[PATCH 14/25] net: dsa: felix: ensure mii_bus->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/mscc_eswitch/felix_switch.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/mscc_eswitch/felix_switch.c b/drivers/net/mscc_eswitch/felix_switch.c
index 6aa79784460d..4c2e57755967 100644
--- a/drivers/net/mscc_eswitch/felix_switch.c
+++ b/drivers/net/mscc_eswitch/felix_switch.c
@@ -258,7 +258,7 @@ static void felix_init(struct udevice *dev)
 	priv->imdio.read = felix_mdio_read;
 	priv->imdio.write = felix_mdio_write;
 	priv->imdio.priv = priv->imdio_base + FELIX_PM_IMDIO_BASE;
-	strncpy(priv->imdio.name, dev->name, MDIO_NAME_LEN);
+	strlcpy(priv->imdio.name, dev->name, MDIO_NAME_LEN);
 
 	/* set up CPU port */
 	out_le32(base + FELIX_QSYS_SYSTEM_EXT_CPU_CFG,
@@ -303,7 +303,7 @@ static int felix_probe(struct udevice *dev)
 		mii_bus->read = felix_mdio_read;
 		mii_bus->write = felix_mdio_write;
 		mii_bus->priv = priv->imdio_base + FELIX_PM_IMDIO_BASE;
-		strncpy(mii_bus->name, dev->name, MDIO_NAME_LEN);
+		strlcpy(mii_bus->name, dev->name, MDIO_NAME_LEN);
 		mdio_register(mii_bus);
 	}
 
-- 
2.25.1