ADV190023 | LDAP channel binding support

Stefan Metzmacher metze at
Wed Feb 26 14:39:19 UTC 2020

Am 26.02.20 um 15:21 schrieb Isaac Boukris via samba-technical:
> On Tue, Feb 25, 2020 at 9:17 PM Isaac Boukris <iboukris at> wrote:
>>> I looked at it a bit, see
>> FYI, I got net-ads working against AD server by adding some logic in
>> source3, look:
>> However the fixed clients aren't working against samba server yet,
>> unless require-strong-auth is set to "no", while non-fixed clients
>> still work. I get this error (I also wonder how can I trigger the
>> source4 client code).
> Actually, Windows client seem to work fine against your source4 server
> code, even with require-strong-auth=yes.  So I'm still missing
> something on the client side :(

Why? I guess the server just completely ignores the channel bindings.
What application on the Windows client uses ldaps?

Note that I fixed the channel binding checksum for NTLMSSP here:;a=commitdiff;h=e5afb9ff2aa23d43d0b968a3eca7ceffe1c8d606

With this commit where're able to pass the LdapEnforceChannelBinding=1

So for NTLMSSP the presence of MsvChannelBindings means strict checking
of the provided channel bindings, even if 16 zero bytes are send.

For kerberos only AD-AP-OPTIONS means strict checking and not ignoring
16 zeros.

And MsvAvTargetName is similar to AD-TARGET-PRINCIPAL.


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