ipvs: Defer ip_vs_ftp unregister during netns cleanup

[ Upstream commit 134121bfd99a06d44ef5ba15a9beb075297c0821 ]

On the netns cleanup path, __ip_vs_ftp_exit() may unregister ip_vs_ftp
before connections with valid cp->app pointers are flushed, leading to a
use-after-free.

Fix this by introducing a global `exiting_module` flag, set to true in
ip_vs_ftp_exit() before unregistering the pernet subsystem. In
__ip_vs_ftp_exit(), skip ip_vs_ftp unregister if called during netns
cleanup (when exiting_module is false) and defer it to
__ip_vs_cleanup_batch(), which unregisters all apps after all connections
are flushed. If called during module exit, unregister ip_vs_ftp
immediately.

Fixes: 61b1ab4583 ("IPVS: netns, add basic init per netns.")
Suggested-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Slavin Liu <slavin452@gmail.com>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Slavin Liu 2025-09-12 01:57:59 +08:00 committed by Greg Kroah-Hartman
parent c9c9458fbd
commit 53717f8a43

View File

@ -53,6 +53,7 @@ enum {
IP_VS_FTP_EPSV,
};
static bool exiting_module;
/*
* List of ports (up to IP_VS_APP_MAX_PORTS) to be handled by helper
* First port is set to the default port.
@ -605,7 +606,7 @@ static void __ip_vs_ftp_exit(struct net *net)
{
struct netns_ipvs *ipvs = net_ipvs(net);
if (!ipvs)
if (!ipvs || !exiting_module)
return;
unregister_ip_vs_app(ipvs, &ip_vs_ftp);
@ -627,6 +628,7 @@ static int __init ip_vs_ftp_init(void)
*/
static void __exit ip_vs_ftp_exit(void)
{
exiting_module = true;
unregister_pernet_subsys(&ip_vs_ftp_ops);
/* rcu_barrier() is called by netns */
}