From 79ac11393328fb1717d17c12e3c0eef0e9fa0647 Mon Sep 17 00:00:00 2001 From: Justin Stitt Date: Mon, 11 Dec 2023 19:10:00 +0000 Subject: [PATCH] net: mdio-gpio: 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 new_bus->id to be NUL-terminated but not NUL-padded based on its prior assignment through snprintf: | snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id); Due to this, 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 use sizeof() instead of a length macro as this more closely ties the maximum buffer size to the destination buffer. Do this for two instances. 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 Signed-off-by: Justin Stitt Reviewed-by: Russell King (Oracle) Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20231211-strncpy-drivers-net-mdio-mdio-gpio-c-v3-1-76dea53a1a52@google.com Signed-off-by: Jakub Kicinski --- drivers/net/mdio/mdio-gpio.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/mdio/mdio-gpio.c b/drivers/net/mdio/mdio-gpio.c index 897b88c50bbb..778db310a28d 100644 --- a/drivers/net/mdio/mdio-gpio.c +++ b/drivers/net/mdio/mdio-gpio.c @@ -123,9 +123,9 @@ static struct mii_bus *mdio_gpio_bus_init(struct device *dev, new_bus->parent = dev; if (bus_id != -1) - snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id); + snprintf(new_bus->id, sizeof(new_bus->id), "gpio-%x", bus_id); else - strncpy(new_bus->id, "gpio", MII_BUS_ID_SIZE); + strscpy(new_bus->id, "gpio", sizeof(new_bus->id)); if (pdata) { new_bus->phy_mask = pdata->phy_mask; -- 2.34.1