net: sched: fix unprotected access to rcu cookie pointer

Fix action attribute size calculation function to take rcu read lock and
access act_cookie pointer with rcu dereference.

Fixes: eec94fdb04 ("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>
This commit is contained in:
Vlad Buslov 2018-07-09 20:26:47 +03:00 committed by David S. Miller
parent 2368957ab5
commit e0479b670d

View File

@ -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 */