From 30c40398b65c4109018124ccdbc3bf0edc741050 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Mon, 27 Sep 2021 14:21:57 +0300 Subject: [PATCH] net: smc911x: 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 Reviewed-by: Ramon Fried --- drivers/net/smc911x.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/smc911x.c b/drivers/net/smc911x.c index 8f420261fa..5d9a73f23d 100644 --- a/drivers/net/smc911x.c +++ b/drivers/net/smc911x.c @@ -425,7 +425,7 @@ static int smc911x_initialize_mii(struct smc911x_priv *priv) if (!mdiodev) return -ENOMEM; - strncpy(mdiodev->name, priv->dev.name, MDIO_NAME_LEN); + strlcpy(mdiodev->name, priv->dev.name, MDIO_NAME_LEN); mdiodev->read = smc911x_miiphy_read; mdiodev->write = smc911x_miiphy_write; -- 2.39.5