drm: Prevent overwriting from userspace underallocating core ioctl structs

Apply the protections from

commit 1b2f148963
Author: Dave Airlie <airlied@redhat.com>
Date:   Sat Aug 14 20:20:34 2010 +1000

    drm: block userspace under allocating buffer and having drivers overwrite it (v2)

to the core ioctl structs as well, for we found one instance where there
is a 32-/64-bit size mismatch and were guilty of writing beyond the end
of the user's buffer.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Airlie <airlied@redhat.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Chris Wilson 2013-10-16 11:22:44 +01:00 committed by Dave Airlie
parent c4249855ac
commit b062672e30

View file

@ -402,9 +402,16 @@ long drm_ioctl(struct file *filp,
cmd = ioctl->cmd_drv;
}
else if ((nr >= DRM_COMMAND_END) || (nr < DRM_COMMAND_BASE)) {
u32 drv_size;
ioctl = &drm_ioctls[nr];
cmd = ioctl->cmd;
drv_size = _IOC_SIZE(ioctl->cmd);
usize = asize = _IOC_SIZE(cmd);
if (drv_size > asize)
asize = drv_size;
cmd = ioctl->cmd;
} else
goto err_i1;