linux-hardening - [PATCH] wifi: wlcore: main: replace deprecated strncpy with strscpy

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Message-ID: <20231018-strncpy-drivers-net-wireless-ti-wlcore-main-c-v1-1-1b1055f482a1@google.com>
Date: Wed, 18 Oct 2023 21:50:01 +0000
From: Justin Stitt <justinstitt@...gle.com>
To: Kalle Valo <kvalo@...nel.org>
Cc: linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-hardening@...r.kernel.org, Justin Stitt <justinstitt@...gle.com>
Subject: [PATCH] wifi: wlcore: main: replace deprecated strncpy with strscpy

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>
---
Note: build-tested only.

Found with: $ rg "strncpy\("
---
 drivers/net/wireless/ti/wlcore/main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ti/wlcore/main.c b/drivers/net/wireless/ti/wlcore/main.c
index bf21611872a3..52a427bd54fa 100644
--- a/drivers/net/wireless/ti/wlcore/main.c
+++ b/drivers/net/wireless/ti/wlcore/main.c
@@ -1126,7 +1126,7 @@ int wl1271_plt_start(struct wl1271 *wl, const enum plt_mode plt_mode)
 
 		/* update hw/fw version info in wiphy struct */
 		wiphy->hw_version = wl->chip.id;
-		strncpy(wiphy->fw_version, wl->chip.fw_ver_str,
+		strscpy(wiphy->fw_version, wl->chip.fw_ver_str,
 			sizeof(wiphy->fw_version));
 
 		goto out;
@@ -2344,7 +2344,7 @@ static int wl12xx_init_fw(struct wl1271 *wl)
 
 	/* update hw/fw version info in wiphy struct */
 	wiphy->hw_version = wl->chip.id;
-	strncpy(wiphy->fw_version, wl->chip.fw_ver_str,
+	strscpy(wiphy->fw_version, wl->chip.fw_ver_str,
 		sizeof(wiphy->fw_version));
 
 	/*

---
base-commit: 58720809f52779dc0f08e53e54b014209d13eebb
change-id: 20231018-strncpy-drivers-net-wireless-ti-wlcore-main-c-c0c28a2ffb0f

Best regards,
--
Justin Stitt <justinstitt@...gle.com>