5.4-stable review patch. If anyone has any objections, please let me know.
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From: Slavin Liu slavin452@gmail.com
[ 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: 61b1ab4583e2 ("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 --- 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 cf925906f59b6..67d0d4f1f0db1 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. @@ -607,7 +608,7 @@ 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); @@ -629,6 +630,7 @@ 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 */ }