From a52956dfc503f8cc5cfe6454959b7049fddb4413 Mon Sep 17 00:00:00 2001
From: Roman Mashak <mrv@mojatatu.com>
Date: Fri, 11 May 2018 14:35:33 -0400
Subject: [PATCH] net sched actions: fix refcnt leak in skbmod
When application fails to pass flags in netlink TLV when replacing
existing skbmod action, the kernel will leak refcnt:
$ tc actions get action skbmod index 1
total acts 0
action order 0: skbmod pipe set smac 00:11:22:33:44:55
index 1 ref 1 bind 0
For example, at this point a buggy application replaces the action with
index 1 with new smac 00:aa:22:33:44:55, it fails because of zero flags,
however refcnt gets bumped:
$ tc actions get actions skbmod index 1
total acts 0
action order 0: skbmod pipe set smac 00:11:22:33:44:55
index 1 ref 2 bind 0
$
Tha patch fixes this by calling tcf_idr_release() on existing actions.
Fixes: 86da71b57383d ("net_sched: Introduce skbmod action")
Signed-off-by: Roman Mashak <mrv@mojatatu.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/sched/act_skbmod.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c
index bbcbdce732cc0..ad050d7d4b46a 100644
--- a/net/sched/act_skbmod.c
+++ b/net/sched/act_skbmod.c
@@ -131,8 +131,11 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
if (exists && bind)
return 0;
- if (!lflags)
+ if (!lflags) {
+ if (exists)
+ tcf_idr_release(*a, bind);
return -EINVAL;
+ }
if (!exists) {
ret = tcf_idr_create(tn, parm->index, est, a,
--
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