bk commit into 5.0 tree (evgen:1.2597) BUG#33675

[eugene]

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ChangeSet@stripped, 2008-01-10 18:54:34+03:00, evgen@stripped +1 -0
  filesort.cc:
    Bug#33675: Usage of an uninitialized memory by filesort in a subquery caused
    server crash.
    Free smaller buffer before allocating bigger one.

  sql/filesort.cc@stripped, 2008-01-10 18:52:24+03:00, evgen@stripped +6 -2
    Bug#33675: Usage of an uninitialized memory by filesort in a subquery caused
    server crash.
    Free smaller buffer before allocating bigger one.

diff -Nrup a/sql/filesort.cc b/sql/filesort.cc
--- a/sql/filesort.cc	2008-01-09 00:39:02 +03:00
+++ b/sql/filesort.cc	2008-01-10 18:52:24 +03:00
@@ -239,10 +239,14 @@ ha_rows filesort(THD *thd, TABLE *table,
   }
   else
   {
+    if (table_sort.buffpek && table_sort.buffpek_len < maxbuffer)
+    {
+      x_free(table_sort.buffpek);
+      table_sort.buffpek= 0;
+    }
     if (!(table_sort.buffpek=
           read_buffpek_from_file(&buffpek_pointers, maxbuffer,
-                                 (table_sort.buffpek_len < maxbuffer ?
-                                  NULL : table_sort.buffpek))))
+                                 table_sort.buffpek)))
       goto err;
     buffpek= (BUFFPEK *) table_sort.buffpek;
     table_sort.buffpek_len= maxbuffer;