> On Mar 28, 2017, at 1:17 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > > Mark Dilger <hornschnor...@gmail.com> writes: >> I don't see anything wrong with adding roles in pg_authid.h with a #define'd >> Oid. That's actually pretty helpful for anyone writing code against the >> database, >> as they don't have to look up the Oid of the role. > >> But why not then grant privileges to that role in information_schema.sql? > > To the extent that the desired privileges can be represented at the SQL > level, I agree that that's a better solution than hard-wiring checks in C > code. The problem comes in with cases where that's not fine-grained > enough. Consider a policy like "anybody can select from pg_stat_activity, > but unless you have privilege X, the query column should read as nulls > except for sessions belonging to you". That behavior can't realistically > be represented as a separate SQL privilege. Right now we have "privilege > X" for this purpose hard-coded as "is superuser", but it would be much > better if it were associated with a grantable role.
Many thanks for all the explanation. I now understand better what the patch is trying to do, and have (with some experimentation) seen flaws in what I was saying upthread. I find the notion of a role not being a group of privileges but instead actually being a privilege confusing, and it made it hard to think about the security implications of the proposal. I'm accustomed to the idea of being able to revoke a privilege from a role, and that doesn't work if the "role" is in some sense a privilege, not a role. I might find it all easier to think about if we named these things privileges and not roles, like pg_read_stats_privilege instead of pg_read_stats_role, and then we could grant pg_read_stats_privilege to roles. But I recall you were saying upthread that you did not want to have privilege bits for each of these types of things. I hope this feature is worth the confusion it causes. mark -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers