act_ife: fix a potential use-after-free

[ Upstream commit 6d784f1625ea68783cc1fb17de8f6cd3e1660c3f ]

Immediately after module_put(), user could delete this
module, so e->ops could be already freed before we call
e->ops->release().

Fix this by moving module_put() after ops->release().

Fixes: ef6980b6becb ("introduce IFE action")
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
index 85757af7f1508522e4dc7468c92cacd402987047..711ccc4607cc5f22f59ffd927144d746174c2ad6 100644 (file)
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -377,7 +377,6 @@ static void _tcf_ife_cleanup(struct tc_action *a, int bind)
        struct tcf_meta_info *e, *n;
 
        list_for_each_entry_safe(e, n, &ife->metalist, metalist) {
-               module_put(e->ops->owner);
                list_del(&e->metalist);
                if (e->metaval) {
                        if (e->ops->release)
@@ -385,6 +384,7 @@ static void _tcf_ife_cleanup(struct tc_action *a, int bind)
                        else
                                kfree(e->metaval);
                }
+               module_put(e->ops->owner);
                kfree(e);
        }
 }