Comment 30 for bug 697197

Description of problem:
The semantics of the ',password' option to -vnc are that it enables the VNC auth scheme. If the VNC server password is unset or empty string, all attempts to authenticate with the server will be explicitly blocked.

This allows applications to enable and selectively allow access for a period of time, before clearing the password again to prevent further access.

Upstream changes have introduced a flaw by disabling all authentication when the password was cleared with upstream commit [1].

[1] http://www.qemu.com/qemu.git/commit/?id=52c18be9e99dabe295321153fda7fce9f76647ac