* [PATCH 6.12 053/262] nbd: restrict sockets to TCP and UDP
[not found] <20251013144326.116493600@linuxfoundation.org>
@ 2025-10-13 14:43 ` Greg Kroah-Hartman
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From: Greg Kroah-Hartman @ 2025-10-13 14:43 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, syzbot+e1cd6bd8493060bd701d,
Eric Dumazet, Mike Christie, Richard W.M. Jones, Jens Axboe,
Yu Kuai, linux-block, nbd, Sasha Levin
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
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