ssh VS openssh-portable

It continues to amaze me that ssh still does not use https PKI and relies on developer manually checking fingerprint (which he supposedly does in a hard-to-google location and realistically he does not check anything). So much care and work went to implement web security and developers still basically live in a self-signed world.

At least put your key to https://github.com/.well-known/ssh/ed25519.pub so I don't need to Google it... And may be some day ssh will support it natively. Someone need to act first.

Default for the last 24 years according to https://github.com/openssh/openssh-portable/blame/385ecb31e1...

They didn't need to use the library to make use of the systemd notify mechanism, which is simple to interface and quite a nice feature in the first place.

The free-standing implementation: https://github.com/openssh/openssh-portable/commit/08f579231...

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.