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* 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 <stddef.h>
#include <stdint.h>
#include <memory>
#include <string>
#include <vector>
#include "absl/functional/any_invocable.h"
#include "absl/memory/memory.h"
#include "absl/strings/string_view.h"
#include "rtc_base/ssl_certificate.h"
#include "rtc_base/ssl_identity.h"
#include "rtc_base/stream.h"
namespace rtc {
// Constants for SSL profile.
constexpr int kTlsNullWithNullNull = 0;
constexpr int kSslCipherSuiteMaxValue = 0xFFFF;
// Constants for SRTP profiles.
constexpr int kSrtpInvalidCryptoSuite = 0;
constexpr int kSrtpAes128CmSha1_80 = 0x0001;
constexpr int kSrtpAes128CmSha1_32 = 0x0002;
constexpr int kSrtpAeadAes128Gcm = 0x0007;
constexpr int kSrtpAeadAes256Gcm = 0x0008;
constexpr int kSrtpCryptoSuiteMaxValue = 0xFFFF;
// Constants for SSL signature algorithms.
constexpr int kSslSignatureAlgorithmUnknown = 0;
constexpr int kSslSignatureAlgorithmMaxValue = 0xFFFF;
// Names of SRTP profiles listed above.
// 128-bit AES with 80-bit SHA-1 HMAC.
extern const char kCsAesCm128HmacSha1_80[];
// 128-bit AES with 32-bit SHA-1 HMAC.
extern const char kCsAesCm128HmacSha1_32[];
// 128-bit AES GCM with 16 byte AEAD auth tag.
extern const char kCsAeadAes128Gcm[];
// 256-bit AES GCM with 16 byte AEAD auth tag.
extern const char kCsAeadAes256Gcm[];
// Given the DTLS-SRTP protection profile ID, as defined in
// , return the SRTP profile
// name, as defined in
std::string SrtpCryptoSuiteToName(int crypto_suite);
// The reverse of above conversion.
int SrtpCryptoSuiteFromName(absl::string_view crypto_suite);
// Get key length and salt length for given crypto suite. Returns true for
// valid suites, otherwise false.
bool GetSrtpKeyAndSaltLengths(int crypto_suite,
int* key_length,
int* salt_length);
// Returns true if the given crypto suite id uses a GCM cipher.
bool IsGcmCryptoSuite(int crypto_suite);
// Returns true if the given crypto suite name uses a GCM cipher.
bool IsGcmCryptoSuiteName(absl::string_view crypto_suite);
// SSLStreamAdapter : A StreamInterfaceAdapter that does SSL/TLS.
// After SSL has been started, the stream will only open on successful
// SSL verification of certificates, and the communication is
// encrypted of course.
// This class was written with SSLAdapter as a starting point. It
// offers a similar interface, with two differences: there is no
// support for a restartable SSL connection, and this class has a
// peer-to-peer mode.
// The SSL library requires initialization and cleanup. Static method
// for doing this are in SSLAdapter. They should possibly be moved out
// to a neutral class.
// Note: TLS_10, TLS_11, and DTLS_10 will all be ignored, and only DTLS1_2 will
// be accepted unless the trial flag WebRTC-LegacyTlsProtocols/Enabled/ is
// passed in or an explicit override is used. Support for the legacy protocol
// versions will be completely removed in the future.
// See
enum SSLProtocolVersion {
enum class SSLPeerCertificateDigestError {
// Errors for Read -- in the high range so no conflict with OpenSSL.
enum { SSE_MSG_TRUNC = 0xff0001 };
// Used to send back UMA histogram value. Logged when Dtls handshake fails.
class SSLStreamAdapter : public StreamInterface {
// Instantiate an SSLStreamAdapter wrapping the given stream,
// (using the selected implementation for the platform).
// Caller is responsible for freeing the returned object.
static std::unique_ptr<SSLStreamAdapter> Create(
std::unique_ptr<StreamInterface> stream,
absl::AnyInvocable<void(SSLHandshakeError)> handshake_error = nullptr);
SSLStreamAdapter() = default;
~SSLStreamAdapter() override = default;
// Specify our SSL identity: key and certificate. SSLStream takes ownership
// of the SSLIdentity object and will free it when appropriate. Should be
// called no more than once on a given SSLStream instance.
virtual void SetIdentity(std::unique_ptr<SSLIdentity> identity) = 0;
virtual SSLIdentity* GetIdentityForTesting() const = 0;
// Call this to indicate that we are to play the server role (or client role,
// if the default argument is replaced by SSL_CLIENT).
// The default argument is for backward compatibility.
// TODO( rename this SetRole to reflect its new function
virtual void SetServerRole(SSLRole role = SSL_SERVER) = 0;
// Do DTLS or TLS.
virtual void SetMode(SSLMode mode) = 0;
// Set maximum supported protocol version. The highest version supported by
// both ends will be used for the connection, i.e. if one party supports
// DTLS 1.0 and the other DTLS 1.2, DTLS 1.0 will be used.
// If requested version is not supported by underlying crypto library, the
// next lower will be used.
virtual void SetMaxProtocolVersion(SSLProtocolVersion version) = 0;
// Set the initial retransmission timeout for DTLS messages. When the timeout
// expires, the message gets retransmitted and the timeout is exponentially
// increased.
// This should only be called before StartSSL().
virtual void SetInitialRetransmissionTimeout(int timeout_ms) = 0;
// StartSSL starts negotiation with a peer, whose certificate is verified
// using the certificate digest. Generally, SetIdentity() and possibly
// SetServerRole() should have been called before this.
// SetPeerCertificateDigest() must also be called. It may be called after
// StartSSLWithPeer() but must be called before the underlying stream opens.
// Use of the stream prior to calling StartSSL will pass data in clear text.
// Calling StartSSL causes SSL negotiation to begin as soon as possible: right
// away if the underlying wrapped stream is already opened, or else as soon as
// it opens.
// StartSSL returns a negative error code on failure. Returning 0 means
// success so far, but negotiation is probably not complete and will continue
// asynchronously. In that case, the exposed stream will open after
// successful negotiation and verification, or an SE_CLOSE event will be
// raised if negotiation fails.
virtual int StartSSL() = 0;
// Specify the digest of the certificate that our peer is expected to use.
// Only this certificate will be accepted during SSL verification. The
// certificate is assumed to have been obtained through some other secure
// channel (such as the signaling channel). This must specify the terminal
// certificate, not just a CA. SSLStream makes a copy of the digest value.
// Returns true if successful.
// `error` is optional and provides more information about the failure.
virtual bool SetPeerCertificateDigest(
absl::string_view digest_alg,
const unsigned char* digest_val,
size_t digest_len,
SSLPeerCertificateDigestError* error = nullptr) = 0;
// Retrieves the peer's certificate chain including leaf certificate, if a
// connection has been established.
virtual std::unique_ptr<SSLCertChain> GetPeerSSLCertChain() const = 0;
// Retrieves the IANA registration id of the cipher suite used for the
// connection (e.g. 0x2F for "TLS_RSA_WITH_AES_128_CBC_SHA").
virtual bool GetSslCipherSuite(int* cipher_suite);
// Retrieves the enum value for SSL version.
// Will return -1 until the version has been negotiated.
virtual SSLProtocolVersion GetSslVersion() const = 0;
// Retrieves the 2-byte version from the TLS protocol.
// Will return false until the version has been negotiated.
virtual bool GetSslVersionBytes(int* version) const = 0;
// Key Exporter interface from RFC 5705
// Arguments are:
// label -- the exporter label.
// part of the RFC defining each exporter
// usage (IN)
// context/context_len -- a context to bind to for this connection;
// optional, can be null, 0 (IN)
// use_context -- whether to use the context value
// (needed to distinguish no context from
// zero-length ones).
// result -- where to put the computed value
// result_len -- the length of the computed value
virtual bool ExportKeyingMaterial(absl::string_view label,
const uint8_t* context,
size_t context_len,
bool use_context,
uint8_t* result,
size_t result_len);
// Returns the signature algorithm or 0 if not applicable.
virtual uint16_t GetPeerSignatureAlgorithm() const = 0;
// DTLS-SRTP interface
virtual bool SetDtlsSrtpCryptoSuites(const std::vector<int>& crypto_suites);
virtual bool GetDtlsSrtpCryptoSuite(int* crypto_suite);
// Returns true if a TLS connection has been established.
// The only difference between this and "GetState() == SE_OPEN" is that if
// the peer certificate digest hasn't been verified, the state will still be
// SS_OPENING but IsTlsConnected should return true.
virtual bool IsTlsConnected() = 0;
// Capabilities testing.
// Used to have "DTLS supported", "DTLS-SRTP supported" etc. methods, but now
// that's assumed.
static bool IsBoringSsl();
// Returns true iff the supplied cipher is deemed to be strong.
// TODO(torbjorng): Consider removing the KeyType argument.
static bool IsAcceptableCipher(int cipher, KeyType key_type);
static bool IsAcceptableCipher(absl::string_view cipher, KeyType key_type);
// TODO(guoweis): Move this away from a static class method. Currently this is
// introduced such that any caller could depend on sslstreamadapter.h without
// depending on specific SSL implementation.
static std::string SslCipherSuiteToName(int cipher_suite);
// Testing only member functions
// Use our timeutils.h source of timing in BoringSSL, allowing us to test
// using a fake clock.
static void EnableTimeCallbackForTesting();
// Deprecated. Do not use this API outside of testing.
// Do not set this to false outside of testing.
void SetClientAuthEnabledForTesting(bool enabled) {
client_auth_enabled_ = enabled;
// Deprecated. Do not use this API outside of testing.
// Returns true by default, else false if explicitly set to disable client
// authentication.
bool GetClientAuthEnabled() const { return client_auth_enabled_; }
// If true (default), the client is required to provide a certificate during
// handshake. If no certificate is given, handshake fails. This applies to
// server mode only.
bool client_auth_enabled_ = true;
} // namespace rtc