diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 89ab9efe522c30bd167d690f60c6b18fc29680a5..afa5497f7c35c3ab5682e66440afc8a888d14414 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -3073,10 +3073,11 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
 	struct net *net = sock_net(&tfile->sk);
 	struct tun_struct *tun;
 	void __user* argp = (void __user*)arg;
-	unsigned int ifindex, carrier;
+	unsigned int carrier;
 	struct ifreq ifr;
 	kuid_t owner;
 	kgid_t group;
+	int ifindex;
 	int sndbuf;
 	int vnet_hdr_sz;
 	int le;
@@ -3132,7 +3133,9 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
 		ret = -EFAULT;
 		if (copy_from_user(&ifindex, argp, sizeof(ifindex)))
 			goto unlock;
-
+		ret = -EINVAL;
+		if (ifindex < 0)
+			goto unlock;
 		ret = 0;
 		tfile->ifindex = ifindex;
 		goto unlock;