On Mon, Feb 27, 2023 at 01:41:27PM -0800, Jacob Keller wrote: > The vhost_get_avail_size and vhost_get_used_size functions compute the size > of structures with flexible array members with an additional 2 bytes if the > VIRTIO_RING_F_EVENT_IDX feature flag is set. Convert these functions to use > struct_size() and size_add() instead of coding the calculation by hand. > > This ensures that the calculations will saturate at SIZE_MAX rather than > overflowing. > > Signed-off-by: Jacob Keller <jacob.e.keller@xxxxxxxxx> > Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx> > Cc: Jason Wang <jasowang@xxxxxxxxxx> > Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx > Cc: kvm@xxxxxxxxxxxxxxx Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Will merge, thanks! > --- > > I found this using a coccinelle patch I developed and submitted at [1]. > > [1]: https://lore.kernel.org/all/20230227202428.3657443-1-jacob.e.keller@xxxxxxxxx/ > > drivers/vhost/vhost.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index f11bdbe4c2c5..43fa626d4e44 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -436,8 +436,7 @@ static size_t vhost_get_avail_size(struct vhost_virtqueue *vq, > size_t event __maybe_unused = > vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; > > - return sizeof(*vq->avail) + > - sizeof(*vq->avail->ring) * num + event; > + return size_add(struct_size(vq->avail, ring, num), event); > } > > static size_t vhost_get_used_size(struct vhost_virtqueue *vq, > @@ -446,8 +445,7 @@ static size_t vhost_get_used_size(struct vhost_virtqueue *vq, > size_t event __maybe_unused = > vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; > > - return sizeof(*vq->used) + > - sizeof(*vq->used->ring) * num + event; > + return size_add(struct_size(vq->used, ring, num), event); > } > > static size_t vhost_get_desc_size(struct vhost_virtqueue *vq, > -- > 2.39.1.405.gd4c25cc71f83 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
