On Fri, Jan 17, 2014 at 5:46 PM, David Laight <David.Laight@xxxxxxxxxx> wrote:
> From: Chen-Yu Tsai
>> snprintf should be passed the complete size of the buffer, including
>> the space for '\0'. The previous code resulted in the *_reset and
>> *_shutdown strings being truncated.
> ...
>> diff --git a/net/rfkill/rfkill-gpio.c b/net/rfkill/rfkill-gpio.c
> ...
>> - snprintf(rfkill->reset_name, len + 6 , "%s_reset", rfkill->name);
>> - snprintf(rfkill->shutdown_name, len + 9, "%s_shutdown", rfkill->name);
>> + snprintf(rfkill->reset_name, len + 7 , "%s_reset", rfkill->name);
>> + snprintf(rfkill->shutdown_name, len + 10, "%s_shutdown", rfkill->name);
>
> I can't find the context for the above, but they look very dubious.
> I'd expect: snprintf(foo, sizeof foo, ...).
> If you are trying to truncate rfkill->name you need to use %.*s.
The driver allocates these buffers on the fly, a few lines above:
len = strlen(rfkill->name);
rfkill->reset_name = devm_kzalloc(&pdev->dev, len + 7, GFP_KERNEL);
rfkill->shutdown_name = devm_kzalloc(&pdev->dev, len + 10, GFP_KERNEL);
I am not trying to truncate rfkill->name. Rather, the buffer length passed
to snprintf was wrong, so the resulting name was truncated by one character.
Thanks,
ChenYu
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