bzr commit into mysql-5.1 branch (mats:3110) Bug#47645

[Mats Kindahl]

#At file:///home/bzr/mkindahl/patching-5.1/ based on revid:mats@stripped

 3110 Mats Kindahl	2009-09-25
      Bug #47645: Segmentation fault when out of memory during handlerton initialization
      
      There is a missing check for memory allocation failure when allocating
      memory for the handlerton structure. If the handlerton init function
      tries to de-reference the pointer, it will cause a segmentation fault
      and crash the server.
      
      This patch fixes the problem by not calling the init function if memory
      allocation failed, and instead reports the error to the caller.
     @ sql/handler.cc
        Add a check if memory allocation succeeded before calling the init
        function. If it failed, it is not necessary to free the memory,
        but the plugin->data is set to NULL to ensure that it can be checked
        for failure.

    modified:
      sql/handler.cc
=== modified file 'sql/handler.cc'
--- a/sql/handler.cc	2009-07-29 08:54:20 +0000
+++ b/sql/handler.cc	2009-09-25 09:29:54 +0000
@@ -430,6 +430,10 @@ int ha_initialize_handlerton(st_plugin_i
 
   hton= (handlerton *)my_malloc(sizeof(handlerton),
                                 MYF(MY_WME | MY_ZEROFILL));
+
+  if (hton == NULL)
+    goto err_no_hton_memory;
+
   /* Historical Requirement */
   plugin->data= hton; // shortcut for the future
   if (plugin->plugin->init && plugin->plugin->init(hton))
@@ -540,6 +544,7 @@ err_deinit:
           
 err:
   my_free((uchar*) hton, MYF(0));
+err_no_hton_memory:
   plugin->data= NULL;
   DBUG_RETURN(1);
 }


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