[PATCH v2] IOMUX: Fix buffer overflow in iomux_replace_device()

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Fri, Apr 23, 2021 at 05:08:05PM +0900, Yuichiro Goto wrote:
> Use of strcat() against an uninitialized buffer would lead
> to buffer overflow. This patch fixes it.

Thanks for report!

Can you also add a Fixes tag?

> Signed-off-by: Yuichiro Goto <goto@k-tech.co.jp>
> Cc: Peter Robinson <pbrobinson@gmail.com>
> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> ---
> 
> Changes for v2:
> - Add "IOMUX" in title
> 
>  common/iomux.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/common/iomux.c b/common/iomux.c
> index b9088aa3b5..27baca6931 100644
> --- a/common/iomux.c
> +++ b/common/iomux.c
> @@ -158,7 +158,10 @@ int iomux_replace_device(const int console, const char *old, const char *new)
>  			return -ENOMEM;
>  		}
>  
> -		strcat(tmp, ",");
> +		if (!arg)
> +			strcpy(tmp, ",");
> +		else
> +			strcat(tmp, ",");
>  		strcat(tmp, name);

It would be better to have it like

	if (arg) {
		strcat(tmp, ",");
		strcat(tmp, name);
	} else
		strcpy(tmp, name);


>  		arg = tmp;

Peter, does it fix your issue seen on ARMv7?

-- 
With Best Regards,
Andy Shevchenko