Hello,
On Fri, 12 Sep 2025, Slavin Liu wrote:
> 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 module_removing is false) and defer it to
Pablo, can you change here module_removing to exiting_module
before applying?
> __ip_vs_cleanup_batch(), which unregisters all apps after all connections
> are flushed. If called during module exit, unregister ip_vs_ftp
> immediately.
>
> Fixes: 61b1ab4583e2 ("IPVS: netns, add basic init per netns.")
> Suggested-by: Julian Anastasov <ja@xxxxxx>
> Signed-off-by: Slavin Liu <slavin452@xxxxxxxxx>
Looks good to me for the nf tree after above text is
changed, thanks!
Signed-off-by: Julian Anastasov <ja@xxxxxx>
> ---
> net/netfilter/ipvs/ip_vs_ftp.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/net/netfilter/ipvs/ip_vs_ftp.c b/net/netfilter/ipvs/ip_vs_ftp.c
> index d8a284999544..206c6700e200 100644
> --- a/net/netfilter/ipvs/ip_vs_ftp.c
> +++ b/net/netfilter/ipvs/ip_vs_ftp.c
> @@ -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 */
> }
> --
> 2.34.1
Regards
--
Julian Anastasov <ja@xxxxxx>
