From: Javier Martinez Canillas <javier@osg.samsung.com>
To: Krzysztof Kozlowski <k.kozlowski@samsung.com>,
Tomasz Figa <tomasz.figa@gmail.com>,
Sylwester Nawrocki <s.nawrocki@samsung.com>,
Linus Walleij <linus.walleij@linaro.org>,
Kukjin Kim <kgene@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-gpio@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: Marek Szyprowski <m.szyprowski@samsung.com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Subject: Re: [PATCH] pinctrl: samsung: Suppress unbinding to prevent theoretical attacks
Date: Fri, 20 May 2016 22:29:50 -0400 [thread overview]
Message-ID: <7d725a0a-216e-40d9-8a65-62eeb2faaf34@osg.samsung.com> (raw)
In-Reply-To: <1463464926-17482-1-git-send-email-k.kozlowski@samsung.com>
Hello Krzysztof,
On 05/17/2016 02:02 AM, Krzysztof Kozlowski wrote:
> Although unbinding a pinctrl driver requires root privileges but it
> still might be used theoretically in certain attacks (by triggering NULL
> pointer exception or memory corruption).
>
> Samsung pincontrol drivers are essential for system operation so their
> removal is not expected. They do not implement remove() driver callback
> and they are not buildable as modules.
>
> Suppression of the unbinding will prevent triggering NULL pointer
> exception like this (Odroid XU3):
>
> $ echo 13400000.pinctrl > /sys/bus/platform/drivers/samsung-pinctrl/unbind
> $ cat /sys/kernel/debug/gpio
>
> Unable to handle kernel NULL pointer dereference at virtual address 00000c44
> pgd = ec41c000
> [00000c44] *pgd=6d448835, *pte=00000000, *ppte=00000000
> Internal error: Oops: 17 [#1] PREEMPT SMP ARM
> (samsung_gpio_get) from [<c034f9a0>] (gpiolib_seq_show+0x1b0/0x26c)
> (gpiolib_seq_show) from [<c01fb8c0>] (seq_read+0x304/0x4b8)
> (seq_read) from [<c02dbc78>] (full_proxy_read+0x4c/0x64)
> (full_proxy_read) from [<c01d9fb0>] (__vfs_read+0x2c/0x110)
> (__vfs_read) from [<c01db400>] (vfs_read+0x8c/0x110)
> (vfs_read) from [<c01db4c4>] (SyS_read+0x40/0x8c)
> (SyS_read) from [<c01078c0>] (ret_fast_syscall+0x0/0x3c)
>
> Suggested-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
> ---
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Best regards,
--
Javier Martinez Canillas
Open Source Group
Samsung Research America
next prev parent reply other threads:[~2016-05-21 2:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-17 6:02 Krzysztof Kozlowski
2016-05-21 2:29 ` Javier Martinez Canillas [this message]
2016-05-26 9:08 ` Linus Walleij
2016-05-27 8:42 ` Krzysztof Kozlowski
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