backport: Bug #55568 from 5.1-security to 5.0-security

> revision-id: alexey.kopytov@sun.com-20100824103548-ikm79qlfrvggyj9h
> parent: sunny.bains@oracle.com-20100816001222-xqc447tr6jwh8c53
> committer: Alexey Kopytov <Alexey.Kopytov@Sun.com>
> branch nick: 5.1-security
> timestamp: Tue 2010-08-24 14:35:48 +0400
> message:
>   Bug #55568: user variable assignments crash server when used
>               within query
>   
>   The server could crash after materializing a derived table
>   which requires a temporary table for grouping.
>   
>   When destroying the temporary table used to execute a query for
>   a derived table, JOIN::destroy() did not clean up Item_fields
>   pointing to fields in the temporary table. This led to
>   dereferencing a dangling pointer when printing out the items
>   tree later in the outer SELECT.
>   
>   The solution is an addendum to the patch for bug37362: in
>   addition to cleaning up items in tmp_all_fields3, do the same
>   for items in tmp_all_fields1, since now we have an example
>   where this is necessary.


sql/field.cc:
  Make sure field->table_name is not set to NULL in
  Field::make_field() to avoid assertion failure in 
  Item_field::make_field() after cleaning up items
  (the assertion fired in udf.test when running
  the test suite with the patch applied).
sql/sql_select.cc:
  In addition to cleaning up items in tmp_all_fields3, do the
  same for items in tmp_all_fields1.
  Introduce a new helper function to avoid code duplication.
sql/sql_select.h:
  Introduce a new helper function to avoid code duplication in
  JOIN::destroy().

mysql-test/r/join.result

@@ -952,4 +952,55 @@ a	b	a	b
 0	0	0	0
 1	1	1	1
 DROP TABLE t1;
+#
+# Bug #55568: user variable assignments crash server when used within
+#             query
+#
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (0), (1);
+SELECT MULTIPOINT(
+1,
+(
+SELECT MULTIPOINT(
+MULTIPOINT(
+1,
+(SELECT COUNT(*) FROM (SELECT 1 FROM t1 GROUP BY a,a) d)
+)
+) FROM t1
+)
+) != COUNT(*) q FROM t1 GROUP BY a;
+q
+NULL
+NULL
+SELECT MULTIPOINT(
+1,
+(
+SELECT MULTIPOINT(
+MULTIPOINT(
+1,
+(SELECT COUNT(*) FROM (SELECT 1 FROM t1 GROUP BY a,a) d)
+)
+) FROM t1
+)
+) != COUNT(*) q FROM t1 GROUP BY a;
+q
+NULL
+NULL
+DROP TABLE t1;
+#
+# Bug #54468: crash after item's print() function when ordering/grouping 
+#             by subquery
+#
+CREATE TABLE t1(a INT, b INT);
+INSERT INTO t1 VALUES (), ();
+SELECT 1 FROM t1
+GROUP BY
+GREATEST(t1.a,
+(SELECT 1 FROM
+(SELECT t1.b FROM t1,t1 t2
+ORDER BY t1.a, t1.a LIMIT 1) AS d)
+);
+1
+1
+DROP TABLE t1;
 End of 5.0 tests.

mysql-test/t/join.test

@@ -747,4 +747,50 @@ SELECT * FROM t1 STRAIGHT_JOIN t1 t2 ON t1.a=t2.a AND t1.a=t2.b ORDER BY t2.a, t
 
 DROP TABLE t1;
 
+--echo #
+--echo # Bug #55568: user variable assignments crash server when used within
+--echo #             query
+--echo #
+
+CREATE TABLE t1 (a INT);
+
+INSERT INTO t1 VALUES (0), (1);
+
+let $i=2;
+while ($i)
+{
+  SELECT MULTIPOINT(
+    1,
+    (
+      SELECT MULTIPOINT(
+        MULTIPOINT(
+          1,
+          (SELECT COUNT(*) FROM (SELECT 1 FROM t1 GROUP BY a,a) d)
+        )
+      ) FROM t1
+    )
+  ) != COUNT(*) q FROM t1 GROUP BY a;
+  dec $i;
+}
+
+DROP TABLE t1;
+
+--echo #
+--echo # Bug #54468: crash after item's print() function when ordering/grouping 
+--echo #             by subquery
+--echo #
+
+CREATE TABLE t1(a INT, b INT);
+INSERT INTO t1 VALUES (), ();
+
+SELECT 1 FROM t1
+GROUP BY
+GREATEST(t1.a,
+         (SELECT 1 FROM
+          (SELECT t1.b FROM t1,t1 t2
+           ORDER BY t1.a, t1.a LIMIT 1) AS d)
+        );
+
+DROP TABLE t1;
+
 --echo End of 5.0 tests.

sql/field.cc

@@ -1365,7 +1365,7 @@ void Field::make_field(Send_field *field)
   }
   else
     field->org_table_name= field->db_name= "";
-  if (orig_table)
+  if (orig_table && orig_table->alias)
   {
     field->table_name= orig_table->alias;
     field->org_col_name= field_name;

sql/sql_select.cc

@@ -2226,13 +2226,8 @@ JOIN::destroy()
 
   cleanup(1);
  /* Cleanup items referencing temporary table columns */
-  if (!tmp_all_fields3.is_empty())
-  {
-    List_iterator_fast<Item> it(tmp_all_fields3);
-    Item *item;
-    while ((item= it++))
-      item->cleanup();
-  }
+  cleanup_item_list(tmp_all_fields1);
+  cleanup_item_list(tmp_all_fields3);
   if (exec_tmp_table1)
     free_tmp_table(thd, exec_tmp_table1);
   if (exec_tmp_table2)
@@ -2243,6 +2238,19 @@ JOIN::destroy()
   DBUG_RETURN(error);
 }
 
+
+void JOIN::cleanup_item_list(List<Item> &items) const
+{
+  if (!items.is_empty())
+  {
+    List_iterator_fast<Item> it(items);
+    Item *item;
+    while ((item= it++))
+      item->cleanup();
+  }
+}
+
+
 /*
   An entry point to single-unit select (a select without UNION).
 

sql/sql_select.h

@@ -489,6 +489,7 @@ public:
   }
 private:
   bool make_simple_join(JOIN *join, TABLE *tmp_table);
+  void cleanup_item_list(List<Item> &items) const;
 };