SASL property for compression layer

[Julien ÉLIE]

Hi,

I am currently working on implementing the NNTP COMPRESS command in the 
InternetNetNews news server.  This commands permits to start a 
compression layer (like the COMPRESS command for IMAP).

I have a question about a possible already active compression layer 
after the use of SASL authentication.  Is there a way to check whether a 
compression layer has been negotiated during SASL authentication?


With OpenSSL, we can use the SSL_get_current_compression() function to 
see whether a compression layer has been negotiated at the same time of 
the TLS encryption layer.  A similar function could be useful in Cyrus 
SASL if it does not already exist.  (Maybe current or future SASL 
mechanisms can or will negotiate a compression layer.)


Note:  it could be a property like SASL_SSF that InternetNewsNews 
already checks after SASL authentication to see whether an encryption 
layer has been negotiated.  If the value of that property is >0, the use 
of STARTTLS is disabled as an encryption layer already exists.

-- 
Julien ÉLIE

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