[PATCH] net-shapers: free rollback entries using kfree_rcu

[Kangzheng Gu <xiaoguai0992@gmail.com>]

net_shaper_rollback() removes NET_SHAPER_NOT_VALID entries and frees
them using kfree(), which can race with net_shaper_nl_get_dumpit() and
lead to a use-after-free in net_shaper_fill_one().

Use kfree_rcu() instead of kfree() to free rollback entries, since
net_shaper_nl_get_dumpit() protects shaper access with rcu_read_lock().

Cc: stable@vger.kernel.org
Fixes: 93954b40f6a4 ("net-shapers: implement NL set and delete operations")
Signed-off-by: Kangzheng Gu <xiaoguai0992@gmail.com>
---
 net/shaper/shaper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/shaper/shaper.c b/net/shaper/shaper.c
index 94bc9c7382ea..8922f7f64768 100644
--- a/net/shaper/shaper.c
+++ b/net/shaper/shaper.c
@@ -434,7 +434,7 @@ static void net_shaper_rollback(struct net_shaper_binding *binding)
 	xa_for_each_marked(&hierarchy->shapers, index, cur,
 			   NET_SHAPER_NOT_VALID) {
 		__xa_erase(&hierarchy->shapers, index);
-		kfree(cur);
+		kfree_rcu(cur, rcu);
 	}
 	xa_unlock(&hierarchy->shapers);
 }
-- 
2.50.1