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Message-ID: <202310182231.052A44F@keescook>
Date: Wed, 18 Oct 2023 22:31:23 -0700
From: Kees Cook <keescook@...omium.org>
To: Justin Stitt <justinstitt@...gle.com>
Cc: Kalle Valo <kvalo@...nel.org>, linux-wireless@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-hardening@...r.kernel.org
Subject: Re: [PATCH] wifi: wlcore: main: replace deprecated strncpy with
strscpy
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@...r.kernel.org
> Signed-off-by: Justin Stitt <justinstitt@...gle.com>
More clear replacements.
Reviewed-by: Kees Cook <keescook@...omium.org>
--
Kees Cook
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