Limit the users that the proxy will hand out SSH keys for

[madwort]

I'm not sure how easy this would be (or worthwhile), but was wondering whether we should allowlist the Github usernames that we hand out SSH keys for via this proxy - this would add an extra layer of safeguarding in case of incorrect usernames.

[madwort]

not a great place to do this, as I think it would be difficult to verify whether the github username is currently a member of the relevant github org (which is potentially the best way to verify whether they currently have access) - but a longer list might help to cut down the possibilities & add to defence in depth.