Re: Fwd: usb printer vs cups

On 17/09/2014 09:21, Hans Petter Selasky wrote:
> On 09/17/14 08:00, Andriy Gapon wrote:
>>
>> Soliciting help.
>>
>> -------- Forwarded Message --------
>>
>>> From my experience I think that cupsd executes backend tools with all uids and
>> gids set to cups and no supplementary groups.  In the case of USB printers the
>> backends need to access /dev/usbctl and /dev/usb/foobar that corresponds to a
>> printer.  That means that the access to those devices must be somehow granted to
>> cups:cups.
>> How do people solve this?  What kind of permissions / configuration do you use?
>>
>> P.S.
>> Maybe I over-generalized the issue to all USB printers.  My personal experience
>> is with an HP printer handled by hplip / hplip-plugin.
>>
> 
> Hi,
> 
> The /usr/ports/print/cups-base should be updated.
> 
> The pkg-message should not say that:
> 
> 
> # FreeBSD 8.x
> add path 'usb*' mode 0770 group cups
> add path 'ugen*' mode 0660 group cups
> 
> add path 'usb/0.2.*' mode 0660 group cups
> 
> Is needed. This is wrong.
> 
> Instead make cups-base install the attached devd configuration file in
> /usr/local/etc/devd/ which does the needed chown for printers only.

The problem is that my printer does not work if I also do not change permissions
on /dev/usbctl.  But I do not really want /dev/usbctl to be owned by cups as
there can be other services / users that need access to usbctl.

Is there anything smarter than mucking with device ownership?

In other words, I have no problem granting cups user or group a full access to
all USB devices.  I have a problem with changing owner or group of USB devices
to cups, because that interferes with other accesses to those devices.

-- 
Andriy Gapon