From: Yueyi Li <liyueyi@live.com>
To: Dave Rodgman <dave.rodgman@arm.com>,
"dsterba@suse.cz" <dsterba@suse.cz>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"w@1wt.eu" <w@1wt.eu>,
"donb@securitymouse.com" <donb@securitymouse.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"markus@oberhumer.com" <markus@oberhumer.com>
Cc: nd <nd@arm.com>
Subject: Re: [PATCH v2] lzo: fix ip overrun during compress.
Date: Fri, 30 Nov 2018 03:05:38 +0000 [thread overview]
Message-ID: <SN1PR13MB030426DBA527C725AE28B5A9DFD30@SN1PR13MB0304.namprd13.prod.outlook.com> (raw)
In-Reply-To: <c03227b3-1c79-d214-5880-19f2f1ea0491@arm.com>
Hi Dave,
On 2018/11/30 0:49, Dave Rodgman wrote:
> On 28/11/2018 1:52 pm, David Sterba wrote:
>
>> The fix is adding a few branches to code that's supposed to be as fast
>> as possible. The branches would be evaluated all the time while
>> protecting against one signle bad page address. This does not look like
>> a good performance tradeoff.
> As an alternative, for all but the first case, instead of:
>
> if (unlikely(OVERFLOW_ADD_CHECK(ip, m_len) || (ip + m_len >= ip_end)))
>
> I'd suggest we do:
>
> if (unlikely((ip_end - ip) <= m_len))
>
> which will be about as efficient as what's currently there, but doesn't
> have issues with overflow.
Ooh, yes, pretty good solution to this, thanks.
> Dave
Thanks,
Yueyi
next prev parent reply other threads:[~2018-11-30 3:05 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-28 7:31 [PATCH v2] lzo: fix ip overrun during compress Yueyi Li
2018-11-28 13:52 ` David Sterba
2018-11-28 14:15 ` Willy Tarreau
2018-11-29 16:49 ` Dave Rodgman
2018-11-30 3:05 ` Yueyi Li [this message]
2018-11-30 12:20 ` Dave Rodgman
2018-12-03 2:46 ` Yueyi Li
2018-12-03 3:05 ` Yueyi Li
2018-12-04 10:20 ` Markus F.X.J. Oberhumer
2018-12-05 3:07 ` Yueyi Li
2018-12-06 15:03 ` Markus F.X.J. Oberhumer
2018-12-12 5:21 ` Yueyi Li
2018-12-12 12:35 ` Markus F.X.J. Oberhumer
2018-12-14 13:56 ` Richard Weinberger
2018-12-14 16:46 ` Kees Cook
2018-12-16 16:56 ` Markus F.X.J. Oberhumer
2018-12-18 9:25 ` Yueyi Li
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