Re: [PATCH] wifi: wlcore: main: replace deprecated strncpy with strscpy

[Kees Cook <keescook@chromium.org>]

On Wed, Oct 18, 2023 at 09:50:01PM +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 fw_version strings to be NUL-terminated based on other similar
> assignments:
> 
> wireless/broadcom/brcm80211/brcmsmac/main.c
> 7867:           snprintf(wlc->wiphy->fw_version,
> 7868:                    sizeof(wlc->wiphy->fw_version), "%u.%u", rev, patch);
> 
> wireless/broadcom/b43legacy/main.c
> 1765:   snprintf(wiphy->fw_version, sizeof(wiphy->fw_version), "%u.%u",
> 
> wireless/broadcom/b43/main.c
> 2730:   snprintf(wiphy->fw_version, sizeof(wiphy->fw_version), "%u.%u",
> 
> wireless/intel/iwlwifi/dvm/main.c
> 1465:   snprintf(priv->hw->wiphy->fw_version,
> 1466:            sizeof(priv->hw->wiphy->fw_version),
> 
> wireless/intel/ipw2x00/ipw2100.c
> 5905:   snprintf(info->fw_version, sizeof(info->fw_version), "%s:%d:%s",
> 
> Based on this, NUL-padding is not required.
> 
> 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@vger.kernel.org
> Signed-off-by: Justin Stitt <justinstitt@google.com>

More clear replacements.

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

-- 
Kees Cook