[PATCH] net: phy: replace deprecated strncpy with ethtool_sprintf

[Justin Stitt <justinstitt@google.com>]

strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

ethtool_sprintf() is designed specifically for get_strings() usage.
Let's replace strncpy in favor of this dedicated helper function.

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>
---
Note: build-tested only.

Found with: $ rg "strncpy\("
---
 drivers/net/phy/nxp-cbtx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/phy/nxp-cbtx.c b/drivers/net/phy/nxp-cbtx.c
index 145703f0a406..6a2c0c193255 100644
--- a/drivers/net/phy/nxp-cbtx.c
+++ b/drivers/net/phy/nxp-cbtx.c
@@ -182,7 +182,7 @@ static int cbtx_get_sset_count(struct phy_device *phydev)
 
 static void cbtx_get_strings(struct phy_device *phydev, u8 *data)
 {
-	strncpy(data, "100btx_rx_err", ETH_GSTRING_LEN);
+	ethtool_sprintf(&data, "100btx_rx_err");
 }
 
 static void cbtx_get_stats(struct phy_device *phydev,

---
base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2
change-id: 20231012-strncpy-drivers-net-phy-nxp-cbtx-c-266285682759

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