[PATCH 4.9 043/108] drm/nouveau: prevent userspace from deleting client object

[Greg Kroah-Hartman]

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

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

From: Ben Skeggs <bskeggs@xxxxxxxxxx>


[ Upstream commit c966b6279f610a24ac1d42dcbe30e10fa61220b2 ]

Signed-off-by: Ben Skeggs <bskeggs@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 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 (!(ret = nvif_unpack(-ENOSYS, &data, &size, 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;