Re: networkmanager should warn if ap changes encryption

[Dan Williams <dcbw redhat com>]

On Tue, 2009-03-24 at 19:17 +0100, Christoph Höger wrote:
> Hi,
> 
> there seems to be an issue with some APs and their enryption value[1].
> Somehow they 'forget' about the chosen encryption and continue
> unencrypted. NM will happily accept that change and continue to use that
> wireless network which leads to the owner not noting the change.

When you say "NM will happily accept that change", what do you mean?
That NM will autoconnect to that AP when it no longer has the security
(would be a bug)?  Or that you can click on it from the menu when it
doesn't have the security, and NM will connect (currently expected, if
incorrect, behavior)?

> To make NM more secure I would argue that NM should notify the user if
> an AP changes _any_ connection parameter since the last successfull
> connection.

Not a bad idea; but this only works if the AP's BSSID has been cached in
a connection.  In that case, selecting it again from the menu would
create an entirely new connection with the new security parameters.
We'd have to work out what the corner-cases are, because SSIDs do
legitimately change security sometimes.

Perhaps this should only be notified if the AP *downgrades* security.

> If this takes time to implement, I am willing to work on a patch for
> that.

Sure, want to take a stab at it?  For now, when the user clicks on an AP
from the menu, you'll need to check the BSSIDs of *all* coaelesced APs
of that NMNetworkMenuItem, and if those BSSIDs exist in a known
NMConnection's 'bssid' or 'seen-bssids' properties, and the security of
the NMNetworkMenuItem is lower than the security in which the BSSID was
found, then don't create the new connection for that AP and warn the
user.

Dan