On 29.10.2024 12:47, Antonio Quartulli wrote:
An ovpn interface will keep carrier always on and let the user
decide when an interface should be considered disconnected.
This way, even if an ovpn interface is not connected to any peer,
it can still retain all IPs and routes and thus prevent any data
leak.
Signed-off-by: Antonio Quartulli <antonio@xxxxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
---
drivers/net/ovpn/main.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/net/ovpn/main.c b/drivers/net/ovpn/main.c
index eead7677b8239eb3c48bb26ca95492d88512b8d4..eaa83a8662e4ac2c758201008268f9633643c0b6 100644
--- a/drivers/net/ovpn/main.c
+++ b/drivers/net/ovpn/main.c
@@ -31,6 +31,13 @@ static void ovpn_struct_free(struct net_device *net)
static int ovpn_net_open(struct net_device *dev)
{
+ /* ovpn keeps the carrier always on to avoid losing IP or route
+ * configuration upon disconnection. This way it can prevent leaks
+ * of traffic outside of the VPN tunnel.
+ * The user may override this behaviour by tearing down the interface
+ * manually.
+ */
+ netif_carrier_on(dev);
If a user cares about the traffic leaking, then he can create a
blackhole route with huge metric:
# ip route add blackhole default metric 10000
Why the network interface should implicitly provide this functionality?
And on another hand, how a routing daemon can learn a topology change
without indication from the interface?
netif_tx_start_all_queues(dev);
return 0;
}
