On Fri, 2014-07-11 at 11:24 +0200, Michael Osipov wrote: > > That is absolutely true. This is an area which I want to improve in curl > mid-term. The reason for fbopenssl was probably some one did not hav a > capable GSS-API version.
Probably. Although that's less of an excuse these days, since everyone *should* have a GSSAPI implementation that does SPNEGO by now. > I waiting for this patch to be merged and then > I could adapt configure.ac and patch the source code in a way were FTP > and SOCKS use KRB5_MECHANISM and HTTP uses SPNEGO_MECHANISM. I firmly believe that the way forward here is to rip out the FBOpenSSL bit altogether. I'm working on that now; to quote the commit message from http://git.infradead.org/users/dwmw2/curl.git/commitdiff/d7bb1f66 [PATCH] Remove all traces of FBOpenSSL SPNEGO support This is just fundamentally broken. SPNEGO (RFC4178) is a protocol which allows client and server to negotiate the underlying mechanism which will actually be used to authenticate. This is *often* Kerberos, and can also be NTLM and other things. And to complicate matters, there are various different OIDs which can be used to specify the Kerberos mechanism too. A SPNEGO exchange will identify *which* GSSAPI mechanism is being used, and will exchange GSSAPI tokens which are appropriate for that mechanism. But this SPNEGO implementation just strips the incoming SPNEGO packet and extracts the token, if any. And completely discards the information about *which* mechanism is being used. Then we *assume* it was Kerberos, and feed the token into gss_init_sec_context() with the default mechanism (GSS_S_NO_OID for the mech_type argument). Furthermore... broken as this code is, it was never even *used* for input tokens anyway, because higher layers of curl would just bail out if the server actually said anything *back* to us in the negotiation. We assume that we send a single token to the server, and it accepts it. If the server wants to continue the exchange (as is required for NTLM and for SPNEGO to do anything useful), then curl was broken anyway. So the only bit which actually did anything was the bit in Curl_output_negotiate(), which always generates an *initial* SPNEGO token saying "Hey, I support only the Kerberos mechanism and this is its token". You could have done that by manually just prefixing the Kerberos token with the appropriate bytes, if you weren't going to do any proper SPNEGO handling. There's no need for the FBOpenSSL library at all. The sane way to do SPNEGO is just to *ask* the GSSAPI library to do SPNEGO. That's what the 'mech_type' argument to gss_init_sec_context() is for. And then it should all Just Workâ˘. That 'sane way' will be added in a subsequent patch, as will bug fixes for our failure to handle any exchange other than a single outbound token to the server which results in immediate success. -- David Woodhouse Open Source Technology Centre david.woodho...@intel.com Intel Corporation
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