linux-kernel - Re: [PATCH] netfilter: account ebt_table

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Date:   Sat, 29 Dec 2018 10:52:15 +0100
From:   Florian Westphal <fw@...len.de>
To:     Michal Hocko <mhocko@...nel.org>
Cc:     Shakeel Butt <shakeelb@...gle.com>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Florian Westphal <fw@...len.de>,
        Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>,
        Roopa Prabhu <roopa@...ulusnetworks.com>,
        Nikolay Aleksandrov <nikolay@...ulusnetworks.com>,
        Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        bridge@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        syzbot+7713f3aa67be76b1552c@...kaller.appspotmail.com
Subject: Re: [PATCH] netfilter: account ebt_table_info to kmemcg

Michal Hocko <mhocko@...nel.org> wrote:
> On Fri 28-12-18 17:55:24, Shakeel Butt wrote:
> > The [ip,ip6,arp]_tables use x_tables_info internally and the underlying
> > memory is already accounted to kmemcg. Do the same for ebtables. The
> > syzbot, by using setsockopt(EBT_SO_SET_ENTRIES), was able to OOM the
> > whole system from a restricted memcg, a potential DoS.
> 
> What is the lifetime of these objects? Are they bound to any process?

No, they are not.
They are free'd only when userspace requests it or the netns is
destroyed.