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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 "CBORWriter.h"
#if ENABLE(WEB_AUTHN)
#include "CBORBinary.h"
namespace cbor {
CBORWriter::~CBORWriter() = default;
// static
std::optional<Vector<uint8_t>> CBORWriter::write(const CBORValue& node, size_t maxNestingLevel)
{
Vector<uint8_t> cbor;
CBORWriter writer(&cbor);
if (writer.encodeCBOR(node, static_cast<int>(maxNestingLevel)))
return cbor;
return std::nullopt;
}
CBORWriter::CBORWriter(Vector<uint8_t>* cbor)
: m_encodedCBOR(cbor)
{
}
bool CBORWriter::encodeCBOR(const CBORValue& node, int maxNestingLevel)
{
if (maxNestingLevel < 0)
return false;
switch (node.type()) {
case CBORValue::Type::None: {
startItem(CBORValue::Type::ByteString, 0);
return true;
}
// Represents unsigned integers.
case CBORValue::Type::Unsigned: {
int64_t value = node.getUnsigned();
startItem(CBORValue::Type::Unsigned, static_cast<uint64_t>(value));
return true;
}
// Represents negative integers.
case CBORValue::Type::Negative: {
int64_t value = node.getNegative();
startItem(CBORValue::Type::Negative, static_cast<uint64_t>(-(value + 1)));
return true;
}
// Represents a byte string.
case CBORValue::Type::ByteString: {
const CBORValue::BinaryValue& bytes = node.getByteString();
startItem(CBORValue::Type::ByteString, static_cast<uint64_t>(bytes.size()));
// Add the bytes.
m_encodedCBOR->appendVector(bytes);
return true;
}
case CBORValue::Type::String: {
// WTFString uses UTF16 but RFC7049 requires UTF8
auto utf8String = node.getString().utf8();
startItem(CBORValue::Type::String, static_cast<uint64_t>(utf8String.length()));
// Add the characters.
m_encodedCBOR->append(utf8String.span());
return true;
}
// Represents an array.
case CBORValue::Type::Array: {
const CBORValue::ArrayValue& array = node.getArray();
startItem(CBORValue::Type::Array, array.size());
for (const auto& value : array) {
if (!encodeCBOR(value, maxNestingLevel - 1))
return false;
}
return true;
}
// Represents a map.
case CBORValue::Type::Map: {
const CBORValue::MapValue& map = node.getMap();
startItem(CBORValue::Type::Map, map.size());
for (const auto& value : map) {
if (!encodeCBOR(value.first, maxNestingLevel - 1))
return false;
if (!encodeCBOR(value.second, maxNestingLevel - 1))
return false;
}
return true;
}
// Represents a simple value.
case CBORValue::Type::SimpleValue: {
const CBORValue::SimpleValue simpleValue = node.getSimpleValue();
startItem(CBORValue::Type::SimpleValue, static_cast<uint64_t>(simpleValue));
return true;
}
default:
break;
}
ASSERT_NOT_REACHED();
return false;
}
void CBORWriter::startItem(CBORValue::Type type, uint64_t size)
{
m_encodedCBOR->append(static_cast<uint8_t>(static_cast<unsigned>(type) << constants::kMajorTypeBitShift));
setUint(size);
}
void CBORWriter::setAdditionalInformation(uint8_t additionalInformation)
{
ASSERT(!m_encodedCBOR->isEmpty());
ASSERT((additionalInformation & constants::kAdditionalInformationMask) == additionalInformation);
m_encodedCBOR->last() |= (additionalInformation & constants::kAdditionalInformationMask);
}
void CBORWriter::setUint(uint64_t value)
{
size_t count = getNumUintBytes(value);
int shift = -1;
// Values under 24 are encoded directly in the initial byte.
// Otherwise, the last 5 bits of the initial byte contains the length
// of unsigned integer, which is encoded in following bytes.
switch (count) {
case 0:
setAdditionalInformation(static_cast<uint8_t>(value));
break;
case 1:
setAdditionalInformation(constants::kAdditionalInformation1Byte);
shift = 0;
break;
case 2:
setAdditionalInformation(constants::kAdditionalInformation2Bytes);
shift = 1;
break;
case 4:
setAdditionalInformation(constants::kAdditionalInformation4Bytes);
shift = 3;
break;
case 8:
setAdditionalInformation(constants::kAdditionalInformation8Bytes);
shift = 7;
break;
default:
ASSERT_NOT_REACHED();
break;
}
for (; shift >= 0; shift--)
m_encodedCBOR->append(0xFF & (value >> (shift * 8)));
}
size_t CBORWriter::getNumUintBytes(uint64_t value)
{
if (value < 24)
return 0;
if (value <= 0xFF)
return 1;
if (value <= 0xFFFF)
return 2;
if (value <= 0xFFFFFFFF)
return 4;
return 8;
}
} // namespace cbor
#endif // ENABLE(WEB_AUTHN)
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