From: Vlad Buslov <vladbu@mellanox.com>
Date: Mon, 9 Jul 2018 20:26:47 +0300
Subject: net: sched: fix unprotected access to rcu cookie pointer
Patch-mainline: v4.19-rc1
Git-commit: e0479b670d394d478907bd4fc22daab6516953c7
References: bsc#1109837
Fix action attribute size calculation function to take rcu read lock and
access act_cookie pointer with rcu dereference.
Fixes: eec94fdb0480 ("net: sched: use rcu for action cookie update")
Reported-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/sched/act_api.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -149,10 +149,15 @@ EXPORT_SYMBOL(__tcf_idr_release);
static size_t tcf_action_shared_attrs_size(const struct tc_action *act)
{
+ struct tc_cookie *act_cookie;
u32 cookie_len = 0;
- if (act->act_cookie)
- cookie_len = nla_total_size(act->act_cookie->len);
+ rcu_read_lock();
+ act_cookie = rcu_dereference(act->act_cookie);
+
+ if (act_cookie)
+ cookie_len = nla_total_size(act_cookie->len);
+ rcu_read_unlock();
return nla_total_size(0) /* action number nested */
+ nla_total_size(IFNAMSIZ) /* TCA_ACT_KIND */