fizz::EncryptedWriteRecordLayer Class Reference

#include <EncryptedRecordLayer.h>

Inheritance diagram for fizz::EncryptedWriteRecordLayer:

Public Member Functions
	~EncryptedWriteRecordLayer () override=default
	EncryptedWriteRecordLayer (EncryptionLevel encryptionLevel)
TLSContent	write (TLSMessage &&msg) const override
virtual void	setAead (folly::ByteRange, std::unique_ptr< Aead > aead)
void	setMaxRecord (uint16_t size)
void	setMinDesiredRecord (uint16_t size)
EncryptionLevel	getEncryptionLevel () const override
Public Member Functions inherited from fizz::WriteRecordLayer
virtual	~WriteRecordLayer ()=default
TLSContent	writeAlert (Alert &&alert) const
TLSContent	writeAppData (std::unique_ptr< folly::IOBuf > &&appData) const
template<typename... Args>
TLSContent	writeHandshake (Buf &&encodedHandshakeMsg, Args &&...args) const
void	setProtocolVersion (ProtocolVersion version) const

Private Member Functions
Buf	getBufToEncrypt (folly::IOBufQueue &queue) const

Private Attributes
std::unique_ptr< Aead >	aead_
uint16_t	maxRecord_ {kMaxPlaintextRecordSize}
uint16_t	desiredMinRecord_ {kMinSuggestedRecordSize}
uint64_t	seqNum_ {0}
EncryptionLevel	encryptionLevel_

Additional Inherited Members
Protected Attributes inherited from fizz::WriteRecordLayer
ProtocolVersion	recordVersion_ {ProtocolVersion::tls_1_2}
bool	useAdditionalData_ {true}

Detailed Description

Definition at line 67 of file EncryptedRecordLayer.h.

Constructor & Destructor Documentation

fizz::EncryptedWriteRecordLayer::~EncryptedWriteRecordLayer ( )

overridedefault

fizz::EncryptedWriteRecordLayer::EncryptedWriteRecordLayer ( EncryptionLevel  encryptionLevel )

explicit

Definition at line 143 of file EncryptedRecordLayer.cpp.

    : encryptionLevel_(encryptionLevel) {}

Member Function Documentation

Buf fizz::EncryptedWriteRecordLayer::getBufToEncrypt ( folly::IOBufQueue &  queue ) const

private

Definition at line 222 of file EncryptedRecordLayer.cpp.

References desiredMinRecord_, folly::IOBufQueue::front(), folly::IOBuf::length(), maxRecord_, folly::IOBufQueue::pop_front(), and folly::IOBufQueue::splitAtMost().

Referenced by write().

                                                                           {
  if (queue.front()->length() > maxRecord_) {
    return queue.splitAtMost(maxRecord_);
  } else if (queue.front()->length() >= desiredMinRecord_) {
    return queue.pop_front();
  } else {
    return queue.splitAtMost(desiredMinRecord_);
  }
}

EncryptionLevel fizz::EncryptedWriteRecordLayer::getEncryptionLevel ( ) const

overridevirtual

Returns the current encryption level of the data that the write record layer writes at.

Implements fizz::WriteRecordLayer.

Definition at line 232 of file EncryptedRecordLayer.cpp.

References encryptionLevel_.

                                                                    {
  return encryptionLevel_;
}

virtual void fizz::EncryptedWriteRecordLayer::setAead ( folly::ByteRange  , std::unique_ptr< Aead >  aead  )

inlinevirtual

Reimplemented in fizz::MockEncryptedWriteRecordLayer.

Definition at line 75 of file EncryptedRecordLayer.h.

References fizz::EncryptedReadRecordLayer::aead_, folly::gen::move, and fizz::EncryptedReadRecordLayer::seqNum_.

                                {
    if (seqNum_ != 0) {
      throw std::runtime_error("aead set after write");
    }
    aead_ = std::move(aead);
  }

void fizz::EncryptedWriteRecordLayer::setMaxRecord ( uint16_t  size )

inline

Definition at line 84 of file EncryptedRecordLayer.h.

References folly::size().

                                   {
    CHECK_GT(size, 0);
    DCHECK_LE(size, kMaxPlaintextRecordSize);
    maxRecord_ = size;
  }

void fizz::EncryptedWriteRecordLayer::setMinDesiredRecord ( uint16_t  size )

inline

Definition at line 90 of file EncryptedRecordLayer.h.

References fizz::EncryptedReadRecordLayer::getEncryptionLevel(), and folly::size().

                                          {
    CHECK_GT(size, 0);
    DCHECK_LE(size, kMaxPlaintextRecordSize);
    desiredMinRecord_ = size;
  }

TLSContent fizz::EncryptedWriteRecordLayer::write ( TLSMessage &&  msg ) const

overridevirtual

Implements fizz::WriteRecordLayer.

Reimplemented in fizz::MockEncryptedWriteRecordLayer.

Definition at line 147 of file EncryptedRecordLayer.cpp.

References aead_, folly::IOBufQueue::append(), fizz::application_data, fizz::TLSContent::contentType, folly::IOBuf::copyBuffer(), folly::IOBuf::create(), fizz::TLSContent::data, folly::IOBufQueue::empty(), fizz::TLSContent::encryptionLevel, encryptionLevel_, getBufToEncrypt(), fizz::kEncryptedHeaderSize, max, folly::gen::move, folly::IOBuf::prependChain(), folly::range(), fizz::WriteRecordLayer::recordVersion_, seqNum_, uint16_t, fizz::WriteRecordLayer::useAdditionalData_, folly::IOBuf::wrapBufferAsValue(), and folly::io::detail::Writable< Derived >::writeBE().

                                                                  {
  folly::IOBufQueue queue;
  queue.append(std::move(msg.fragment));
  std::unique_ptr<folly::IOBuf> outBuf;
  std::array<uint8_t, kEncryptedHeaderSize> headerBuf;
  auto header = folly::IOBuf::wrapBufferAsValue(folly::range(headerBuf));
  aead_->setEncryptedBufferHeadroom(kEncryptedHeaderSize);
  while (!queue.empty()) {
    auto dataBuf = getBufToEncrypt(queue);
    // Currently we never send padding.

    // check if we have enough room to add the encrypted footer.
    if (!dataBuf->isShared() &&
        dataBuf->prev()->tailroom() >= sizeof(ContentType)) {
      // extend it and add it
      folly::io::Appender appender(dataBuf.get(), 0);
      appender.writeBE(static_cast<ContentTypeType>(msg.type));
    } else {
      // not enough or shared - let's add enough for the tag as well
      auto encryptedFooter = folly::IOBuf::create(
          sizeof(ContentType) + aead_->getCipherOverhead());
      folly::io::Appender appender(encryptedFooter.get(), 0);
      appender.writeBE(static_cast<ContentTypeType>(msg.type));
      dataBuf->prependChain(std::move(encryptedFooter));
    }

    if (seqNum_ == std::numeric_limits<uint64_t>::max()) {
      throw std::runtime_error("max write seq num");
    }

    // we will either be able to memcpy directly into the ciphertext or
    // need to create a new buf to insert before the ciphertext but we need
    // it for additional data
    header.clear();
    folly::io::Appender appender(&header, 0);
    appender.writeBE(
        static_cast<ContentTypeType>(ContentType::application_data));
    appender.writeBE(static_cast<ProtocolVersionType>(recordVersion_));
    auto ciphertextLength =
        dataBuf->computeChainDataLength() + aead_->getCipherOverhead();
    appender.writeBE<uint16_t>(ciphertextLength);

    auto cipherText = aead_->encrypt(
        std::move(dataBuf), useAdditionalData_ ? &header : nullptr, seqNum_++);

    std::unique_ptr<folly::IOBuf> record;
    if (!cipherText->isShared() &&
        cipherText->headroom() >= kEncryptedHeaderSize) {
      // prepend and then write it in
      cipherText->prepend(kEncryptedHeaderSize);
      memcpy(cipherText->writableData(), header.data(), header.length());
      record = std::move(cipherText);
    } else {
      record = folly::IOBuf::copyBuffer(header.data(), header.length());
      record->prependChain(std::move(cipherText));
    }

    if (!outBuf) {
      outBuf = std::move(record);
    } else {
      outBuf->prependChain(std::move(record));
    }
  }

  if (!outBuf) {
    outBuf = folly::IOBuf::create(0);
  }

  TLSContent content;
  content.data = std::move(outBuf);
  content.contentType = msg.type;
  content.encryptionLevel = encryptionLevel_;
  return content;
}

Member Data Documentation

std::unique_ptr<Aead> fizz::EncryptedWriteRecordLayer::aead_

private

Definition at line 101 of file EncryptedRecordLayer.h.

Referenced by write().

uint16_t fizz::EncryptedWriteRecordLayer::desiredMinRecord_ {kMinSuggestedRecordSize}

private

Definition at line 104 of file EncryptedRecordLayer.h.

Referenced by getBufToEncrypt().

EncryptionLevel fizz::EncryptedWriteRecordLayer::encryptionLevel_

private

Definition at line 107 of file EncryptedRecordLayer.h.

Referenced by getEncryptionLevel(), and write().

uint16_t fizz::EncryptedWriteRecordLayer::maxRecord_ {kMaxPlaintextRecordSize}

private

Definition at line 103 of file EncryptedRecordLayer.h.

Referenced by getBufToEncrypt().

uint64_t fizz::EncryptedWriteRecordLayer::seqNum_ {0}

mutableprivate

Definition at line 106 of file EncryptedRecordLayer.h.

Referenced by write().

---

The documentation for this class was generated from the following files:

• proxygen/fizz/fizz/record/EncryptedRecordLayer.h
• proxygen/fizz/fizz/record/EncryptedRecordLayer.cpp