Re: "set role" semantics - Mailing list pgsql-general
| From | Bryn Llewellyn |
|---|---|
| Subject | Re: "set role" semantics |
| Date | |
| Msg-id | E3224C71-F868-49C2-9C86-EB8AA67637E1@yugabyte.com Whole thread Raw |
| In response to | Re: "set role" semantics (Adrian Klaver <adrian.klaver@aklaver.com>) |
| Responses |
Re: "set role" semantics
(Guillaume Lelarge <guillaume@lelarge.info>)
Re: "set role" semantics (Adrian Klaver <adrian.klaver@aklaver.com>) Re: "set role" semantics ("David G. Johnston" <david.g.johnston@gmail.com>) Re: "set role" semantics (Adrian Klaver <adrian.klaver@aklaver.com>) |
| List | pgsql-general |
adrian.klaver@aklaver.com wrote:david.g.johnston@gmail.com wrote:bryn@yugabyte.com wrote:
Notice that I didn't grant "connect" on either of the databases, "d1" or "d2", to any of the roles, "clstr$mgr, "d1$mgr", or "d2$mgr".You didn't have to since PUBLIC gets that privilege and you didn't revoke it.https://www.postgresql.org/docs/current/ddl-priv.html
Revoking PUBLIC has been explained before to you (Bryn Llewellyn).
A quick search:
https://www.postgresql.org/message-id/2176817.1644613186@sss.pgh.pa.us
https://www.postgresql.org/message-id/CAKFQuwayij%3DAQRQxJhFuJ3Qejq3E-PfiBjJ9CoHx_L_46BEgXQ@mail.gmail.com
https://www.postgresql.org/message-id/CAKFQuwZVq-LerGMTN0E3_7MqhJwtuJuzf0GSnKG32mH_Qf24Zw@mail.gmail.com
Here's an extract from the script that I copied in my first email:
create database d1;
revoke all on database d1 from public;
create database d2;
revoke all on database d2 from public;
Didn't I do exactly what you both said that I failed to do?
*Summary*
My experiments (especially below) show that "set role" has special semantics that differ from starting a session from cold:
"set role" allows a role that lacks "connect" on some database to end up so that the "current_database()" shows that forbidden database.
My question still stands: where can I read the account of this? I'm also interested to know _why_ it was decided not to test for the "connect" privilege when "set role" is used.
*Detail*
I suppose that the script that I first showed you conflated too many separable notions. (My aim was to you show what my overall aim was). Here's a drastically cut down version. It still demonstrates the behavior that I asked about.
create role joe
nosuperuser
nocreaterole
nocreatedb
noreplication
nobypassrls
connection limit -1
login password 'p';
create database d1;
revoke all on database d1 from public;
\c d1 postgres
set role joe;
select current_database()||' > '||session_user||' > '||current_user;I'm still able to end up with "Joe" as the "current_user" and "d1" (to which Joe cannot connect) as the "current_database()".
I then did the sanity test that I should have shown you at the outset. (Sorry that I didn't do that.) I started a session from cold, running "psql" on a client machine where the server machine is called "u" (for Ubuntu) in my "/etc/hosts", thus:
psql -h u -p 5432 -d d1 -U joe
The connect attempt was rejected with the error that I expected: "User does not have CONNECT privilege".
I wondered if the fact that the "session_user" was "postgres" in my tests was significant. So I did a new test. (As ever, I started with a freshly created cluster to be sure that no earlier tests had left a trace.)
create role mary
nosuperuser
noinherit
nocreaterole
nocreatedb
noreplication
nobypassrls
connection limit -1
login password 'p';
create role joe
nosuperuser
noinherit
nocreaterole
nocreatedb
noreplication
nobypassrls
connection limit -1
login password 'p';
create database d1;
revoke all on database d1 from public;
grant connect on database d1 to mary;
grant joe to mary;
nosuperuser
noinherit
nocreaterole
nocreatedb
noreplication
nobypassrls
connection limit -1
login password 'p';
create role joe
nosuperuser
noinherit
nocreaterole
nocreatedb
noreplication
nobypassrls
connection limit -1
login password 'p';
create database d1;
revoke all on database d1 from public;
grant connect on database d1 to mary;
grant joe to mary;
Then I did this on the client machine:
psql -h u -p 5432 -d d1 -U mary
set role joe;
Here, too, I ended up with "Joe" as the "current_user" and "d1" (to which Joe cannot connect) as the "current_database()".
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