sandboxed-api/sandboxed_api/sandbox2/namespace.h
Wiktor Garbacz 8a7d0d1cb3 Use a nested userns&mntns to pre-pivot_root
This addresses a latency issue - chroot_fs_refs called inside pivot_root
in the kernel can take several milliseconds on machines with many threads
running.
This might not always reduce latency for custom forkservers, as additional
fork can be more costly than pivot_root.

PiperOrigin-RevId: 281306284
Change-Id: If503ac76a70e5438e94caf708d79cb0219c66def
2019-11-19 09:02:28 -08:00

73 lines
2.2 KiB
C++

// Copyright 2019 Google LLC. All Rights Reserved.
//
// 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.
// The sandbox2::Namespace class defines ways of inserting the sandboxed process
// into Linux namespaces.
#ifndef SANDBOXED_API_SANDBOX2_NAMESPACE_H_
#define SANDBOXED_API_SANDBOX2_NAMESPACE_H_
#include <sys/types.h>
#include <cstdint>
#include <memory>
#include <string>
#include "absl/base/macros.h"
#include "sandboxed_api/sandbox2/mounts.h"
#include "sandboxed_api/sandbox2/violation.pb.h"
namespace sandbox2 {
class Namespace final {
public:
// Performs the namespace setup (mounts, write the uid_map, etc.).
static void InitializeNamespaces(uid_t uid, gid_t gid, int32_t clone_flags,
const Mounts& mounts, bool mount_proc,
const std::string& hostname,
bool avoid_pivot_root);
static void InitializeInitialNamespaces(uid_t uid, gid_t gid);
Namespace() = delete;
Namespace(const Namespace&) = delete;
Namespace& operator=(const Namespace&) = delete;
Namespace(bool allow_unrestricted_networking, Mounts mounts,
std::string hostname);
void DisableUserNamespace();
// Returns all needed CLONE_NEW* flags.
int32_t GetCloneFlags() const;
// Stores information about this namespace in the protobuf structure.
void GetNamespaceDescription(NamespaceDescription* pb_description);
Mounts& mounts() { return mounts_; }
const Mounts& mounts() const { return mounts_; }
const std::string& hostname() const { return hostname_; }
private:
friend class StackTracePeer;
int32_t clone_flags_;
Mounts mounts_;
std::string hostname_;
};
} // namespace sandbox2
#endif // SANDBOXED_API_SANDBOX2_NAMESPACE_H_