Comment 12 for bug 86843

That's a nice and simple patch - however, the fact remains that the whole implementation of gksu is flawed: it is a wrapper around sudo, under the assumption that sudo does not use any other PAM but the default. For example, gdm correctly shows "Password or swipe finger" - as gksudo should. This patch only fixes pam_thinkfinger, and if you are using pam_bioapi, which does something a little differently (it only implements the fingerprinting - it does not accept a password - I've set it up so that if fingerprint fails then sudo falls back onto the normal password prompt) - then a patch of this type would not work.

I have wrote what I think in a similar bug: https://bugs.launchpad.net/bugs/15093. I sent an e-mail to the Ubuntu guy assigned to this bug, with my thoughts and an offer of help, but I have not yet received a reply which has put me pursuing a more long term, permanent fix.