fizz::EncryptedReadRecordLayer Class Reference

#include <EncryptedRecordLayer.h>

Inheritance diagram for fizz::EncryptedReadRecordLayer:

Public Member Functions
	~EncryptedReadRecordLayer () override=default
	EncryptedReadRecordLayer (EncryptionLevel encryptionLevel)
folly::Optional< TLSMessage >	read (folly::IOBufQueue &buf) override
virtual void	setAead (folly::ByteRange, std::unique_ptr< Aead > aead)
virtual void	setSkipFailedDecryption (bool enabled)
void	setProtocolVersion (ProtocolVersion version)
EncryptionLevel	getEncryptionLevel () const override
Public Member Functions inherited from fizz::ReadRecordLayer
virtual	~ReadRecordLayer ()=default
virtual folly::Optional< Param >	readEvent (folly::IOBufQueue &socketBuf)
virtual bool	hasUnparsedHandshakeData () const

Private Member Functions
folly::Optional< Buf >	getDecryptedBuf (folly::IOBufQueue &buf)

Private Attributes
EncryptionLevel	encryptionLevel_
std::unique_ptr< Aead >	aead_
bool	skipFailedDecryption_ {false}
bool	useAdditionalData_ {true}
uint64_t	seqNum_ {0}

Additional Inherited Members
Static Public Member Functions inherited from fizz::ReadRecordLayer
static folly::Optional< Param >	decodeHandshakeMessage (folly::IOBufQueue &buf)

Detailed Description

Definition at line 20 of file EncryptedRecordLayer.h.

Constructor & Destructor Documentation

fizz::EncryptedReadRecordLayer::~EncryptedReadRecordLayer ( )

overridedefault

fizz::EncryptedReadRecordLayer::EncryptedReadRecordLayer ( EncryptionLevel  encryptionLevel )

explicit

Definition at line 21 of file EncryptedRecordLayer.cpp.

    : encryptionLevel_(encryptionLevel) {}

Member Function Documentation

folly::Optional< Buf > fizz::EncryptedReadRecordLayer::getDecryptedBuf ( folly::IOBufQueue &  buf )

private

Definition at line 25 of file EncryptedRecordLayer.cpp.

References aead_, fizz::alert, folly::IOBufQueue::chainLength(), fizz::change_cipher_spec, folly::IOBuf::coalesce(), folly::IOBuf::data(), folly::IOBufQueue::empty(), folly::IOBufQueue::front(), fizz::illegal_parameter, folly::IOBuf::length(), max, folly::gen::move, folly::none, folly::io::detail::CursorBase< Derived, BufType >::pull(), folly::range(), seqNum_, skipFailedDecryption_, fizz::toString(), folly::IOBufQueue::trimStart(), uint16_t, useAdditionalData_, and folly::IOBuf::wrapBufferAsValue().

Referenced by read(), and setProtocolVersion().

                          {
  while (true) {
    folly::io::Cursor cursor(buf.front());

    if (buf.empty() || !cursor.canAdvance(kEncryptedHeaderSize)) {
      return folly::none;
    }

    std::array<uint8_t, kEncryptedHeaderSize> ad;
    folly::io::Cursor adCursor(cursor);
    adCursor.pull(ad.data(), ad.size());
    folly::IOBuf adBuf{folly::IOBuf::wrapBufferAsValue(folly::range(ad))};

    auto contentType =
        static_cast<ContentType>(cursor.readBE<ContentTypeType>());
    cursor.skip(sizeof(ProtocolVersion));

    auto length = cursor.readBE<uint16_t>();
    if (length == 0) {
      throw std::runtime_error("received 0 length encrypted record");
    }
    if (length > kMaxEncryptedRecordSize) {
      throw std::runtime_error("received too long encrypted record");
    }
    if (buf.chainLength() < (cursor - buf.front()) + length) {
      return folly::none;
    }

    if (contentType == ContentType::alert && length == 2) {
      auto alert = decode<Alert>(cursor);
      throw std::runtime_error(folly::to<std::string>(
          "received plaintext alert in encrypted record: ",
          toString(alert.description)));
    }

    std::unique_ptr<folly::IOBuf> encrypted;
    cursor.clone(encrypted, length);
    buf.trimStart(cursor - buf.front());

    if (contentType == ContentType::change_cipher_spec) {
      encrypted->coalesce();
      if (encrypted->length() == 1 && *encrypted->data() == 0x01) {
        continue;
      } else {
        throw FizzException(
            "received ccs", AlertDescription::illegal_parameter);
      }
    }

    TLSMessage msg;
    if (seqNum_ == std::numeric_limits<uint64_t>::max()) {
      throw std::runtime_error("max read seq num");
    }
    if (skipFailedDecryption_) {
      auto decryptAttempt = aead_->tryDecrypt(
          std::move(encrypted), useAdditionalData_ ? &adBuf : nullptr, seqNum_);
      if (decryptAttempt) {
        seqNum_++;
        skipFailedDecryption_ = false;
        return decryptAttempt;
      } else {
        continue;
      }
    } else {
      return aead_->decrypt(
          std::move(encrypted),
          useAdditionalData_ ? &adBuf : nullptr,
          seqNum_++);
    }
  }
}

EncryptionLevel fizz::EncryptedReadRecordLayer::getEncryptionLevel ( ) const

overridevirtual

Returns the current encryption level of the data that the read record layer can process.

Implements fizz::ReadRecordLayer.

Definition at line 139 of file EncryptedRecordLayer.cpp.

References encryptionLevel_.

Referenced by fizz::EncryptedWriteRecordLayer::setMinDesiredRecord(), and setProtocolVersion().

                                                                   {
  return encryptionLevel_;
}

folly::Optional< TLSMessage > fizz::EncryptedReadRecordLayer::read ( folly::IOBufQueue &  buf )

overridevirtual

Reads a fragment from the record layer. Returns an empty optional if insuficient data available. Throws if data malformed. On success, advances buf the amount read.

Implements fizz::ReadRecordLayer.

Definition at line 98 of file EncryptedRecordLayer.cpp.

References folly::io::detail::CursorBase< Derived, BufType >::advanceToEnd(), fizz::alert, folly::IOBufQueue::append(), fizz::application_data, folly::IOBuf::create(), data, fizz::TLSMessage::fragment, folly::IOBufQueue::front(), getDecryptedBuf(), fizz::handshake, folly::IOBufQueue::move(), folly::gen::move, folly::none, folly::IOBufQueue::trimEnd(), and fizz::TLSMessage::type.

                          {
  auto decryptedBuf = getDecryptedBuf(buf);
  if (!decryptedBuf) {
    return folly::none;
  }

  folly::IOBufQueue decrypted;
  decrypted.append(std::move(*decryptedBuf));

  folly::io::Cursor paddingCursor(decrypted.front());
  paddingCursor.advanceToEnd();
  while (!*(paddingCursor -= 1).data()) {
  }
  TLSMessage msg;
  msg.type = static_cast<ContentType>(paddingCursor.readBE<ContentTypeType>());
  decrypted.trimEnd(paddingCursor.totalLength() + sizeof(ContentType));
  msg.fragment = decrypted.move();

  switch (msg.type) {
    case ContentType::handshake:
    case ContentType::alert:
    case ContentType::application_data:
      break;
    default:
      throw std::runtime_error(folly::to<std::string>(
          "received encrypted content type ",
          static_cast<ContentTypeType>(msg.type)));
  }

  if (!msg.fragment) {
    if (msg.type == ContentType::application_data) {
      msg.fragment = folly::IOBuf::create(0);
    } else {
      throw std::runtime_error("received empty fragment");
    }
  }

  return std::move(msg);
}

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

inlinevirtual

Reimplemented in fizz::MockEncryptedReadRecordLayer.

Definition at line 28 of file EncryptedRecordLayer.h.

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

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

void fizz::EncryptedReadRecordLayer::setProtocolVersion ( ProtocolVersion  version )

inline

Definition at line 41 of file EncryptedRecordLayer.h.

References getDecryptedBuf(), getEncryptionLevel(), fizz::getRealDraftVersion(), fizz::tls_1_3_20, fizz::tls_1_3_21, fizz::tls_1_3_22, fizz::tls_1_3_23, and useAdditionalData_.

                                                   {
    auto realVersion = getRealDraftVersion(version);
    if (realVersion == ProtocolVersion::tls_1_3_23 ||
        realVersion == ProtocolVersion::tls_1_3_22 ||
        realVersion == ProtocolVersion::tls_1_3_21 ||
        realVersion == ProtocolVersion::tls_1_3_20) {
      useAdditionalData_ = false;
    } else {
      useAdditionalData_ = true;
    }
  }

virtual void fizz::EncryptedReadRecordLayer::setSkipFailedDecryption ( bool  enabled )

inlinevirtual

Definition at line 37 of file EncryptedRecordLayer.h.

References skipFailedDecryption_.

                                                     {
    skipFailedDecryption_ = enabled;
  }

Member Data Documentation

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

private

Definition at line 59 of file EncryptedRecordLayer.h.

Referenced by getDecryptedBuf(), setAead(), and fizz::EncryptedWriteRecordLayer::setAead().

EncryptionLevel fizz::EncryptedReadRecordLayer::encryptionLevel_

private

Definition at line 58 of file EncryptedRecordLayer.h.

Referenced by getEncryptionLevel().

uint64_t fizz::EncryptedReadRecordLayer::seqNum_ {0}

mutableprivate

Definition at line 64 of file EncryptedRecordLayer.h.

Referenced by getDecryptedBuf(), setAead(), and fizz::EncryptedWriteRecordLayer::setAead().

bool fizz::EncryptedReadRecordLayer::skipFailedDecryption_ {false}

private

Definition at line 60 of file EncryptedRecordLayer.h.

Referenced by getDecryptedBuf(), and setSkipFailedDecryption().

bool fizz::EncryptedReadRecordLayer::useAdditionalData_ {true}

private

Definition at line 62 of file EncryptedRecordLayer.h.

Referenced by getDecryptedBuf(), and setProtocolVersion().

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

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