QSsl: cannot abort() QSslSocket in response to peerVerifyError/sslErrors signals

[OpenSSL backend]

This behavior used to work in Qt 4.

QSslSocket::abort() and QSslSocket::close (called by abort()), do not update the QSslSocket's socket state.

Consider an SSL server that is accepting a client.

The server is inside the QSslSocketPrivate::startHandshake() method, and emits peerVerifyError.

The slot of peerVerifyError in turn calls QSslSocket::abort() on the socket to terminate it immediately.

The documentation for the peerVerifyError siganl says this is a valid use-case: "[...] By connecting to this signal, you can manually choose to tear down the connection from inside the connected slot before the handshake has completed. [...]".

Unfortunately, calling abort() doesn't update the socket state.

After emitting peerVerifyError(), QSslSocket attempts to determine whether the socket is still connected – or if the slot decided to tear down the connection.

Unfortunately, this check always returns ConnectedState – because abort()/close() do not update the state to UnconnectedState after tearing down the connection.

The result is that QSslSocket continues execution of QSslSocket::startHandshake() and, eventually calls continueHandshake(), which tries to dereference the 'SSL *' for the connection – which is now NULL.

Boom.