[gnutls-devel] Server sends incorrect extensions for resumption handshake?

Nikos Mavrogiannopoulos nmav at gnutls.org
Tue Jul 9 09:29:56 CEST 2013

On Sun, Jun 30, 2013 at 4:52 AM, Peter Dettman
<peter.dettman at bouncycastle.org> wrote:

> Firstly, the ec_point_formats extension is included in the session
> resumption ServerHello. This appears to violate RFC 3546 2.3. "If [...] the
> older session is resumed, then the server MUST ignore extensions appearing
> in the client hello, and send a server hello containing no extensions[.]"
> (later RFC updates contain similar clauses) . Please understand that the
> problem is probably broader than just the ec_point_formats extension; the
> server shouldn't be sending any. The only exception to that rule that I am
> aware of is from RFC 5746, renegotiation_info, which appears to say that
> this extension is per-connection, and can always be sent. This is the second
> issue I want to raise: while gnutls-serv sends renegotiation_info during the
> initial handshake, it does _not_ send it during a resumption handshake.

Hello Peter,
 I can verify that indeed serverhello may contain some extensions when
resuming, but I cannot see how the renegotiation_info is not sent
while resuming. Could you let me know how I can reproduce your test?


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