[openssl-dev] [openssl.org #4069] Malformed Client Hello messages are accepted (custom message padding and length)

[Hubert Kario via RT]

On Friday 02 October 2015 11:51:10 Alessandro Ghedini via RT wrote:
> On Fri, Oct 02, 2015 at 11:26:36am +0000, Hubert Kario via RT wrote:
> > Current git checkout of 1.0.1, 1.0.2 and master accept malformed
> > Client Hello messages.
> > 
> > If the client sends a Client Hello message with extensions.length
> > field equal to 0, but padded with bytes
> > FF01 0001 00
> > then the Server Hello will contain the renegotiation_info extension.
> 
> Yup, ssl_scan_clienthello_tlsext() extracts the length but then it
> doesn't do anything with it.
> 
> I wrote a patch [0] that fixes this specific problem in master, but
> the tlsfuzzer script has a bunch of other failures. Incidentally,
> with my patch applied, the tlsfuzzer test takes a lot less time (like
> it's seconds faster), not quite sure if that's good or bad...

yes, all of the tests combined should finish in under 500ms on anything 
resembling a modern PC.

any kind of "timed out" from tlsfuzzer means that the other side was 
expecting more data where it shouldn't have

-- 
Regards,
Hubert Kario
Quality Engineer, QE BaseOS Security team
Web: www.cz.redhat.com
Red Hat Czech s.r.o., Purkyňova 99/71, 612 45, Brno, Czech Republic
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