Yeah, that works! Isaac, thanks a lot! Just curious, is this the right to
do this or should libcurl explicitly does the rnds lookup? The spn name
with the ip address is not a valid name anyway I guess.

Best regards,
Bill

On Sun, Oct 18, 2015 at 2:12 AM, Isaac Boukris <iboukris_at_gmail.com> wrote:

> Hi,
>
> On Sun, Oct 18, 2015 at 3:03 AM, Wenlong Dong <wdong87_at_gmail.com> wrote:
> > Hi,
> >
> > When Curl forms the service principal given the service name, it simply
> > formats the service principal name with "<service_name>/<host_name>" in
> > Curl_sasl_build_spn. The "<host_name>" is basically the host name part of
> > the URL. So if the host name is an IP address, the SPN would be wrong
> > according to the following doc:
> >
> http://web.mit.edu/kerberos/krb5-1.5/krb5-1.5.4/doc/krb5-user/What-is-a-Kerberos-Principal_003f.html
> >>> In the case of a host, the instance is the fully qualified hostname,
> >>> e.g., daffodil.mit.edu.
> >
> > Because of this, the kerberos ticket generated by KDC is unusable by the
> > service. What's worse is that JDK would pass on calling
> > GSSContext.acceptSecContext() silently but in fact it could not even get
> the
> > client's principal name. This affects SPNEGO scenario for libcurl.
> >
> > Could libcurl perform a reverse DNS lookup to get the fully qualified
> > hostname?
>
> I think you might be able to achieve this at the KRB library level
> ('rdns=true' under 'libdefaults' in 'krb5.conf').
>
> HTH
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Received on 2015-10-18