Bug#978011: udev: uaccess is set before ID_SMARTCARD_READER

[Michael Biebl]

Hello Vincent

Am 24.12.20 um 12:04 schrieb Vincent Pelletier:
> I have a smartcard reader which exposes the CCID class (0x0b) on its function.
> I see there are udev rules to grant uaccess based on this:
> 
>    $ rgrep SMARTCARD /lib/udev/rules.d
>    70-uaccess.rules:ENV{ID_SMARTCARD_READER}=="?*", TAG+="uaccess"
>    99-systemd.rules:SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ENV{ID_USB_INTERFACES}=="*:0b????:*", ENV{ID_SMARTCARD_READER}="1"
>    99-systemd.rules:ENV{ID_SMARTCARD_READER}=="?*", TAG+="systemd", ENV{SYSTEMD_WANTS}+="smartcard.target", ENV{SYSTEMD_USER_WANTS}+="smartcard.target"
> 
> Which make me think that there is an intent to grant uaccess to these devices.
> 
> but while the ones in 99-systemd.rules have an effect (see below for
> "udevadm info", note ID_SMARTCARD_READER=1 and
> SYSTEMD_*WANTS=smartcard.target being present), the TAG+="uaccess" does not.
> 
> I suspect this is because of the file ordering: 70-uaccess vs. 99-systemd .
> 
> Wouldn't it make more sense to apply the uaccess rules after setting the
> ID_SMARTCARD_READER flag ?
> 
> I have no special knowledge of these files, and I suspect it is not as easy as
> reordering them. I guess a fix would rather be to set these flags much earlier,
> then setting the uaccess rules in 60-uaccess.rules, and finally setting the
> SYSTEMD_*WANTS in 99-sustemd.rules.

TBH, I can't answer that downstream, as I have no knowledge in that 
specific area. What I did find is, that some packages, like gpg, do set 
this variable prior to 70-uaccess.
I'm not sure if this specific rule you posted above is supposed to get 
the uaccess tag or not.
At a cursory glance, this might indeed be an oversight, but I'm not 
sure. Could you raise this upstream please at
https://github.com/systemd/systemd/issues

Regards,
Michael


[1] https://codesearch.debian.net/search?q=ID_SMARTCARD_READER&literal=1

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