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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Wed, 30 Jan 2019 17:43:34 +0200
Message-ID: <CAHp75VfHDN7Q1YjFd7XM8tFpCcPphaDm0fvOaxHzko5AvF6jEw@mail.gmail.com>
Subject: Re: [PATCH v2] platform/x86: wmi: fix potential null pointer dereference
To:     Mattias Jacobsson <2pi@mok.nu>
Cc:     Darren Hart <dvhart@infradead.org>,
        Andy Shevchenko <andy@infradead.org>,
        Platform Driver <platform-driver-x86@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Wed, Jan 30, 2019 at 5:15 PM Mattias Jacobsson <2pi@mok.nu> wrote:
>
> In the function wmi_dev_match() the variable id is dereferenced without
> first performing a NULL check. The variable can for example be NULL if
> a WMI driver is registered without specifying the id_table field in
> struct wmi_driver.
>
> Add a NULL check and return that the driver can't handle the device if
> the variable is NULL.
>

Good for me, thanks!

> Fixes: 844af950da94 ("platform/x86: wmi: Turn WMI into a bus driver")
> Signed-off-by: Mattias Jacobsson <2pi@mok.nu>
> ---
>  drivers/platform/x86/wmi.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index bea35be68706..b0f3d8ecd898 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -768,6 +768,9 @@ static int wmi_dev_match(struct device *dev, struct device_driver *driver)
>         struct wmi_block *wblock = dev_to_wblock(dev);
>         const struct wmi_device_id *id = wmi_driver->id_table;
>
> +       if (id == NULL)
> +               return 0;
> +
>         while (id->guid_string) {
>                 uuid_le driver_guid;
>
> --
> 2.20.1
>


-- 
With Best Regards,
Andy Shevchenko