The receiver (kcheckpass) reads a string and if it is !nullptr, reads an int:
msg = GRecvStr ();
if (msg && (GRecvInt() & IsPassword) && !*msg)
The sender (kscreenlocker_greet) sends a string and if it is not empty,
sends an int:
GSendStr(m_password.toUtf8().constData());
if (!m_password.isEmpty()) {
// IsSecret GSendInt(1);
}
This does not work out for empty strings, as those still have a length of 1,
resulting in kcheckpass waiting indefinitely for an int that does not get sent.
Testing for a nullptr on the sender side instead of the string length fixes this.
Also clean up the code duplication and IsSecret (1)/IsPassword (2) mismatch.
BUG: 380491