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

[Rafael J. Wysocki]

On Fri, Oct 20, 2023 at 1:06 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
>
> On Thu, Oct 19, 2023 at 10:47:58PM +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.
> >
> > We know dev->name should be NUL-terminated based on the presence of a
> > manual NUL-byte assignment.
> >
> > NUL-padding is not required as dev is already zero-allocated which
> > renders any further NUL-byte assignments redundant:
> > dev = pnp_alloc_dev(&pnpacpi_protocol, num, pnpid); --->
> >   dev = kzalloc(sizeof(struct pnp_dev), GFP_KERNEL);
> >
> > 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. This simplifies the code and makes
> > the intent/behavior more obvious.
> >
> > 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>
>
> Looks clean to me!
>
> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

Applied as 6.7 material, thanks!