Re: [PATCH 5/5] host/rootfs: add wayland group

[Alyssa Ross <hi@alyssa.is>]

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Demi Marie Obenour <demiobenour@gmail.com> writes:

> On 12/9/25 05:59, Alyssa Ross wrote:
>> On Tue, Dec 09, 2025 at 05:55:22AM -0500, Demi Marie Obenour wrote:
>>> On 12/9/25 03:56, Alyssa Ross wrote:
>>>> This will allow clients running as unprivileged users to connect to
>>>> the compositor.
>>>>
>>>> Signed-off-by: Alyssa Ross <hi@alyssa.is>
>>>> ---
>>>>  host/rootfs/image/etc/s6-linux-init/run-image/etc/group | 1 +
>>>>  host/rootfs/image/etc/s6-rc/weston/run                  | 5 +++++
>>>>  2 files changed, 6 insertions(+)
>>>>
>>>> diff --git a/host/rootfs/image/etc/s6-linux-init/run-image/etc/group b/host/rootfs/image/etc/s6-linux-init/run-image/etc/group
>>>> index e3ade46..fe72eb7 100644
>>>> --- a/host/rootfs/image/etc/s6-linux-init/run-image/etc/group
>>>> +++ b/host/rootfs/image/etc/s6-linux-init/run-image/etc/group
>>>> @@ -13,3 +13,4 @@ disk:x:11:
>>>>  cdrom:x:12:
>>>>  tape:x:13:
>>>>  kvm:x:14:
>>>> +wayland:x:15:
>>>> diff --git a/host/rootfs/image/etc/s6-rc/weston/run b/host/rootfs/image/etc/s6-rc/weston/run
>>>> index aa1e7b6..7cb182f 100644
>>>> --- a/host/rootfs/image/etc/s6-rc/weston/run
>>>> +++ b/host/rootfs/image/etc/s6-rc/weston/run
>>>> @@ -20,4 +20,9 @@ importas -i home HOME
>>>>  cd $home
>>>>  if { udevadm wait /dev/dri/card0 }
>>>>  unshare --cgroup --ipc --net --uts
>>>> +
>>>> +s6-envuidgid root
>>>> +s6-envuidgid -g wayland
>>>> +s6-applyuidgid -Uz
>>>> +umask 002
>>>>  weston -S $WAYLAND_DISPLAY
>>>
>>> Can the socket be chmod'd after Weston starts?  Running with 002
>>> umask is not great.
>> 
>> If we use sd-notify-adapter, then I think so, but it wouldn't be very
>> nice.
>
> Using sd-notify-adapter is probably a good idea anyway, so that nothing
> tries to connect to the socket before it is there to connect to.

Oh, right, we actually already have readiness notification via
/etc/xdg/weston/autolaunch.  It won't run as root soon, but we could
wait for that in the run script and do the chmod there.

>> What's the problem with umask 002?
>
> It means that any files created by the service are group-writable and
> world-readable, which is almost never what one wants.  It means that
> the service can't even trust a file it itself created.

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