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>

diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index 57ea45e..8151104 100644 (file)
--- 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;