KaiGai Kohei <kaigai@ak.jp.nec.com> wrote:
> Tom Lane wrote:
> > Takahiro Itagaki <itagaki.takahiro@oss.ntt.co.jp> writes:
> >> <structname>pg_largeobject</structname> should not be readable by the
> >> public, since the catalog contains data in large objects of all users.
> >
> > This is going to be a problem, because it will break applications that
> > expect to be able to read pg_largeobject. Like, say, pg_dump.
>
> Is it a right behavior, even if we have permission checks on large objects?
Can we use column-level access control here?
REVOKE ALL ON pg_largeobject FROM PUBLIC;
=> GRANT SELECT (loid) ON pg_largeobject TO PUBLIC;
We use "SELECT loid FROM pg_largeobject LIMIT 1" in pg_dump. We could
replace pg_largeobject_metadata instead if we try to fix only pg_dump,
but it's no wonder that any other user applications use such queries.
I think to allow reading loid is a balanced solution.
> If so, we can inject a hardwired rule to prevent to select pg_largeobject
> when lo_compat_privileges is turned off, instead of REVOKE ALL FROM PUBLIC.
Is it enough to run "GRANT SELECT ON pg_largeobject TO PUBLIC" ?
Regards,
---
Takahiro Itagaki
NTT Open Source Software Center
