GotaTun -- Mullvad's WireGuard Implementation in Rust

(mullvad.net)

281 points | by km 4 hours ago

9 comments

  • Hakkin 3 hours ago
    I definitely noticed the performance boost on my Pixel 8, for some reason it seems to really not like wireguard-go, it struggled to pull even 100mbps, maybe something unoptimized on Google's custom hardware. With the new GotaTun version I can pull 500mbps+, though unfortunately it also seems to have introduced a bug that randomly prevents the phone from entering a deep sleep state, so occasionally my battery will randomly start draining at 10x normal speed if I have it enabled until I reboot.
    • chneu 22 minutes ago
      MTU strikes again. 1320.
    • vjerancrnjak 1 hour ago
      Same behavior on raspberry pi 5. Might be just lack of arm optimizations.
      • wyldfire 18 minutes ago
        It's very likely that VPNs like this are not CPU-bound, even on somewhat whimpy CPUs. I'd wager even some microcontrollers could sling 500megabits/sec around without trouble.
    • Hasnep 2 hours ago
      Oh, this is the reason the Mullvad app on my Pixel 6a was suddenly able to connect in less than a second where before it would take 5-10 seconds, nice!
  • turblety 3 hours ago
    Nice, I love WireGuard. I ended up building WrapGuard [1] to run applications without root access to the host and choose Go to write it in. I don't really know Rust, but does it make more sense for firmware/networking type software? Is there even a difference?

    1. https://github.com/puzed/wrapguard

    • jpeeler 44 minutes ago
      Very cool. I may use this, but also curious what the best choice would be if you don't need encryption. I'm specifically wanting to enable some local container networking using apple's new container tool [1]. I know I could just use Docker...

      [1] https://github.com/apple/container/issues/670

    • skylurk 3 hours ago
      Pick the devil you know, as they say.
    • chjj 2 hours ago
      Very cool project. Is it always an LD_PRELOAD or can it function as a standalone SOCKS proxy similar to wireproxy?
      • turblety 1 hour ago
        Thanks chjj. Yeah it's always LD_PRELOAD. There is wireproxy [1] though that might do what you want?

        1. https://github.com/whyvl/wireproxy

        • throwaway894345 33 minutes ago
          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)?
          • turblety 27 minutes ago
            Yeah you are right. Can you think of any way we could capture that traffic too?
            • yjftsjthsd-h 12 minutes ago
              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

            • throwaway894345 16 minutes ago
              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!

    • unrealhoang 3 hours ago
      from TFA, the main advantage would be for embedded (as a library) use case, FFI with Go is harder.
    • maxmcd 2 hours ago
      I believe you are making use of gVisor’s userspace TCP implementation. I’m not sure if there is something similar in Rust that would be so easy to set up like this.
  • nevi-me 3 hours ago
    If anyone working on the implementation is here, was it not possible to upstream your changes to BoringTun? The blog mentions some changes but doesn't go into detail on that aspect.
    • embedding-shape 3 hours ago
      I'm guessing because BoringTun has been in a state of "currently undergoing a restructuring" for something like 3 years by now, I'm guessing Mullvad wasn't too keen to maybe/maybe not be able to contribute, and much more prefer being in 100% control of their own implementation.

      As someone who wants to see Wireguard succeed and in even wider use, this move makes sense from that perspective too. The more implementations we have available, the more we can trust that the protocol is secure and stable enough. Personally I also have about 100x more trust in Mullvad than Cloudflare both in terms of security but more importantly privacy, but that's just the cherry on top.

    • kevincox 15 minutes ago
      BoringTun is unmaintained. There are various forks being developed.

      I work at Obscura VPN and faced with boringtun bugs a few years ago we evaluated a few of the forks and switched our client to be based on top of NepTUN (https://github.com/NordSecurity/NepTUN).

      I am curious why Mullvad started their own fork rather than building on top of one of the existing ones. It would be nice if there could be reconsolidation somewhere.

  • imcritic 3 hours ago
    I wish they would improve wireguard-the-protocol as well: wireguard doesn't stand a chance against gov/isp blocks.
    • razighter777 3 hours ago
      That's more of a job for an encapsulating protocol. (shadowsocks or similar) Wireguard isn't designed to be obfuscating alone. It's just a simple l3 udp tunnel with a minimal attack surface.
      • nrds 7 minutes ago
        That's the traditional answer parroted in the Wireguard documentation but a few hours' serious thought and design is enough to reveal the fatal flaw: any encapsulating protocol will have to reinvent and duplicatively implement all of the routing logic. Perr-based routing is at least 50% of wireguard's value proposition. Having to reimplement it at the higher level defeats the purpose. No, obfuscation _has_ to be part of the same protocol as routing.

        (Btw, same sort of thing occurs with zfs combining raid and filesystem to close the parity raid write hole. Often strictly layered systems with separation of concerns are less than the sum of their parts.)

      • Hendrikto 2 hours ago
        > It's just a simple l3 udp tunnel

        Wait, isn’t UDP L4? Am I missing something?

        • gwehrli 1 hour ago
          Wireguard is a L3 VPN that uses UDP (L4) for tunneling. Thats probably what was meant.
        • eurg 2 hours ago
          Yes, but it tunnels arbitrary IP packets encapsulated in UDP.
    • holysoles 21 minutes ago
      The mullvad apps do offer obfuscation options (shadowsocks, etc) but i agree it would be nice if something was baked into wireguard itself. I recently went through setting up shadowsocks over wg for my homelab and it was a good bit of effort
    • tvshtr 2 hours ago
      There are forks of wg because of this. Like amnezia-wg
    • DANmode 2 hours ago
      Known Limitations

      WireGuard is a protocol that, like all protocols, makes necessary trade-offs. This page summarizes known limitations due to these trade-offs.

      Deep Packet Inspection

      WireGuard does not focus on obfuscation. Obfuscation, rather, should happen at a layer above WireGuard, with WireGuard focused on providing solid crypto with a simple implementation. It is quite possible to plug in various forms of obfuscation, however.

      tl;dr Read the docs.

      • mycall 1 hour ago
        Mullvad does exactly this.
    • tetris11 2 hours ago
      Anywhere I can read more about this?
  • alias_neo 2 hours ago
    Is there any way to switch to this implementation for generic WireGuard users?

    I tried downloading their Android app, but it's not generally usable for people who host our own WireGuard, which is fair enough.

  • mintflow 1 hour ago
    For the similar reason I do not using any go based proxy code in my MintFlow app, and use rust to implement some proxy protocols.

    But my app’s wireguard is natively implemented by fdio vpp plugin, so it’s based on C.

    • Bigpet 1 hour ago
      I would not have guessed that iOS allows enough access to APIs to implement anything vpp-based. Very cool to see. I also enjoyed working with vpp (for the brief 6 months that I had with it).
      • mintflow 1 hour ago
        I was thinking that's hard, but I noticed that vpp get ported to FreeBSD using epoll shim library, and I learnt apple Darwin use some some userland of FreeBSD to do POSIX compatibility, then after some tests and hacking, most related to minor POSIX API adaptation such as mmap and one major coroutine need add some assembly code, and it work! But I think most disappointed to me is that apple do lack some vectorized network IO unless do some kernel extension or other sort non standard ways.
  • intsunny 2 hours ago
    Its funny, this is another of the billions of reasons why Mullvad should be the VPN of choice. But so many fucking people can't ever get over that their favorite social media influencer/Youtuber is offering a code for 200% off of NordShark VPN, now with extra AI.
    • Philip-J-Fry 1 hour ago
      Mullvad is great for privacy. But it's blocked by pretty much every VPN block list. NordVPN at the very least bypasses all the ones I regularly encounter.

      I do use Mullvad for most web browsing though. But Imgur for example is blocked on it, and it's blocked in the UK, so I need NordVPN if I want to see any images there.

      Most people's VPN usage is literally just geolocation restrictions and Nord is really good at that.

      • Gander5739 32 minutes ago
        Aren't proxies good enough for that purpose?
    • Spunkie 1 hour ago
      I love and use mullvad myself but I don't think they are very competitive for the average person. They mostly just care about getting around geo blocks on websites and streaming services, which mullvad puts 0 effort into facilitating.
    • eatbitseveryday 2 hours ago
      It became less of a choice for many after they sadly had to disable port forwarding.
      • jorvi 2 hours ago
        Yeah, their reasoning is solid (easy to abuse) but it is still a very useful feature.

        AFAIK, at the moment your choices are AirVPN and ProtonVPN. AirVPN has static port forwarding and Proton has UPNP port forwarding.

        • gruez 1 hour ago
          private internet access has port forwarding too
    • Aurornis 1 hour ago
      Mullvad seems to care and be competent about privacy, but most average VPN users aren’t seeking the most extreme privacy. They just want something cheap that lets them do geolocation things or access the most websites.
      • AJ007 13 minutes ago
        The average VPN user is knowledge-less. At best their internet usage data is being sold to third party analytics companies. At worst third parties are routing their own bots through their local connection.
    • swexbe 1 hour ago
      I wish I could use Mullvad. But their IPs are banned from many streaming services and they don't change them often enough so I am stuck with Nord.
    • aitchnyu 1 hour ago
      Not to mention holding companies which snap up 15 competing VPNs and whitelabel most of them.
    • tumdum_ 2 hours ago
      You do know that NordSec maintains its own rust fork of BoringTun: https://github.com/NordSecurity/NepTUN ? :)
  • ur-whale 3 hours ago
    One meta thing I've always wondered ... Are multiple implementations of the same protocol good or bad for security?

    Probably naively, I'm thinking:

        - diversity: good
        - doubling the attack surface: real bad
    
    What do the security folks out there think of the topic?
    • mwalser 3 hours ago
      I wouldn't say that multiple implementations are duplicating the attack surface since most users will not end up running them in parallel.
      • ur-whale 2 hours ago
        I meant at a global level (think as if you're attacking all wireguard users, not a single one)
        • swiftcoder 2 hours ago
          The increased attack surface mostly only affects that one particular implementation though. So, yes, twice as many implementations that may contain exploitable bugs, but each new implementation could only be used to exploit a fraction of the total user base
          • rlpb 2 hours ago
            > could only be used to exploit a fraction

            If anything this is a even a good thing, since it means that each individual vulnerability an attacker finds is less valuable to them.

    • lugu 59 minutes ago
      Competitions helps in multiple ways. It improve tooling, test suites, CVE response time, documentation and evolution of the protocol. There are some counter examples where compatibility suck, like DLNA but the problem often come from the spec.
    • embedding-shape 3 hours ago
      I think the general consensus is that it improves security of the protocol, but obviously that won't matter much if the implementation gets something wrong or has worse security by itself.

      Issues in the protocol itself would need all implementations to change, but issues in the implementation would obviously be isolated to one implementation. For something like Wireguard, I'd wager a guess that issues in the implementations are more common than issues in the protocol, at least at this stage.

    • stevefan1999 3 hours ago
      That's really good because it means it will be able to have more exposure, more exposure means more improvement, more improvement eventually dig out bad bugs and reduces the attack surface in the long run
    • saidnooneever 1 hour ago
      dont fix if it ain't broken. look at sudo-rs and other rust ports.

      ofc, thats a cynical view.

      i personally think its a bad idea to duplicate efforts. better combine them. otherwise u risk making mistakes that were already solved. missing lessons already learnt.

  • bjhsuw8ud 3 hours ago
    [flagged]