Patch "drm/vmwgfx: avoid calling vzalloc with a 0 size in vmw_get_cap_3d_ioctl()" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

drm/vmwgfx: avoid calling vzalloc with a 0 size in vmw_get_cap_3d_ioctl()

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drm-vmwgfx-avoid-calling-vzalloc-with-a-0-size-in-vmw_get_cap_3d_ioctl.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Murray McAllister <[email protected]>
Date: Mon, 27 Mar 2017 11:15:12 +0200
Subject: drm/vmwgfx: avoid calling vzalloc with a 0 size in vmw_get_cap_3d_ioctl()

From: Murray McAllister <[email protected]>

commit 63774069d9527a1aeaa4aa20e929ef5e8e9ecc38 upstream.

In vmw_get_cap_3d_ioctl(), a user can supply 0 for a size that is used in vzalloc(). This eventually calls dump_stack() (in warn_alloc()), which can leak useful addresses to dmesg.

Add check to avoid a size of 0.

---
 drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -186,7 +186,7 @@ int vmw_get_cap_3d_ioctl(struct drm_devi
 	bool gb_objects = !!(dev_priv->capabilities & SVGA_CAP_GBOBJECTS);
 	struct vmw_fpriv *vmw_fp = vmw_fpriv(file_priv);
 
-	if (unlikely(arg->pad64 != 0)) {
+	if (unlikely(arg->pad64 != 0 || arg->max_size == 0)) {
 		DRM_ERROR("Illegal GET_3D_CAP argument.\n");
 		return -EINVAL;
 	}

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/drm-vmwgfx-avoid-calling-vzalloc-with-a-0-size-in-vmw_get_cap_3d_ioctl.patch queue-4.4/drm-vmwgfx-null-pointer-dereference-in-vmw_surface_define_ioctl.patch