src VS ports

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...

I think OpenBSD comes the closest to what you want with its two easy to use syscalls that provide syscall filtering and restricting access to paths:

https://man.openbsd.org/pledge.2

https://man.openbsd.org/unveil.2

A few random examples:

https://github.com/tmux/tmux/blob/c8494dff7b6b9a996866edaf8c...

https://github.com/openbsd/ports/blob/master/www/mozilla-fir...

https://github.com/openbsd/ports/blob/master/www/mozilla-fir...

To get the best isolation you need to patch the source — the application needs to go through initial setup and then drop privileges to the absolute possible minimum. But it's easy to make custom wrappers for third-party applications — the above profiles taken from the OpenBSD ports tree are the proof.

Have you checked the no-ip port: https://github.com/openbsd/ports/blob/master/net/no-ip/pkg/noip2.rc

> https://github.com/openbsd/ports/commit/bf33ea5f3ff390d8cde3...

Now, this is surprising. I randomly clicked on that link and I immediately see that the code and the patch has a bug. It only checks the first 8 characters:

    -      if (gr != NULL && strncmp(gr->gr_name, "operator", 8) == 0)

Some people are working around this by using obsdfreqd, some by patching sys/kern/sched_bsd.c (change if (hw_power) to if (0 && hw_power)), some by simply setting to a lower speed (sysctl hw.perfpolicy=manual and hw.setperf=99 might be enough as this disables turbo mode found on some CPUs).

You could also look into a port that has a hard dependency on openssl like: https://github.com/openbsd/ports/tree/master/security/sslscan

For me it's the ease of management and good documentation.

For example, during 6.8 to 6.9 upgrade, there was a major postgresql upgrade.

It is mentioned in the doc https://www.openbsd.org/faq/upgrade69.html (see Special packages at the bottom).

You're redirected to the package README with special instructions on how to setup and upgrade: https://github.com/openbsd/ports/blob/master/databases/postg...

Et voilà, everything is explained.

On debian, if I am not careful, I'll do an upgrade and risk breaking something during a db migration (I'm looking at you MySQL upgrades...).

Godot engine gamecontroller support. This is limited and incomplete, but it's a start. A huge number of indie games made with Godot are released every week; most of which work at least partially with an XBox {360,One} controller. You can follow This Week in Godot if you're interested.

> OpenBSD has handled this case for some years. I do not know if there was any breakage or fallout from this.

The other thing about OpenBSD is that when they make a change to their OS, they also go through to make sure all the (third-party) ports/packages:

* https://cvsweb.openbsd.org/ports/

* https://github.com/openbsd/ports

do not break. So they're create patches for the software and and submit them upstream.