Source/WebCore/Modules/webauthn/fido/FidoHidPacket.h

// Copyright 2017 The Chromium Authors. All rights reserved.
// Copyright (C) 2018 Apple Inc. All rights reserved.
//
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#pragma once

#if ENABLE(WEB_AUTHN)

#include "FidoConstants.h"
#include <wtf/Noncopyable.h>
#include <wtf/Vector.h>

namespace fido {

// HID Packets are defined by the specification at
// https://fidoalliance.org/specs/fido-v2.0-ps-20170927/fido-client-to-authenticator-protocol-v2.0-ps-20170927.html#message-and-packet-structure
// Packets are one of two types, initialization packets and continuation
// packets. HID Packets have header information and a payload. If a
// FidoHidInitPacket cannot store the entire payload, further payload
// information is stored in HidContinuationPackets.
class WEBCORE_EXPORT FidoHidPacket {
    WTF_MAKE_FAST_ALLOCATED;
    WTF_MAKE_NONCOPYABLE(FidoHidPacket);
public:
    FidoHidPacket(Vector<uint8_t>&& data, uint32_t channelId);
    virtual ~FidoHidPacket() = default;

    virtual Vector<uint8_t> getSerializedData() const = 0;
    const Vector<uint8_t>& getPacketPayload() const { return m_data; }
    uint32_t channelId() const { return m_channelId; }

protected:
    FidoHidPacket();

    Vector<uint8_t> m_data;
    uint32_t m_channelId = kHidBroadcastChannel;
};

// FidoHidInitPacket, based on the CTAP specification consists of a header with
// data that is serialized into a IOBuffer. A channel identifier is allocated by
// the CTAP device to ensure its system-wide uniqueness. Command identifiers
// determine the type of message the packet corresponds to. Payload length
// is the length of the entire message payload, and the data is only the portion
// of the payload that will fit into the HidInitPacket.
class WEBCORE_EXPORT FidoHidInitPacket : public FidoHidPacket {
public:
    // Creates a packet from the serialized data of an initialization packet. As
    // this is the first packet, the payload length of the entire message will be
    // included within the serialized data. Remaining size will be returned to
    // inform the callee how many additional packets to expect.
    static std::unique_ptr<FidoHidInitPacket> createFromSerializedData(const Vector<uint8_t>&, size_t* remainingSize);

    FidoHidInitPacket(uint32_t channelId, FidoHidDeviceCommand, Vector<uint8_t>&& data, uint16_t payloadLength);

    Vector<uint8_t> getSerializedData() const final;
    FidoHidDeviceCommand command() const { return m_command; }
    uint16_t payloadLength() const { return m_payloadLength; }

private:
    FidoHidDeviceCommand m_command;
    uint16_t m_payloadLength;
};

// FidoHidContinuationPacket, based on the CTAP Specification consists of a
// header with data that is serialized into an IOBuffer. The channel identifier
// will be identical to the identifier in all other packets of the message. The
// packet sequence will be the sequence number of this particular packet, from
// 0x00 to 0x7f.
class WEBCORE_EXPORT FidoHidContinuationPacket : public FidoHidPacket {
public:
    // Creates a packet from the serialized data of a continuation packet. As an
    // HidInitPacket would have arrived earlier with the total payload size,
    // the remaining size should be passed to inform the packet of how much data
    // to expect.
    static std::unique_ptr<FidoHidContinuationPacket> createFromSerializedData(const Vector<uint8_t>&, size_t* remainingSize);

    FidoHidContinuationPacket(uint32_t channelId, uint8_t sequence, Vector<uint8_t>&& data);

    Vector<uint8_t> getSerializedData() const final;
    uint8_t sequence() const { return m_sequence; }

private:
    uint8_t m_sequence;
};

} // namespace fido

#endif // ENABLE(WEB_AUTHN)