net: dsa: b53: Use strlcpy() for ethtool::get_strings

Our statistics strings are allocated at initialization without being
bound to a specific size, yet, we would copy ETH_GSTRING_LEN bytes using
memcpy() which would create out of bounds accesses, this was flagged by
KASAN. Replace this with strlcpy() to make sure we are bound the source
buffer size and we also always NUL-terminate strings.

Fixes: 967dd82ffc52 ("net: dsa: b53: Add support for Broadcom RoboSwitch")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/b53/b53_common.c

@@ -814,8 +814,8 @@ void b53_get_strings(struct dsa_switch *ds, int port, uint8_t *data)
 	unsigned int i;
 
 	for (i = 0; i < mib_size; i++)
-		memcpy(data + i * ETH_GSTRING_LEN,
-		       mibs[i].name, ETH_GSTRING_LEN);
+		strlcpy(data + i * ETH_GSTRING_LEN,
+			mibs[i].name, ETH_GSTRING_LEN);
 }
 EXPORT_SYMBOL(b53_get_strings);