tun: forbid iface creation with rtnl ops

It's not supported right now (the goal of the initial patch was to support 'ip link del' only). Before the patch: $ ip link add foo type tun [ 239.632660] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 [snip] [ 239.636410] RIP: 0010:register_netdevice+0x8e/0x3a0 This panic occurs because dev->netdev_ops is not set by tun_setup(). But to have something usable, it will require more than just setting netdev_ops. Fixes: f019a7a ("tun: Implement ip link del tunXXX") CC: Eric W. Biederman <[email protected]> Signed-off-by: Nicolas Dichtel <[email protected]> Signed-off-by: David S. Miller <[email protected]>
penberg · Dec 1, 2018 · 35b827b · 35b827b
1 parent 436c945
commit 35b827b
Showing 1 changed file with 3 additions and 3 deletions.
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
@@ -2293,9 +2293,9 @@ static void tun_setup(struct net_device *dev)
 static int tun_validate(struct nlattr *tb[], struct nlattr *data[],
 			struct netlink_ext_ack *extack)
 {
-	if (!data)
-		return 0;
-	return -EINVAL;
+	NL_SET_ERR_MSG(extack,
+		       "tun/tap creation via rtnetlink is not supported.");
+	return -EOPNOTSUPP;
 }
 
 static size_t tun_get_size(const struct net_device *dev)