net: mcdmafec: ensure bus->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_mcdmafec.c b/drivers/net/fsl_mcdmafec.c
index c20aef4ab28dd20bcca07cebcd42de551dd7f9d1..e103f79305e788e2effc5fe29e7bc2eb77e262b1 100644 (file)
--- a/drivers/net/fsl_mcdmafec.c
+++ b/drivers/net/fsl_mcdmafec.c
@@ -541,7 +541,7 @@ static int mcdmafec_probe(struct udevice *dev)
        info->bus = mdio_alloc();
        if (!info->bus)
                return -ENOMEM;
-       strncpy(info->bus->name, dev->name, MDIO_NAME_LEN);
+       strlcpy(info->bus->name, dev->name, MDIO_NAME_LEN);
        info->bus->read = mcffec_miiphy_read;
        info->bus->write = mcffec_miiphy_write;