Linux

47561 readers

718 users here now

From Wikipedia, the free encyclopedia

Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

Rules

Posts must be relevant to operating systems running the Linux kernel. GNU/Linux or otherwise.
No misinformation
No NSFW content
No hate speech, bigotry, etc

Related Communities

Community icon by Alpár-Etele Méder, licensed under CC BY 3.0

founded 5 years ago

MODERATORS

AgreeableLandscape@lemmy.ml

nooter692@lemmy.ml

MarcellusDrum@lemmy.ml

cypherpunks@lemmy.ml

cyclohexane@lemmy.ml

d3Xt3r@lemmy.nz

sharing my simple wireguard kill-switch for Linux (lemmings.world)

submitted 4 months ago by xabadak@lemmings.world to c/linux@lemmy.ml

18 comments fedilink hide all child comments

In light of the recent TunnelVision vulnerability I wanted to share a simple firewall that I wrote for wireguard VPNs.

https://codeberg.org/xabadak/wg-lockdown

If you use a fancy official VPN client from Mullvad, PIA, etc, you won't need this since most clients already have a kill switch built in (also called Lockdown Mode in Mullvad). This is if you use a barebones wireguard VPN like me, or if your VPN client has a poorly-designed kill switch (like NordVPN, more info here).

A firewall should mitigate the vulnerability, though it does create a side-channel that can be exploited in extremely unlikely circumstances, so a better solution would be to use network namespaces (more info here). Unfortunately I'm a noob and I couldn't find any scripts or tools to do it that way.

you are viewing a single comment's thread
view the rest of the comments

[–] xabadak@lemmings.world 1 points 4 months ago* (last edited 4 months ago)

Actually my firewall is persistent, just like many of the other good VPN clients, so "kill switch" is a bit of a misnomer. Which is why I called it wg-lockdown, named after Mullvad's lockdown mode. Persistent firewalls are effective, they just add a very tiny side-channel, as discussed in the link in my post. I just used the terms "kill switch" in my post because that's what many other people use.

Though the point about the LAN is a good point, I didn't consider that. I added LAN access because without it, the firewall was interfering with the networking of my docker container and virtual machines, which use local subnets. Even the official Mullvad client has issues with this. What do you recommend in this case? Manually whitelist the local subnets used by docker and my other virtual networks?

Edit: actually upon reading Mullvad's statement on TunnelVision, I realized that my firewall is still effective because it only allows traffic directed to LAN IP's to bypass the VPN. So regular internet traffic will be blocked if the attacker tries to redirect it to the LAN. I'm glad I used Mullvad as a reference implementation 😅