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 <edumazet@google.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Richard W.M. Jones <rjones@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Yu Kuai <yukuai1@huaweicloud.com>
Cc: linux-block@vger.kernel.org
Cc: nbd@other.debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 6463d0e8d0cef71e73e67fecd16de4dec1c75da7..87b0b78249da3325023949585f4daf40486c9692 100644 (file)
--- 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;