linux-kernel - Re: [PATCH 1/2] regmap: Add range check in _regmap_raw

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150219102750.GC3198@finisterre.sirena.org.uk>
Date:	Thu, 19 Feb 2015 19:27:50 +0900
From:	Mark Brown <broonie@...nel.org>
To:	Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 1/2] regmap: Add range check in _regmap_raw_read()

On Thu, Feb 19, 2015 at 08:40:39AM +0000, Srinivas Kandagatla wrote:

> +	/* Check for readable registers before we start */
> +	for (i = 0; i < count; i++)
> +		if (!regmap_readable(map, reg + (i * map->reg_stride)))
> +			return -EINVAL;

That's starting to look pretty expensive especially if what we're
looking for is just max_register really...  This is one of the reasons
we're not religious about checking for readability everywhere, and
obviously even if we avoid triggering this particular thing we still
have to cope with both the caller and devices that didn't specify
readability.  A cheaper check for just max_register would be less
concerning but it feels like we're trying to paper over a symptom with
this rather than fix a problem.

Download attachment "signature.asc" of type "application/pgp-signature" (474 bytes)