如何检查TLS握手是否已在Twisted中完成

Question

这是对此问题的跟进:当没有数据通过Twisted TLSConnection发送时,SSL握手失败

我已经实现了一个简单的SSL服务器,一旦客户端连接就关闭连接.

我用openssl测试它,我得到了这次握手失败:

$ openssl s_client -connect localhost:12345                             
CONNECTED(00000003) 2329:error:140790E5:SSL routines:SSL23_WRITE
:ssl handshake failure:s23_lib.c:188: 

问题是TLS.Connection.loseConnection不等待正在进行的握手,只是断开客户端.

附加的回调OpenSSL.SSL.Connection.do_handshake会很棒......但不幸的是我不知道是否可以这样做......或者如何做到这一点.

我非常感谢任何有关如何测试TLS握手的提示.非常感谢!

这是代码

class ApplicationProtocol(Protocol):
        '''Protocol that closes the connection when connection is made.'''
        def connectionMade(self):
            self.transport.loseConnection()

# Here is a barebone TLS Server
serverFactory = ServerFactory()
serverFactory.protocol = ApplicationProtocol
server_cert_path = 'server.pem'
serverContextFactory = DefaultOpenSSLContextFactory(
            privateKeyFileName = server_cert_path,
            certificateFileName = server_cert_path,
            sslmethod=SSL.SSLv23_METHOD)

tlsFactory = TLSMemoryBIOFactory(serverContextFactory, False, serverFactory)
reactor.listenTCP(12345, tlsFactory)
#reactor.listenSSL(12345, serverFactory, serverContextFactory)

---

现在我解决这个问题非常脏,而且不是100%有效.

def tls_lose_connection(self):
    """
    Monkey patching for TLSMemoryBIOProtocol to wait for handshake to end,
    before closing the connection.

    Send a TLS close alert and close the underlying connection.
    """

    def close_connection():
        self.disconnecting = True
        if not self._writeBlockedOnRead:
            self._tlsConnection.shutdown()
            self._flushSendBIO()
            self.transport.loseConnection()

    # If we don't know if the handshake was done, we wait for a bit
    # and the close the connection.
    # This is done to avoid closing the connection in the middle of a
    # handshake.
    if not self._handshakeDone:
        reactor.callLater(0.5, close_connection)
    else:
        close_connection()


TLSMemoryBIOProtocol.loseConnection = tls_lose_connection

Answer 1

我提供的代码实现了Jean-Paul的答案.

class ProxyClientTLSContextFactory(ssl.ClientContextFactory):
    isClient = 1

def getContext(self):
    ctx = SSL.Context(SSL.TLSv1_METHOD)
    logger = logging.GetLogger()
    def infoCallback(conn, where, ret):
        # conn is a OpenSSL.SSL.Connection
        # where is a set of flags telling where in the handshake we are
        # See http://www.openssl.org/docs/ssl/SSL_CTX_set_info_callback.html
        logger.debug("infoCallback %s %d %d" % (conn, where, ret))
        if where & SSL.SSL_CB_HANDSHAKE_START:
            logger.debug("Handshake started")
        if where & SSL.SSL_CB_HANDSHAKE_DONE:
            logger.debug("Handshake done")
    ctx.set_info_callback(infoCallback)
    return ctx

我在infoCallback()内部遇到的问题是我不知道如何从SSL.Connection返回到相关的Twisted Protocol实例.

我想做的是在建立连接并完成TLS握手后调用我的Protocol实例上的回调,这样我就可以确保在继续之前证书验证是我喜欢的.

Answer 2

SSL 上下文对象可以使用“信息回调”进行配置 - Context.set_info_callback。这是 SSL_CTX_set_info_callback 的包装。不幸的是，pyOpenSSL 没有公开稍微方便一点（在本例中）的用于为单个连接指定回调的 SSL_set_info_callback 。

除此之外，握手完成时会调用信息回调。通过一些技巧，您应该能够将此通知转换为延迟或协议上的其他回调。

有关详细信息，请参阅pyOpenSSL set_info_callback 文档和OpenSSL SSL_CTX_set_info_callback 文档。