[PATCH v3] IOMUX: Fix buffer overflow in iomux_replace_device()

[Andy Shevchenko]

On Mon, Apr 26, 2021 at 08:08:03AM +0900, Yuichiro Goto wrote:
> Use of strcat() against an uninitialized buffer would lead
> to buffer overflow. This patch fixes it.

Reviewed-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>

> Fixes: 694cd5618c ("IOMUX: Introduce iomux_replace_device()")
> Signed-off-by: Yuichiro Goto <goto at k-tech.co.jp>
> Cc: Peter Robinson <pbrobinson at gmail.com>
> Cc: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
> Cc: Nicolas Saenz Julienne <nsaenzjulienne at suse.de>
> ---
> 
> Changes for v3:
> - Add a Fixes tag in commit message
> - Refactor the patch per suggestion from Andy Shevchenko
> 
> Changes for v2:
> - Add "IOMUX" in title
> 
>  common/iomux.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/common/iomux.c b/common/iomux.c
> index b9088aa3b5..c428f7110a 100644
> --- a/common/iomux.c
> +++ b/common/iomux.c
> @@ -158,8 +158,12 @@ int iomux_replace_device(const int console, const char *old, const char *new)
>  			return -ENOMEM;
>  		}
>  
> -		strcat(tmp, ",");
> -		strcat(tmp, name);
> +		if (arg) {
> +			strcat(tmp, ",");
> +			strcat(tmp, name);
> +		}
> +		else
> +			strcpy(tmp, name);
>  
>  		arg = tmp;
>  		size = strlen(tmp) + 1;
> -- 
> 2.17.1
> 

-- 
With Best Regards,
Andy Shevchenko