[PATCH 4.4 26/46] drm/nouveau: prevent userspace from deleting client object

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ben Skeggs <bske...@redhat.com>


[ Upstream commit c966b6279f610a24ac1d42dcbe30e10fa61220b2 ]

Signed-off-by: Ben Skeggs <bske...@redhat.com>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/gpu/drm/nouveau/nouveau_usif.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/nouveau/nouveau_usif.c
+++ b/drivers/gpu/drm/nouveau/nouveau_usif.c
@@ -313,7 +313,8 @@ usif_ioctl(struct drm_file *filp, void _
        if (nvif_unpack(argv->v0, 0, 0, true)) {
                /* block access to objects not created via this interface */
                owner = argv->v0.owner;
-               if (argv->v0.object == 0ULL)
+               if (argv->v0.object == 0ULL &&
+                   argv->v0.type != NVIF_IOCTL_V0_DEL)
                        argv->v0.owner = NVDRM_OBJECT_ANY; /* except client */
                else
                        argv->v0.owner = NVDRM_OBJECT_USIF;