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 cb79fadedb40c8ecf89ebb087b869af8702b935e..52018df8a51e3233a047ed6f9cffc96d3679dcf9 100644 (file)
--- a/contrib/pgstattuple/pgstattuple.c
+++ b/contrib/pgstattuple/pgstattuple.c
@@ -1,5 +1,5 @@
 /*
- * $PostgreSQL: pgsql/contrib/pgstattuple/pgstattuple.c,v 1.20 2005/10/15 02:49:06 momjian Exp $
+ * $PostgreSQL: pgsql/contrib/pgstattuple/pgstattuple.c,v 1.20.2.1 2009/03/31 22:56:05 tgl Exp $
  *
  * Copyright (c) 2001,2002     Tatsuo Ishii
  *
@@ -115,6 +115,16 @@ pgstattuple_real(Relation rel, FunctionCallInfo fcinfo)
        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 descriptor for our result type */
        if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
                elog(ERROR, "return type must be a row type");