From: Mark Brown <broonie@opensource.wolfsonmicro.com>
To: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Cc: alsa-devel@alsa-project.org, patches@opensource.wolfsonmicro.com,
Liam Girdwood <lrg@slimlogic.co.uk>
Subject: Re: [PATCH] ASoC: soc-core: Support debugfs entries larger than PAGE_SIZE bytes
Date: Wed, 2 Feb 2011 13:37:12 +0000 [thread overview]
Message-ID: <20110202133712.GQ12743@opensource.wolfsonmicro.com> (raw)
In-Reply-To: <1296653296.4393.1.camel@dplaptop.localdomain>
On Wed, Feb 02, 2011 at 01:28:16PM +0000, Dimitris Papastamos wrote:
> On Wed, 2011-02-02 at 13:07 +0000, Mark Brown wrote:
> > Why do we need the access_ok() here? I'd really expect copy_to_user()
> > to do the right thing here and simple_read_from_buffer() doesn't do
> > this.
> I thought it'd be a problem if userspace provides a pointer that points
> in kernelspace. The call to access_ok() ensures that the pointer lies
> indeed in userspace. I noticed that simple_read_from_buffer() doesn't
> do this, but I did not see how this could harm things.
My expectation is that access_ok() would only be used if we were parsing
userspace passed values directly, having to do the check before doing a
copy_to_user() reads like we're doing something wrong.
next prev parent reply other threads:[~2011-02-02 13:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-02 11:29 [PATCH] ASoC: soc-core: Support debugfs entries larger than PAGE_SIZE bytes Dimitris Papastamos
2011-02-02 13:07 ` Mark Brown
2011-02-02 13:28 ` Dimitris Papastamos
2011-02-02 13:37 ` Mark Brown [this message]
-- strict thread matches above, loose matches on Subject: below --
2011-02-02 13:58 Dimitris Papastamos
2011-02-02 20:47 ` Liam Girdwood
2011-02-02 20:48 ` Mark Brown
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