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Date: Fri, 23 Feb 2024 09:50:10 -0800
From: Kees Cook <keescook@chromium.org>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Jonathan Cameron <jic23@kernel.org>,
	Lars-Peter Clausen <lars@metafoo.de>,
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	linux-iio@vger.kernel.org, Nathan Chancellor <nathan@kernel.org>,
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	Bill Wendling <morbo@google.com>,
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	Tomislav Denis <tomislav.denis@avl.com>,
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2] iio: pressure: dlhl60d: Initialize empty DLH bytes
Message-ID: <202402230949.E06F3297@keescook>
References: <20240223172936.it.875-kees@kernel.org>
 <ZdjaOLVd1yxNXhsp@smile.fi.intel.com>
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On Fri, Feb 23, 2024 at 07:47:36PM +0200, Andy Shevchenko wrote:
> On Fri, Feb 23, 2024 at 09:29:39AM -0800, Kees Cook wrote:
> > 3 bytes were being read but 4 were being written. Explicitly initialize
> > the unused bytes to 0 and refactor the loop to use direct array
> > indexing, which appears to silence a Clang false positive warning[1].
> 
> ...
> 
> >  	for_each_set_bit(chn, indio_dev->active_scan_mask,
> > -		indio_dev->masklength) {
> > -		memcpy(tmp_buf + i,
> > +			 indio_dev->masklength) {
> > +		memcpy(&tmp_buf[i++],
> >  			&st->rx_buf[1] + chn * DLH_NUM_DATA_BYTES,
> >  			DLH_NUM_DATA_BYTES);
> > -		i++;
> >  	}
> 
> Not that I'm against the changes, but they (in accordance with the commit
> message) are irrelevant to this fix. I prefer fixes to be more focused on
> the real issues.

Jonathan, let me know if you'd prefer I split this patch...

-- 
Kees Cook