On Oct 19, 2015 12:20 AM, "Wenlong Dong" <wdong87_at_gmail.com> wrote:
>
> 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.

I think the gssapi library is a better place for name canonization.

> 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

-------------------------------------------------------------------
List admin: http://cool.haxx.se/list/listinfo/curl-library
Etiquette: http://curl.haxx.se/mail/etiquette.html
Received on 2015-10-18