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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 <memory>
#include <string>
#include <vector>
#include "webrtc/base/stream.h"
#include "webrtc/base/sslidentity.h"
namespace rtc {
// Constants for SSL profile.
const int TLS_NULL_WITH_NULL_NULL = 0;
// Constants for SRTP profiles.
#ifndef SRTP_AES128_CM_SHA1_80
const int SRTP_AES128_CM_SHA1_80 = 0x0001;
#ifndef SRTP_AES128_CM_SHA1_32
const int SRTP_AES128_CM_SHA1_32 = 0x0002;
#ifndef SRTP_AEAD_AES_128_GCM
const int SRTP_AEAD_AES_128_GCM = 0x0007;
#ifndef SRTP_AEAD_AES_256_GCM
const int SRTP_AEAD_AES_256_GCM = 0x0008;
// Cipher suite to use for SRTP. Typically a 80-bit HMAC will be used, except
// in applications (voice) where the additional bandwidth may be significant.
// A 80-bit HMAC is always used for SRTCP.
// 128-bit AES with 80-bit SHA-1 HMAC.
extern const char CS_AES_CM_128_HMAC_SHA1_80[];
// 128-bit AES with 32-bit SHA-1 HMAC.
extern const char CS_AES_CM_128_HMAC_SHA1_32[];
// 128-bit AES GCM with 16 byte AEAD auth tag.
extern const char CS_AEAD_AES_128_GCM[];
// 256-bit AES GCM with 16 byte AEAD auth tag.
extern const char CS_AEAD_AES_256_GCM[];
// 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(const std::string& 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(const std::string& crypto_suite);
struct CryptoOptions {
CryptoOptions() {}
// Helper method to return an instance of the CryptoOptions with GCM crypto
// suites disabled. This method should be used instead of depending on current
// default values set by the constructor.
static CryptoOptions NoGcm();
// Enable GCM crypto suites from RFC 7714 for SRTP. GCM will only be used
// if both sides enable it.
bool enable_gcm_crypto_suites = false;
// 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.
enum SSLProtocolVersion {
// 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 StreamAdapterInterface {
// Instantiate an SSLStreamAdapter wrapping the given stream,
// (using the selected implementation for the platform).
// Caller is responsible for freeing the returned object.
static SSLStreamAdapter* Create(StreamInterface* stream);
explicit SSLStreamAdapter(StreamInterface* stream);
~SSLStreamAdapter() override;
void set_ignore_bad_cert(bool ignore) { ignore_bad_cert_ = ignore; }
bool ignore_bad_cert() const { return ignore_bad_cert_; }
void set_client_auth_enabled(bool enabled) { client_auth_enabled_ = enabled; }
bool client_auth_enabled() const { return client_auth_enabled_; }
// 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(SSLIdentity* identity) = 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;
// 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.
virtual bool SetPeerCertificateDigest(const std::string& digest_alg,
const unsigned char* digest_val,
size_t digest_len) = 0;
// Retrieves the peer's X.509 certificate, if a connection has been
// established. It returns the transmitted over SSL, including the entire
// chain.
virtual std::unique_ptr<SSLCertificate> GetPeerCertificate() 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);
virtual int GetSslVersion() 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(const std::string& label,
const uint8_t* context,
size_t context_len,
bool use_context,
uint8_t* result,
size_t result_len);
// DTLS-SRTP interface
virtual bool SetDtlsSrtpCryptoSuites(const std::vector<int>& crypto_suites);
virtual bool GetDtlsSrtpCryptoSuite(int* crypto_suite);
// Capabilities testing
static bool HaveDtls();
static bool HaveDtlsSrtp();
static bool HaveExporter();
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(const std::string& 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);
sigslot::signal1<SSLHandshakeError> SignalSSLHandshakeError;
// If true, the server certificate need not match the configured
// server_name, and in fact missing certificate authority and other
// verification errors are ignored.
bool ignore_bad_cert_;
// 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_;
} // namespace rtc