net: davinci_emac: 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>

diff --git a/drivers/net/ti/davinci_emac.c b/drivers/net/ti/davinci_emac.c
index bfe1b84cd566ba6f6c986ab5b67f344625ad7f23..2dfadbd82d5bcaf997e106817f590a3b6eb8b1f6 100644 (file)
--- a/drivers/net/ti/davinci_emac.c
+++ b/drivers/net/ti/davinci_emac.c
@@ -816,7 +816,7 @@ static int davinci_emac_probe(struct udevice *dev)
                struct mii_dev *mdiodev = mdio_alloc();
                if (!mdiodev)
                        return -ENOMEM;
-               strncpy(mdiodev->name, phy[i].name, MDIO_NAME_LEN);
+               strlcpy(mdiodev->name, phy[i].name, MDIO_NAME_LEN);
                mdiodev->read = davinci_mii_phy_read;
                mdiodev->write = davinci_mii_phy_write;