Re: [PATCH v2] vsock/virtio: Fix unsigned integer wrap around in virtio_transport_has_space()

[Stefano Garzarella]

On Mon, Dec 11, 2023 at 07:23:17PM +0300, Nikolay Kuratov wrote:
> We need to do signed arithmetic if we expect condition
> `if (bytes < 0)` to be possible
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE
>
> Fixes: 06a8fc78367d ("VSOCK: Introduce virtio_vsock_common.ko")
> Signed-off-by: Nikolay Kuratov <kniv@xxxxxxxxxxxxxx>
> ---
>
> V1 -> V2: Added Fixes section

Please, next time carry also R-b tags.

> net/vmw_vsock/virtio_transport_common.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>

Thanks,
Stefano

> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
> index c8e162c9d1df..6df246b53260 100644
> --- a/net/vmw_vsock/virtio_transport_common.c
> +++ b/net/vmw_vsock/virtio_transport_common.c
> @@ -843,7 +843,7 @@ static s64 virtio_transport_has_space(struct vsock_sock *vsk)
> 	struct virtio_vsock_sock *vvs = vsk->trans;
> 	s64 bytes;
>
> -	bytes = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
> +	bytes = (s64)vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
> 	if (bytes < 0)
> 		bytes = 0;
>
> --
> 2.34.1