From 73894f6938056560357841846158df1b9014af1d Mon Sep 17 00:00:00 2001 From: Vladimir Oltean <vladimir.oltean@nxp.com> Date: Mon, 27 Sep 2021 14:21:52 +0300 Subject: [PATCH] net: macb: ensure mdiodev->name is NULL terminated after MDIO_NAME_LEN truncation strncpy() simply bails out when copying a source string whose size exceeds the destination string size, potentially leaving the destination string unterminated. One possible way to address is to pass MDIO_NAME_LEN - 1 and a previously zero-initialized destination string, but this is more difficult to maintain. The chosen alternative is to use strlcpy(), which properly limits the copy len in the (srclen >= size) case to "size - 1", and which is also more efficient than the strncpy() byte-by-byte implementation by using memcpy. The destination string returned by strlcpy() is always NULL terminated. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Ramon Fried <rfried.dev@gmail.com> --- drivers/net/macb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/macb.c b/drivers/net/macb.c index 57ea45e2dc..8151104acf 100644 --- a/drivers/net/macb.c +++ b/drivers/net/macb.c @@ -1245,7 +1245,7 @@ int macb_eth_initialize(int id, void *regs, unsigned int phy_addr) struct mii_dev *mdiodev = mdio_alloc(); if (!mdiodev) return -ENOMEM; - strncpy(mdiodev->name, netdev->name, MDIO_NAME_LEN); + strlcpy(mdiodev->name, netdev->name, MDIO_NAME_LEN); mdiodev->read = macb_miiphy_read; mdiodev->write = macb_miiphy_write; @@ -1403,7 +1403,7 @@ static int macb_eth_probe(struct udevice *dev) macb->bus = mdio_alloc(); if (!macb->bus) return -ENOMEM; - strncpy(macb->bus->name, dev->name, MDIO_NAME_LEN); + strlcpy(macb->bus->name, dev->name, MDIO_NAME_LEN); macb->bus->read = macb_miiphy_read; macb->bus->write = macb_miiphy_write; -- 2.39.5