net: qe: uec: 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/qe/uec.c b/drivers/qe/uec.c
index 5da971ddc0afe8ff0cc9e677e5f4df875ae43f80..c4bd5c4a147f5ff1fc96f3558023c4e17c79c7ab 100644 (file)
--- a/drivers/qe/uec.c
+++ b/drivers/qe/uec.c
@@ -1407,7 +1407,7 @@ int uec_initialize(struct bd_info *bis, struct uec_inf *uec_info)
 
        if (!mdiodev)
                return -ENOMEM;
-       strncpy(mdiodev->name, dev->name, MDIO_NAME_LEN);
+       strlcpy(mdiodev->name, dev->name, MDIO_NAME_LEN);
        mdiodev->read = uec_miiphy_read;
        mdiodev->write = uec_miiphy_write;