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This article gave me more appreciation for the stance of the Linux community. So to sum up. Valorant's anti-cheat, which the author sees something like an idea

• gjsman-1000 1y ago
  - … but successfully, more or less, prevents most cheating attempts which would also make the game unplayable regardless. For anyone saying “just do server side,” no, it’s physically impossible to stop all cheating that way until we have internet faster than human perception.
  • dvdkon 1y ago
    Sure, but you could stop the most blatant wallhacks at least, but most times I see a video of a cheater, it's something stupid like that. It can't be that hard to do occlusion calculations server-side, right? Don't let perfect be the enemy of good.
    • gjsman-1000 1y ago
      When it comes to cheating, perfect is the enemy of good. This is one of those rare cases where the phrase doesn’t hold. The problem is that server-side occlusion is only a small piece of the puzzle. A naïve implementation means hundreds of thousands of raycasts per second, which doesn’t scale. Real engines rely on precomputed visibility sets, spatial partitioning, and still have to leak some data client-side for responsiveness. Basically - the kernel level check is not laziness, but for unsolvable problems without huge compute costs or latency.
      • dvdkon 1y ago
        Fine, then let's not bother with anti-cheat at all, since an aimbot can work by just filming the screen and sending HID events over USB. Anti-cheat is like DRM: You have to make do with a compromise. Hundreds of thousands of raycasts per second sounds doable to me, but couldn't you just use a GPU and some simplified level geometry? That ought to scale well enough. It's not free or perfect (knowing the position of a hand a cheat will be able to estimate where the head is anyway), but that's not the goal, right?
        • whatevaa 1y ago
          There is a video of DYI aimbot of using a camera and sending electrical impulses into his arm to make him do certain adjustments. It's a bit hit and miss but seems refineable. It's cat and mouse game.
          • pxc 1y ago
            Is cyborg doping even cheating? At least at this stage it's still high effort and DIY. That almost makes it legitimate to me
            • internetter 1y ago
              many sport communities call doping cheating
              • pxc 1y ago
                and that's reasonable! but it's not a given. It's different from other kinds of cheating and some of its motivations are unusual when it comes to cheating restrictions (e.g., long-term health of players)
          • dpoloncsak 1y ago
            This is probably the video? https://www.youtube.com/watch?v=x-EbjGSRyKA&pp=ygUZYmFzaWNhbGx5IGhvbWVsZXNzIGFpbWJvdA%3D%3D https://www.youtube.com/watch?v=x-EbjGSRyKA&pp=ygUZYmFzaWNhb... BasicallyHomeless has made it his life mission to eradicate cheating in video games.
    • orbital-decay 1y ago
      >It can't be that hard to do occlusion calculations server-side, right? I think you already know the answer. Yes, it's bottlenecked by latency and jitter (of the laggiest player, no less), and in addition to that the maximum possible movement velocity makes it much much worse in fast paced games. It's been attempted a few times since at least late 90's, with predictable results. In other words, complete server-side calculations are a fantasy. Besides, they won't even remotely make cheating impossible or even harder! Even complete hardware lockdown won't.
    • vel0city 1y ago
      If the server sends your client "you hear footsteps from this location" then you know where they are.
    • olaulaja 1y ago
      It can be rather difficult, mostly due to the occlusion calculations having to be conservative (must count visible things as visible, allowed to count invisible as visible, or things pop) and latency (must account for every possible position within max move speed * max latency, or things pop) The naive raycast from player camera to other player would be fine for perf but may count partially visible as invisible, so its unacceptable. You'd have to raycast every pixel of the potentially visible player model to stay conservative. With movement + latency this expands to every pixel the player model could potentially occupy during your max latency period, and you need to consider the viewer moving too! In practice this expands to a visibility test between two spheres with radius max_latency*max_movespeed + player_model_radius. Now, you could theoretically do a bunch of random raycasts between the spheres and get an answer that is right some of the time, but it would be a serious violation of our conservativeness criteria and the performance would get worse with more rays/better results. Also keep in mind that we need to do this for every single player/player pair a few dozen times per second, so it needs to be fast! To do this, you need a dedicated data structure that maps volumes to other volumes visible from said volume. There are a few, and they are all non-trivial and/or slow to build well. (google for eg. potentially visible set, cell-portal graph + occlusion). You also trade performance for precision, and in practice you walls might become 'transparent' a bit too early. With all this being done, we can actually "do occlusion calculations server-side". There's just one problem with this that I still don't know a solution for, namely precision. With fast players and imprecise conservative visibility, things you care about are going to count as visible pretty often, including stuff like enemies peeking from behind a corner (because they could have moved at full sprint for 100ms and the end of the wall is rounded away in your acceleration structure anyway) so all this complexity might not get you that much, particularly if your game is fast paced. You'd prevent some wallhacks but not the ones that really matter. TLDR yes, it's actually hard and might not be good enough anyway
    • Hikikomori 1y ago
      In a 2d game? Sure, no problem, all Dota types have them. In games like CS and Valorant? Yes, they already do that, they have maps with simple geometry so its possible. Games with open world geometry with buildings with windows etc? Will be almost useless to implement anyway. You need to avoid pop-in effects so positions needs to be sent 1-2m before they are visible, its what they do in cs/valorant but it doesn't really work with complex geometry.
  • Enginerrrd 1y ago
    I actually think this is one area where AI and statistics applied to player behavior are actually the right answer, similar to how they catch chess cheaters. I've seen videos where cheats are particularly easy to detect if you are also cheating. I.e. when you have all the information, you can start to see players reacting to other players before they should be able to detect them. So it should be possible to build a repertoire of cheating examples and clean examples using high level players to catch a fair amount of cheating behavior. And while I understand that there are ways to mitigate this and its an arms race, the less obvious the cheats are, the less effective they are, almost by definition. If someone is consistently reacting outside the range of normal human reaction times, they're cheating. If they randomize it enough to be within human range, well, mission accomplished, kind of. If they're reacting to other players in impossible ways by avoiding them or aiming toward them before they can be seen with unusual precision or frequency, they're cheating. A lot of complex game dynamics can be simplified to 2D vectors and it shouldn't be that computationally intensive to process.
    • xg15 1y ago
      Fully agreeing with this. I think there are two different approaches when people think of "server side": The first is "never trust the client", i.e. realtime validation and having the server be the sole authority on the current game state. This is the straightforward solution to think of for programmers, but it's also practically infeasible due to latency, etc. But what the server could do is a "trust but verify" approach: accept data from the clients when they submit it, but have some background processes that can analyze the data for anomalies and, if too much of it was detected, trigger a ban. The only problem I see with this approach is that cheaters might react by repeatedly making new accounts and playing as them until the verification process has caught up and bans the account. Cheating would be more obvious - as cheaters would have to start over with a beginner character every time - but it could still be annoying. So the problem of ban evasion would become even more important. And I don't really see how a purely server-side solution could work there.
• koakuma-chan 1y ago
  > - is somehow not a spyware or data protection risk at all... Don't worry, it's owned by Tencent.
  • NewsaHackO 1y ago
    The author made the most ridiculous arguments, had to stop reading after that point.
  • ykonstant 1y ago
    Phew!
• Retr0id 1y ago
  - and, by design, is resistant to auditing, analysis, or user-modification
  • gjsman-1000 1y ago
    If you trust Microsoft with your OS; I suppose you should trust Microsoft when they sign kernel modules, right? ;)
    • ACCount37 1y ago
      It's a good thing that Microsoft has never signed an anticheat kernel module that turned out to be so vulnerable that some malware installed it on purpose to gain more system access.
      • internetter 1y ago
        for the lucky 10000: https://www.trendmicro.com/en_us/research/22/h/ransomware-actor-abuses-genshin-impact-anti-cheat-driver-to-kill-antivirus.html https://www.trendmicro.com/en_us/research/22/h/ransomware-ac...
        • dylan604 1y ago
          Thanks for the link. I read the GP's comment, and was thinking that was an ballsy if not hilarious move on the hacker's part. Your link saved me the trouble of searching. I'm not a gamer, so I don't keep up with these details. Whether you like it or not, the cheat devs are definitely HN level types
• mitkebes 1y ago
  I also always hear a lot of people complain about cheaters in Valorant, so all of that compromised personal security doesn't actually stop cheaters. Honestly I feel like you should only use kernel anticheat on a dedicated machine that's kept 100% separate from any of your personal data. That's a lot to ask of people, but you really shouldn't have anything you don't consider public data on the same hardware.
  • pfooti 1y ago
    A dedicated machine with no other general purpose apps that has minimal private data on it sounds like a gaming console.
    • wakawaka28 1y ago
      Or a virtual machine...
      • superb_dev 1y ago
        And with PCIe pass through you can get near bare metal performance. You won’t be able to play Valorant though
      • Gigachad 1y ago
        Anti cheat won't run in a VM
        • wakawaka28 1y ago
          Why not?
          • dandersch 1y ago
            It can work on a vm, but for Valorant specifically it seems that detecting a vm triggers the anticheat and gets you banned. I believe this is the case for most anticheats except VAC. You can try to evade the detection, but then you just enter the same cat & mouse game as a cheater. Whether allowing/disallowing VMs actually cuts down on cheaters? I don't know.
• zaptheimpaler 1y ago
  Except that this kernel driver is audited and signed by Microsoft, whom you also trust with the rest of your kernel if you use Windows at all.
  • sidewndr46 1y ago
    I don't think Microsoft auditing of code it signs. Wasn't Crowdstrike signed by Microsoft?
    • ronsor 1y ago
      It was. All Windows kernel drivers are. Microsoft doesn't do any auditing besides "is this the most obvious malware?"
  • Hikikomori 1y ago
    They don't audit them. Private cheat sellers user signed drivers because they have a small set of customers so they're unlikely to be reported or detected.
• everdrive 1y ago
  Strongly agreed. Some people want kernel-level anticheat for Linux. I think that's a huge mistake. Ideally, kernel-level anticheat would be done away with altogether. More realistically, I'm just going to avoid any games which use kernel-level anticheat, even if it means missing out.
  • thewebguyd 1y ago
    I got roasted on linux subreddits for saying as much. We should not be encouraging this crap to come to Linux, it needs to go away for good. IIRC, even Microsoft was getting fed up with hands in the kernel after Cloudstrike so we may see it disappear eventually if Microsoft starts cracking down.
    • ykonstant 1y ago
      Wait, people on linux subreddits support kernel-level anti-cheat?
      • everdrive 1y ago
        I had the same experience as the parent; opposition to kernel-level anticheat was very unpopular. I think the people on reddit don't understand that in principle, linux could be made to be exactly as bad as any other OS, and that kernel-level anticheat is just one step on the journey there.
  • Hikikomori 1y ago
    So you're just okay with people cheating then?
    • everdrive 1y ago
      That's a rude strawman of the point I was making. Kernel-level anticheat is just too great of a cost. Your entire system is compromised so that you can play some (usually lousy) AAA games. I oppose kernel-level anticheat because once it's in place, it will proliferate, even to single player games, just as it has in Windows. In other words, once it's broadly supported, the number of games available to me (assuming I want to avoid kernel-level anticheat) will actually _shrink _.
• Stevvo 1y ago
  In Valorant's defence: 1) There is a 100k bug-bounty on the anti-cheat: https://hackerone.com/riot?type=team https://hackerone.com/riot?type=team 2) The anti-cheat is the game's entire reason for being. It is the main focus of the development and marketing. People buy Valorant for the anti-cheat; they are willing to accept a kernel driver as a trade off for fairer competition.
  • mudkipdev 1y ago
    'Buy valorant'?
    • Stevvo 1y ago
      I didn't realise the game is free of charge. You could replace 'buy' with 'install', but my point stands; people play Valorant because they want a competitive shooter with difficult anti-cheat rather than the unique art style or gameplay attributes.
  • brendoelfrendo 1y ago
    Based on the install base and the level of access it could theoretically provide, I think a 0-day has a good shot at being worth more than $100k. Definitely worth more than that if you happen to know your high-value target plays League. Fair competition is all well and good, but there are other ways to do it and I can already tell you that the war on kernel-level anti cheat is well under way. There are already people cheating in Valorant, and that will not slow down. If anything, it's going to get more common because cheaters and cheat creators are some of the most diligent people out there.
• shaokind 1y ago
  Honest question: do you segment your activities on your computer on different users? No? In which case, what practical spyware risk does a kernel level driver add that user mode software can’t do? User mode software can spy on your clipboard, surreptitiously take screenshots, and take data out of your system. That spooks me enough that, if I don’t trust a software manufacturer, I don’t install it. Kernel mode makes no practical difference in my security posture.
  • throwaway01934 1y ago
    > User mode software can spy on your clipboard, surreptitiously take screenshots, and take data out of your system Not on any properly secured Linux machine. But yes, it's generally a bad idea to install software you don't trust, a category that anticheats slot nicely into, given their resistantance to auditing and analysis.
    • vilunov 1y ago
      A properly secured Linux machine is a unicorn. The Linux desktop ecosystem is struggling a lot with putting software in namespaces. People still install software with their package managers outside Flatpak, there is no isolation of data, not to say many workflows depend on the whole user directory being available to access.
  • xg15 1y ago
    For starters: - Creating a unique ID that is directly bound to hardware. - Accessing the memory of any process, including browsers or messengers. - Installing persistent background processes that are hidden from the rest of the system. But I think that's the wrong question. Talking about the kernel driver is a distraction. The abuse scenario that I think is most likely would be that the game and/or anticheat vendor uses the hardware ID for user profiling instead of just ban enforcement, and that the "logging" functionality is coopted to detect software or activities that aren't related to cheats at all, but are just competition of the vendor or can once against be used for profiling, etc. None of that strictly requires a kernel driver. Most of that stuff could be easily done with a usermode daemon. But under normal circumstances, there is no way I'd install such a program. Only in the name of cheat prevention, suddenly it gets permissible to make users install that stuff if all they want to do is play some game.
• brendoelfrendo 1y ago
  The way I described it to a friend was to use this analogy: Imagine you have someone over for game night, and before you play they say "Oh, by the way, I need the keys to the filing cabinet where you keep all your tax returns and whatnot." To which you might respond, "Wait, you need to read my tax returns before we can play this game?" And they say, "Oh, I'm not going to read them, I just need to hold the key while we play." And you would rightly tell them to piss off and get out of your house, because that makes no sense. If you really wanted to torture the metaphor, you could I guess argue that they need full access to your house just in case you decide to pull some loaded dice out of the filing cabinet or something, but that's not really the important thing to me. The important thing is that, regardless of whether or not I trust the developer of the anti-cheat, the game just isn't that important.
• foresto 1y ago
  And it gets circumvented anyway. https://www.youtube.com/watch?v=RwzIq04vd0M https://www.youtube.com/watch?v=RwzIq04vd0M It seems to me that kernel-level anti-cheat is little more than a speed bump for determined cheaters.
  • 7bit 1y ago
    Having one determined cheater ist worth not having 1000 cheaters because they fear getting banned.
    • 63stack 1y ago
      The video showing one person cheating does not mean there aren't a 1000 others doing the same
    • foresto 1y ago
      Or: Deterring some casual cheaters is not worth having my whole system pwned by employees of a game publisher and whomever else figures out how to exploit their code. Obviously, our personal priorities differ. That's fine, but yours don't invalidate my earlier point. By the way, it's never just one determined cheater. Once discovered, circumvention techniques get shared, just as with mod chips and exploit scripts. It's only a matter of time before anyone willing to do a little reading or buy a little hardware can use them. And they do. (Often on alt accounts, with no fear of getting banned.) In other words, any relief from game cheaters is bound to be temporary, while harm from spyware or exploit is irreparable to anyone who values the privacy of their data. This is why kernel-level anti-cheat systems are so widely criticized. They might make sense on dedicated gaming machines, where the risks are low, but the situation is very different on general-purpose computers.
• pjmlp 1y ago
  It is the same stance as calling Windows games, developed for Windows, using DirectX, without any consideration of the studios to ever target GNU/Linux, even though they might actually target Android/Linux with other titles, Linux games. Because somehow Proton is better than standing for actual GNU/Linux games. So like IBM with OS/2 and Windows, studios keep ignoring Linux, and let Valve do whatever is needed, it is Valve's problem to sort out.
• torginus 1y ago
  And since the game has access to the anticheat running in the kernel, every Valorant bug is a potential root level kernel exploit.