Re: copy.c handling for RLS is insecure - Mailing list pgsql-hackers

From Stephen Frost
Subject Re: copy.c handling for RLS is insecure
Date
Msg-id 20141127070305.GN28859@tamriel.snowman.net
Whole thread Raw
In response to Re: copy.c handling for RLS is insecure  (Stephen Frost <sfrost@snowman.net>)
Responses Re: copy.c handling for RLS is insecure
List pgsql-hackers
Robert,

* Stephen Frost (sfrost@snowman.net) wrote:
> * Robert Haas (robertmhaas@gmail.com) wrote:
> > In DoCopy, some RLS-specific code constructs a SelectStmt to handle
> > the case where COPY TO is invoked on an RLS-protected relation.  But I
> > think this step is bogus in two ways:
> >
> >             /* Build FROM clause */
> >             from = makeRangeVar(NULL, RelationGetRelationName(rel), 1);
> >
> > First, because relations are schema objects, there could be multiple
> > relations with the same name.  The RangeVar might end up referring to
> > a different one of those objects than the user originally specified.
>
> Argh.  That's certainly no good.  It should just be using the RangeVar
> relation passed in from CopyStmt, no?  We don't have to address the case
> where it's NULL (tho we should perhaps Assert(), just to be sure), as
> that would only happen in the COPY select_with_parens ... production and
> this is only for the normal 'COPY relname' case.

Alright, I've done the change to use the RangeVar from CopyStmt, but
also added a check wherein we verify that the relation's OID returned
from the planned query is the same as the relation's OID that we did the
RLS check on- if they're different, we throw an error.  Please let me
know if there are any remaining concerns.
Thanks!
    Stephen

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