[PATCH 01/25] arch: powerpc: mpc85xx: ensure mdiodev->name is NULL terminated after MDIO_NAME_LEN truncation

Vladimir Oltean vladimir.oltean at nxp.com
Mon Sep 27 13:21:41 CEST 2021


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 at nxp.com>
---
 arch/powerpc/cpu/mpc85xx/ether_fcc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/cpu/mpc85xx/ether_fcc.c b/arch/powerpc/cpu/mpc85xx/ether_fcc.c
index 3c4eb1a7eba9..1f6f55707321 100644
--- a/arch/powerpc/cpu/mpc85xx/ether_fcc.c
+++ b/arch/powerpc/cpu/mpc85xx/ether_fcc.c
@@ -444,7 +444,7 @@ int fec_initialize(struct bd_info *bis)
 		struct mii_dev *mdiodev = mdio_alloc();
 		if (!mdiodev)
 			return -ENOMEM;
-		strncpy(mdiodev->name, dev->name, MDIO_NAME_LEN);
+		strlcpy(mdiodev->name, dev->name, MDIO_NAME_LEN);
 		mdiodev->read = bb_miiphy_read;
 		mdiodev->write = bb_miiphy_write;
 
-- 
2.25.1



More information about the U-Boot mailing list