Subject: Re: [PATCH] net/mlx4_core: replace deprecated strncpy with strscpy

From: Kees Cook <[email-masked]>
Date: Wed, 11 Oct 2023 14:30:54 -0700

On Wed, Oct 11, 2023 at 09:04:37PM +0000, Justin Stitt wrote:
> `strncpy` is deprecated for use on NUL-terminated destination strings
> [1] and as such we should prefer more robust and less ambiguous string
> interfaces.
> 
> We expect `dst` to be NUL-terminated based on its use with format
> strings:
> |       mlx4_dbg(dev, "Reporting Driver Version to FW: %s\n", dst);
> 
> Moreover, NUL-padding is not required.

Yup, since it's only use is for the above report.

> 
> Considering the above, a suitable replacement is `strscpy` [2] due to
> the fact that it guarantees NUL-termination on the destination buffer
> without unnecessarily NUL-padding.
> 
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
> Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
> Link: https://github.com/KSPP/linux/issues/90
> Cc: [email-masked]
> Signed-off-by: Justin Stitt <[email-masked]>

Thanks!

Reviewed-by: Kees Cook <[email-masked]>

-- 
Kees Cook