From: Miroslav Lichvar <mlichvar@redhat.com>
To: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: linux-kernel@vger.kernel.org,
John Stultz <john.stultz@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Prarit Bhargava <prarit@redhat.com>,
Richard Cochran <richardcochran@gmail.com>,
Arnd Bergmann <arnd@arndb.de>
Subject: Re: [RFC][PATCH] timekeeping: Limit system time to prevent 32-bit time_t overflow
Date: Thu, 16 Apr 2015 09:54:50 +0200 [thread overview]
Message-ID: <20150416075450.GY32271@localhost> (raw)
In-Reply-To: <20150415223154.65c8d05e@lxorguk.ukuu.org.uk>
On Wed, Apr 15, 2015 at 10:31:54PM +0100, One Thousand Gnomes wrote:
> On Wed, 15 Apr 2015 17:41:28 +0200
> Miroslav Lichvar <mlichvar@redhat.com> wrote:
> > larger value. When the maximum is reached in normal time accumulation,
> > the clock will be stepped back by one week.
>
> Which itself is open to exploits and dirty tricks and causes bizarre
> problems.
Any examples? I think it shouldn't be any worse than having system
clock with incorrect time and making a backward step, which is a well
understood problem.
> IMHO it doesn't actually improve the situation.
Do you have a 32-bit system for testing? Try "date -s @2147483600",
wait one minute and see if it's not worth preventing.
I think the power consumption alone is worth it. If there is some
widely used application/service in which the overflow triggers an
infinite loop making requests to a network service, maybe it could
prevent a DDoS attack.
--
Miroslav Lichvar
prev parent reply other threads:[~2015-04-16 7:55 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-09 16:45 Preventing 32-bit time_t overflow Miroslav Lichvar
2015-04-09 17:05 ` John Stultz
2015-04-15 15:41 ` [RFC][PATCH] timekeeping: Limit system time to prevent " Miroslav Lichvar
2015-04-15 16:02 ` Arnd Bergmann
2015-04-15 16:17 ` Justin Keller
2015-04-16 7:56 ` Miroslav Lichvar
2015-04-15 21:31 ` One Thousand Gnomes
2015-04-16 7:54 ` Miroslav Lichvar [this message]
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