arch: powerpc: mpc85xx: ensure mdiodev->name is NULL terminated after MDIO_NAME_LEN...

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/arch/powerpc/cpu/mpc85xx/ether_fcc.c b/arch/powerpc/cpu/mpc85xx/ether_fcc.c
index 3c4eb1a7eba942b225f5cb59546319ff0243c3d1..1f6f55707321e9b66bde9ad9437521f7b70a63f9 100644 (file)
--- a/arch/powerpc/cpu/mpc85xx/ether_fcc.c
+++ b/arch/powerpc/cpu/mpc85xx/ether_fcc.c
@@ -444,7 +444,7 @@ int fec_initialize(struct bd_info *bis)
                struct mii_dev *mdiodev = mdio_alloc();
                if (!mdiodev)
                        return -ENOMEM;
-               strncpy(mdiodev->name, dev->name, MDIO_NAME_LEN);
+               strlcpy(mdiodev->name, dev->name, MDIO_NAME_LEN);
                mdiodev->read = bb_miiphy_read;
                mdiodev->write = bb_miiphy_write;