From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: [patch net 1/2] net: sched: fix clsact init error path Date: Fri, 15 Dec 2017 12:40:12 +0100 Message-ID: <20171215114013.6425-2-jiri@resnulli.us> References: <20171215114013.6425-1-jiri@resnulli.us> Cc: davem@davemloft.net, jhs@mojatatu.com, xiyou.wangcong@gmail.com, mlxsw@mellanox.com, daniel@iogearbox.net To: netdev@vger.kernel.org Return-path: Received: from mail-wm0-f68.google.com ([74.125.82.68]:45207 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754389AbdLOLkR (ORCPT ); Fri, 15 Dec 2017 06:40:17 -0500 Received: by mail-wm0-f68.google.com with SMTP id 9so16859425wme.4 for ; Fri, 15 Dec 2017 03:40:16 -0800 (PST) In-Reply-To: <20171215114013.6425-1-jiri@resnulli.us> Sender: netdev-owner@vger.kernel.org List-ID: From: Jiri Pirko Since in qdisc_create, the destroy op is called when init fails, we don't do cleanup in init and leave it up to destroy. This fixes use-after-free when trying to put already freed block. Fixes: 6e40cf2d4dee ("net: sched: use extended variants of block_get/put in ingress and clsact qdiscs") Signed-off-by: Jiri Pirko --- net/sched/cls_api.c | 4 ++-- net/sched/sch_ingress.c | 6 +----- 2 files changed, 3 insertions(+), 7 deletions(-) diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index f40256a..b91ea03 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -351,6 +351,8 @@ void tcf_block_put_ext(struct tcf_block *block, struct Qdisc *q, { struct tcf_chain *chain; + if (!block) + return; /* Hold a refcnt for all chains, except 0, so that they don't disappear * while we are iterating. */ @@ -377,8 +379,6 @@ void tcf_block_put(struct tcf_block *block) { struct tcf_block_ext_info ei = {0, }; - if (!block) - return; tcf_block_put_ext(block, block->q, &ei); } diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c index 5ecc38f..5e1cd2e 100644 --- a/net/sched/sch_ingress.c +++ b/net/sched/sch_ingress.c @@ -190,7 +190,7 @@ static int clsact_init(struct Qdisc *sch, struct nlattr *opt) err = tcf_block_get_ext(&q->egress_block, sch, &q->egress_block_info); if (err) - goto err_egress_block_get; + return err; net_inc_ingress_queue(); net_inc_egress_queue(); @@ -198,10 +198,6 @@ static int clsact_init(struct Qdisc *sch, struct nlattr *opt) sch->flags |= TCQ_F_CPUSTATS; return 0; - -err_egress_block_get: - tcf_block_put_ext(q->ingress_block, sch, &q->ingress_block_info); - return err; } static void clsact_destroy(struct Qdisc *sch) -- 2.9.5