Gaopeng Chen - Sun China wrote:
>>> architecture design. Many biometric devices integrate the
> verification
>>> function in the firmware. If biometric device is virtualized in X,
>>> pam_bio can't access the device, how can we implement the
> verification?
>>> let gdm call bio_verify() directly? It's too weired. Similar to
>> What do we do with keyboards and displays today? The PAM function
>> talks to the verifier, and the framework itself handles the I/O to the
>> user.
>>
>> That same model seems to apply here.
> For the biometric devices that just capture images(just as keyboards get
> username/password), the PAM module gets the image and verify it by
> comparing with data records. They have the same model. However, for the
> biometric devices that integrate the verification module in the
> firmware, the devices directly return the verification/identification
> result(the data records are preloaded into the firmware). If the
> biometric devices are virtualized in X and only accessed by the
> application, how does the PAM module implement the authentication? So
> I'd like to keep the biometric devices accessed by PAM modules, just
> like smartcard and javacard cases.
> )))
>
> And it would need a lot of resources to update all the X applications.
What X applications would need updating? Just the PAM clients, which I
thought already needed updating in your proposal to support fingerprints.
I don't know if the model for X Input Extension devices (i.e. those other
than core keyboard and mouse) supports reading back something as large as
an image from an input device though - it's usually reporting something
small like coordinates, or an integer value. In fact, due to the X
Protocol limit on event sizes, you'ld probably have to just send the event
to notify there was a fingerprint image available, then wait for the
application to call for the data via some other method (a new X extension
perhaps, or putting it into a pixmap that can be read via convential X
calls like XGetImage).
--
-Alan Coopersmith- alan.coopersmith at sun.com
Sun Microsystems, Inc. - X Window System Engineering
