Thank you both for bringing this to my attention, your points are invaluable.
If this is something which gets set from server on client side. can client override this?. Can i change this to something less and try?. Has anyone tried?.
Whats the option in openssl.conf or some other place?.
-thanks
harish
On Mon, Jan 25, 2021 at 11:08 PM Matt Caswell <matt@xxxxxxxxxxx> wrote:
On 23/01/2021 15:22, John Thoe wrote:
> Hi list,
>
> The session reuse question posted on the mailing list earlier
> (https://mta.openssl.org/pipermail/openssl-users/2021-January/013360.html)
> reminded of a somewhat similar question I have.
>
> As per the docs,
> https://www.openssl.org/docs/man1.0.2/man3/SSL_get_default_timeout.html,
> it says the default value is 300 seconds for which a session resuse
> will be accepted. The docs say that it is the same for all
> protocols.
>
> However I tried it with my setup where I didn't explicitly set the
> timeout and I am getting 7200 seconds as the default value. s_client
> output: TLS session ticket lifetime hint: 7200 (seconds). My client
> openssl.conf has no setting override (not that it should matter
> because this is a server preference). No OpenSSL settings on the
> server have been modified as well.
Looks to me like the docs are wrong. They probably should say 7200.
>
> In ssl/ssl_sess.c#L80, the code matches the document: ss->timeout =
> 60 * 5 + 4; /* 5 minute timeout by default */ ... (with additional
> four seconds?)
This gets set during construction and then later overwritten when we
actually get a new session via "ssl_get_new_session":
/* If the context has a default timeout, use it */
if (s->session_ctx->session_timeout == 0)
ss->timeout = SSL_get_default_timeout(s);
else
ss->timeout = s->session_ctx->session_timeout;
In most cases SSL_get_default_timeout() calls tls1_default_timeout() (it
can end up somewhere different for certain protocol versions - but all
the different variants are the same!):
long tls1_default_timeout(void)
{
/*
* 2 hours, the 24 hours mentioned in the TLSv1 spec is way too long for
* http, the cache would over fill
*/
return (60 * 60 * 2);
}
60 * 60 * 2 = 7200
Matt
