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Comment by turblety | Hacker News Reader

Thanks chjj. Yeah it's always LD_PRELOAD. There is wireproxy [1] though that might do what you want?

Correct me if I’m wrong, but if you use LD_PRELOAD, presumably it will not work for applications that circumvent libc, such as Go binaries (at least those with CGo disabled)?

Yeah you are right. Can you think of any way we could capture that traffic too?

Tor does this the right way on Linux. You make a separate user namespace with access only to the WireGuard network adapter and run the program inside of that. You want the kernel involved if you want any sort of guarantee:

https://blog.torproject.org/introducing-oniux-tor-isolation-...

How does this work in something like Kubernetes where you have a sidebar container configuring the network for the main container without affecting others on the same host?

I think all containers share the same netns in a pod. You restrict the pod to only the Wireguard peer IP, and have a (NET_ADMIN) sidecar container create an interface (tun/kernel wg) and update the routing tables for the netns. Then I believe the traffic from the other containers in the pod is tunneled.

Can you use user namespaces to create a network namespace with the VPN active and stick applications in that namespace?

From a quick search, https://blog.thea.codes/nordvpn-wireguard-namespaces/ sees to have at least the bones of a decent solution, though I've not had a chance to dig very far. A lot of results use root to set up the namespace, but I was pretty sure that shouldn't be needed with a new kernel and user namespaces enabled

It would be a non-trivial amount of work but syscall user dispatch lets you intercept syscalls on modern linux if you really want to.

https://docs.kernel.org/admin-guide/syscall-user-dispatch.ht...

I have no idea. I’ve never messed with it, but maybe something like eBPF to intercept network syscalls? Not sure if that’s a thing—especially without root access? Mostly I was just thinking the project page could use a disclaimer since, in Go, it is common to bypass libc. :shrug:

This seems like a very cool, useful project though!

ptrace: https://github.com/hmgle/graftcp

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