From: Eric Dumazet Date: Tue, 9 Sep 2025 13:22:43 +0000 (+0000) Subject: nbd: restrict sockets to TCP and UDP X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9f7c02e031570e8291a63162c6c046dc15ff85b0;p=thirdparty%2Fkernel%2Fstable.git nbd: restrict sockets to TCP and UDP Recently, syzbot started to abuse NBD with all kinds of sockets. Commit cf1b2326b734 ("nbd: verify socket is supported during setup") made sure the socket supported a shutdown() method. Explicitely accept TCP and UNIX stream sockets. Fixes: cf1b2326b734 ("nbd: verify socket is supported during setup") Reported-by: syzbot+e1cd6bd8493060bd701d@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/CANn89iJ+76eE3A_8S_zTpSyW5hvPRn6V57458hCZGY5hbH_bFA@mail.gmail.com/T/#m081036e8747cd7e2626c1da5d78c8b9d1e55b154 Signed-off-by: Eric Dumazet Cc: Mike Christie Cc: Richard W.M. Jones Cc: Jens Axboe Cc: Yu Kuai Cc: linux-block@vger.kernel.org Cc: nbd@other.debian.org Signed-off-by: Jens Axboe --- diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 6463d0e8d0cef..87b0b78249da3 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;