Hi,

There is some trouble to enable SPDY on a DNSSec/TLSA protected domain.

Context : 2 domains, a.example.org and b.example.net Hosted behind the same IP 2 differents TLS certificates, both valid for A and B (eg. *.example.org for both) Content on A use content of B (eg. domain sharding, virtual server for isolation…).

SPDY (for speed purpose I guess) currently fetch the content for both domains A and B throught the same socket, without TLS renegociation, because A certificate is also valid for B domain and contents share the same IP. But this way, SPDY potentially breaks TLSA validation if B TLSA entry isn’t valid for the A certificat. So currently, SPDY usage is not compatible with valid DNSSec/TLSA usage.

SPDY must not choose by itself if it can reuse a certificate or not. 2 differents certificates must be use if server administrator declare 2 differents certificates, even if the IP is the same and/or one certificate seems valid for another domain. Security purpose must be a priority on speed purpose.

In this case, SPDY break TLSA, but the current TLS behaviour of SPDY can break all others client-side usages of TLS (custom OCSP responders, certificate or key pinning, hardcoded server certificate verification…) in case of the SPDY « TLS implementation » choices lead to different behaviours or are unaware of things than official and standard TLS stacks use.

What version/revision number of mod_spdy are you using?

https://github.com/eousphoros/mod-spdy commit ab03b622681feec912d0f46bb284eb2d38b35948

What version of Apache are you using, and on what operating system? (Use apache2ctl -v to check.)

Server version: Apache/2.4.10 (Debian) Server built: Nov 18 2014 14:21:53

What browser version did you use to access the mod_spdy server? On what operating system? What flags was the browser invoked with? (For Chrome/Chromium, go to about:version to check.)

Iceweasel 31.3.0esr-1, Debian Testing