From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: Mon, 27 Sep 2021 11:21:47 +0000 (+0300)
Subject: net: ep93xx: ensure mdiodev->name is NULL terminated after MDIO_NAME_LEN truncation
X-Git-Tag: baikal/mips/sdk5.9~15^2^2~102^2~6^2~18
X-Git-Url: https://git.baikalelectronics.ru/?a=commitdiff_plain;h=cea8799cbaa90cfac8a6aa6b4b765b8a108e2fc6;p=uboot.git

net: ep93xx: 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 <vladimir.oltean@nxp.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
---

diff --git a/drivers/net/ep93xx_eth.c b/drivers/net/ep93xx_eth.c
index 0218349b04..9f8df7de06 100644
--- a/drivers/net/ep93xx_eth.c
+++ b/drivers/net/ep93xx_eth.c
@@ -427,7 +427,7 @@ int ep93xx_miiphy_initialize(struct bd_info * const bd)
 	struct mii_dev *mdiodev = mdio_alloc();
 	if (!mdiodev)
 		return -ENOMEM;
-	strncpy(mdiodev->name, "ep93xx_eth0", MDIO_NAME_LEN);
+	strlcpy(mdiodev->name, "ep93xx_eth0", MDIO_NAME_LEN);
 	mdiodev->read = ep93xx_miiphy_read;
 	mdiodev->write = ep93xx_miiphy_write;