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Date: Tue, 4 May 2010 10:14:43 -0500
From: "Serge E. Hallyn" <serue@us.ibm.com>
To: David Howells <dhowells@redhat.com>
Cc: lkml <linux-kernel@vger.kernel.org>, Ashwin Ganti <ashwin.ganti@gmail.com>,
       Greg KH <greg@kroah.com>, rsc@swtch.com, ericvh@gmail.com,
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       Alan Cox <alan@lxorguk.ukuu.org.uk>,
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Subject: Re: [PATCH 3/3] RFC: p9auth: add p9auth fs
Message-ID: <20100504151443.GA18700@us.ibm.com>
References: <20100427164517.GC7530@us.ibm.com>
 <20100427164139.GA7359@us.ibm.com>
 <4067.1272985037@redhat.com>
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Quoting David Howells (dhowells@redhat.com):
> Serge E. Hallyn <serue@us.ibm.com> wrote:
> 
> > +	result = kzalloc(MAX_DIGEST_SIZE, GFP_KERNEL);
> > ...
> > +	ret = crypto_hash_digest(&desc, &sg, plain_text_size, result);
> 
> Does result have to be pre-cleared?
> 
> > +	user_buf = kzalloc(count+1, GFP_KERNEL);
> > +	if (!user_buf)
> > +		goto out;
> > +
> > +	if (copy_from_user(user_buf, buffer, count)) {
> 
> user_buf doesn't need preclearing.  It's just a waste of time.  This occurs
> three times.

Hm, yeah, the first doesn't need it at all, and the latter two
should just kmalloc and set user_buf[count] = '\0'.

thanks,

-serge