Commit ec5b0f60 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

net/sched: cls_u32: fix possible leak in u32_init_knode() 



While investigating a related syzbot report,
I found that whenever call to tcf_exts_init()
from u32_init_knode() is failing, we end up
with an elevated refcount on ht->refcnt

To avoid that, only increase the refcount after
all possible errors have been evaluated.

Fixes: b9a24bb7 ("net_sched: properly handle failure case of tcf_exts_init()")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Acked-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 3db09e76

net/sched/cls_u32.c

+4 −4
Original line number Diff line number Diff line
@@ -815,10 +815,6 @@ static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp, 
	new->flags = n->flags;

	RCU_INIT_POINTER(new->ht_down, ht);



	/* bump reference count as long as we hold pointer to structure */

	if (ht)

		ht->refcnt++;



#ifdef CONFIG_CLS_U32_PERF

	/* Statistics may be incremented by readers during update

	 * so we must keep them in tact. When the node is later destroyed
@@ -840,6 +836,10 @@ static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp, 
		return NULL;

	}



	/* bump reference count as long as we hold pointer to structure */

	if (ht)

		ht->refcnt++;



	return new;

}