Re: [PATCH] firmware: ti_sci: fix strncat length check

[Nishanth Menon]

On Wed, Jan 11, 2017 at 7:37 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> gcc-7 notices that the length we pass to strncat is wrong:
>
> drivers/firmware/ti_sci.c: In function 'ti_sci_probe':
> drivers/firmware/ti_sci.c:204:32: error: specified bound 50 equals the size of the destination [-Werror=stringop-overflow=]
>
> Instead of the total length, we must pass the length of the
> remaining space here.
>
> Fixes: aa276781a64a ("firmware: Add basic support for TI System Control Interface (TI-SCI) protocol")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
>  drivers/firmware/ti_sci.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
> index 874ff32db366..00cfed3c3e1a 100644
> --- a/drivers/firmware/ti_sci.c
> +++ b/drivers/firmware/ti_sci.c
> @@ -202,7 +202,8 @@ static int ti_sci_debugfs_create(struct platform_device *pdev,
>         info->debug_buffer[info->debug_region_size] = 0;
>
>         info->d = debugfs_create_file(strncat(debug_name, dev_name(dev),
> -                                             sizeof(debug_name)),
> +                                             sizeof(debug_name) -
> +                                             sizeof("ti_sci_debug@")),
>                                       0444, NULL, info, &ti_sci_debug_fops);
>         if (IS_ERR(info->d))
>                 return PTR_ERR(info->d);

Aargh.. thanks.... Santosh: if you could pick this up.. using
strlen(debug_name) might be an overkill here.

Acked-by: Nishanth Menon <nm@xxxxxx>

---
Regards,
Nishanth Menon