net: enetc: ensure imdio.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>

diff --git a/drivers/net/fsl_enetc.c b/drivers/net/fsl_enetc.c
index f56f9e7..915c7c8 100644 (file)
--- a/drivers/net/fsl_enetc.c
+++ b/drivers/net/fsl_enetc.c
@@ -269,7 +269,7 @@ static void enetc_start_pcs(struct udevice *dev)
                priv->imdio.read = enetc_mdio_read;
                priv->imdio.write = enetc_mdio_write;
                priv->imdio.priv = priv->port_regs + ENETC_PM_IMDIO_BASE;
-               strncpy(priv->imdio.name, dev->name, MDIO_NAME_LEN);
+               strlcpy(priv->imdio.name, dev->name, MDIO_NAME_LEN);
                if (!miiphy_get_dev_by_name(priv->imdio.name))
                        mdio_register(&priv->imdio);
        }