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// Copyright (c) 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef QUICHE_QUIC_CORE_CRYPTO_TLS_CONNECTION_H_
#define QUICHE_QUIC_CORE_CRYPTO_TLS_CONNECTION_H_
#include <vector>
#include "absl/strings/string_view.h"
#include "third_party/boringssl/src/include/openssl/ssl.h"
#include "quic/core/quic_types.h"
namespace quic {
// TlsConnection wraps BoringSSL's SSL object which represents a single TLS
// connection. Callbacks set in BoringSSL which are called with an SSL* argument
// will get dispatched to the TlsConnection object owning that SSL. In turn, the
// TlsConnection will delegate the implementation of that callback to its
// Delegate.
//
// The owner of the TlsConnection is responsible for driving the TLS handshake
// (and other interactions with the SSL*). This class only handles mapping
// callbacks to the correct instance.
class QUIC_EXPORT_PRIVATE TlsConnection {
public:
// A TlsConnection::Delegate implements the methods that are set as callbacks
// of TlsConnection.
class QUIC_EXPORT_PRIVATE Delegate {
public:
virtual ~Delegate() {}
protected:
// Certificate management functions:
// Verifies the peer's certificate chain. It may use
// SSL_get0_peer_certificates to get the cert chain. This method returns
// ssl_verify_ok if the cert is valid, ssl_verify_invalid if it is invalid,
// or ssl_verify_retry if verification is happening asynchronously.
virtual enum ssl_verify_result_t VerifyCert(uint8_t* out_alert) = 0;
// QUIC-TLS interface functions:
// SetWriteSecret provides the encryption secret used to encrypt messages at
// encryption level |level|. The secret provided here is the one from the
// TLS 1.3 key schedule (RFC 8446 section 7.1), in particular the handshake
// traffic secrets and application traffic secrets. The provided write
// secret must be used with the provided cipher suite |cipher|.
virtual void SetWriteSecret(EncryptionLevel level,
const SSL_CIPHER* cipher,
const std::vector<uint8_t>& write_secret) = 0;
// SetReadSecret is similar to SetWriteSecret, except that it is used for
// decrypting messages. SetReadSecret at a particular level is always called
// after SetWriteSecret for that level, except for ENCRYPTION_ZERO_RTT,
// where the EncryptionLevel for SetWriteSecret is
// ENCRYPTION_FORWARD_SECURE.
virtual bool SetReadSecret(EncryptionLevel level,
const SSL_CIPHER* cipher,
const std::vector<uint8_t>& read_secret) = 0;
// WriteMessage is called when there is |data| from the TLS stack ready for
// the QUIC stack to write in a crypto frame. The data must be transmitted
// at encryption level |level|.
virtual void WriteMessage(EncryptionLevel level,
absl::string_view data) = 0;
// FlushFlight is called to signal that the current flight of messages have
// all been written (via calls to WriteMessage) and can be flushed to the
// underlying transport.
virtual void FlushFlight() = 0;
// SendAlert causes this TlsConnection to close the QUIC connection with an
// error code corersponding to the TLS alert description |desc| sent at
// level |level|.
virtual void SendAlert(EncryptionLevel level, uint8_t desc) = 0;
friend class TlsConnection;
};
TlsConnection(const TlsConnection&) = delete;
TlsConnection& operator=(const TlsConnection&) = delete;
// Functions to convert between BoringSSL's enum ssl_encryption_level_t and
// QUIC's EncryptionLevel.
static EncryptionLevel QuicEncryptionLevel(enum ssl_encryption_level_t level);
static enum ssl_encryption_level_t BoringEncryptionLevel(
EncryptionLevel level);
SSL* ssl() const { return ssl_.get(); }
protected:
// TlsConnection does not take ownership of any of its arguments; they must
// outlive the TlsConnection object.
TlsConnection(SSL_CTX* ssl_ctx, Delegate* delegate);
// Creates an SSL_CTX and configures it with the options that are appropriate
// for both client and server. The caller is responsible for ownership of the
// newly created struct.
//
// The provided |cert_verify_mode| is passed in as the |mode| argument for
// |SSL_CTX_set_verify|. See
// https://commondatastorage.googleapis.com/chromium-boringssl-docs/ssl.h.html#SSL_VERIFY_NONE
// for a description of possible values.
static bssl::UniquePtr<SSL_CTX> CreateSslCtx(int cert_verify_mode);
// From a given SSL* |ssl|, returns a pointer to the TlsConnection that it
// belongs to. This helper method allows the callbacks set in BoringSSL to be
// dispatched to the correct TlsConnection from the SSL* passed into the
// callback.
static TlsConnection* ConnectionFromSsl(const SSL* ssl);
private:
// Registered as the callback for SSL_CTX_set_custom_verify. The
// implementation is delegated to Delegate::VerifyCert.
static enum ssl_verify_result_t VerifyCallback(SSL* ssl, uint8_t* out_alert);
// TlsConnection implements SSL_QUIC_METHOD, which provides the interface
// between BoringSSL's TLS stack and a QUIC implementation.
static const SSL_QUIC_METHOD kSslQuicMethod;
// The following static functions make up the members of kSslQuicMethod:
static int SetReadSecretCallback(SSL* ssl,
enum ssl_encryption_level_t level,
const SSL_CIPHER* cipher,
const uint8_t* secret,
size_t secret_len);
static int SetWriteSecretCallback(SSL* ssl,
enum ssl_encryption_level_t level,
const SSL_CIPHER* cipher,
const uint8_t* secret,
size_t secret_len);
static int WriteMessageCallback(SSL* ssl,
enum ssl_encryption_level_t level,
const uint8_t* data,
size_t len);
static int FlushFlightCallback(SSL* ssl);
static int SendAlertCallback(SSL* ssl,
enum ssl_encryption_level_t level,
uint8_t desc);
Delegate* delegate_;
bssl::UniquePtr<SSL> ssl_;
};
} // namespace quic
#endif // QUICHE_QUIC_CORE_CRYPTO_TLS_CONNECTION_H_
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