From: Dan Carpenter <dan.carpenter@oracle.com>
To: Lars-Peter Clausen <lars@metafoo.de>
Cc: Ian Abbott <abbotti@mev.co.uk>, Xi Wang <xi.wang@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"devel@driverdev.osuosl.org" <devel@driverdev.osuosl.org>,
Mori Hess <fmhess@users.sourceforge.net>,
"security@kernel.org" <security@kernel.org>,
Lucas De Marchi <lucas.demarchi@profusion.mobi>,
Greg Kroah-Hartman <gregkh@suse.de>,
Ian Abbott <ian.abbott@mev.co.uk>,
Franky Lin <frankyl@broadcom.com>,
Greg Dietsche <Gregory.Dietsche@cuw.edu>,
Mark Pearson <markpearson_de@yahoo.de>
Subject: Re: [PATCH] comedi: integer overflow in do_insnlist_ioctl()
Date: Thu, 24 Nov 2011 00:51:11 +0300 [thread overview]
Message-ID: <20111123215111.GD3258@mwanda> (raw)
In-Reply-To: <4ECD6873.7080106@metafoo.de>
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On Wed, Nov 23, 2011 at 10:41:07PM +0100, Lars-Peter Clausen wrote:
> > if (insnlist.n_insns <= ULONG_MAX / sizeof(struct comedi_insn))
> > insns =
> > kmalloc(sizeof(struct comedi_insn) * insnlist.n_insns,
> > GFP_KERNEL);
> > if (!insns)
> > ...
> >
> > (note that insns is initialized to NULL).
> >
>
> Just use kcalloc, it will do the right thing for you.
>
I think the reason why I didn't do that in my original patch is that
kcalloc() has a memset(..., 0, ...) in it so it's a slow down. But
this isn't performance critical code so that would work.
regards,
dan carpenter
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next prev parent reply other threads:[~2011-11-23 21:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-23 0:49 [PATCH] comedi: integer overflow in do_insnlist_ioctl() Xi Wang
2011-11-23 6:13 ` Dan Carpenter
2011-11-23 13:59 ` Xi Wang
2011-11-23 14:50 ` Dan Carpenter
2011-11-23 16:06 ` Ian Abbott
2011-11-23 16:53 ` [PATCH v2] " Xi Wang
2011-11-23 21:41 ` [PATCH] " Lars-Peter Clausen
2011-11-23 21:51 ` Dan Carpenter [this message]
2011-11-24 19:07 ` Xi Wang
2011-11-25 7:25 ` Dan Carpenter
2011-11-25 21:46 ` [PATCH v3] " Xi Wang
2011-11-27 2:52 ` Greg KH
2011-11-27 11:25 ` Dan Carpenter
2011-11-27 21:24 ` Greg KH
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