net: bcm-sf2: 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/bcm-sf2-eth.c b/drivers/net/bcm-sf2-eth.c
index c862c141461c9e91452aa13b001c7f1cd6bdfb81..88dc3ab384668af05b1e0592a858465cbbfe2ea5 100644 (file)
--- a/drivers/net/bcm-sf2-eth.c
+++ b/drivers/net/bcm-sf2-eth.c
@@ -250,7 +250,7 @@ int bcm_sf2_eth_register(struct bd_info *bis, u8 dev_num)
 
        if (!mdiodev)
                return -ENOMEM;
-       strncpy(mdiodev->name, dev->name, MDIO_NAME_LEN);
+       strlcpy(mdiodev->name, dev->name, MDIO_NAME_LEN);
        mdiodev->read = eth->miiphy_read;
        mdiodev->write = eth->miiphy_write;