[PATCH 6.12 053/262] nbd: restrict sockets to TCP and UDP

[PATCH 6.12 053/262] nbd: restrict sockets to TCP and UDP

[Greg Kroah-Hartman]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 9f7c02e031570e8291a63162c6c046dc15ff85b0 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/block/nbd.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index c705acc4d6f4b..de692eed98740 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1156,6 +1156,14 @@ 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;
-- 
2.51.0