Thread: pgsql: In REFRESH MATERIALIZED VIEW, set user ID before running user co

In REFRESH MATERIALIZED VIEW, set user ID before running user code.

It intended to, but did not, achieve this.  Adopt the new standard of
setting user ID just after locking the relation.  Back-patch to v10 (all
supported versions).

Reviewed by Simon Riggs.  Reported by Alvaro Herrera.

Security: CVE-2022-1552

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/34ff15660b4f752e3941d661c3896fd96b1571f9

Modified Files
--------------
src/backend/commands/matview.c           | 30 +++++++++++-------------------
src/test/regress/expected/privileges.out | 16 ++++++++++++++++
src/test/regress/sql/privileges.sql      | 17 +++++++++++++++++
3 files changed, 44 insertions(+), 19 deletions(-)