RE: [EXTERNAL] Re: [PoC] Federated Authn/z with OAUTHBEARER

We can support both passing the token from an upstream client and libpq implementing OAUTH2 protocol to obtaining one.

Libpq implementing OAUTHBEARER is needed for community/3rd party tools to have user-friendly authentication experience:
1. For community client tools, like pg_admin, psql etc.
Example experience: pg_admin would be able to open a popup dialog to authenticate customer and keep refresh token to avoid asking the user frequently.
2. For 3rd party connectors supporting generic OAUTH with any provider. Useful for datawiz clients, like Tableau or ETL tools. Those can support both user and client OAUTH flows.

Libpq passing toked directly from an upstream client is useful in other scenarios:
1. Enterprise clients, built with .Net / Java and using provider-specific authentication libraries, like MSAL for AAD. Those can also support more advance provider-specific token acquisition flows.
2. Resource-tight (like IoT) clients. Those can be compiled without optional libpq flag not including the iddawc or other dependency.

Thanks!
Andrey.

-----Original Message-----
From: Jacob Champion <jchampion(at)timescale(dot)com>
Sent: Wednesday, September 21, 2022 9:03 AM
To: mahendrakar s <mahendrakarforpg(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org; smilingsamay(at)gmail(dot)com; andres(at)anarazel(dot)de; Andrey Chudnovskiy <Andrey(dot)Chudnovskiy(at)microsoft(dot)com>; Mahendrakar Srinivasarao <mahendrakars(at)microsoft(dot)com>
Subject: [EXTERNAL] Re: [PoC] Federated Authn/z with OAUTHBEARER

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On Tue, Sep 20, 2022 at 4:19 PM Jacob Champion <jchampion(at)timescale(dot)com> wrote:
> > 2. Add support to pass on the OAuth bearer token. In this
> > obtaining the bearer token is left to 3rd party application or user.
> >
> > ./psql -U <username> -d 'dbname=postgres
> > oauth_client_id=<client_id> oauth_bearer_token=<token>
>
> This hurts, but I think people are definitely going to ask for it,
> given the frightening practice of copy-pasting these (incredibly
> sensitive
> secret) tokens all over the place...

After some further thought -- in this case, you already have an opaque Bearer token (and therefore you already know, out of band, which provider needs to be used), you're willing to copy-paste it from whatever service you got it from, and you have an extension plugged into Postgres on the backend that verifies this Bearer blob using some procedure that Postgres knows nothing about.

Why do you need the OAUTHBEARER mechanism logic at that point? Isn't that identical to a custom password scheme? It seems like that could be handled completely by Samay's pluggable auth proposal.

--Jacob