Re: [PoC] Federated Authn/z with OAUTHBEARER - Mailing list pgsql-hackers

> On 7 Feb 2025, at 06:48, Jacob Champion <jacob.champion@enterprisedb.com> wrote:
>
> On Thu, Feb 6, 2025 at 2:02 PM Daniel Gustafsson <daniel@yesql.se> wrote:
>> Attached is a v46 which is v45 minus the now committed patch.
>
> Thank you! Attached is v47, which creeps ever closer to the finish line.

Great, thanks!  Below are a few quick comments after a first read-through and
compile/test cycle:

> - 0005 warns at configure time if libcurl doesn't have a nonblocking
> DNS implementation.

Is it really enough to do this at build time?  A very small percentage of users
running this will also be building their own libpq so the warning is lost on
them.  That being said, I'm not entirely sure what else we could do (bleeping a
warning every time is clearly not userfriendly) so maybe this is a TODO in the
code?

> - 0006 augments bare Asserts during client-side JSON parsing with code
> that will fail gracefully in production builds as well.

+  oauth_json_set_error(ctx,       /* don't bother translating */
With the project style format for translator comments this should be:

    +  /* translator: xxx */
    +  oauth_json_set_error(ctx,

> - 0007 escapes binary data during the printing of libcurl debug
> output. (If you're having a bad enough day to need the debug spray,
> you're probably not in the mood for the sound of a hundred BELs.)

Does it make sense to prefix the printing in debug_callback() with some header
stating that the following data is debug output from curl and not postgres?  I
have a feeling I'm stockholm syndromed by knowing the internals so I'm not sure
if that would be helpful to someone not knowing the implementation details.

> - 0008 parses and passes through the expires_in and optional
> verification_uri_complete fields from the device endpoint to any
> custom user prompt. (We do not use them ourselves, at the moment. But
> after seeing some nice demos of RHEL/PAM/sssd support for device flow
> QR codes at FOSDEM, I think we're definitely going to want to make
> those available to devs.)

Aha, cool!  I was a bit surprised to not find a definition of expires_in in RFC
8628, as in what happens if -1 is passed?  8628 seems to broadly speaking fall
into the category of "just dont do the wrong thing and all will be fine" =/.
Another question that comes to mind is how the reciever should interpret the
information since it doesn't know when the device_code/user_code was generated
so it doesn't know how much of expires_in which has already passed.  (Which is
not something for us to solve, just a general observation.)

+   even if they can't use the non-textual method. Review the RFC's
+   <ulink url="https://datatracker.ietf.org/doc/html/rfc8628#section-3.3.1">notes
+   on non-textual verification</ulink>.
To align more with the rest of the documentation I think something along these
lines is better: "For more information, see section 3.3.1 in <ulink ..>RFC
8628</ulink>.

      Assert(cnt == 1);
-     return 1;                       /* don't fall through in release builds */
+     return 0;
While not introduced in this fixup patch, reading it again now I sort of think
we should make that Assert(false) to clearly indicate that we don't think the
assertion will ever pass, we're just asking to error out since we already know
the failure condition holds.

> - 0009 is gold-plating for the OAUTH_STEP_WAIT_INTERVAL state:

+  actx_error(actx, "failed to create timer kqueue: %m");
Maybe we should add a translator note explaining that kqueue should not be
translated since it's very easy to mistake it for "queue".  Doing it on the
first string including kqueue should be enough I suppose.

--
Daniel Gustafsson