Re: Broken SSH Key Parsing

On Wed, 2 Sept 2026 at 19:14, Tristan Partin <tristan(at)partin(dot)io> wrote:

> On Mon Aug 31, 2026 at 8:39 PM UTC, Magnus Hagander wrote:
> > On Mon, 31 Aug 2026 at 22:25, Tristan Partin <tristan(at)partin(dot)io> wrote:
> >
> >> On Mon Aug 17, 2026 at 7:53 PM UTC, Magnus Hagander wrote:
> >> > On Mon, 17 Aug 2026 at 18:08, Tristan Partin <tristan(at)partin(dot)io>
> wrote:
> >> >
> >> >> On Tue Aug 11, 2026 at 8:08 PM UTC, Tristan Partin wrote:
> >> >> > Hey folks,
> >> >> >
> >> >> > I just got access to a Git repository on postgresql.org, so I
> started
> >> >> > going through the motions of adding an SSH key to my profile. I was
> >> >> > unable to add my key as-is, so I figured that I would flag the
> issue.
> >> My
> >> >> > public SSH key looks something like this:
> >> >> >
> >> >> > ecdsa-sha2-nistp256
> >> >>
> >>
> AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBDPYnw8WWCrgL0sXijK7BY1Qz7KJlQZNe+ErNNwmfqazAd/CuTNNdENj21R6iR2CsjoEZ1prFcj/hPDV/j4nf7s=
> >> >> email(at)example(dot)com (hostname)
> >> >> >
> >> >> > Accordingto to SSH key documentation[0], an SSH key is composed of
> >> >> > 3 components:
> >> >> >
> >> >> > A B C
> >> >> >
> >> >> > A: The key type
> >> >> > B: Base64-encoded public key
> >> >> > C: An optional comment
> >> >> >
> >> >> > The problem with this key in particular is the comment. If I remove
> >> >> > `(hostname)` from the key, postgresql.org will accept the key. I
> have
> >> >> > a suspicion that we are probably incorrectly validating the key.
> Some
> >> >> > pseudocode that would illustrate my hypothesis:
> >> >> >
> >> >> > keys = []
> >> >> > for t in text.splitlines():
> >> >> > sections = t.split(" ")
> >> >> > if len(sections) < 2 or len(sections) > 3:
> >> >> > raise ValueError("Invalid SSH key format")
> >> >> >
> >> >> > keys.append(OpenSSHKey(sections[0], sections[1],
> >> >> sections[2] if len(sections) == 3 else None))
> >> >> >
> >> >> > I am happy to investigate this further if I can get read access to
> the
> >> >> > postgresql.org site.
> >> >> >
> >> >> > I find my current comment format, including the hostname, to be
> useful
> >> >> > when identifying the email and machine the key belongs to. I'll
> work
> >> >> > around it for now.
> >> >> >
> >> >> > [0]: https://sshref.dev/#intro_legc_pub
> >> >>
> >> >> Here is a patch to improve things a bit. We should probably add some
> >> >> unit tests for this
> >> >>
> >> >
> >> >
> >> > Wouldn't it be safer to just cut the options if they are included? If
> we
> >> > don't then we have to also audit every downstream consumer of the keys
> >> > through the authentication system so they know how to deal with those
> >> keys,
> >> > since we're chagning the exchanged format there, since as it is now we
> >> just
> >> > pass it straight through.
> >>
> >> Sounds reasonable. How are these SSH keys consumed? Do they just make
> >> their way into a Git server config somewhere?
> >>
> >
> > It's a couple of different ones as well but fundamentally yes,that's how
> > they work.
>
> What are your thoughts on reworking the UI/UX for saving SSH keys on
> postgresql.org? I'm thinking we could take a more GitHub-like approach.
> User adds one key at a time instead of the \n deliminated text entry
> that we currently have. I think it would make it easier to understand
> which SSH key is causing a failure. Additionally, I think it would make
> the validation process a bit nicer.
>

Yeah, that would definitely be an improvement I think! The current one is
basically a "quick-fix, we didn't originally think of the need to have more
than one key".

--
Magnus Hagander
Me: https://www.hagander.net/ <http://www.hagander.net/>
Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>