Re: using polkit

2013/12/18 Nikos Mavrogiannopoulos <[email protected]>:
> On Tue, 2013-12-17 at 22:27 +0100, [email protected] wrote:
>> Hi,
>> maybe i miss something, but what would be a normal use case?
>> Mostly a smart card has own mechanisms for access control  e.g. by
>> using pin, biometrics or so for operations like sign.
>> In case of private keys it is mostly forbidden to read them per
>> default.
>
> Hello,
>  Indeed smart cards _may_ have some access control method (but they are
> not required to). The smart card access control currently is very
> coarse (as I can erase every smart card in the system without any
> special permissions), and several files on the card like certificates are
> almost never protected.
>
> What the patch ensures is that only admin-authorized processes can talk
> to the hardware. That means:
> * Only authorized processes can extract the public information in the
> card.
> * Only authorized processes can erase the card.
> * Only authorized processes can talk to the card firmware (cards may
> have bugs as any other kind of software).
>
> Moreover, authorization policy is tied to the system processes rather
> than being an external process that depends on the smart card in
> use. For example, a PIN-enabled smart card can never distinguish a
> local user from a console one, however polkit policies can.

I am still not convinced that Policy Kit is a good solution for the
problems you describe.

If the card can be erased or modified without any previous
authentication (PIN or secure message) then that is the problem of the
card (or card provider).

If you want to avoid a remote user to use a PIN protected card the
best is to use a pinpad reader with a firewall. The PIN will only be
entered using the pinpad. Any PIN verification command will be
rejected by the reader firewall.

But maybe I missed something.

Regards,

-- 
 Dr. Ludovic Rousseau