// Check UID of process.
{
struct stat sb;
const int result = fstat(pid_fd.get(), &sb);
if (result == -1) {
PLOG(ERROR) << "Failed to stat /proc/" << pid;
return -errno;
}
if (sb.st_uid != AID_SYSTEM) {
LOG(ERROR) << "Only system can mount appfuse. UID expected=" << AID_SYSTEM
<< ", actual=" << sb.st_uid;
return -EPERM;
}
}
// Matches so far, but refuse to touch if in root namespace
{
std::string rootName;
std::string pidName;
if (!android::vold::Readlinkat(dir.get(), "1/ns/mnt", &rootName) ||
!android::vold::Readlinkat(pid_fd.get(), "ns/mnt", &pidName)) {
PLOG(ERROR) << "Failed to read namespaces";
return -EPERM;
}
if (rootName == pidName) {
LOG(ERROR) << "Don't mount appfuse in root namespace";
return -EPERM;
}
}
// We purposefully leave the namespace open across the fork
unique_fd ns_fd(openat(pid_fd.get(), "ns/mnt", O_RDONLY)); // not O_CLOEXEC
if (ns_fd.get() < 0) {
PLOG(ERROR) << "Failed to open namespace for /proc/" << pid << "/ns/mnt";
return -errno;
}
int child = fork();
if (child == 0) {
if (setns(ns_fd.get(), CLONE_NEWNS) != 0) {
PLOG(ERROR) << "Failed to setns";
_exit(-errno);
}
if (command == "mount") {
_exit(mountInNamespace(uid, device_fd, path));
} else if (command == "unmount") {
// If it's just after all FD opened on mount point are closed, umount2 can fail with
// EBUSY. To avoid the case, specify MNT_DETACH.
if (umount2(path.c_str(), UMOUNT_NOFOLLOW | MNT_DETACH) != 0 && errno != EINVAL &&
errno != ENOENT) {
PLOG(ERROR) << "Failed to unmount directory.";
_exit(-errno);
}
if (rmdir(path.c_str()) != 0) {
PLOG(ERROR) << "Failed to remove the mount directory.";
_exit(-errno);
}
_exit(android::OK);
} else {
LOG(ERROR) << "Unknown appfuse command " << command;
_exit(-EPERM);
}
}
if (child == -1) {
PLOG(ERROR) << "Failed to folk child process";
return -errno;
}
android::status_t status;
TEMP_FAILURE_RETRY(waitpid(child, &status, 0));
return status;
}
int VolumeManager::createObb(const std::string& sourcePath, const std::string& sourceKey,
int32_t ownerGid, std::string* outVolId) {
int id = mNextObbId++;
auto vol = std::shared_ptr<android::vold::VolumeBase>(
new android::vold::ObbVolume(id, sourcePath, sourceKey, ownerGid));
vol->create();
mObbVolumes.push_back(vol);
*outVolId = vol->getId();
return android::OK;
}
int VolumeManager::destroyObb(const std::string& volId) {
auto i = mObbVolumes.begin();
while (i != mObbVolumes.end()) {
if ((*i)->getId() == volId) {
(*i)->destroy();
i = mObbVolumes.erase(i);
} else {
++i;
}
}
return android::OK;
}
int VolumeManager::mountAppFuse(uid_t uid, pid_t pid, int mountId,
android::base::unique_fd* device_fd) {
std::string name = std::to_string(mountId);
// Check mount point name.
std::string path;
if (getMountPath(uid, name, &path) != android::OK) {
LOG(ERROR) << "Invalid mount point name";
return -1;
}
// Create directories.
const android::status_t result = android::vold::PrepareDir(path, 0700, 0, 0);
if (result != android::OK) {
PLOG(ERROR) << "Failed to prepare directory " << path;
return -1;
}
// Open device FD.
device_fd->reset(open("/dev/fuse", O_RDWR)); // not O_CLOEXEC
if (device_fd->get() == -1) {
PLOG(ERROR) << "Failed to open /dev/fuse";
return -1;
}
// Mount.
return runCommandInNamespace("mount", uid, pid, path, device_fd->get());
}
int VolumeManager::unmountAppFuse(uid_t uid, pid_t pid, int mountId) {
std::string name = std::to_string(mountId);
// Check mount point name.
std::string path;
if (getMountPath(uid, name, &path) != android::OK) {
LOG(ERROR) << "Invalid mount point name";
return -1;
}
return runCommandInNamespace("unmount", uid, pid, path, -1 /* device_fd */);
}