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 `module_removing` 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
__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>
---
net/netfilter/ipvs/ip_vs_ftp.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/netfilter/ipvs/ip_vs_ftp.c b/net/netfilter/ipvs/ip_vs_ftp.c
index d8a284999544..4db58c42ff9a 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 module_exiting;
/*
* 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 || !module_exiting)
return;
unregister_ip_vs_app(ipvs, &ip_vs_ftp);
@@ -627,7 +628,9 @@ static int __init ip_vs_ftp_init(void)
*/
static void __exit ip_vs_ftp_exit(void)
{
+ module_exiting = true;
unregister_pernet_subsys(&ip_vs_ftp_ops);
+ module_exiting = false;
/* rcu_barrier() is called by netns */
}
--
2.34.1
