pgsql: Prevent privilege escalation in explicit calls to PL validators.

Prevent privilege escalation in explicit calls to PL validators.

The primary role of PL validators is to be called implicitly during
CREATE FUNCTION, but they are also normal functions that a user can call
explicitly.  Add a permissions check to each validator to ensure that a
user cannot use explicit validator calls to achieve things he could not
otherwise achieve.  Back-patch to 8.4 (all supported versions).
Non-core procedural language extensions ought to make the same two-line
change to their own validators.

Andres Freund, reviewed by Tom Lane and Noah Misch.

Security: CVE-2014-0061

Branch
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REL9_2_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/1d701d28a796ea2d1a4d2be9e9ee06209eaea040

Modified Files
--------------
doc/src/sgml/plhandler.sgml         |    5 ++-
src/backend/catalog/pg_proc.c       |    9 ++++
src/backend/commands/functioncmds.c |    1 -
src/backend/utils/fmgr/fmgr.c       |   84 +++++++++++++++++++++++++++++++++++
src/include/fmgr.h                  |    1 +
src/pl/plperl/plperl.c              |    4 ++
src/pl/plpgsql/src/pl_handler.c     |    3 ++
src/pl/plpython/plpy_main.c         |    4 ++
8 files changed, 109 insertions(+), 2 deletions(-)