Re: [PoC] Federated Authn/z with OAUTHBEARER

Jacob Champion <jacob.champion@enterprisedb.com>

From: Jacob Champion <jacob.champion@enterprisedb.com>
To: Andres Freund <andres@anarazel.de>
Cc: Daniel Gustafsson <daniel@yesql.se>, Peter Eisentraut <peter@eisentraut.org>, Antonin Houska <ah@cybertec.at>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2025-02-24T17:39:52Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →
  1. meson: Fix install-quiet after clean

  2. oauth: Run Autoconf tests with correct compiler flags

  3. Link libpq with libdl if the platform needs that.

  4. Doc: correct spelling of meson switch.

  5. oauth: Correct SSL dependency for libpq-oauth.a

  6. oauth: Fix Autoconf build on macOS

  7. oauth: Move the builtin flow into a separate module

  8. Remove a stray "pgrminclude" annotation

  9. oauth: Simplify copy of PGoauthBearerRequest

  10. oauth: Improve validator docs on interruptibility

  11. oauth: Disallow synchronous DNS in libcurl

  12. oauth: Fix postcondition for set_timer on macOS

  13. oauth: Use IPv4-only issuer in oauth_validator tests

  14. Work around OAuth/EVFILT_TIMER quirk on NetBSD.

  15. oauth: Fix incorrect const markers in struct

  16. Add missing entry to oauth_validator test .gitignore

  17. cirrus: Temporarily fix libcurl link error

  18. Add support for OAUTHBEARER SASL mechanism

  19. libpq: Handle asynchronous actions during SASL

  20. require_auth: prepare for multiple SASL mechanisms

  21. Move PG_MAX_AUTH_TOKEN_LENGTH to libpq/auth.h

  22. Make SASL max message length configurable

  23. jsonapi: fully initialize dummy lexer

  24. common/jsonapi: support libpq as a client

  25. Remove fe_memutils from libpgcommon_shlib

  26. Revert ECPG's use of pnstrdup()

  27. Explicitly require password for SCRAM exchange

  28. Refactor SASL exchange to return tri-state status

On Fri, Feb 21, 2025 at 9:19 AM Andres Freund <andres@anarazel.de> wrote:
> I don't think we can generally rely on all blocking system calls to be
> interruptible by signals on all platforms?

Probably not; I wasn't sure how much detail to put in here after "must
remain interruptible."

> And, probably worse, isn't relying on getting EINTR rather racy, due to the
> chance of the signal arriving between CHECK_FOR_INTERRUPTS() and the blocking
> system call?

That is worse, and to be honest I hadn't ever thought about that race
condition before your email. So wait... how do people actually rely on
EINTR in production-grade client software? pselect/ppoll exist,
clearly, but they're used so rarely IME. (Have we all just been
subconsciously trained to mash Ctrl-C until the program finally stops?
I'm honestly kind of horrified by this revelation.)

Anyway, yes, this documentation clearly needs to be strengthened.

> Is it a good idea to support that? We e.g. rely on libpq connections made by
> the backend to be interruptible. Admittedly that's, I think, already not
> bulletproof, due to libpq's DNS lookups going through libc if connection
> string contains a name that needs to be looked up, but this seems to make that
> a bit worse?

A bit. The same for Kerberos, IIRC. Is the current configure warning
not strong enough to imply that the packager is on shaky ground? (I
patterned that off of the LDAP crash warning, which seemed much worse
to me. :D)

We can always declare non-support, I suppose, but anyone who doesn't
care about that problem (say, because they just want to use
single-connection psql) is then stuck hacking around it.

--Jacob