On 14.06.2014 10:23, Kaspar Brand wrote:
> On 13.06.2014 16:55, Rainer Jung wrote:
>> Now since a long time most clients do no longer rely on the server
>> caching the sessions. Instead they use TLS session resumption (RFC
>> 5077).
> 
> "without server-side state"/"stateless" is actually the important term
> from this RFC (session resumption is a standard protocol feature).
> 
>> Currently mod_ssl does not provide a way to control the time how long
>> such a ticket may be used by the client. As far as I can see, there is
>> no specific API in OpenSSL for that, but there is a general API allowing
>> to set a session timeout that is checked whenever a session is
>> reconstructed.
> 
> What OpenSSL function do you have in mind? SSL_SESSION_set_timeout?

I was hoping SSL_CTX_set_timeout() would do the trick.

> AFAICT, t1_lib.c:tls_decrypt_ticket simply restores the (relative)
> timeout for the SSL_SESSION, which is set to 5 minutes by default... but
> if I'm understanding correctly, you are concerned about clients reusing
> "old" tickets, is that correct? (If so, then I guess there's currently
> no other way than switching to a new ticket encryption key, see also [1]).

Yes that's my concern. I will give SSL_CTX_set_timeout() a try over the
weekend.

> Kaspar
> 
> [1]
> https://mail-archives.apache.org/mod_mbox/httpd-dev/201308.mbox/%3C20130821111727.GA7331%40redhat.com%3E
> or
> https://mail-archives.apache.org/mod_mbox/httpd-dev/201309.mbox/%3C52248C40.7070206%40opensslfoundation.com%3E

Regards,

Rainer

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