From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Florian Westphal <fw@strlen.de>
Cc: Jay Elliott <jelliott@arista.com>, netfilter-devel@vger.kernel.org
Subject: Re: [PATCH v4] netfilter: conntrack: clamp timeouts to INT_MAX
Date: Tue, 28 Nov 2017 01:14:57 +0100 [thread overview]
Message-ID: <20171128001457.GA1805@salvia> (raw)
In-Reply-To: <20171128001244.GE23412@breakpoint.cc>
On Tue, Nov 28, 2017 at 01:12:44AM +0100, Florian Westphal wrote:
> Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > On Wed, Nov 15, 2017 at 03:01:13PM -0800, Jay Elliott wrote:
> > > When the conntracking code multiplies a timeout by HZ, it can overflow
> > > from positive to negative; this causes it to instantly expire. To
> > > protect against this the multiplication is done in 64-bit so we can
> > > prevent it from exceeding INT_MAX.
> >
> > This is something you must be observing via conntrack utility or
> > conntrackd?
>
> nf_ct_is_expired() will consider a ct as expired if the delta
> between current time and the (future) timeout is > 2**31.
>
> This triggers when ctnetlink configures a timeout larger than 2**31.
>
> The patch looks correct to me.
>
> Acked-by: Florian Westphal <fw@strlen.de>
I'll pass this to net instead, this is likely breaking conntrackd.
Thanks.
prev parent reply other threads:[~2017-11-28 0:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-15 23:01 [PATCH v4] netfilter: conntrack: clamp timeouts to INT_MAX Jay Elliott
2017-11-27 23:24 ` Pablo Neira Ayuso
2017-11-28 0:12 ` Florian Westphal
2017-11-28 0:14 ` Pablo Neira Ayuso [this message]
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