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 301aa124962f132e1332e79ceee60ce7502ec941..a298945ae62bcc3daada4ac7997a242172cc0710 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"
@@ -2746,6 +2747,12 @@ 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,