Hi Jacob and Daniel, Thanks for your feedback.
>@Daniel - I think thats conflating session_user and current_user, SET ROLE is not a login event. This is by design and discussed in the documentation.. Agreed, I am using those terms loosely. I have updated option 4 in the proposal document. I have crossed it out. Option 5 is more suitable "SET SESSION AUTHORIZATION" for further consideration. >@Daniel - but it's important to remember that we need to cover the functionality in terms of *tests* first, performance benchmarking is another concern. For implementation absolutely, but not for a basic feasibility prototype. A quick non-secure non-reliable prototype is probably an important first-step to confirming which options work best for the stated goals. Importantly, if the improvement is only 5% (whatever that might mean), then the project is probably not work starting. But I do expect that a benchmark will prove benefits that justify the resources to build the feature(s). >@Jacob - A more modern approach might be to attach the authentication to the packet itself (e.g. cryptographically, with a MAC), if the goal is to enable per-statement authentication anyway. In theory that turns the middleware into a message passer instead of a confusable deputy. But it requires more complicated setup between the client and server. I did consider this, but I ruled it out. I have now added it to the proposal document, and included two Issues. Please review and let me know whether I might be mistaken. >@Jacob - Having protocol-level tests for bytes on the wire would not only help proposals like this but also get coverage for a huge number of edge cases. Magnus has added src/test/protocol for the server, written in Perl, in his PROXY proposal. And I've added a protocol suite for both the client and server, written in Python/pytest, in my OAuth proof of concept. I think something is badly needed in this area. Thanks for highlighting this emerging work. I have noted this in the proposal in the Next Steps section. --Todd Note: Here is the proposal document link again - https://docs.google.com/document/d/1u6mVKEHfKtR80UrMLNYrp5D6cCSW1_arcTaZ9HcAKlw/edit# On Tue, 23 Nov 2021 at 12:12, Jacob Champion <pchamp...@vmware.com> wrote: > On Sat, 2021-11-20 at 16:16 -0500, Tom Lane wrote: > > One more point is that the proposed business about > > > > * ImpersonateDatabaseUser will either succeed silently (0-RTT), or > > fail. Upon failure, no further commands will be processed until > > ImpersonateDatabaseUser succeeds. > > > > seems to require adding a huge amount of complication on the server side, > > and complication in the protocol spec itself, to save a rather minimal > > amount of complication in the middleware. Why can't we just say that > > a failed "impersonate" command leaves the session in the same state > > as before, and it's up to the pooler to do something about it? We are > > in any case trusting the pooler not to send commands from user A to > > a session logged in as user B. > > When combined with the 0-RTT goal, I think a silent ignore would just > invite more security problems. Todd is effectively proposing packet > pipelining, so the pipeline has to fail shut. > > A more modern approach might be to attach the authentication to the > packet itself (e.g. cryptographically, with a MAC), if the goal is to > enable per-statement authentication anyway. In theory that turns the > middleware into a message passer instead of a confusable deputy. But it > requires more complicated setup between the client and server. > > > PS: I wonder how we test such a feature meaningfully without > > incorporating a pooler right into the Postgres tree. I don't > > want to do that, for sure. > > Having protocol-level tests for bytes on the wire would not only help > proposals like this but also get coverage for a huge number of edge > cases. Magnus has added src/test/protocol for the server, written in > Perl, in his PROXY proposal. And I've added a protocol suite for both > the client and server, written in Python/pytest, in my OAuth proof of > concept. I think something is badly needed in this area. > > --Jacob > -- -- Todd Hubers
