diff options
| -rw-r--r-- | drivers/vhost/vhost.c | 10 | ||||
| -rw-r--r-- | include/uapi/linux/virtio_ring.h | 7 |
2 files changed, 14 insertions, 3 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index ed71b5347a76..cb807d0ea498 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -713,9 +713,13 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp) r = -EFAULT; break; } - if ((a.avail_user_addr & (sizeof *vq->avail->ring - 1)) || - (a.used_user_addr & (sizeof *vq->used->ring - 1)) || - (a.log_guest_addr & (sizeof *vq->used->ring - 1))) { + + /* Make sure it's safe to cast pointers to vring types. */ + BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE); + BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE); + if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) || + (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) || + (a.log_guest_addr & (sizeof(u64) - 1))) { r = -EINVAL; break; } diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h index 61c818a7fe70..a3318f31e8e7 100644 --- a/include/uapi/linux/virtio_ring.h +++ b/include/uapi/linux/virtio_ring.h @@ -101,6 +101,13 @@ struct vring { struct vring_used *used; }; +/* Alignment requirements for vring elements. + * When using pre-virtio 1.0 layout, these fall out naturally. + */ +#define VRING_AVAIL_ALIGN_SIZE 2 +#define VRING_USED_ALIGN_SIZE 4 +#define VRING_DESC_ALIGN_SIZE 16 + /* The standard layout for the ring is a continuous chunk of memory which looks * like this. We assume num is a power of 2. * |