RFR: 8245527: LDAP Cnannel Binding support for Java GSS/Kerberos

Sean Mullan sean.mullan at oracle.com
Tue Jun 9 15:35:47 UTC 2020

On 6/8/20 5:33 PM, Alexey Bakhtin wrote:
> Hello Sean,
> Yes, I think we'll need CSR and release notes as soon as this patch adds new property.
> I do not know exact process for it, so I will be grateful if you could explain me exact steps.

The CSR process is documented at 
https://wiki.openjdk.java.net/display/csr/Main. It should be fairly 
self-explanatory but let me know if you have questions.

For the release note, we can tackle that later once the CSR is approved 
now I have tagged the issue with the "release-note=yes" label so we 
don't forget it.

> This patch was developed to address compatibility issue with new LDAP authentication over SSL/TLS announced by Microsoft [1]. It is not related to RFC 5801. In my opinion “com.sun.jndi.ldap.tls.cbtype” name looks more suitable for this property and should allow backport it to early JDK versions.

Good point about backporting.

What RFC or specification defines the format you are using for the 
channel binding in TlsChannelBinding.java, specifically where the type 
prefix is encoded as "tls-server-end-point:" followed by the binding 
data? I have looked through various RFCs but I can't find exactly where 
this format is defined, so I am wondering if this is a standard encoding 
or not.


> [1] - https://support.microsoft.com/en-au/help/4034879/how-to-add-the-ldapenforcechannelbinding-registry-entry
> Regards
> Alexey
>> On 8 Jun 2020, at 22:03, Sean Mullan <sean.mullan at oracle.com> wrote:
>> (resending to all lists on the review)
>> I'm just catching up a bit on this review.
>> Sorry if this has mentioned before, but are you planning to write a CSR and release note? I think this is needed for the com.sun.jndi.ldap.tls.cbtype property. I'm also wondering if this property should be documented in the javadocs, and why it is not a standard property (i.e. "java.naming.ldap.tls.cbtype").
>> I was also wondering what relation this has to the "G2" standard SASL mechanisms defined in RFC 5801 [1], and whether that is something we should be using to negotiate this channel binding, and if not, why not. Or if this is something that is implementation-specific and will only work with Microsoft LDAP technology, in which case, we might want to make that more explicit, perhaps by including "microsoft" or something like that in the property name.
>> Thanks,
>> Sean
>> [1] https://tools.ietf.org/html/rfc5801
>> On 6/8/20 9:07 AM, Aleks Efimov wrote:
>>> Hi Alexey,
>>> I've looked through LdapCtx/LdapClient/SaslBind changes:
>>> Do we need to check if CHANNEL_BINDING is set explicitly for all connection types? Maybe we can move the check inside 'if (conn.sock instanceof SSLSocket) {' block.
>>> Also, instead of setting CHANNEL_BINDING in context environment and then removing it in finally block, it would be better to clone the environment, put calculated CHANNEL_BINDING into it, and pass the cloned one to Sasl.createSaslClient.
>>> Another suggestion about the code that verifies if both properties are set before connection is started:
>>> As you've already mentioned the new code in LdapCtx is only needed for checking if timeout is set. Could we try to remove LdapCtx::cbType field and all related methods from LdapCtx (this class is already over-complicated and hard to read) and replace it with some static method in LdapSasl? It will help to localize all changes to LdapSasl except for one line in LdapCtx.
>>> I mean something like this:
>>> Replace
>>> +
>>> +            // verify LDAP channel binding property
>>> +            if (cbType != null && connectTimeout == -1)
>>> +                    throw new NamingException(TlsChannelBinding.CHANNEL_BINDING_TYPE +
>>> +                            " property requires " +
>>> +                            CONNECT_TIMEOUT +
>>> +                            " property is set.");
>>> With
>>> + LdapSasl.checkCbParameters((String)envprops.get(TlsChannelBinding.CHANNEL_BINDING_TYPE), connectTimeout);
>>> And add something like that to LdapSasl (or maybe pass the full env here):
>>> + public static void checkCbParameters(String cbTypePropertyValue, int connectTimeout) throws NamingException {
>>> +     TlsChannelBindingType cbType = TlsChannelBinding.parseType(cbTypePropertyValue);
>>> +     // verify LDAP channel binding property
>>> +     if (cbType != null && connectTimeout == -1) {
>>> +         throw new NamingException(TlsChannelBinding.CHANNEL_BINDING_TYPE +
>>> +                 " property requires com.sun.jndi.ldap.connect.timeout" +
>>> +                 " property is set.");
>>> +     }
>>> + }
>>> Other LdapCtx/LdapClient/SaslBind  changes look fine to me.
>>> With Kind Regards,
>>> Aleksei
>>> On 06/06/2020 20:45, Alexey Bakhtin wrote:
>>>> Hello Max, Daniel,
>>>> Thank you for review.
>>>> Please review new version of the patch :
>>>> http://cr.openjdk.java.net/~abakhtin/8245527/webrev.v5/
>>>> In this version:
>>>> - TlsChannelBinding class is moved into the com.sun.jndi.ldap.sasl package
>>>> - SSL Ceritificate related code is moved from LdapClient  into the LdapSasl.saslBind method
>>>> - verification and removal of internal property is also moved to LdapSasl.saslBind method
>>>> - verification of connectTimeout property is moved to LdapCtx.connect. I’ve found that connectionTimeout could be assigned later then cbType
>>>> The test for this issue is not ready yet. I did not find any suitable test case that can be reused.
>>>> Thank you
>>>> Alexey
>>>>> On 6 Jun 2020, at 09:44, Weijun Wang <weijun.wang at oracle.com> wrote:
>>>>>> On Jun 6, 2020, at 2:41 PM, Weijun Wang <weijun.wang at oracle.com> wrote:
>>>>>>> On Jun 5, 2020, at 11:03 PM, Alexey Bakhtin <alexey at azul.com> wrote:
>>>>>>> Hello Max,
>>>>>>> Thank you a lot for review.
>>>>>>> Could you check the new version of the patch :
>>>>>>> http://cr.openjdk.java.net/~abakhtin/8245527/webrev.v4/
>>>>>>> I’ve made the following changes:
>>>>>>> - TlsChannelBinding class is moved to java.naming module.
>>>>>>> java.security.sasl module is not affected any more
>>>>>>> - I pass tlsCB.getData() directly to the SASL mechanism as you suggested
>>>>>>> - I’ve made some guards to prevent application from using "com.sun.security.sasl.tlschannelbinding” property directly:
>>>>>>>      - LdapClient verifies if internal property is not set
>>>>>> 245                     // Prepare TLS Channel Binding data
>>>>>> 246                     if (conn.sock instanceof SSLSocket) {
>>>>>> 247                         // Internal property cannot be set explicitly
>>>>>> 248                         if (env.get(TlsChannelBinding.CHANNEL_BINDING) != null) {
>>>>>> 249                             throw new NamingException(TlsChannelBinding.CHANNEL_BINDING +
>>>>>> 250                                     " property cannot be set explicitly");
>>>>>> 251                         }
>>>>>> If not TLS, this property value be kept there and visible inside the SASL mech.
>>>>>>>      - GssKrb5Client uses props.remove() to read and remove internal property
>>>>> Maybe you can remove the value in LdapClient.java, in case the mech used is not GSSAPI. You can remove it in a finally block after line 303.
>>>>> --Max
>>>>>> Traditionally, we use "com.sun..." name which is a JDK supported name (although not at Java SE level), you might want to use a name which is even more internal.
>>>>>> Thanks,
>>>>>> Max
>>>>>> p.s. I see that NTLM also supports ChannelBinding. I'll see if I can improve the NTLM SASL mech to support it.

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