From d4d294f16fd7dff44615eb6f8b2ccbca004e07eb Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Mon, 27 Sep 2021 14:21:54 +0300 Subject: [PATCH] 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 Reviewed-by: Ramon Fried --- drivers/net/mscc_eswitch/felix_switch.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/mscc_eswitch/felix_switch.c b/drivers/net/mscc_eswitch/felix_switch.c index 0cab671908..711dd441bb 100644 --- a/drivers/net/mscc_eswitch/felix_switch.c +++ b/drivers/net/mscc_eswitch/felix_switch.c @@ -257,7 +257,7 @@ static void felix_init(struct udevice *dev) 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 @@ static int felix_probe(struct udevice *dev) 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); } -- 2.39.5