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Date: Mon, 8 Nov 2010 11:38:53 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: <ilkka.koskinen@nokia.com>
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Subject: Re: [PATCH] input: spi: Driver for SPI data stream driven vibrator
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On Mon, 8 Nov 2010 12:08:07 +0100
<ilkka.koskinen@nokia.com> wrote:

> Hi,
> 
> >From: ext Alan Cox [mailto:alan@lxorguk.ukuu.org.uk]
> >Sent: 08 November, 2010 01:52
> >
> >> +	datalen = p->custom_len * sizeof(p->custom_data[0]);
> >
> >signed
> >
> >> +	if (datalen > MAX_EFFECT_SIZE) {
> >
> >unsigned
> 
> It should be unsigned. I'll fix it.
> 
> >> +	memcpy(einfo->buf, p->custom_data, datalen);
> >
> >ungood
> 
> Yep, that's clearly wrong too. Should be copy_from_user() I suppose.

That I hadn't considered - and I'm not sure whether the caller is passed
a kernel copy or not. The problem I was looking at was just the signed
case

	datalen < 0
	if (datalen > MAX ..)
		Nope

	memcpy(kernel, mysource, vastly more than intended (unsigned))