From: Jacopo Mondi <jacopo@jmondi.org>
To: Kangjie Lu <kjlu@umn.edu>
Cc: pakki001@umn.edu, Mauro Carvalho Chehab <mchehab@kernel.org>,
linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] media: renesas-ceu: fix a potential NULL pointer dereference
Date: Sat, 9 Mar 2019 10:58:03 +0100 [thread overview]
Message-ID: <20190309095803.edauvethw232h45t@uno.localdomain> (raw)
In-Reply-To: <20190309071424.3600-1-kjlu@umn.edu>
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Hi Kangjie,
thanks for the patch.
On Sat, Mar 09, 2019 at 01:14:24AM -0600, Kangjie Lu wrote:
> In case of_match_device cannot find a match, the check returns
> -EINVAL to avoid a potential NULL pointer dereference
>
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
> drivers/media/platform/renesas-ceu.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/renesas-ceu.c b/drivers/media/platform/renesas-ceu.c
> index 150196f7cf96..4aa807c0b6c7 100644
> --- a/drivers/media/platform/renesas-ceu.c
> +++ b/drivers/media/platform/renesas-ceu.c
> @@ -1682,7 +1682,10 @@ static int ceu_probe(struct platform_device *pdev)
>
> if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
> ceu_data = of_match_device(ceu_of_match, dev)->data;
> - num_subdevs = ceu_parse_dt(ceudev);
> + if (unlikely(!ceu_data))
> + num_subdevs = -EINVAL;
> + else
> + num_subdevs = ceu_parse_dt(ceudev);
I don't think this fix is required to be honest.
If we call of_match_device() here we're sure CONFIG_OF is enabled, and
if the driver probed, so a matching compatible string has proved to
exist.
Furthermore, if you want to protect against of_match_device()
returning a NULL pointer, you should change this line first, as it
would dereference an invalid pointer:
ceu_data = of_match_device(ceu_of_match, dev)->data;
but again, I don't think this might happen.
Thanks
j
> } else if (dev->platform_data) {
> /* Assume SH4 if booting with platform data. */
> ceu_data = &ceu_data_sh4;
> --
> 2.17.1
>
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next prev parent reply other threads:[~2019-03-09 9:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-09 7:14 [PATCH] media: renesas-ceu: fix a potential NULL pointer dereference Kangjie Lu
2019-03-09 9:58 ` Jacopo Mondi [this message]
2019-03-28 15:30 ` Hans Verkuil
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