tree 51ccb65b8e26b3347099af3f466ad0fedc6e1cb6
parent 15b63d35261ba3351d07e7937252f18bb6cbf814
author Thomas Hellstrom <thellstrom@vmware.com> 1327427661 +0100
committer Dave Airlie <airlied@redhat.com> 1327483665 +0000

drm: Fix authentication kernel crash

If the master tries to authenticate a client using drm_authmagic and
that client has already closed its drm file descriptor,
either wilfully or because it was terminated, the
call to drm_authmagic will dereference a stale pointer into kmalloc'ed memory
and corrupt it.

Typically this results in a hard system hang.

This patch fixes that problem by removing any authentication tokens
(struct drm_magic_entry) open for a file descriptor when that file
descriptor is closed.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>