• From: Denmark
  • Registered: 2021-03-02
  • Posts: 10

Topic: How to add new Key Share extension into New Session Ticket packet?

Hello everyone,

I am using the client/server example and specifically TLS 1.3
I would like to customize the New Session Ticket packet from the initial handshake, by adding an extra extension to it which will provide a DH public key parameter.

I am currently in the function 

SendTls13NewSessionTicket

of the tls13.c file right before the 

ret = SendBuffered(ssl);

line. I have tried add a new extension to my New Session Ticket message with:

  • wolfSSL_UseKeyShare

  • TLSX_KeyShare_Use

  • TLSX_KeyShare_Parse

but unfortunately I get for all a segmentation fault for all of them.
Why do I have this issue and how can I add that ?

Thank you in advance

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  • Registered: 2015-10-07
  • Posts: 430

Re: How to add new Key Share extension into New Session Ticket packet?

Hi cxenof03,

As we've discussed offline you might consider using the TLS v1.3 early data feature to send the public key. Otherwise you would need to make some very specific changes inside the wolfSSL code to inject an additional extension.

Thanks,
David Garske, wolfSSL

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