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// Copyright 2015 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 <mach/mach.h>
#include <stdint.h>
#include <map>
#include "base/gtest_prod_util.h"
#include "base/mac/scoped_mach_port.h"
#include "base/macros.h"
#include "base/memory/scoped_vector.h"
#include "base/process/port_provider_mac.h"
#include "base/synchronization/lock.h"
#include "ipc/attachment_broker_privileged.h"
#include "ipc/ipc_export.h"
#include "ipc/mach_port_attachment_mac.h"
namespace base {
class PortProvider;
} // namespace base
namespace IPC {
// This class is a concrete subclass of AttachmentBrokerPrivileged for the
// OSX platform.
// An example of the typical process by which a Mach port gets brokered.
// Definitions:
// 1. Let there be three processes P1, U2, U3. P1 is privileged.
// 2. U2 wants to send a Mach port M2 to U3. If this port is inserted into P1,
// it will be called M1. If it is inserted into U3, it will be called M3.
// 3. name() returns a serializable representation of a Mach port that can be
// passed over chrome IPC.
// 4. pid() returns the process id of a process.
// Process:
// 1. U2 sends a AttachmentBrokerMsg_DuplicateMachPort message to P1. The
// message contains name(M2), and pid(U3).
// 2. P1 extracts M2 into its own namespace, making M1.
// 3. P1 makes a new Mach port R in U3.
// 4. P1 sends a mach_msg with M1 to R.
// 5. P1 sends name(R) to U3.
// 6. U3 retrieves the queued message from R. The kernel automatically
// translates M1 into the namespace of U3, making M3.
// The logic of this class is a little bit more complex becauese any or all of
// P1, U2 and U3 may be the same, and depending on the exact configuration,
// the creation of R may not be necessary.
// For the rest of this file, and the corresponding implementation file, R will
// be called the "intermediate Mach port" and M3 the "final Mach port".
class IPC_EXPORT AttachmentBrokerPrivilegedMac
: public AttachmentBrokerPrivileged,
public base::PortProvider::Observer {
explicit AttachmentBrokerPrivilegedMac(base::PortProvider* port_provider);
~AttachmentBrokerPrivilegedMac() override;
// IPC::AttachmentBroker overrides.
bool SendAttachmentToProcess(
const scoped_refptr<IPC::BrokerableAttachment>& attachment,
base::ProcessId destination_process) override;
void DeregisterCommunicationChannel(Endpoint* endpoint) override;
// IPC::Listener overrides.
bool OnMessageReceived(const Message& message) override;
// base::PortProvider::Observer override.
void OnReceivedTaskPort(base::ProcessHandle process) override;
using MachPortWireFormat = internal::MachPortAttachmentMac::WireFormat;
// Contains all the information necessary to broker an attachment into a
// destination process. The only thing that prevents an AttachmentPrecusor
// from being immediately processed is if |port_provider_| does not yet have a
// task port for |pid|.
class IPC_EXPORT AttachmentPrecursor {
AttachmentPrecursor(const base::ProcessId& pid,
base::mac::ScopedMachSendRight port_to_insert,
const BrokerableAttachment::AttachmentId& id);
// Caller takes ownership of |port_|.
base::mac::ScopedMachSendRight TakePort();
base::ProcessId pid() const { return pid_; }
const BrokerableAttachment::AttachmentId id() const { return id_; }
// The pid of the destination process.
const base::ProcessId pid_;
// The final Mach port, as per definition at the top of this file.
base::mac::ScopedMachSendRight port_;
// The id of the attachment.
const BrokerableAttachment::AttachmentId id_;
// Contains all the information necessary to extract a send right and create
// an AttachmentPrecursor. The only thing that prevents an AttachmentExtractor
// from being immediately processed is if |port_provider_| does not yet have a
// task port for |source_pid|.
class IPC_EXPORT AttachmentExtractor {
AttachmentExtractor(const base::ProcessId& source_pid,
const base::ProcessId& dest_pid,
mach_port_name_t port,
const BrokerableAttachment::AttachmentId& id);
base::ProcessId source_pid() const { return source_pid_; }
base::ProcessId dest_pid() const { return dest_pid_; }
mach_port_name_t port() const { return port_to_extract_; }
const BrokerableAttachment::AttachmentId id() const { return id_; }
const base::ProcessId source_pid_;
const base::ProcessId dest_pid_;
mach_port_name_t port_to_extract_;
const BrokerableAttachment::AttachmentId id_;
// IPC message handlers.
void OnDuplicateMachPort(const Message& message);
// Duplicates the Mach port referenced from |wire_format| from
// |source_process| into |wire_format|'s destination process.
MachPortWireFormat DuplicateMachPort(const MachPortWireFormat& wire_format,
base::ProcessId source_process);
// |task_port| is the task port of another process.
// |port_to_insert| must be a send right in the current task's name space.
// Creates an intermediate Mach port in |pid| and sends |port_to_insert| as a
// mach_msg to the intermediate Mach port.
// Returns the intermediate port on success, and MACH_PORT_NULL on failure.
// This method takes ownership of |port_to_insert|. On success, ownership is
// passed to the intermediate Mach port.
mach_port_name_t CreateIntermediateMachPort(
mach_port_t task_port,
base::mac::ScopedMachSendRight port_to_insert);
// Extracts a copy of the send right to |named_right| from |task_port|.
// Returns MACH_PORT_NULL on error.
base::mac::ScopedMachSendRight ExtractNamedRight(
mach_port_t task_port,
mach_port_name_t named_right);
// Copies an existing |wire_format|, but substitutes in a different mach port.
MachPortWireFormat CopyWireFormat(const MachPortWireFormat& wire_format,
uint32_t mach_port);
// |wire_format.destination_process| must be this process.
// |wire_format.mach_port| must be the final Mach port.
// Consumes a reference to |wire_format.mach_port|, as ownership is implicitly
// passed to the consumer of the Chrome IPC message.
// Makes an attachment, queues it, and notifies the observers.
void RoutePrecursorToSelf(AttachmentPrecursor* precursor);
// |wire_format.destination_process| must be another process.
// |wire_format.mach_port| must be the intermediate Mach port.
// Ownership of |wire_format.mach_port| is implicitly passed to the process
// that receives the Chrome IPC message.
// Returns |false| on irrecoverable error.
bool RouteWireFormatToAnother(const MachPortWireFormat& wire_format);
// Atempts to broker all precursors whose destination is |pid|. Has no effect
// if |port_provider_| does not have the task port for |pid|.
void SendPrecursorsForProcess(base::ProcessId pid);
// Brokers a single precursor into the task represented by |task_port|.
// Returns |false| on irrecoverable error.
bool SendPrecursor(AttachmentPrecursor* precursor, mach_port_t task_port);
// Add a precursor to |precursors_|. Takes ownership of |port|.
void AddPrecursor(base::ProcessId pid,
base::mac::ScopedMachSendRight port,
const BrokerableAttachment::AttachmentId& id);
// Atempts to process all extractors whose source is |pid|. Has no effect
// if |port_provider_| does not have the task port for |pid|.
void ProcessExtractorsForProcess(base::ProcessId pid);
// Processes a single extractor whose source pid is represented by
// |task_port|.
void ProcessExtractor(AttachmentExtractor* extractor, mach_port_t task_port);
// Add an extractor to |extractors_|.
void AddExtractor(base::ProcessId source_pid,
base::ProcessId dest_pid,
mach_port_name_t port,
const BrokerableAttachment::AttachmentId& id);
// The port provider must live at least as long as the AttachmentBroker.
base::PortProvider* port_provider_;
// For each ProcessId, a vector of precursors that are waiting to be
// sent.
std::map<base::ProcessId, ScopedVector<AttachmentPrecursor>*> precursors_;
base::Lock precursors_lock_;
// For each ProcessId, a vector of extractors that are waiting to be
// processed.
std::map<base::ProcessId, ScopedVector<AttachmentExtractor>*> extractors_;
base::Lock extractors_lock_;
} // namespace IPC