2013/3/17 Chris Wilson chris@chris-wilson.co.uk:
On Mon, Mar 18, 2013 at 07:42:58AM +1000, Dave Airlie wrote:
On Mon, Mar 18, 2013 at 7:40 AM, Chris Wilson chris@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 chris@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:
Thanks, trinity can indeed set the in/out bits randomly, in a way that does not match the driver ioctl definition.
Your patch almost fixes this. For the driver ioctls we will want to grab the cmd from cmd_drv. So the patch should be:
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 25f91cd..5210f33 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_drv; } else if ((nr >= DRM_COMMAND_END) || (nr < DRM_COMMAND_BASE)) { ioctl = &drm_ioctls[nr];
Can you please submit this officially?
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