[cups-devel] IPP backend not supporting multiple Authentication header fields?

[Joschi Brauchle]

Dear all,

I am trying to print via IPP to a kerberized windows print server, but 
the IPP backend always requests a username and password, instead of 
using Negotiate authentication.


The problem seems to be that the windows print server returns the 
following header:
----------------------
HTTP/1.1 401 Unauthorized
Content-Type	text/html
Server	Microsoft-IIS/8.5
WWW-Authenticate	Negotiate
WWW-Authenticate	NTLM
Date	Tue, 14 Oct 2014 15:26:11 GMT
Content-Length	1344
----------------------

I modified the ipp.c backend source code to debug print the 
authentication header field contents, which show "NTLM" only.
Hence, the following ipp.c code lines
----------------------
         if (!strncmp(www_auth, "Negotiate", 9))
           auth_info_required = "negotiate";
         else if (www_auth[0])
           auth_info_required = "username,password";
----------------------
fail to use negotiate auth and always go for username+password!

Is this observation correct that multiple authentication header fields 
are ignored except the last one?

Best regards,
Joschi Brauchle
-- 
Dipl.-Ing. Joschi Brauchle, M.S.

Institute for Communications Engineering (LNT)
Technische Universitaet Muenchen (TUM)
80290 Munich, Germany

Tel (work): +49 89 289-23474
Fax (work): +49 89 289-23490
E-mail: joschi.brauchle at tum.de
Web: http://www.lnt.ei.tum.de/