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

From: Kees Cook
Date: Wed Oct 11 2023 - 17:31:01 EST


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: linux-hardening@xxxxxxxxxxxxxxx
> Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx>

Thanks!

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

--
Kees Cook