netdev - [PATCH net-next v10 05/23] ovpn: keep carrier always on

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20241025-b4-ovpn-v10-5-b87530777be7@openvpn.net>
Date: Fri, 25 Oct 2024 11:14:04 +0200
From: Antonio Quartulli <antonio@...nvpn.net>
To: Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, 
 Paolo Abeni <pabeni@...hat.com>, Donald Hunter <donald.hunter@...il.com>, 
 Antonio Quartulli <antonio@...nvpn.net>, Shuah Khan <shuah@...nel.org>, 
 donald.hunter@...il.com, sd@...asysnail.net, ryazanov.s.a@...il.com, 
 Andrew Lunn <andrew@...n.ch>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-kselftest@...r.kernel.org
Subject: [PATCH net-next v10 05/23] ovpn: keep carrier always on

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@...nvpn.net>
Reviewed-by: Andrew Lunn <andrew@...n.ch>
---
 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);
 	netif_tx_start_all_queues(dev);
 	return 0;
 }

-- 
2.45.2