🐛 BUG: ssh-rsa keys not accepted with lighthouse sshd config option

[noyez]

What version of nebula are you using?

1.6.1

What operating system are you using?

Linux

Describe the Bug

I'm not sure where else to put this but in case someone else runs in this same issue, i thought it would be helpful to create this report. Also I can't say i'm well versed in ssh key types/algorithms or nebula, so perhaps something else is awry here.

While trying to enable the sshd option to use the list-hostmap command. i used the existing bug report #640 to guide me however it didn't work b/c it seems the ssh-rsa -- the default key type when creating ssh-keys -- is not an accepted algorithm for the lighthouse ssh-keys feature (this took me a while to figure out).

The symptoms is that once the sshd feature was configured, and i tried to ssh into the instance the following error would be reported on the nebula lighthouse instance:
error="[ssh: no auth passed yet]" remoteAddress="127.0.0.1:47282" subsystem=sshd

While the ssh-client was getting generated the following logs:

 » ssh -i ssh_user.key -p 2222 localhost -l root -v list-hostmap
OpenSSH_8.9p1 Ubuntu-3, OpenSSL 3.0.2 15 Mar 2022
...
debug1: Will attempt key: ssh_user.key RSA SHA256:ds2gAHOMY9+hlqaFV6fAtWx4iLT33HC3KYBYvB0LyKk explicit
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering public key: ssh_user.key RSA SHA256:ds2gAHOMY9+hlqaFV6fAtWx4iLT33HC3KYBYvB0LyKk explicit
debug1: send_pubkey_test: no mutual signature algorithm
debug1: No more authentication methods to try.
root@localhost: Permission denied (publickey).

Note: debug1: No more authentication methods to try.

Then i decided to recreate the auth keys using the ed25519 algorithm rather than the default rsa algo:

ssh-keygen -f ssh_user.key -t ed25519

Then : ssh -i ssh_user.key -p 2222 localhost -l root

and all was good.

Logs from affected hosts

No response

Config files from affected hosts

No response

[wadey]

It looks like this was just fixed upstream in x/crypto v0.3.0

golang/go#49952 (comment)

[noyez]

I'll close since its not a direct bug in nebula, and if anyone else hits this bug hopefully this issue will pop-up in their search.

[wadey]

#780 will fix this