[racket-dev] ECDHE patch for Racket's OpenSSL bindings.

From: Edward Lee (e45lee at uwaterloo.ca)
Date: Wed Apr 9 19:35:20 EDT 2014

My patch does not include any C code; I have not audited any existing
OpenSSL code, but to the best of my knowledge, OpenSSL + (EC)DHE is
commonly used across webservers today.

To answer your second point, the
perfect forward secrecy extensions are disabled by default, and
must be explicitly enabled on the server.
(by calling ssl-server-context-enable-dhe! and ssl-server-context-enable-ecdhe!)

Perfect Forward Secrecy, to some extent mitigates the damage
that can be done when private keys are compromised (like what happened
recently); it at least prevents an attacker from decrypting any SSL conversations
he/she may have recorded previously.  Currently, if server private keys are
compromised, with Racket's OpenSSL's current mode of operations, all
previous encrypted conversations can be decrypted.

Given what has happened recently, I am sure we can all agree that
anything that mitigates the damage when private keys are compromised is
a Good Thing.

On Wed, Apr 09, 2014 at 04:47:44PM -0400, Neil Van Dyke wrote:
> * Is anyone up to auditing the C code?  To support my earlier
> concern ("http://lists.racket-lang.org/dev/archive/2014-February/013935.html"),
> you've probably heard in the last few days about a C oops bug in
> OpenSSL that has compromised the private keys of 2/3 of the Internet
> for over a year now.  I think we are going to keep seeing exploits
> like this in SSL/TLS/etc. implementations, because some of the
> protocols are hairy, and the implementations don't seem to be
> perfect like they we need them to be.
> * Are all the new (to Racket) OpenSSL code paths enabled by this
> change disabled *entirely* by default, or are there some
> new-to-Racket code paths that can be negotiated by the other party
> with the default Racket use of OpenSSL?  The reason I ask is that I
> believe that the fewer unnecessary OpenSSL code paths available, the
> fewer OpenSSL vulnerabilities available.
> (BTW, I'm not harshing on OpenSSL entirely.  OpenSSL been
> indispensible for some of my work, dealing with myriad oddball
> security protocols that no one wants to take the huge development
> cost hit of coding and validating from scratch.  But I don't have a
> high level of confidence in the code.)
> Neil V.
> Edward Lee wrote at 04/09/2014 04:20 PM:
> >I previously submitted this patch in late January; I've not received any
> >progress updates with regards to this patch recently - did this patch
> >get lost between then and now?
> >
> >This patch adds Perfect Forward Secrecy to Racket's OpenSSL bindings.
> >This patch has been tested on Ubuntu 12.04 (and appears to work
> >correctly in a production environment).

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