ed25519 keys not working

[brianmhunt]

Not sure if this is an issue here or upstream, but I just wanted to give a heads up that ed25519 host keys do not appear to be supported.

When running e.g.

conn = new require('ssh2')()
conn.connect({
  host: 'host.local',
  port: "22",
  username: "bmh",
  agent: process.env['SSH_AUTH_SOCK'],
  debug: console.log})

The output includes:

DEBUG: (local) Host key formats: ssh-rsa,ssh-dss
DEBUG: (remote) Host key formats: ssh-rsa,ssh-dss,ecdsa-sha2-nistp256,ssh-ed25519

I doubt there's anything on my end (Mac OS X 10.11.1; node 5.0.0; fresh package install of ssh2@04.12); it looks like the support is simply not yet in ssh2-streams. I can re-file a bug there, if that is preferable.

🍻

[brianmhunt]

Notable link on ed25519 support in Node: nodejs/node#2144

Two options:

• https://github.com/paixaop/node-sodium
• https://github.com/dazoe/ed25519

[mscdex]

Yes, this is a known issue. The problem though is that the pure js implementations for some of these algorithms that OpenSSL currently does not support are slow.

I think I would only want to start incorporating these pure js algorithm solutions once there is the ability to override the hard-coded list of algorithms, ciphers, etc. This way if someone doesn't want to use the pure js algorithms (for performance reasons), then they can (easily) opt out of that. However, I haven't had time to work on this.

[brianmhunt]

Thanks @mscdex

I appreciate the concerns over performance issue and opting-out.

As host key algorithm itself is only run once per connection, the performance of that particular implementation should not be a big concern. That said, I understand why you would want to make sure an opt-out scheme of some sort would be in place before going down this road.

Cheers.

[mscdex]

FWIW I've just landed ECDSA support in ssh2/ssh2-streams and it works, but will need to write tests for it yet.

I'm still not sure when/if OpenSSL will support ed25519 though. There is an ed25519 issue on OpenSSL's repo here FWIW. There is also another OpenSSL github issue for curve25519 here that is supposedly "in progress" and a related node issue here.

I should also note I would be open to the possibility of having an optionalDependency on a compiled addon that implemented ed* key support.

[stefreak]

openssl/openssl#309 says "x25519 is in [OpenSSL] 1.1"

Can this be implemented now? I would appreciate it enormously :)

[mscdex]

It won't be supported at least until OpenSSL 1.1.x is included in a version of node. See this PR for more information.

[karlhorky]

I suppose nodejs/node#18770 is the more updated issue now (OpenSSL 1.1.1).

[karlhorky]

Oh wait, reading a bit deeper, in that issue there is the line:

We currently have 1.1.0 support in Node

Looks like this is supported after all now:

Node.js 10: nodejs/node#16130 (comment)
Node.js 8 backport: nodejs/node#18622 (comment)

[Eugeny]

@mscdex could you please also consider adding an ed25519 PPK parser?