Don't allow CREATE TABLE AS to put relations in pg_global.

This was never intended to be allowed, and is blocked for an ordinary
CREATE TABLE, but CREATE TABLE AS slipped through the cracks.  This
commit won't do anything to fix existing cases where this has loophole
has been exploited, but it still seems prudent to lock it down going
forward.

Back-branch commit only, as this problem has been refactored away
on the master branch.

Andres Freund

diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index bcab54397f2fafeebb8beccba8d010761cb963bc..657a778290a0caff9fafaf2ac1953a0766980e85 100644 (file)
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -38,6 +38,7 @@
 #include "access/xact.h"
 #include "catalog/heap.h"
 #include "catalog/namespace.h"
+#include "catalog/pg_tablespace.h"
 #include "catalog/toasting.h"
 #include "commands/tablespace.h"
 #include "commands/trigger.h"
@@ -2249,6 +2250,12 @@ OpenIntoRel(QueryDesc *queryDesc)
                           get_tablespace_name(tablespaceId));
    }
 
+   /* In all cases disallow placing user relations in pg_global */
+   if (tablespaceId == GLOBALTABLESPACE_OID)
+       ereport(ERROR,
+               (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+                errmsg("only shared relations can be placed in pg_global tablespace")));
+
    /* Parse and validate any reloptions */
    reloptions = transformRelOptions((Datum) 0,
                                     into->options,