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/*
* libjingle
* Copyright 2004--2008, Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef TALK_BASE_OPENSSLSTREAMADAPTER_H__
#define TALK_BASE_OPENSSLSTREAMADAPTER_H__
#include <string>
#include <vector>
#include "talk/base/buffer.h"
#include "talk/base/sslstreamadapter.h"
#include "talk/base/opensslidentity.h"
typedef struct ssl_st SSL;
typedef struct ssl_ctx_st SSL_CTX;
typedef struct x509_store_ctx_st X509_STORE_CTX;
namespace talk_base {
// This class was written with OpenSSLAdapter (a socket adapter) as a
// starting point. It has similar structure and functionality, with
// the peer-to-peer mode added.
//
// Static methods to initialize and deinit the SSL library are in
// OpenSSLAdapter. This class also uses
// OpenSSLAdapter::custom_verify_callback_ (a static field). 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 OpenSSLIdentity;
///////////////////////////////////////////////////////////////////////////////
class OpenSSLStreamAdapter : public SSLStreamAdapter {
public:
explicit OpenSSLStreamAdapter(StreamInterface* stream);
virtual ~OpenSSLStreamAdapter();
virtual void SetIdentity(SSLIdentity* identity);
// Default argument is for compatibility
virtual void SetServerRole(SSLRole role = SSL_SERVER);
virtual void SetPeerCertificate(SSLCertificate* cert);
virtual bool SetPeerCertificateDigest(const std::string& digest_alg,
const unsigned char* digest_val,
size_t digest_len);
virtual bool GetPeerCertificate(SSLCertificate** cert) const;
virtual int StartSSLWithServer(const char* server_name);
virtual int StartSSLWithPeer();
virtual void SetMode(SSLMode mode);
virtual StreamResult Read(void* data, size_t data_len,
size_t* read, int* error);
virtual StreamResult Write(const void* data, size_t data_len,
size_t* written, int* error);
virtual void Close();
virtual StreamState GetState() const;
// Key Extractor interface
virtual bool ExportKeyingMaterial(const std::string& label,
const uint8* context,
size_t context_len,
bool use_context,
uint8* result,
size_t result_len);
// DTLS-SRTP interface
virtual bool SetDtlsSrtpCiphers(const std::vector<std::string>& ciphers);
virtual bool GetDtlsSrtpCipher(std::string* cipher);
// Capabilities interfaces
static bool HaveDtls();
static bool HaveDtlsSrtp();
static bool HaveExporter();
protected:
virtual void OnEvent(StreamInterface* stream, int events, int err);
private:
enum SSLState {
// Before calling one of the StartSSL methods, data flows
// in clear text.
SSL_NONE,
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
};
enum { MSG_TIMEOUT = MSG_MAX+1};
// 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.
// Go from state SSL_NONE to either SSL_CONNECTING or SSL_WAIT,
// depending on whether the underlying stream is already open or
// not.
int StartSSL();
// 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.
void Error(const char* context, int err, bool signal);
void Cleanup();
// Override MessageHandler
virtual void OnMessage(Message* msg);
// Flush the input buffers by reading left bytes (for DTLS)
void FlushInput(unsigned int left);
// SSL library configuration
SSL_CTX* SetupSSLContext();
// SSL verification check
bool SSLPostConnectionCheck(SSL* ssl, const char* server_name,
const X509* peer_cert,
const std::string& peer_digest);
// SSL certification verification error handler, called back from
// the openssl library. Returns an int interpreted as a boolean in
// the C style: zero means verification failure, non-zero means
// passed.
static int SSLVerifyCallback(int ok, X509_STORE_CTX* store);
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, mostly useful in peer-to-peer mode.
scoped_ptr<OpenSSLIdentity> identity_;
// in traditional mode, the server name that the server's certificate
// must specify. Empty in peer-to-peer mode.
std::string ssl_server_name_;
// The certificate that the peer must present or did present. Initially
// null in traditional mode, until the connection is established.
scoped_ptr<OpenSSLCertificate> peer_certificate_;
// In peer-to-peer mode, the digest of the certificate that
// the peer must present.
Buffer peer_certificate_digest_value_;
std::string peer_certificate_digest_algorithm_;
// OpenSSLAdapter::custom_verify_callback_ result
bool custom_verification_succeeded_;
// The DtlsSrtp ciphers
std::string srtp_ciphers_;
// Do DTLS or not
SSLMode ssl_mode_;
};
/////////////////////////////////////////////////////////////////////////////
} // namespace talk_base
#endif // TALK_BASE_OPENSSLSTREAMADAPTER_H__
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