linux-kernel - Re: [PATCH v9 03/17] platform/x86: dell-wmi: clean up wmi descriptor check

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Message-ID: <20171017184445.c5endis7tzncplrz@pali>
Date:   Tue, 17 Oct 2017 20:44:45 +0200
From:   Pali Rohár <pali.rohar@...il.com>
To:     Mario Limonciello <mario.limonciello@...l.com>
Cc:     dvhart@...radead.org, Andy Shevchenko <andy.shevchenko@...il.com>,
        LKML <linux-kernel@...r.kernel.org>,
        platform-driver-x86@...r.kernel.org,
        Andy Lutomirski <luto@...nel.org>, quasisec@...gle.com,
        rjw@...ysocki.net, mjg59@...gle.com, hch@....de,
        Greg KH <greg@...ah.com>, Alan Cox <gnomes@...rguk.ukuu.org.uk>
Subject: Re: [PATCH v9 03/17] platform/x86: dell-wmi: clean up wmi descriptor
 check

On Tuesday 17 October 2017 13:21:47 Mario Limonciello wrote:
> Some cases the wrong type was used for errors and checks can be
> done more cleanly.
> 
> Signed-off-by: Mario Limonciello <mario.limonciello@...l.com>
> Reviewed-by: Edward O'Callaghan <quasisec@...gle.com>
> Suggested-by: Andy Shevchenko <andy.shevchenko@...il.com>
> ---
>  drivers/platform/x86/dell-wmi.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
> index 2cfaaa8faf0a..ece2fe341f01 100644
> --- a/drivers/platform/x86/dell-wmi.c
> +++ b/drivers/platform/x86/dell-wmi.c
> @@ -663,19 +663,19 @@ static int dell_wmi_check_descriptor_buffer(struct wmi_device *wdev)
>  
>  	buffer = (u32 *)obj->buffer.pointer;
>  
> -	if (buffer[0] != 0x4C4C4544 && buffer[1] != 0x494D5720) {
> -		dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature (%*ph)\n",
> -			8, buffer);
> +	if (strncmp(obj->string.pointer, "DELL WMI", 8) != 0) {
> +		dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature (%8ph)\n",
> +			buffer);
>  		ret = -EINVAL;
>  		goto out;
>  	}
>  
>  	if (buffer[2] != 0 && buffer[2] != 1)
> -		dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%d)\n",
> +		dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%u)\n",
>  			buffer[2]);

To be correct, buffer[2] is of type "u32", not of type "unsigned". So
this patch does not fix it properly.

>  
>  	if (buffer[3] != 4096)
> -		dev_warn(&wdev->dev, "Dell descriptor buffer has invalid buffer length (%d)\n",
> +		dev_warn(&wdev->dev, "Dell descriptor buffer has invalid buffer length (%u)\n",
>  			buffer[3]);
>  
>  	priv->interface_version = buffer[2];

-- 
Pali Rohár
pali.rohar@...il.com