Re: [PATCH v2] HID: uhid: replace deprecated strncpy with strscpy

[Kees Cook]

On Tue, Oct 03, 2023 at 09:01:58PM +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.
> 
> A suitable replacement is `strscpy` [2] due to the fact that it
> guarantees NUL-termination on the destination buffer without
> unnecessarily NUL-padding.
> 
> Furthermore, let's make sure `hid->xyz` and `ev->u.create2.xyz` are the
> same size at compile time to prevent silent truncation.
> 
> With these changes, it is abundantly clear what the intent and behavior
> of the code is -- We are getting a string to string copy with
> NUL-termination and no truncation.
> 
> 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
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx>

Great! This looks much simpler to me. Thanks for adjusting it.

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

-- 
Kees Cook