Re: lircd daemon as regular user => device access problems
- Date: Sat, 11 Feb 2017 11:46:14 +0100
- From: Alec Leamas <leamas.alec@xxxxxxxxx>
- Subject: Re: lircd daemon as regular user => device access problems
On 11/02/17 10:29, Bastien Roucaries wrote:
Le 10 février 2017 16:13:15 GMT+01:00, Alec Leamas <leamas.alec@xxxxxxxxx> a écrit :
Proposed /dev/ permissions after installing lirc:
- The /dev/lirc? devices are set user:group lirc:lirc and mode 660
- The lirc user is added to the input group, to access /dev/input
- The lirc user is added to the dialout group to access /dev/ttyS
- The /var/lock dir is root:root 755 in my stretch box but this is
seemingly #813703; assuming this will be fixed to 1777.
- lirc user gets read access to all USB character devices using a udev
rule invoking facl(1).
I know that getting permission is harder than to be forgiven, but
perhaps it makes sense to have a discussion first?
The possibly controversial issue is the USB devices. However, without
this rule a large part of lirc users will be forced to painful udev
Can we list USB device needed (whitelist) ?
I don't think so. The number of devices used by lircd is large, and the
USB ids are not always well-defined...
It might be possible to whitelist "most" devices, leaving it up to users
of "uncommon" devices to fix it on their own. More work for both package
maintainers and users, although more safe...
Personally I don't think read access to character devices should be that
sensitive. The most obvious concern are hardware login dongles. Of
those, most seems to be mass storage devices; these are *not* covered by
the udev rule. Neither is yubikey devices.
Also, whatever risks there are we are already taking them when running
lircd as root.