s3:libads: sasl wrapped LDAP connections against with kerberos and arcfour-hmac-md5

This fixes a regression in commit 2cb07ba50decdfd6d08271cd2b3d893ff95f5af9
(s3:libads: make use of ads_sasl_spnego_gensec_bind() for GSS-SPNEGO with Kerberos)
that prevents things like 'net ads join' from working against a Windows 2003 domain.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=11804

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Günther Deschner <gd@samba.org>
Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Tue Apr 12 23:02:56 CEST 2016 on sn-devel-144

diff --git a/source3/libads/sasl.c b/source3/libads/sasl.c
index 4fcd733681b95c7aad244ce1ef94e082c5cca456..22aa9cf4bb73c627734711388ab1217892067389 100644 (file)
--- a/source3/libads/sasl.c
+++ b/source3/libads/sasl.c
@@ -312,7 +312,13 @@ static ADS_STATUS ads_sasl_spnego_gensec_bind(ADS_STRUCT *ads,
                ads->ldap.out.max_unwrapped = gensec_max_input_size(auth_generic_state->gensec_security);
 
                ads->ldap.out.sig_size = max_wrapped - ads->ldap.out.max_unwrapped;
-               ads->ldap.in.min_wrapped = ads->ldap.out.sig_size;
+               /*
+                * Note that we have to truncate this to 0x2C
+                * (taken from a capture with LDAP unbind), as the
+                * signature size is not constant for Kerberos with
+                * arcfour-hmac-md5.
+                */
+               ads->ldap.in.min_wrapped = MIN(ads->ldap.out.sig_size, 0x2C);
                ads->ldap.in.max_wrapped = max_wrapped;
                status = ads_setup_sasl_wrapping(ads, &ads_sasl_gensec_ops, auth_generic_state->gensec_security);
                if (!ADS_ERR_OK(status)) {