chrome/browser/chromeos/crostini/crostini_share_path.cc

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/chromeos/crostini/crostini_share_path.h"

#include "base/atomic_ref_count.h"
#include "base/bind.h"
#include "base/files/file_util.h"
#include "base/optional.h"
#include "chrome/browser/chromeos/crostini/crostini_manager.h"
#include "chrome/browser/chromeos/crostini/crostini_pref_names.h"
#include "chrome/browser/chromeos/crostini/crostini_share_path_factory.h"
#include "chrome/browser/chromeos/crostini/crostini_util.h"
#include "chrome/browser/chromeos/drive/drive_integration_service.h"
#include "chrome/browser/chromeos/file_manager/path_util.h"
#include "chrome/browser/chromeos/file_manager/volume_manager.h"
#include "chrome/browser/profiles/profile.h"
#include "chromeos/constants/chromeos_features.h"
#include "chromeos/dbus/concierge/service.pb.h"
#include "chromeos/dbus/dbus_thread_manager.h"
#include "chromeos/dbus/seneschal_client.h"
#include "components/prefs/pref_service.h"
#include "components/prefs/scoped_user_pref_update.h"
#include "content/public/browser/browser_thread.h"
#include "storage/browser/fileapi/external_mount_points.h"
#include "storage/browser/fileapi/file_system_url.h"
#include "url/gurl.h"

namespace {

void OnSeneschalSharePathResponse(
    base::OnceCallback<void(bool, std::string)> callback,
    base::Optional<vm_tools::seneschal::SharePathResponse> response) {
  if (!response) {
    std::move(callback).Run(false, "System error");
    return;
  }
  std::move(callback).Run(response.value().success(),
                          response.value().failure_reason());
}

void OnVmRestartedForSeneschal(
    Profile* profile,
    std::string vm_name,
    base::OnceCallback<void(bool, std::string)> callback,
    vm_tools::seneschal::SharePathRequest request,
    crostini::CrostiniResult result) {
  auto* crostini_manager = crostini::CrostiniManager::GetForProfile(profile);
  base::Optional<crostini::VmInfo> vm_info =
      crostini_manager->GetVmInfo(std::move(vm_name));
  if (!vm_info || vm_info->state != crostini::VmState::STARTED) {
    std::move(callback).Run(false, "VM could not be started");
    return;
  }
  request.set_handle(vm_info->info.seneschal_server_handle());
  chromeos::DBusThreadManager::Get()->GetSeneschalClient()->SharePath(
      request,
      base::BindOnce(&OnSeneschalSharePathResponse, std::move(callback)));
}

void OnSeneschalUnsharePathResponse(
    base::OnceCallback<void(bool, std::string)> callback,
    base::Optional<vm_tools::seneschal::UnsharePathResponse> response) {
  if (!response) {
    std::move(callback).Run(false, "System error");
    return;
  }
  std::move(callback).Run(response.value().success(),
                          response.value().failure_reason());
}

void LogErrorResult(const std::string& operation,
                    const base::FilePath& cros_path,
                    const base::FilePath& container_path,
                    bool result,
                    std::string failure_reason) {
  if (!result) {
    LOG(WARNING) << "Error " << operation << " " << cros_path << ": "
                 << failure_reason;
  }
}

// Barrier Closure that captures the first instance of error.
class ErrorCapture {
 public:
  ErrorCapture(int num_callbacks_left,
               base::OnceCallback<void(bool, std::string)> callback)
      : num_callbacks_left_(num_callbacks_left),
        callback_(std::move(callback)) {
    DCHECK_GE(num_callbacks_left, 0);
    if (num_callbacks_left == 0)
      std::move(callback_).Run(true, "");
  }

  void Run(const base::FilePath& cros_path,
           const base::FilePath& container_path,
           bool success,
           std::string failure_reason) {
    if (!success) {
      LOG(WARNING) << "Error SharePath=" << cros_path.value()
                   << ", FailureReason=" << failure_reason;
      if (success_) {
        success_ = false;
        first_failure_reason_ = failure_reason;
      }
    }

    if (!--num_callbacks_left_)
      std::move(callback_).Run(success_, first_failure_reason_);
  }

 private:
  int num_callbacks_left_;
  base::OnceCallback<void(bool, std::string)> callback_;
  bool success_ = true;
  std::string first_failure_reason_;
};  // class

}  // namespace

namespace crostini {

CrostiniSharePath* CrostiniSharePath::GetForProfile(Profile* profile) {
  return CrostiniSharePathFactory::GetForProfile(profile);
}

CrostiniSharePath::CrostiniSharePath(Profile* profile)
    : profile_(profile),
      mount_event_seneschal_callback_(base::BindRepeating(LogErrorResult)) {
  if (auto* vmgr = file_manager::VolumeManager::Get(profile_))
    vmgr->AddObserver(this);
}

CrostiniSharePath::~CrostiniSharePath() {}

void CrostiniSharePath::AddObserver(Observer* obs) {
  observers_.AddObserver(obs);
}

void CrostiniSharePath::CallSeneschalSharePath(std::string vm_name,
                                               const base::FilePath& path,
                                               bool persist,
                                               SharePathCallback callback) {
  base::FilePath container_path;

  // Verify path is in one of the allowable mount points.
  // This logic is similar to DownloadPrefs::SanitizeDownloadTargetPath().
  if (!path.IsAbsolute() || path.ReferencesParent()) {
    std::move(callback).Run(container_path, false, "Path must be absolute");
    return;
  }

  vm_tools::seneschal::SharePathRequest request;
  base::FilePath drivefs_path;
  base::FilePath relative_path;
  drive::DriveIntegrationService* integration_service = nullptr;
  if (base::FeatureList::IsEnabled(chromeos::features::kDriveFs)) {
    integration_service =
        drive::DriveIntegrationServiceFactory::GetForProfile(profile_);
  }
  base::FilePath drivefs_mount_point_path;
  base::FilePath drivefs_mount_name;

  // Allow MyFiles|Downloads directory and subdirs.
  bool allowed_path = false;
  base::FilePath my_files =
      file_manager::util::GetMyFilesFolderForProfile(profile_);
  base::FilePath android_files(file_manager::util::kAndroidFilesPath);
  base::FilePath removable_media(file_manager::util::kRemovableMediaPath);
  if (my_files == path || my_files.AppendRelativePath(path, &relative_path)) {
    allowed_path = true;
    if (base::FeatureList::IsEnabled(chromeos::features::kMyFilesVolume)) {
      request.set_storage_location(
          vm_tools::seneschal::SharePathRequest::MY_FILES);
      container_path = container_path.Append("MyFiles");
    } else {
      request.set_storage_location(
          vm_tools::seneschal::SharePathRequest::DOWNLOADS);
      container_path = container_path.Append("MyFiles/Downloads");
    }
    request.set_owner_id(crostini::CryptohomeIdForProfile(profile_));
  } else if (base::FeatureList::IsEnabled(chromeos::features::kDriveFs) &&
             integration_service &&
             (drivefs_mount_point_path =
                  integration_service->GetMountPointPath())
                 .AppendRelativePath(path, &drivefs_path) &&
             base::FilePath("/media/fuse")
                 .AppendRelativePath(drivefs_mount_point_path,
                                     &drivefs_mount_name)) {
    // Allow subdirs of DriveFS except .Trash.
    request.set_drivefs_mount_name(drivefs_mount_name.value());
    base::FilePath root("root");
    base::FilePath team_drives("team_drives");
    base::FilePath computers("Computers");
    base::FilePath trash(".Trash");  // Not to be shared!
    if (root == drivefs_path ||
        root.AppendRelativePath(drivefs_path, &relative_path)) {
      // My Drive and subdirs.
      allowed_path = true;
      request.set_storage_location(
          vm_tools::seneschal::SharePathRequest::DRIVEFS_MY_DRIVE);
      container_path = container_path.Append("GoogleDrive/MyDrive");
    } else if (team_drives == drivefs_path ||
               team_drives.AppendRelativePath(drivefs_path, &relative_path)) {
      // Team Drives and subdirs.
      allowed_path = true;
      request.set_storage_location(
          vm_tools::seneschal::SharePathRequest::DRIVEFS_TEAM_DRIVES);
      container_path = container_path.Append("GoogleDrive/TeamDrives");
    } else if (computers == drivefs_path ||
               computers.AppendRelativePath(drivefs_path, &relative_path)) {
      // Computers and subdirs.
      allowed_path = true;
      request.set_storage_location(
          vm_tools::seneschal::SharePathRequest::DRIVEFS_COMPUTERS);
      container_path = container_path.Append("GoogleDrive/Computers");

      // TODO(crbug.com/917920): Do not allow Computers Grand Root, or single
      // Computer Root to be shared until DriveFS enforces allowed write paths.
      std::vector<base::FilePath::StringType> components;
      relative_path.GetComponents(&components);
      if (components.size() < 2) {
        allowed_path = false;
      }
    } else if (trash == drivefs_path || trash.IsParent(drivefs_path)) {
      // Note: Do not expose .Trash which would allow linux apps to make
      // permanent deletes from Drive.  This branch is not especially required,
      // but is included to make it explicit that .Trash should not be shared.
      allowed_path = false;
    }
  } else if (path == android_files ||
             android_files.AppendRelativePath(path, &relative_path)) {
    // Allow Android files and subdirs.
    allowed_path = true;
    request.set_storage_location(
        vm_tools::seneschal::SharePathRequest::PLAY_FILES);
    container_path = container_path.Append("PlayFiles");
  } else if (removable_media.AppendRelativePath(path, &relative_path)) {
    // Allow subdirs of /media/removable.
    allowed_path = true;
    request.set_storage_location(
        vm_tools::seneschal::SharePathRequest::REMOVABLE);
    container_path = container_path.Append("removable");
  }

  if (!allowed_path) {
    std::move(callback).Run(container_path, false, "Path is not allowed");
    return;
  }

  // We will not make a blocking call to verify the path exists since
  // we don't want to block, and seneschal must verify this regardless.

  // Even if VM is not running, save to prefs now.
  if (persist) {
    RegisterPersistedPath(path);
  }

  request.mutable_shared_path()->set_path(relative_path.value());
  request.mutable_shared_path()->set_writable(true);
  container_path = container_path.Append(relative_path);

  // Restart VM if not currently running.
  auto* crostini_manager = crostini::CrostiniManager::GetForProfile(profile_);
  base::Optional<crostini::VmInfo> vm_info =
      crostini_manager->GetVmInfo(vm_name);
  if (!vm_info || vm_info->state != crostini::VmState::STARTED) {
    crostini_manager->RestartCrostini(
        vm_name, crostini::kCrostiniDefaultContainerName,
        base::BindOnce(&OnVmRestartedForSeneschal, profile_, std::move(vm_name),
                       base::BindOnce(std::move(callback), container_path),
                       std::move(request)));
    return;
  }

  request.set_handle(vm_info->info.seneschal_server_handle());
  chromeos::DBusThreadManager::Get()->GetSeneschalClient()->SharePath(
      request,
      base::BindOnce(&OnSeneschalSharePathResponse,
                     base::BindOnce(std::move(callback), container_path)));
}

void CrostiniSharePath::CallSeneschalUnsharePath(
    std::string vm_name,
    const base::FilePath& path,
    base::OnceCallback<void(bool, std::string)> callback) {
  // Return success if VM is not currently running.
  auto* crostini_manager = crostini::CrostiniManager::GetForProfile(profile_);
  base::Optional<crostini::VmInfo> vm_info =
      crostini_manager->GetVmInfo(std::move(vm_name));
  if (!vm_info || vm_info->state != crostini::VmState::STARTED) {
    std::move(callback).Run(true, "VM not running");
    return;
  }

  // Convert path to a virtual path relative to one of the external mounts,
  // then get it as a FilesSystemURL to convert to a path inside crostini,
  // then remove /mnt/chromeos/ base dir prefix to get the path to unshare.
  storage::ExternalMountPoints* mount_points =
      storage::ExternalMountPoints::GetSystemInstance();
  base::FilePath virtual_path;
  base::FilePath inside;
  bool result = mount_points->GetVirtualPath(path, &virtual_path);
  if (result) {
    storage::FileSystemURL url = mount_points->CreateCrackedFileSystemURL(
        GURL(), storage::kFileSystemTypeExternal, virtual_path);
    result = file_manager::util::ConvertFileSystemURLToPathInsideCrostini(
        profile_, url, &inside);
  }
  base::FilePath unshare_path;
  if (!result || !crostini::ContainerChromeOSBaseDirectory().AppendRelativePath(
                     inside, &unshare_path)) {
    std::move(callback).Run(false, "Invalid path to unshare");
    return;
  }

  vm_tools::seneschal::UnsharePathRequest request;
  request.set_handle(vm_info->info.seneschal_server_handle());
  request.set_path(unshare_path.value());
  chromeos::DBusThreadManager::Get()->GetSeneschalClient()->UnsharePath(
      request,
      base::BindOnce(&OnSeneschalUnsharePathResponse, std::move(callback)));
}

void CrostiniSharePath::SharePath(std::string vm_name,
                                  const base::FilePath& path,
                                  bool persist,
                                  SharePathCallback callback) {
  DCHECK(callback);
  if (!base::FeatureList::IsEnabled(chromeos::features::kCrostiniFiles)) {
    std::move(callback).Run(path, false, "Flag crostini-files not enabled");
    return;
  }
  CallSeneschalSharePath(std::move(vm_name), path, persist,
                         std::move(callback));
}

void CrostiniSharePath::SharePaths(
    std::string vm_name,
    std::vector<base::FilePath> paths,
    bool persist,
    base::OnceCallback<void(bool, std::string)> callback) {
  base::RepeatingCallback<void(const base::FilePath&, const base::FilePath&,
                               bool, std::string)>
      barrier = base::BindRepeating(
          &ErrorCapture::Run,
          base::Owned(new ErrorCapture(paths.size(), std::move(callback))));
  for (const auto& path : paths) {
    CallSeneschalSharePath(vm_name, path, persist,
                           base::BindOnce(barrier, std::move(path)));
  }
}

void CrostiniSharePath::UnsharePath(
    std::string vm_name,
    const base::FilePath& path,
    base::OnceCallback<void(bool, std::string)> callback) {
  PrefService* pref_service = profile_->GetPrefs();
  ListPrefUpdate update(pref_service, crostini::prefs::kCrostiniSharedPaths);
  base::ListValue* shared_paths = update.Get();
  if (!shared_paths->Remove(base::Value(path.value()), nullptr))
    LOG(WARNING) << "Unshared path not in prefs: " << path.value();
  CallSeneschalUnsharePath(std::move(vm_name), path, std::move(callback));
  for (Observer& observer : observers_) {
    observer.OnUnshare(path);
  }
}

bool CrostiniSharePath::GetAndSetFirstForSession() {
  bool result = first_for_session_;
  first_for_session_ = false;
  return result;
}

std::vector<base::FilePath> CrostiniSharePath::GetPersistedSharedPaths() {
  std::vector<base::FilePath> result;
  if (!base::FeatureList::IsEnabled(chromeos::features::kCrostiniFiles))
    return result;
  PrefService* pref_service = profile_->GetPrefs();
  const base::ListValue* shared_paths =
      pref_service->GetList(prefs::kCrostiniSharedPaths);
  // Paths in <cryptohome>/Downloads need to be migrated to
  // <cryptohome>/MyFiles/Downloads.
  bool swap_for_migrate_required = false;
  base::ListValue migrated_paths;
  for (const auto& shared_path : *shared_paths) {
    base::FilePath path(shared_path.GetString());
    base::FilePath migrated;
    if (file_manager::util::MigrateFromDownloadsToMyFiles(profile_, path,
                                                          &migrated)) {
      swap_for_migrate_required = true;
      path = migrated;
    }
    migrated_paths.AppendString(path.value());
    result.emplace_back(path);
  }

  // If any paths were modified during migration, update prefs.
  if (swap_for_migrate_required) {
    ListPrefUpdate update(pref_service, crostini::prefs::kCrostiniSharedPaths);
    base::ListValue* shared_paths = update.Get();
    shared_paths->Swap(&migrated_paths);
  }

  return result;
}

void CrostiniSharePath::SharePersistedPaths(
    base::OnceCallback<void(bool, std::string)> callback) {
  SharePaths(kCrostiniDefaultVmName, GetPersistedSharedPaths(),
             false /* persist */, std::move(callback));
}

void CrostiniSharePath::RegisterPersistedPath(const base::FilePath& path) {
  PrefService* pref_service = profile_->GetPrefs();
  ListPrefUpdate update(pref_service, crostini::prefs::kCrostiniSharedPaths);
  base::ListValue* shared_paths = update.Get();
  // Check if path exists, remove paths that are children of new path.
  bool exists = false;
  auto it = shared_paths->begin();
  while (it != shared_paths->end()) {
    base::FilePath existing(it->GetString());
    if (path == existing) {
      exists = true;
    } else if (path.IsParent(existing)) {
      it = shared_paths->Erase(it, nullptr);
      continue;
    }
    ++it;
  }
  if (!exists)
    shared_paths->Append(std::make_unique<base::Value>(path.value()));
}

void CrostiniSharePath::OnVolumeMounted(chromeos::MountError error_code,
                                        const file_manager::Volume& volume) {
  if (!base::FeatureList::IsEnabled(chromeos::features::kCrostiniFiles) ||
      error_code != chromeos::MountError::MOUNT_ERROR_NONE ||
      !crostini::CrostiniManager::GetForProfile(profile_)->IsVmRunning(
          kCrostiniDefaultVmName)) {
    return;
  }
  auto paths = GetPersistedSharedPaths();
  for (const auto& path : paths) {
    if (path == volume.mount_path() || volume.mount_path().IsParent(path)) {
      CallSeneschalSharePath(kCrostiniDefaultVmName, path, false,
                             base::BindOnce(mount_event_seneschal_callback_,
                                            "share-on-mount", path));
    }
  }
}

void CrostiniSharePath::OnVolumeUnmounted(chromeos::MountError error_code,
                                          const file_manager::Volume& volume) {
  if (!base::FeatureList::IsEnabled(chromeos::features::kCrostiniFiles) ||
      error_code != chromeos::MountError::MOUNT_ERROR_NONE ||
      !crostini::CrostiniManager::GetForProfile(profile_)->IsVmRunning(
          kCrostiniDefaultVmName)) {
    return;
  }
  auto paths = GetPersistedSharedPaths();
  for (const auto& path : paths) {
    if (path == volume.mount_path() || volume.mount_path().IsParent(path)) {
      CallSeneschalUnsharePath(
          kCrostiniDefaultVmName, path,
          base::BindOnce(mount_event_seneschal_callback_, "unshare-on-unmount",
                         path, path));
    }
  }
}

}  // namespace crostini