On Fri, Apr 17, 2015 at 08:04:13AM +0200, Heinrich Schuchardt wrote:
> A string written by the user may not be zero terminated.
> 
> sscanf may read memory beyond the buffer if no zero byte
> is found.
> 
> Signed-off-by: Heinrich Schuchardt <xypron.g...@gmx.de>
> ---
>  drivers/usb/chipidea/debug.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/chipidea/debug.c b/drivers/usb/chipidea/debug.c
> index dfb05ed..ef08af3 100644
> --- a/drivers/usb/chipidea/debug.c
> +++ b/drivers/usb/chipidea/debug.c
> @@ -88,9 +88,13 @@ static ssize_t ci_port_test_write(struct file *file, const 
> char __user *ubuf,
>       char buf[32];
>       int ret;
>  
> -     if (copy_from_user(buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
> +     count = min_t(size_t, sizeof(buf) - 1, count);
> +     if (copy_from_user(buf, ubuf, count))
>               return -EFAULT;

Any reasons to change above?
>  
> +     /* sscanf requires a zero terminated string */
> +     buf[count] = 0;
> +

I prefer using '\0'

>       if (sscanf(buf, "%u", &mode) != 1)
>               return -EINVAL;
>  
> -- 
> 2.1.4
> 

-- 

Best Regards,
Peter Chen
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