pg_temp implicit search path: functions vs. tables

Started by Josh Kupershmidtover 15 years ago3 messagesgeneral
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#1Josh Kupershmidt
schmiddy@gmail.com

Hi all,

I notice slightly different handling of the implicit search_path for
temporary tables and temporary functions. Consider:

(with a default search path):

# SHOW search_path;
search_path
----------------
"$user",public
(1 row)

BEGIN;
CREATE TABLE pg_temp.bar();

CREATE FUNCTION pg_temp.foofunc() RETURNS int AS $$
SELECT 1;
$$ LANGUAGE SQL;

SELECT * FROM bar;
SELECT * FROM foofunc();

COMMIT;

The select from temporary table bar above succeeds, but I get:
ERROR: function foofunc() does not exist

if I don't schema-qualify the function as pg_temp.foofunc(). So,
pg_temp is being implicitly included in the default search path when
looking for tables, but not for functions. Is there a reason for this
difference?

Josh

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Josh Kupershmidt (#1)
Re: pg_temp implicit search path: functions vs. tables

Josh Kupershmidt <schmiddy@gmail.com> writes:

pg_temp is being implicitly included in the default search path when
looking for tables, but not for functions. Is there a reason for this
difference?

Yes. They used to be the same, but awhile back we decided it was a
security hole to look for functions or operators in the implicit temp
schema. It makes it too easy for someone to substitute a trojan-horse
function that will be picked up in preference to whatever's in the
normal search path. See CVE-2007-2138.

If you actually do want to define and call temporary functions, you
can include "pg_temp" in the search path explicitly, or perhaps better,
explicitly qualify the intentional calls with pg_temp.

regards, tom lane

#3Josh Kupershmidt
schmiddy@gmail.com
In reply to: Tom Lane (#2)
Re: pg_temp implicit search path: functions vs. tables

On Thu, Oct 21, 2010 at 12:47 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

Josh Kupershmidt <schmiddy@gmail.com> writes:

pg_temp is being implicitly included in the default search path when
looking for tables, but not for functions. Is there a reason for this
difference?

Yes.  They used to be the same, but awhile back we decided it was a
security hole to look for functions or operators in the implicit temp
schema.  It makes it too easy for someone to substitute a trojan-horse
function that will be picked up in preference to whatever's in the
normal search path.  See CVE-2007-2138.

If you actually do want to define and call temporary functions, you
can include "pg_temp" in the search path explicitly, or perhaps better,
explicitly qualify the intentional calls with pg_temp.

Thanks, thought it might be something like that.

Josh