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Message-ID: <da442a04-9db8-4951-98b4-3e149ea06415@gmx.de>
Date: Fri, 29 Mar 2024 01:21:27 +0100
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Subject: Re: [PATCH] platform/x86: panasonic-laptop: fix NULL dereference
To: Maxim Korotkov <korotkov.maxim.s@gmail.com>,
 Kenneth Chan <kenneth.t.chan@gmail.com>
Cc: Len Brown <len.brown@intel.com>,
 Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
 Harald Welte <laforge@gnumonks.org>, Matthew Garrett <mjg@redhat.com>,
 Ivan Kapranov <i.kapranov@securitycode.ru>, lvc-project@linuxtesting.org,
 platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20240328103518.169604-1-korotkov.maxim.s@gmail.com>
Content-Language: en-US
From: Armin Wolf <W_Armin@gmx.de>
In-Reply-To: <20240328103518.169604-1-korotkov.maxim.s@gmail.com>
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Am 28.03.24 um 11:35 schrieb Maxim Korotkov:

> When initializing the pcc by calling acpi_driver_data(), the "device"
> pointer was dereferenced without checking for NULL. This seems like
> a logical mistake.
>
> Added a pointer check to ensure that it is valid
> before using it for pcc initialization.

Hi,

is this check even needed? I think the ACPI driver core takes care
of passing a valid ACPI device pointer to acpi_pcc_hotkey_remove().

Thanks,
Armin Wolf

> Found by Security Code and Linux Verification Center(linuxtesting.org)
>
> Fixes: 709ee531c153 ("panasonic-laptop: add Panasonic Let's Note laptop =
extras driver v0.94")
>
> Signed-off-by: Maxim Korotkov <korotkov.maxim.s@gmail.com>
> ---
>   drivers/platform/x86/panasonic-laptop.c | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/x86/panasonic-laptop.c b/drivers/platform/=
x86/panasonic-laptop.c
> index cf845ee1c7b1..de29758b0384 100644
> --- a/drivers/platform/x86/panasonic-laptop.c
> +++ b/drivers/platform/x86/panasonic-laptop.c
> @@ -1067,9 +1067,12 @@ static int acpi_pcc_hotkey_add(struct acpi_device=
 *device)
>
>   static void acpi_pcc_hotkey_remove(struct acpi_device *device)
>   {
> -	struct pcc_acpi *pcc =3D acpi_driver_data(device);
> +	struct pcc_acpi *pcc;
>
> -	if (!device || !pcc)
> +	if (!device)
> +		return;
> +	pcc =3D acpi_driver_data(device);
> +	if (!pcc)
>   		return;
>
>   	i8042_remove_filter(panasonic_i8042_filter);