blob: 3c94ecd2ced93d7c72450fb0df209be59754cb8b [file] [log] [blame]
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
#include <openssl/ossl_typ.h>
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include <string>
#include <vector>
#include "absl/strings/string_view.h"
#include "absl/types/optional.h"
#include "rtc_base/buffer.h"
#include "rtc_base/boringssl_identity.h"
#include "rtc_base/openssl_identity.h"
#include "api/task_queue/pending_task_safety_flag.h"
#include "rtc_base/ssl_identity.h"
#include "rtc_base/ssl_stream_adapter.h"
#include "rtc_base/stream.h"
#include "rtc_base/system/rtc_export.h"
#include "rtc_base/task_utils/repeating_task.h"
namespace rtc {
// This class was written with OpenSSLAdapter (a socket adapter) as a
// starting point. It has similar structure and functionality, but uses a
// "peer-to-peer" mode, verifying the peer's certificate using a digest
// sent over a secure signaling channel.
// Static methods to initialize and deinit the SSL library are in
// OpenSSLAdapter. These should probably be moved out to a neutral class.
// In a few cases I have factored out some OpenSSLAdapter code into static
// methods so it can be reused from this class. Eventually that code should
// probably be moved to a common support class. Unfortunately there remain a
// few duplicated sections of code. I have not done more restructuring because
// I did not want to affect existing code that uses OpenSSLAdapter.
// This class does not support the SSL connection restart feature present in
// OpenSSLAdapter. I am not entirely sure how the feature is useful and I am
// not convinced that it works properly.
// This implementation is careful to disallow data exchange after an SSL error,
// and it has an explicit SSL_CLOSED state. It should not be possible to send
// any data in clear after one of the StartSSL methods has been called.
// Look in sslstreamadapter.h for documentation of the methods.
class SSLCertChain;
// If `allow` has a value, its value determines if legacy TLS protocols are
// allowed, overriding the default configuration.
// If `allow` has no value, any previous override is removed and the default
// configuration is restored.
RTC_EXPORT void SetAllowLegacyTLSProtocols(const absl::optional<bool>& allow);
class OpenSSLStreamAdapter final : public SSLStreamAdapter {
explicit OpenSSLStreamAdapter(std::unique_ptr<StreamInterface> stream);
~OpenSSLStreamAdapter() override;
void SetIdentity(std::unique_ptr<SSLIdentity> identity) override;
SSLIdentity* GetIdentityForTesting() const override;
// Default argument is for compatibility
void SetServerRole(SSLRole role = SSL_SERVER) override;
bool SetPeerCertificateDigest(
absl::string_view digest_alg,
const unsigned char* digest_val,
size_t digest_len,
SSLPeerCertificateDigestError* error = nullptr) override;
std::unique_ptr<SSLCertChain> GetPeerSSLCertChain() const override;
// Goes from state SSL_NONE to either SSL_CONNECTING or SSL_WAIT, depending
// on whether the underlying stream is already open or not.
int StartSSL() override;
void SetMode(SSLMode mode) override;
void SetMaxProtocolVersion(SSLProtocolVersion version) override;
void SetInitialRetransmissionTimeout(int timeout_ms) override;
[[deprecated("")]] StreamResult
Read(void* data, size_t data_len, size_t* read, int* error) override;
StreamResult Read(rtc::ArrayView<uint8_t> data,
size_t& read,
int& error) override;
[[deprecated("")]] StreamResult Write(
const void* data,
size_t data_len,
size_t* written,
int* error) override;
StreamResult Write(rtc::ArrayView<const uint8_t> data,
size_t& written,
int& error) override;
void Close() override;
StreamState GetState() const override;
// TODO(guoweis): Move this away from a static class method.
static std::string SslCipherSuiteToName(int crypto_suite);
bool GetSslCipherSuite(int* cipher) override;
SSLProtocolVersion GetSslVersion() const override;
bool GetSslVersionBytes(int* version) const override;
// Key Extractor interface
bool ExportKeyingMaterial(absl::string_view label,
const uint8_t* context,
size_t context_len,
bool use_context,
uint8_t* result,
size_t result_len) override;
// DTLS-SRTP interface
bool SetDtlsSrtpCryptoSuites(const std::vector<int>& crypto_suites) override;
bool GetDtlsSrtpCryptoSuite(int* crypto_suite) override;
bool IsTlsConnected() override;
// Capabilities interfaces.
static bool IsBoringSsl();
static bool IsAcceptableCipher(int cipher, KeyType key_type);
static bool IsAcceptableCipher(absl::string_view cipher, KeyType key_type);
// Use our timeutils.h source of timing in BoringSSL, allowing us to test
// using a fake clock.
static void EnableTimeCallbackForTesting();
enum SSLState {
// Before calling one of the StartSSL methods, data flows
// in clear text.
SSL_WAIT, // waiting for the stream to open to start SSL negotiation
SSL_CONNECTING, // SSL negotiation in progress
SSL_CONNECTED, // SSL stream successfully established
SSL_ERROR, // some SSL error occurred, stream is closed
SSL_CLOSED // Clean close
void OnEvent(StreamInterface* stream, int events, int err);
void PostEvent(int events, int err);
void SetTimeout(int delay_ms);
// The following three methods return 0 on success and a negative
// error code on failure. The error code may be from OpenSSL or -1
// on some other error cases, so it can't really be interpreted
// unfortunately.
// Prepare SSL library, state is SSL_CONNECTING.
int BeginSSL();
// Perform SSL negotiation steps.
int ContinueSSL();
// Error handler helper. signal is given as true for errors in
// asynchronous contexts (when an error method was not returned
// through some other method), and in that case an SE_CLOSE event is
// raised on the stream with the specified error.
// A 0 error means a graceful close, otherwise there is not really enough
// context to interpret the error code.
// `alert` indicates an alert description (one of the SSL_AD constants) to
// send to the remote endpoint when closing the association. If 0, a normal
// shutdown will be performed.
void Error(absl::string_view context, int err, uint8_t alert, bool signal);
void Cleanup(uint8_t alert);
// Flush the input buffers by reading left bytes (for DTLS)
void FlushInput(unsigned int left);
// SSL library configuration
SSL_CTX* SetupSSLContext();
// Verify the peer certificate matches the signaled digest.
bool VerifyPeerCertificate();
// SSL certificate verification callback. See SSL_CTX_set_custom_verify.
static enum ssl_verify_result_t SSLVerifyCallback(SSL* ssl,
uint8_t* out_alert);
// SSL certificate verification callback. See
// SSL_CTX_set_cert_verify_callback.
static int SSLVerifyCallback(X509_STORE_CTX* store, void* arg);
bool WaitingToVerifyPeerCertificate() const {
return GetClientAuthEnabled() && !peer_certificate_verified_;
bool HasPeerCertificateDigest() const {
return !peer_certificate_digest_algorithm_.empty() &&
const std::unique_ptr<StreamInterface> stream_;
rtc::Thread* const owner_;
webrtc::ScopedTaskSafety task_safety_;
webrtc::RepeatingTaskHandle timeout_task_;
SSLState state_;
SSLRole role_;
int ssl_error_code_; // valid when state_ == SSL_ERROR or SSL_CLOSED
// Whether the SSL negotiation is blocked on needing to read or
// write to the wrapped stream.
bool ssl_read_needs_write_;
bool ssl_write_needs_read_;
SSL* ssl_;
SSL_CTX* ssl_ctx_;
// Our key and certificate.
std::unique_ptr<BoringSSLIdentity> identity_;
std::unique_ptr<OpenSSLIdentity> identity_;
// The certificate chain that the peer presented. Initially null, until the
// connection is established.
std::unique_ptr<SSLCertChain> peer_cert_chain_;
bool peer_certificate_verified_ = false;
// The digest of the certificate that the peer must present.
Buffer peer_certificate_digest_value_;
std::string peer_certificate_digest_algorithm_;
// The DtlsSrtp ciphers
std::string srtp_ciphers_;
// Do DTLS or not
SSLMode ssl_mode_;
// Max. allowed protocol version
SSLProtocolVersion ssl_max_version_;
// A 50-ms initial timeout ensures rapid setup on fast connections, but may
// be too aggressive for low bandwidth links.
int dtls_handshake_timeout_ms_ = 50;
// TODO( Completely remove this option in M84.
const bool support_legacy_tls_protocols_flag_;
} // namespace rtc