[PATCH 4.14 17/41] kcm: Fix use-after-free caused by clonned sockets

[Greg Kroah-Hartman]

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

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

From: Kirill Tkhai <ktk...@virtuozzo.com>

[ Upstream commit eb7f54b90bd8f469834c5e86dcf72ebf9a629811 ]

(resend for properly queueing in patchwork)

kcm_clone() creates kernel socket, which does not take net counter.
Thus, the net may die before the socket is completely destructed,
i.e. kcm_exit_net() is executed before kcm_done().

Reported-by: syzbot+5f1a04e374a635efc...@syzkaller.appspotmail.com
Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/kcm/kcmsock.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1672,7 +1672,7 @@ static struct file *kcm_clone(struct soc
        __module_get(newsock->ops->owner);
 
        newsk = sk_alloc(sock_net(osock->sk), PF_KCM, GFP_KERNEL,
-                        &kcm_proto, true);
+                        &kcm_proto, false);
        if (!newsk) {
                sock_release(newsock);
                return ERR_PTR(-ENOMEM);