[patch] null after free

[Havoc Pennington]

On Mon, 2004-10-04 at 16:28 -0400, John (J5) Palmieri wrote:
> What is actually happening is that on an error in the fill_user_info
> function in dbus-sysdeps.c we are jumping to the failed section which
> frees the DBusUserInfo structure:
> 
> failed:
>   _DBUS_ASSERT_ERROR_IS_SET (error);
>   _dbus_user_info_free (info);
>   return FALSE;

Ah, this is just plain old crackrock; should not free info there.

> However this returns FALSE and an error to the caller which then calls
> free_user_info (which calls _dbus_user_info_free somewhere down the
> line).  Here is an example from dbus-userdb.c
> (_dbus_user_database_lookup):
> 
> if (!_dbus_user_info_fill_uid (info, uid, error))
>   {
>     _DBUS_ASSERT_ERROR_IS_SET (error);
>     free_user_info (info);
>     return NULL;
>   }
> 
> This is just one example but it happens a couple of times.  The question
> is where is it best to free the structure?  The DBusUserInfo field is
> passed into fill_user_info so I feel this is not the place it should be
> freed.  However if it is not freed there we must make sure the error is
> handled everywhere else.  Any opinions?
> 

Yes, the error should be handled and freed everywhere else. The same
code that allocs should free.

Havoc