使用qt进行SSL握手时出错

Question

I came to you today because I've got a problem with my Client+Server app. I built a server and client app which were working fine with QTcpSocket but I thought about adding some security and going for QSslSocket with delayed handshake . The problem is that my client is acting really weirdly. Here is the situation :

• If I use connectToHostEncrypted() in my Client and call startServerEncryption() just after geting the socket in my incomingConnection slot it works fine.
• But if I delay the handshake (by doing some read/write in the socket) and call later startServerEncryption() , I got the error : Error during SSL handshake: error:1408F10B:SSL routines:SSL3_GET_RECORD:wrong version number on server side. I've also tried to use startClientEncryption() on client side but I get the same error.

The certificate is self-signed and loaded and applied to the socket correctly on server (I checked by testing the first situation with openssl s_client and the server accept all the protocol that I can test with (SSLv3, TLSv1, TLSv1.1, TLSv1.2).I cannot test with SSLv2 : on the Client, using this protocol with QSslSocket::setProtocol(QSsl::SslV2) show the error unsupported protocol and openssl s_client won't connect with the -ssl2 argument, it just show the available arguments.

I'm using Qt 5.9.1 and I've installed OpenSSL-Win32 v1.0.2L to get the dlls. I'm also compiling with msvc2015 32bit on Windows 7 64bit. I hope that you can help me (and sorry for my bad english), Nicolas.

Answer 1

I've just found my error : I was using a readyRead slot which was using socket->readAll() and that prevented the SSL handshake ! I've also discovered that you need to call both startClientEncryption and startServerEncryption to make a SSL handshake.