On Fri, Sep 5, 2025 at 1:03 PM Eric Dumazet <edumazet@xxxxxxxxxx> wrote:
>
> On Fri, Sep 5, 2025 at 1:00 PM syzbot
> <syzbot+e1cd6bd8493060bd701d@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Note to NBD maintainers : I held about 20 syzbot reports all pointing
to NBD accepting various sockets, I can release them if needed, if you prefer
to triage them.
>
> Question to NBD maintainers.
>
> What socket types are supposed to be supported by NBD ?
>
> I was thinking adding a list of supported ones, assuming TCP and
> stream unix are the only ones:
>
> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> index 6463d0e8d0ce..87b0b78249da 100644
> --- a/drivers/block/nbd.c
> +++ b/drivers/block/nbd.c
> @@ -1217,6 +1217,14 @@ static struct socket *nbd_get_socket(struct
> nbd_device *nbd, unsigned long fd,
> if (!sock)
> return NULL;
>
> + if (!sk_is_tcp(sock->sk) &&
> + !sk_is_stream_unix(sock->sk)) {
> + dev_err(disk_to_dev(nbd->disk), "Unsupported socket:
> should be TCP or UNIX.\n");
> + *err = -EINVAL;
> + sockfd_put(sock);
> + return NULL;
> + }
> +
> if (sock->ops->shutdown == sock_no_shutdown) {
> dev_err(disk_to_dev(nbd->disk), "Unsupported socket:
> shutdown callout must be supported.\n");
> *err = -EINVAL;
