openssh-portable VS src

Unless I'm misunderstanding what this is about RFC5647 merely points out that the sequence number is included as AAD due to RFC4253 requirements. The [email protected] specification is not exactly the most rigorous thing I've ever seen (https://github.com/openssh/openssh-portable/blob/master/PROT...) but reading it, the sequence number is only included in the IV, and not as AAD, which directly runs afoul of the RFC4253 section 6.4 requirement for it to be included in the MAC.

The key layout is described in https://github.com/openssh/openssh-portable/blob/master/PROT... and you can view it pretty easily via

cat private_key_here | head -n -1 | tail -n +2 | base64 -d | xxd

One I created in 2016 is using aes256-cbc with bcrypt for the kdf, which isn't awful at all.

Interestingly, it looks like ssh-agent disables core dumps[1], but I don't see similar usage for sshd

1: https://github.com/openssh/openssh-portable/blob/694150ad927...

There's a current pull request for adding AF_UNIX support, which should make all kinds of exciting forwarding possible, since it will make it easy to proxy ssh connections through an arbitrary local process which can do anything to forward the data to the remote end.

https://github.com/openssh/openssh-portable/pull/431

OpenSSH server (allows connecting to containers)

It doesn't, at least not for generic/unmodified cryptographic applications.

WebAuthN signatures are of a very specific challenge/response format that applications need to explicitly support. For example, SSH had to add new key and signature formats [1] to support it.

Theoretically, a blockchain/cryptocurrency application could adopt the WebAuthN signature format as its canonical or an alternative signature format, but I'm not aware of any popular one having done so.

[1] https://github.com/openssh/openssh-portable/blob/master/PROT...

I just tested it and looked at the code briefly; the client fortunately does seem to remove all keys not provided by the server: https://github.com/openssh/openssh-portable/blob/36c6c3eff5e...

It seems like at least a `known_hosts` compromise would be "self-healing" after connecting to the legitimate github.com server once.

And OpenVAS and OpenSSH and OpenBSD and OpenNN and OpenAFS and on and on and on

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...