Re: [PATCH] ibmvnic: replace deprecated strncpy with strscpy

From: Kees Cook
Date: Tue Oct 10 2023 - 18:51:40 EST


On Mon, Oct 09, 2023 at 11:19:57PM +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.
>
> NUL-padding is not required as the buffer is already memset to 0:
> | memset(adapter->fw_version, 0, 32);
>
> Note that another usage of strscpy exists on the same buffer:
> | strscpy((char *)adapter->fw_version, "N/A", sizeof(adapter->fw_version));
>
> 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, this looks right to me.

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

--
Kees Cook