On Wed, Sep 13, 2023 at 12:51:05AM +0000, Justin Stitt wrote:
> `strncpy` is deprecated for use on NUL-terminated destination strings [1].
> 
> We should prefer more robust and less ambiguous string interfaces.
> 
> `buf` is expected to be NUL-terminated for its eventual use in
> `kstrtoul()` and NUL-padding is not required.
> 
> Due to the above, a suitable replacement is `strscpy` [2] due to the
> fact that it guarantees NUL-termination on the destination buffer.
> 
> 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-harden...@vger.kernel.org
> Signed-off-by: Justin Stitt <justinst...@google.com>
> ---
> Note: build-tested only.
> ---
>  drivers/crypto/intel/qat/qat_common/qat_uclo.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/crypto/intel/qat/qat_common/qat_uclo.c 
> b/drivers/crypto/intel/qat/qat_common/qat_uclo.c
> index ce837bcc1cab..e2f82128043e 100644
> --- a/drivers/crypto/intel/qat/qat_common/qat_uclo.c
> +++ b/drivers/crypto/intel/qat/qat_common/qat_uclo.c
> @@ -200,7 +200,7 @@ static int qat_uclo_parse_num(char *str, unsigned int 
> *num)
>       unsigned long ae = 0;
>       int i;
>  
> -     strncpy(buf, str, 15);
> +     strscpy(buf, str, sizeof(buf));
>       for (i = 0; i < 16; i++) {
>               if (!isdigit(buf[i])) {

I was initially worried when I saw this walking the entire contents, but
I see it is explicitly zeroed on the stack first, so this is fine:

        char buf[16] = {0};


Reviewed-by: Kees Cook <keesc...@chromium.org>

-Kees

>                       buf[i] = '\0';
> 
> ---
> base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c
> change-id: 
> 20230913-strncpy-drivers-crypto-intel-qat-qat_common-qat_uclo-c-0f4b16830f59
> 
> Best regards,
> --
> Justin Stitt <justinst...@google.com>
> 

-- 
Kees Cook

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