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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/browser/sandbox_host_linux.h"
#include <sys/socket.h>
#include <memory>
#include "base/no_destructor.h"
#include "base/posix/eintr_wrapper.h"
namespace content {
// Runs on the main thread at startup.
SandboxHostLinux::SandboxHostLinux() = default;
// static
SandboxHostLinux* SandboxHostLinux::GetInstance() {
static base::NoDestructor<SandboxHostLinux> instance;
return instance.get();
}
void SandboxHostLinux::Init() {
DCHECK(!initialized_);
initialized_ = true;
int fds[2];
// We use SOCK_SEQPACKET rather than SOCK_DGRAM to prevent the sandboxed
// processes from sending datagrams to other sockets on the system. The
// sandbox may prevent the sandboxed process from calling socket() to create
// new sockets, but it'll still inherit some sockets. With AF_UNIX+SOCK_DGRAM,
// it can call sendmsg to send a datagram to any (abstract) socket on the same
// system. With SOCK_SEQPACKET, this is prevented.
CHECK(socketpair(AF_UNIX, SOCK_SEQPACKET, 0, fds) == 0);
child_socket_ = fds[0];
// The SandboxIPC client is not expected to read from |child_socket_|.
// Instead, it reads from a temporary socket sent with the request.
PCHECK(0 == shutdown(child_socket_, SHUT_RD)) << "shutdown";
const int browser_socket = fds[1];
// The SandboxIPC handler is not expected to write to |browser_socket|.
// Instead, it replies on a temporary socket provided by the caller.
PCHECK(0 == shutdown(browser_socket, SHUT_WR)) << "shutdown";
int pipefds[2];
CHECK(0 == pipe(pipefds));
const int child_lifeline_fd = pipefds[0];
childs_lifeline_fd_ = pipefds[1];
ipc_handler_ =
std::make_unique<SandboxIPCHandler>(child_lifeline_fd, browser_socket);
ipc_thread_ = std::make_unique<base::DelegateSimpleThread>(
ipc_handler_.get(), "sandbox_ipc_thread");
ipc_thread_->Start();
}
} // namespace content
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