net: dsa: felix: ensure mii_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/mscc_eswitch/felix_switch.c b/drivers/net/mscc_eswitch/felix_switch.c
index 0cab671..711dd44 100644
--- a/drivers/net/mscc_eswitch/felix_switch.c
+++ b/drivers/net/mscc_eswitch/felix_switch.c
@@ -257,7 +257,7 @@
priv->imdio.read = felix_mdio_read;
priv->imdio.write = felix_mdio_write;
priv->imdio.priv = priv->imdio_base + FELIX_PM_IMDIO_BASE;
- strncpy(priv->imdio.name, dev->name, MDIO_NAME_LEN);
+ strlcpy(priv->imdio.name, dev->name, MDIO_NAME_LEN);
/* set up CPU port */
out_le32(base + FELIX_QSYS_SYSTEM_EXT_CPU_CFG,
@@ -302,7 +302,7 @@
mii_bus->read = felix_mdio_read;
mii_bus->write = felix_mdio_write;
mii_bus->priv = priv->imdio_base + FELIX_PM_IMDIO_BASE;
- strncpy(mii_bus->name, dev->name, MDIO_NAME_LEN);
+ strlcpy(mii_bus->name, dev->name, MDIO_NAME_LEN);
mdio_register(mii_bus);
}