Fix contrib/pgstattuple and contrib/pageinspect to prevent attempts to read

temporary tables of other sessions; that is unsafe because of the way our
buffer management works.  Per report from Stuart Bishop.
This is redundant with the bufmgr.c checks in HEAD, but not at all redundant
in the back branches.

diff --git a/contrib/pgstattuple/pgstattuple.c b/contrib/pgstattuple/pgstattuple.c
index e2fab7863eb4ef8ed05d08695380552395cec858..40fe4f1961c73d3cc2516af80e8c352e5f7d629e 100644 (file)
--- a/contrib/pgstattuple/pgstattuple.c
+++ b/contrib/pgstattuple/pgstattuple.c
@@ -1,5 +1,5 @@
 /*
- * $PostgreSQL: pgsql/contrib/pgstattuple/pgstattuple.c,v 1.17 2004/10/15 22:39:38 tgl Exp $
+ * $PostgreSQL: pgsql/contrib/pgstattuple/pgstattuple.c,v 1.17.4.1 2009/03/31 22:56:18 tgl Exp $
  *
  * Copyright (c) 2001,2002     Tatsuo Ishii
  *
@@ -116,6 +116,16 @@ pgstattuple_real(Relation rel)
        int                     i;
        Datum           result;
 
+       /*
+        * Reject attempts to read non-local temporary relations; we would
+        * be likely to get wrong data since we have no visibility into the
+        * owning session's local buffers.
+        */
+       if (isOtherTempNamespace(RelationGetNamespace(rel)))
+               ereport(ERROR,
+                               (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+                                errmsg("cannot access temporary tables of other sessions")));
+
        /*
         * Build a tuple description for a pgstattupe_type tuple
         */