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// Copyright 2017 The Chromium Authors. All rights reserved.
// Copyright (C) 2018 Apple Inc. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "config.h"
#include "ApduCommand.h"
#if ENABLE(WEB_AUTHN)
namespace apdu {
namespace {
// APDU command data length is 2 bytes encoded in big endian order.
uint16_t parseMessageLength(const Vector<uint8_t>& message, size_t offset)
{
ASSERT(message.size() >= offset + 2);
return (message[offset] << 8) | message[offset + 1];
}
} // namespace
std::optional<ApduCommand> ApduCommand::createFromMessage(const Vector<uint8_t>& message)
{
if (message.size() < kApduMinHeader || message.size() > kApduMaxLength)
return std::nullopt;
uint8_t cla = message[0];
uint8_t ins = message[1];
uint8_t p1 = message[2];
uint8_t p2 = message[3];
size_t responseLength = 0;
Vector<uint8_t> data;
switch (message.size()) {
// No data present; no expected response.
case kApduMinHeader:
break;
// Invalid encoding sizes.
case kApduMinHeader + 1:
case kApduMinHeader + 2:
return std::nullopt;
// No data present; response expected.
case kApduMinHeader + 3:
// Fifth byte must be 0.
if (message[4])
return std::nullopt;
responseLength = parseMessageLength(message, kApduCommandLengthOffset);
// Special case where response length of 0x0000 corresponds to 65536
// as defined in ISO7816-4.
if (!responseLength)
responseLength = kApduMaxResponseLength;
break;
default:
// Fifth byte must be 0.
if (message[4])
return std::nullopt;
auto dataLength = parseMessageLength(message, kApduCommandLengthOffset);
if (message.size() == dataLength + kApduCommandDataOffset) {
// No response expected.
data.appendRange(message.begin() + kApduCommandDataOffset, message.end());
} else if (message.size() == dataLength + kApduCommandDataOffset + 2) {
// Maximum response size is stored in final 2 bytes.
data.appendRange(message.begin() + kApduCommandDataOffset, message.end() - 2);
auto responseLengthOffset = kApduCommandDataOffset + dataLength;
responseLength = parseMessageLength(message, responseLengthOffset);
// Special case where response length of 0x0000 corresponds to 65536
// as defined in ISO7816-4.
if (!responseLength)
responseLength = kApduMaxResponseLength;
} else
return std::nullopt;
break;
}
return ApduCommand(cla, ins, p1, p2, responseLength, WTFMove(data));
}
ApduCommand::ApduCommand(uint8_t cla, uint8_t ins, uint8_t p1, uint8_t p2, size_t responseLength, Vector<uint8_t>&& data)
: m_cla(cla)
, m_ins(ins)
, m_p1(p1)
, m_p2(p2)
, m_responseLength(responseLength)
, m_data(WTFMove(data))
{
}
Vector<uint8_t> ApduCommand::getEncodedCommand() const
{
Vector<uint8_t> encoded = { m_cla, m_ins, m_p1, m_p2 };
// If data exists, request size (Lc) is encoded in 3 bytes, with the first
// byte always being null, and the other two bytes being a big-endian
// representation of the request size. If data length is 0, response size (Le)
// will be prepended with a null byte.
if (!m_data.isEmpty()) {
size_t dataLength = m_data.size();
encoded.append(0x0);
if (dataLength > kApduMaxDataLength)
dataLength = kApduMaxDataLength;
encoded.append((dataLength >> 8) & 0xff);
encoded.append(dataLength & 0xff);
encoded.appendRange(m_data.begin(), m_data.begin() + dataLength);
} else if (m_responseLength > 0)
encoded.append(0x0);
if (m_responseLength > 0) {
size_t responseLength = m_responseLength;
if (responseLength > kApduMaxResponseLength)
responseLength = kApduMaxResponseLength;
// A zero value represents a response length of 65,536 bytes.
encoded.append((responseLength >> 8) & 0xff);
encoded.append(responseLength & 0xff);
}
return encoded;
}
} // namespace apdu
#endif // ENABLE(WEB_AUTHN)
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