netdev - [PATCH net 2/7] net/sched: fix idr leak in the error path of tcf_simp

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Date:   Mon, 19 Mar 2018 01:06:12 +0100
From:   Davide Caratti <dcaratti@...hat.com>
To:     Cong Wang <xiyou.wangcong@...il.com>,
        Jiri Pirko <jiri@...nulli.us>,
        Jamal Hadi Salim <jhs@...atatu.com>,
        "David S. Miller" <davem@...emloft.net>
Cc:     netdev@...r.kernel.org
Subject: [PATCH net 2/7] net/sched: fix idr leak in the error path of tcf_simp_init()

if the kernel fails to duplicate 'sdata', creation of a new action fails
with -ENOMEM. However, subsequent attempts to install the same action
using the same value of 'index' systematically fail with -ENOSPC, and
that value of 'index' will no more be usable by act_simple, until rmmod /
insmod of act_simple.ko is done:

 # tc actions add action simple sdata hello index 100
 # tc actions list action simple

        action order 0: Simple <hello>
         index 100 ref 1 bind 0
 # tc actions flush action simple
 # tc actions add action simple sdata hello index 100
 RTNETLINK answers: Cannot allocate memory
 We have an error talking to the kernel
 # tc actions flush action simple
 # tc actions add action simple sdata hello index 100
 RTNETLINK answers: No space left on device
 We have an error talking to the kernel
 # tc actions add action simple sdata hello index 100
 RTNETLINK answers: No space left on device
 We have an error talking to the kernel
 ...

Fix this in the error path of tcf_simp_init(), calling tcf_idr_release()
in place of tcf_idr_cleanup().

Fixes: 65a206c01e8e ("net/sched: Change act_api and act_xxx modules to use IDR")
Suggested-by: Cong Wang <xiyou.wangcong@...il.com>
Signed-off-by: Davide Caratti <dcaratti@...hat.com>
---
 net/sched/act_simple.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index 425eac11f6da..b1f38063ada0 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -121,7 +121,7 @@ static int tcf_simp_init(struct net *net, struct nlattr *nla,
 		d = to_defact(*a);
 		ret = alloc_defdata(d, defdata);
 		if (ret < 0) {
-			tcf_idr_cleanup(*a, est);
+			tcf_idr_release(*a, bind);
 			return ret;
 		}
 		d->tcf_action = parm->action;
-- 
2.14.3