linux-kernel - Re: [PATCH] clk: samsung: Suppress unbinding to prevent theoretical attacks

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Date:	Fri, 20 May 2016 22:30:30 -0400
From:	Javier Martinez Canillas <javier@....samsung.com>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Sylwester Nawrocki <s.nawrocki@...sung.com>,
	Tomasz Figa <tomasz.figa@...il.com>,
	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...eaurora.org>,
	Kukjin Kim <kgene@...nel.org>,
	linux-samsung-soc@...r.kernel.org, linux-clk@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH] clk: samsung: Suppress unbinding to prevent theoretical
 attacks

Hello Krzysztof,

On 05/17/2016 03:26 AM, Krzysztof Kozlowski wrote:
> Although unbinding a driver requires root privileges but it still might
> be used theoretically in certain attacks (by triggering NULL pointer
> exception or memory corruption if driver does not provide proper remove
> callbacks or core does not handle it).
> 
> Samsung clock drivers are essential for system operation so their
> removal is not expected. More over, the Exynos3250 ISP clock driver does
> not implement remove() driver callback and it is not buildable as
> modules.
> 
> Suppress the unbind interface for Exynos3250 ISP and S3C2410 DCLK clock
> drivers.
> 
> Suggested-by: Marek Szyprowski <m.szyprowski@...sung.com>
> Cc: Marek Szyprowski <m.szyprowski@...sung.com>
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
> ---

Reviewed-by: Javier Martinez Canillas <javier@....samsung.com>

Best regards,
-- 
Javier Martinez Canillas
Open Source Group
Samsung Research America