sctp: close UDP tunnel sockets during netns teardown

proc_sctp_do_udp_port() starts per-net SCTP UDP tunneling sockets when
net.sctp.udp_port is set, and stops/restarts them when the sysctl value
changes. The netns exit path does not stop these sockets, so a namespace
can be torn down while its SCTP UDP tunnel sockets are still installed.

Close the UDP tunnel sockets from sctp_ctrlsock_exit() after unregistering
the per-net sysctl table. This prevents new sysctl writes from racing in
while the sockets are being released, and closes the sockets before the
control socket is destroyed.

Fixes: 046c052b475e ("sctp: enable udp tunneling socks")
Cc: stable@vger.kernel.org
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/b9f1f02b0780ad6a719e2413f5f0bb8eb7702d94.1782585631.git.roxy520tt%40gmail.com
Signed-off-by: Zhiling Zou <roxy520tt@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Acked-by: Xin Long <lucien.xin@gmail.com>
Link: https://patch.msgid.link/6dab75f22855cb219e2e30a5497cab03b970ab91.1784033357.git.roxy520tt@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 49d9740b1e0f6deac07ae66f418e619a20a4be04..27c26e12f95d82fc56f8ea4e0dd70f4218f8119a 100644 (file)
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1460,6 +1460,7 @@ static int __net_init sctp_ctrlsock_init(struct net *net)
 static void __net_exit sctp_ctrlsock_exit(struct net *net)
 {
        sctp_sysctl_net_unregister(net);
+       sctp_udp_sock_stop(net);
 
        /* Free the control endpoint.  */
        inet_ctl_sock_destroy(net->sctp.ctl_sock);