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From: Matthew Wilcox <willy@infradead.org>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: dianzhangchen0@gmail.com, linux-kernel@vger.kernel.org,
	mhocko@kernel.org
Subject: Re: [PATCH] mm/slab_common.c: fix possible spectre-v1 in kmalloc_slab()
Date: Wed, 29 May 2019 17:04:45 -0700	[thread overview]
Message-ID: <20190530000445.GB23461@bombadil.infradead.org> (raw)
In-Reply-To: <20190529203106.GA26268@avx2>

On Wed, May 29, 2019 at 11:31:06PM +0300, Alexey Dobriyan wrote:
> > I think it makes more sense to sanitize size in size_index_elem(),
> > don't you?
> 
> > -	return (bytes - 1) / 8;
> > +	return array_index_nospec((bytes - 1) / 8, ARRAY_SIZE(size_index));
> 
> I think it should be fixed in poll.
> Literally every small variable kmalloc call is going through this function.

We could do that too, but don't we then have to audit every ioctl and
similar to see if there's a k(v)malloc based on a size passed from
userspace?

  reply	other threads:[~2019-05-30  0:04 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-29 20:31 Alexey Dobriyan
2019-05-30  0:04 ` Matthew Wilcox [this message]
  -- strict thread matches above, loose matches on Subject: below --
2019-05-29 12:37 Dianzhang Chen
2019-05-29 16:25 ` Michal Hocko
2019-05-29 16:39   ` Dianzhang Chen
2019-05-29 17:49     ` Michal Hocko
2019-05-30  5:20       ` Dianzhang Chen
2019-05-30  6:24         ` Michal Hocko
2019-05-30  7:01           ` Dianzhang Chen
2019-05-29 19:48 ` Matthew Wilcox
2019-05-30  5:21   ` Dianzhang Chen

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