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I have an anti-cheat startup, and Linux support is a big priority for us. The segmentation problem on Linux is a real challenge for us. It’s likely we will only

I have an anti-cheat startup, and Linux support is a big priority for us. The segmentation problem on Linux is a real challenge for us. It’s likely we will only ever be able to support the big distros, and we also are exploring using TPM remote attestation. Both of these things take away user freedom to tinker with their systems, an ability Linux enthusiasts enjoy. But with this freedom implicitly comes with the freedom to cheat in online video games. I’m happy to hear thoughts on this.

blibble 6y ago
how would you stop someone sticking in a dodgy PCI card (disguised as an innocent one) that can read the entire machine's memory using DMA?
- invokestatic 6y ago
  I’m not going to go into specifics but there are several software methods to both detect and prevent these sorts of attacks, since DMA requires cooperation from the host CPU. There are several anticheats in production today that employ these techniques with great success.
  - Unklejoe 6y ago
    > since DMA requires cooperation from the host CPU Not really. I mean, yes, in the sense that the IOMMU has to be configured to allow it, but after that, it's fair game. Any PCI device can read within the inbound translation window.
digikata 6y ago
Require video card PCIe passthrough and host the game on KVM? Take something like firecracker or some runt kernel, don't do a full system vm, just enough to run the game and anti-cheat?
- invokestatic 6y ago
  I guess I don’t understand what the goal of that would be, since the kvm host still must be trusted.
Thaxll 6y ago
Why would Linux be a priority with you when actually no one use that platform at scale where anticheat matters?
- invokestatic 6y ago
  For the same reason that I have decided to have our CI build and test on ARMv8, even though hardly any (PC) games are on that architecture. I try to be forward thinking, even if it may be a longshot. Apple's M1 may just bring an era of even further segmentation of desktop platforms. I want to be prepared for that.
  - deleted 6y ago
    [deleted]
  - Thaxll 6y ago
    I work in AAA studios and I worked on online anti cheat, you won't be able to sell your anti cheat if you advertise it as working on Linux, studios don't want there game running on Linux / virtualization because of cheating.
    - invokestatic 6y ago
      If they don’t want it on Linux it’s up to them. I’m just providing the tools to do it if they decide to be on that platform.
jcastro 6y ago
> Both of these things take away user freedom to tinker with their systems, an ability Linux enthusiasts enjoy. I just want to play video games and I use linux - in order to play multiplayer video games I need anticheat and this means giving that up. I would also argue that other than a minority of vocal users no one wakes up in the morning looking forward to tinker with their system, we just sometimes have to, doesn't mean we like it.
q3k 6y ago
> and we also are exploring using TPM remote attestation I can already tell this is very likely not going to work fully, or even work for a sizeable chunk of Linux installations out there. Many platforms don't have TPMs, or have TPMs from unknown CAs. Or firmware that you're not aware of. Or even worse, people might just be running a Linux distribution that you don't know about. Or a patched kernel. Or a bootloader that doesn't measure the next stage into TPM. Not to mention, even the most popular distributions allow you to do anything with root access, things that you just won't be able to measure, but that might allow people to cheat. TPMs really only make sense for _very_ controlled environments if you want to prevent hardware tampering at this level. The diversity of Linux distributions (and PCs in general) truly works against you here.
deleted 6y ago
[deleted]

blibble 6y ago

how would you stop someone sticking in a dodgy PCI card (disguised as an innocent one) that can read the entire machine's memory using DMA?

invokestatic 6y ago
I’m not going to go into specifics but there are several software methods to both detect and prevent these sorts of attacks, since DMA requires cooperation from the host CPU. There are several anticheats in production today that employ these techniques with great success.
- Unklejoe 6y ago
  > since DMA requires cooperation from the host CPU Not really. I mean, yes, in the sense that the IOMMU has to be configured to allow it, but after that, it's fair game. Any PCI device can read within the inbound translation window.

digikata 6y ago

Require video card PCIe passthrough and host the game on KVM? Take something like firecracker or some runt kernel, don't do a full system vm, just enough to run the game and anti-cheat?

invokestatic 6y ago
I guess I don’t understand what the goal of that would be, since the kvm host still must be trusted.

Thaxll 6y ago

Why would Linux be a priority with you when actually no one use that platform at scale where anticheat matters?

invokestatic 6y ago
For the same reason that I have decided to have our CI build and test on ARMv8, even though hardly any (PC) games are on that architecture. I try to be forward thinking, even if it may be a longshot. Apple's M1 may just bring an era of even further segmentation of desktop platforms. I want to be prepared for that.
- deleted 6y ago
  [deleted]
- Thaxll 6y ago
  I work in AAA studios and I worked on online anti cheat, you won't be able to sell your anti cheat if you advertise it as working on Linux, studios don't want there game running on Linux / virtualization because of cheating.
  - invokestatic 6y ago
    If they don’t want it on Linux it’s up to them. I’m just providing the tools to do it if they decide to be on that platform.

jcastro 6y ago

> Both of these things take away user freedom to tinker with their systems, an ability Linux enthusiasts enjoy. I just want to play video games and I use linux - in order to play multiplayer video games I need anticheat and this means giving that up. I would also argue that other than a minority of vocal users no one wakes up in the morning looking forward to tinker with their system, we just sometimes have to, doesn't mean we like it.

q3k 6y ago

> and we also are exploring using TPM remote attestation I can already tell this is very likely not going to work fully, or even work for a sizeable chunk of Linux installations out there. Many platforms don't have TPMs, or have TPMs from unknown CAs. Or firmware that you're not aware of. Or even worse, people might just be running a Linux distribution that you don't know about. Or a patched kernel. Or a bootloader that doesn't measure the next stage into TPM. Not to mention, even the most popular distributions allow you to do anything with root access, things that you just won't be able to measure, but that might allow people to cheat. TPMs really only make sense for _very_ controlled environments if you want to prevent hardware tampering at this level. The diversity of Linux distributions (and PCs in general) truly works against you here.

deleted 6y ago

[deleted]