[PATCH 12/25] net: macb: ensure mdiodev->name is NULL terminated after MDIO_NAME_LEN truncation

[Vladimir Oltean]

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 at nxp.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 57ea45e2dc7f..8151104acfc0 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;
 
-- 
2.25.1