On 21.06.2016 15:24, Axel Davy wrote: > On 21/06/2016 01:26, Michel Dänzer wrote: >> On 20.06.2016 20:06, Frank Binns wrote: >>> On 20/06/16 10:48, Michel Dänzer wrote: >>>> On 18.06.2016 02:41, Frank Binns wrote: >>>>> Up until now, DRI3 was only used for devices that have render nodes, >>>>> unless >>>>> overridden via an environment variable, with it falling back to DRI2 >>>>> otherwise. >>>>> This limitation was there in order to support WL_bind_wayland_display >>>>> as it >>>>> requires client opened device node fds to be authenticated, which >>>>> isn't possible >>>>> when using DRI3. This is an unfortunate compromise as DRI3 provides >>>>> security >>>>> benefits over DRI2. >>>> What exactly is it that works with render nodes but not with >>>> unauthenticated non-render nodes? Isn't that a kernel bug? >>> The problem isn't that something doesn't work with unauthenticated >>> non-render nodes (wouldn't that be the kernel bug?) but that if a >>> client opens the primary/legacy node it needs the resulting fd to >>> be authenticated, which isn't supported by the X11 DRI3 protocol. >> Authentication is required for using certain ioctls of non-render nodes. >> It sounds like some ioctls are allowed to be used with render nodes but >> not with unauthenticated non-render nodes, which seems like a kernel bug >> — why would an ioctl be safe to use without authentication via a render >> node but not via a non-render node? >> >> So, which ioctls required by WL_bind_wayland_display don't work with an >> unauthenticated non-render node? >> >> > The ioctl to authenticate is possible only when you have the master node > (owned by the DDX when using X, or by the wayland compositor when using > Wayland). There is only one master node. > > > On of the motives of render-nodes is precisely to fix these limitations.
I understand all of that, but it doesn't answer my question. :) Since WL_bind_wayland_display works with a render node, it means that all ioctls it needs work without authentication when using a render node. The question is, why do the same ioctls require authentication when using a non-render node? -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
