From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: Re: [PATCH 09/14] net: sched: don't release reference on action overwrite Date: Wed, 16 May 2018 09:50:29 +0200 Message-ID: <20180516075029.GD1972@nanopsycho> References: <1526308035-12484-1-git-send-email-vladbu@mellanox.com> <1526308035-12484-10-git-send-email-vladbu@mellanox.com> <20180516074332.GB1972@nanopsycho> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, davem@davemloft.net, jhs@mojatatu.com, xiyou.wangcong@gmail.com, pablo@netfilter.org, kadlec@blackhole.kfki.hu, fw@strlen.de, ast@kernel.org, daniel@iogearbox.net, edumazet@google.com, keescook@chromium.org, linux-kernel@vger.kernel.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, kliteyn@mellanox.com To: Vlad Buslov Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org Wed, May 16, 2018 at 09:47:32AM CEST, vladbu@mellanox.com wrote: > >On Wed 16 May 2018 at 07:43, Jiri Pirko wrote: >> Mon, May 14, 2018 at 04:27:10PM CEST, vladbu@mellanox.com wrote: >>>Return from action init function with reference to action taken, >>>even when overwriting existing action. >>> >>>Action init API initializes its fourth argument (pointer to pointer to >>>tc action) to either existing action with same index or newly created >>>action. In case of existing index(and bind argument is zero), init >>>function returns without incrementing action reference counter. Caller >>>of action init then proceeds working with action without actually >>>holding reference to it. This means that action could be deleted >>>concurrently. To prevent such scenario this patch changes action init >> >> Be imperative to the codebase in the patch description. >> >> >>>behavior to always take reference to action before returning >>>successfully. >> >> Where's the balance? Who does the release instead? I'm probably missing >> something. > >I've resplit these patches for V2 to always do take/release in same >patch. Good. Thanks. > >> >>> >>>Signed-off-by: Vlad Buslov >>>--- >>> net/sched/act_bpf.c | 8 ++++---- >>> net/sched/act_connmark.c | 5 +++-- >>> net/sched/act_csum.c | 8 ++++---- >>> net/sched/act_gact.c | 5 +++-- >>> net/sched/act_ife.c | 12 +++++------- >>> net/sched/act_ipt.c | 5 +++-- >>> net/sched/act_mirred.c | 5 ++--- >>> net/sched/act_nat.c | 5 +++-- >>> net/sched/act_pedit.c | 5 +++-- >>> net/sched/act_police.c | 8 +++----- >>> net/sched/act_sample.c | 8 +++----- >>> net/sched/act_simple.c | 5 +++-- >>> net/sched/act_skbedit.c | 5 +++-- >>> net/sched/act_skbmod.c | 8 +++----- >>> net/sched/act_tunnel_key.c | 8 +++----- >>> net/sched/act_vlan.c | 8 +++----- >>> 16 files changed, 51 insertions(+), 57 deletions(-) >>> >>>diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c >>>index 5d95c43..5554bf7 100644 >>>--- a/net/sched/act_bpf.c >>>+++ b/net/sched/act_bpf.c >>>@@ -311,9 +311,10 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla, >>> if (bind) >>> return 0; >>> >>>- tcf_idr_release(*act, bind); >>>- if (!replace) >>>+ if (!replace) { >>>+ tcf_idr_release(*act, bind); >>> return -EEXIST; >>>+ } >>> } >>> >>> is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS]; >> >> [...] >