AreWeAntiCheatYet VS src

I only really play single player, but I have run into this too. This is a great resource to keep track of progress - https://areweanticheatyet.com/

It varies by game. https://areweanticheatyet.com/ is an interesting resource for that because they also track announcements by developers about whether or not linux support is eventually planned.

AFAIK the games that don't work are more modern, competetive games that use Anticheat. https://areweanticheatyet.com/ is a good resource to see the status of your game.

It is game by game basis. Use this guide to see if the game you play is supported or not.

The only caveat to that is online games with anti-cheat. EAC and BattlEye both support Linux but requires studios to tick a box, many of which refuse. Any kernel-layer AC that doesn't have a userspace component will not run on Linux. Can see a list of games and their AC support here.

> except Multiplayer online games

That's no longer the case. I'd say about now, there are more multiplayer games that you can play, as opposed to ones you can't play.

See: https://areweanticheatyet.com/ as reference, but it's not very up-to-date, so https://www.protondb.com/ would probably be a better reference.

Only listed the 'bigger' ones, but you have a rather full list here if you want to check your favorite games: arwianticheatyet.com

Source: AreWeAntiCheatYet

Nope, just works. There are some games that use invasive kernel-level anticheat that wont work as Linux sensibly blocks anything that shouldn't be messing with the kernel, but I'm not personally interested in those games anyway. EAC and Battleye both support Linux, but requires devs to tick a box, which there's several that can't be bothered.

The OpenBSD project released 7.4 of their OS on 16 Oct 2023 as their 55th release 💫

Well since https://www.openbsd.org/ still says

> Only two remote holes in the default install, in a heck of a long time!

I'm assuming not, but I could always be mistaken.

> building a cat from scratch

> That would be an interesting project.

Here is the source code of the OpenBSD implementation of cat:

> https://github.com/openbsd/src/blob/master/bin/cat/cat.c

and here of the GNU coreutils implementation:

> https://github.com/coreutils/coreutils/blob/master/src/cat.c

Thus: I don't think building a cat from scratch or creating a tutorial about that topic is particularly hard (even though the HN audience would likely be interested in it). :-)

> I don't know how they define `MAX`, but I'm guessing it's a typical "a>b?a:b"

Indeed: https://github.com/openbsd/src/blob/master/sys/sys/param.h#L...

> Then `SYS_kbind` seems to be a signed int.

It's an untyped #define: https://github.com/openbsd/src/blob/master/sys/sys/syscall.h...

I believe your whole analysis is correct, that running an elf file with an openbsd.syscalls entry with .sysno > INT_MAX will allow an out-of-bounds write.

I can reproduce it. And this is the commit that causes the issue: https://github.com/openbsd/src/commit/d21788ce70be80e9c4ed0c52c149e01147c4a823

This doesn’t really change your conclusion, but I think that’s the wrong file. This is the real doas afaict: https://github.com/openbsd/src/blob/master/usr.bin/doas/doas...

Still just a tidy 1072 lines in that folder though.

I spent 5 minutes staring at your file trying to understand how on earth it does the things in the man page, but of course it doesn’t.

OpenBSD developers are making serious effort to kill off indirect syscalls, the base system is completely clean, take a look at the work Andrew Fresh did to adapt Perl. He write a complete syscall "dispatcher" or emulator for the Perl syscall function so that it calls the libc stubs.

https://github.com/openbsd/src/commit/312e26c80be876012ae979...

The ports tree is also being cleansed of syscall(2) usage, until they're all gone.

msyscall, pinsyscall, recent mandatory IBT/BTI, xonly. OpenBSD is making waves, but people aren't really seeing them yet.

Actually, I got it wrong, too many vulnerabilities in flight. They did fix it: https://github.com/openbsd/src/commit/375ccafb2eb77de6cf240e...