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From: Cong Wang <xiyou.wangcong@gmail.com>
To: Roman Mashak <mrv@mojatatu.com>
Cc: David Miller <davem@davemloft.net>,
	Linux Kernel Network Developers <netdev@vger.kernel.org>,
	kernel@mojatatu.com, Jamal Hadi Salim <jhs@mojatatu.com>,
	Jiri Pirko <jiri@resnulli.us>,
	Alexander Duyck <alexander.duyck@gmail.com>
Subject: Re: [PATCH net-next 1/1] net sched actions: fix invalid pointer dereferencing if skbedit flags missing
Date: Thu, 10 May 2018 10:54:21 -0700	[thread overview]
Message-ID: <CAM_iQpWPPcjmWC6e2hWoxhQRNuCNHwZvhSQqTtvKUt=MwoiwhA@mail.gmail.com> (raw)
In-Reply-To: <1525900723-17625-1-git-send-email-mrv@mojatatu.com>

On Wed, May 9, 2018 at 2:18 PM, Roman Mashak <mrv@mojatatu.com> wrote:
> The caller calls action's ->init() and passes pointer to "struct tc_action *a",
> which later may initialized to point at the existing action, otherwise
> "struct tc_action *a" is still invalid, and therefore dereferencing it is error.

So technically we just need to check if(exists) before calling
tcf_idr_release(), right?


>
> So checking flags should be done as early as possible, before idr lookups.

In theory, this could break the case of binding an existing action.
But in practice it seems nonsense to pass invalid flags in this case
either, so probably this is okay.

BTW, this should be a candidate for -net and possibly -stable too.

      reply	other threads:[~2018-05-10 17:54 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-09 21:18 [PATCH net-next 1/1] net sched actions: fix invalid pointer dereferencing if skbedit flags missing Roman Mashak
2018-05-10 17:54 ` Cong Wang [this message]

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