Messages in this thread | | | Date | Tue, 24 Oct 2023 10:28:48 -0700 | From | Kees Cook <> | Subject | Re: [PATCH] s390/ctcm: replace deprecated strncpy with strscpy |
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On Mon, Oct 23, 2023 at 07:35:07PM +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 chid to be NUL-terminated based on its use with format > strings: > > CTCM_DBF_TEXT_(SETUP, CTC_DBF_INFO, "%s(%s) %s", CTCM_FUNTAIL, > chid, ok ? "OK" : "failed"); > > Moreover, NUL-padding is not required as it is _only_ used in this one > instance with a format string. > > 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. > > We can also drop the +1 from chid's declaration as we no longer need to > be cautious about leaving a spot for a NUL-byte. Let's use the more > idiomatic strscpy usage of (dest, src, sizeof(dest)) as this more > closely ties the destination buffer to the length. > > 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@vger.kernel.org > Signed-off-by: Justin Stitt <justinstitt@google.com>
Yeah, all looks correct to me.
Reviewed-by: Kees Cook <keescook@chromium.org>
-- Kees Cook
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