Re: (ITS#8474) Securely Erase BerElement Buffer After Use

[hyc@symas.com]

alcronin@cisco.com wrote:
> Full_Name: Alan Cronin
> Version: 2.4.44
> OS: Windows 8.1
> URL: https://dl.dropboxusercontent.com/u/82343475/SecurelyEraseBuffer.diff
> Submission from: (NULL) (2001:420:4041:2003:f942:59a5:545f:b334)
>
>
> The following patch is a modification to the OpenLDAP BerElement buffer. The
> buffer can be used to contain the LDAP request including the password for
> authentication. While this is free'd when it is no longer needed, the contents
> of the buffer is not overwritten from memory. This can lead to someone reading
> the memory of the process and determining what the password is. The change
> included in this patch will iterate over the memory and clear it. This will
> remove any trace of the password by the time execution is handed back to the
> caller.

Why would you insert a performance pessimization into every use of the LBER 
library, rather than just erasing the password from a Bind request?

Why would you use an explicitly coded loop setting one character at a time, 
instead of using libc's memset() which has probably been well optimized?

> The attached patch file is derived from OpenLDAP Software. All of the
> modifications to OpenLDAP Software represented in the following patch(es) were
> developed by Alan Cronin alcronin@cisco.com. I have not assigned rights and/or
> interest in this work to any party.
> The attached file is derived from OpenLDAP Software. All of the modifications to
> OpenLDAP Software represented in the following patch(es) were developed by Cisco
> Systems, Inc.. Cisco Systems, Inc. has not assigned rights and/or interest in
> this work to any party. I, Alan Cronin am authorized by Cisco Systems, Inc., my
> employer, to release this work under the following terms.
> Cisco Systems, Inc. hereby place the following modifications to OpenLDAP
> Software (and only these modifications) into the public domain. Hence, these
> modifications may be freely used and/or redistributed for any purpose with or
> without attribution and/or other notice.
>
>


-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/