scram-sha-1-plus

[Jeremy Harris]

Problem:
  gsasl_client_start(gsasl_ctx , "SCRAM-SHA-1-PLUS", &sctx)

fails with GSASL_NO_CB_TLS_UNIQUE.  But you can't provide that
prop until you have the sctx.

What is the expected sequence of calls?


As far as I can see from the example utility code, you have to
provide _a_ prop during some callbacks that happen when the
callback is first provided, back at just after gsasl_init()
is called.

The prop is then presumably set on some irrelevant sctx, which
happens by luck to still be around during the processing of
gsasl_client_start().  You can then override the prop by
another setting, using the real channel-binding (which I
only obtain between gsasl_init() and gsasl_client_start(),
having only just made the TCP and TLS connection) on the
then-legitimate sctx.

I have it operational, but it feels fragile.
-- 
Cheers,
  Jeremy