diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 3c9985f29950..5ce580f413b9 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1496,11 +1496,13 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 	switch (tun->flags & TUN_TYPE_MASK) {
 	case IFF_TUN:
 		if (tun->flags & IFF_NO_PI) {
-			switch (skb->data[0] & 0xf0) {
-			case 0x40:
+			u8 ip_version = skb->len ? (skb->data[0] >> 4) : 0;
+
+			switch (ip_version) {
+			case 4:
 				pi.proto = htons(ETH_P_IP);
 				break;
-			case 0x60:
+			case 6:
 				pi.proto = htons(ETH_P_IPV6);
 				break;
 			default: