Re: [TLS] I-D Action: draft-ietf-tls-negotiated-ff-dhe-10.txt

The client don't receive the ServerKeyExchange message containing the DHE key at all until after they sent the ClientHello.

________________________________
> From: bascule@gmail.com 
> Date: Tue, 2 Jun 2015 23:35:46 -0700 
> To: geoffk@geoffk.org 
> CC: tls@ietf.org 
> Subject: Re: [TLS] I-D Action: draft-ietf-tls-negotiated-ff-dhe-10.txt 
> 
> On Tue, Jun 2, 2015 at 11:32 PM, Geoffrey Keating 
> <geoffk@geoffk.org<mailto:geoffk@geoffk.org>> wrote: 
> It's covered in section 4: 
> 
> If at least one FFDHE ciphersuite is present in the client 
> ciphersuite list, and the Supported Groups extension is either absent 
> from the ClientHello 
> 
> Unless I'm mistaken, unless you configure the 
> jdk.tls.disabledAlgorithms property explicitly (with e.g. "DHE keySize 
>> 2048"), Java clients are aborting *before* they send the ClientHello. 
> Please let me know if you're seeing otherwise. I could be mistaken and 
> perhaps there's a server-side workaround for this that isn't "disable 
> all DHE ciphersuites". But this is what I've personally observed and 
> have been advising people about. 
> 
> I'm not saying it can't be fixed with additional 
> configuration/errata/etc, I'm arguing that it's *breaking clients in 
> the field right now* 
> 
> tl;dr: I am seeing *widespread TLS breakages* because of this resulting 
> in *huge outages* for Java clients 
> 
> -- 
> Tony Arcieri 
> 
> _______________________________________________ TLS mailing list 
> TLS@ietf.org https://www.ietf.org/mailman/listinfo/tls 