On Mon, Mar 18, 2013 at 07:42:58AM +1000, Dave Airlie wrote: > On Mon, Mar 18, 2013 at 7:40 AM, Chris Wilson <ch...@chris-wilson.co.uk> > wrote: > > On Sun, Mar 17, 2013 at 08:50:03PM +0100, Daniel Vetter wrote: > >> On Sat, Mar 16, 2013 at 11:19 AM, Chris Wilson <ch...@chris-wilson.co.uk> > >> wrote: > >> > If *userspace* doesn't request either IOC_IN | IOC_OUT in their ioctl > >> > command (which are seperate from the ioctl number), then kdata is set to > >> > NULL. > >> > >> Doesn't that mean that we need these checks everywhere? Or at least a > >> fixup in drm core proper? > > > > That's my conclusion. We either add a flag to ask drm_ioctl to prevent > > passing NULL pointers (as the existing behaviour may be useful > > somewhere, and I have not checked all callees) or saturate our callbacks > > with NULL checks. > > Do we have the kernel's expected IOC_IN/IOC_OUT flags at that point as well? > > we could check them and block NULL in that case.
Yes. For the core ioctls, we use drm_ioctls[nr].cmd rather than the value passed in by userspace for the IOC_IN|IN_OUT bits. So: diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 25f91cd..79b8bd1 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -408,6 +408,7 @@ long drm_ioctl(struct file *filp, usize = asize = _IOC_SIZE(cmd); if (drv_size > asize) asize = drv_size; + cmd = ioctl->cmd; } else if ((nr >= DRM_COMMAND_END) || (nr < DRM_COMMAND_BASE)) { ioctl = &drm_ioctls[nr]; -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx