virtio: reject shm region if length is zero

md-sami · mstsirkin · commit 206cc44588f7 · 2025-05-28T03:19:03.000-04:00
Prevent usage of shared memory regions where the length is zero,
as such configurations are not valid and may lead to unexpected behavior.

Signed-off-by: Sami Uddin &lt;sami.md.ko@gmail.com&gt;
Message-Id: &lt;20250511222153.2332-1-sami.md.ko@gmail.com&gt;
Signed-off-by: Michael S. Tsirkin &lt;mst@redhat.com&gt;
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
@@ -329,6 +329,8 @@ static inline
 bool virtio_get_shm_region(struct virtio_device *vdev,
 			   struct virtio_shm_region *region, u8 id)
 {
+	if (!region->len)
+		return false;
 	if (!vdev->config->get_shm_region)
 		return false;
 	return vdev->config->get_shm_region(vdev, region, id);

Original file line number	Diff line number	Diff line change
`@@ -329,6 +329,8 @@ static inline`
`329`	`329`	`bool virtio_get_shm_region(struct virtio_device *vdev,`
`330`	`330`	`struct virtio_shm_region *region, u8 id)`
`331`	`331`	`{`
	`332`	`+ if (!region->len)`
	`333`	`+ return false;`
`332`	`334`	`if (!vdev->config->get_shm_region)`
`333`	`335`	`return false;`
`334`	`336`	`return vdev->config->get_shm_region(vdev, region, id);`