r15484: Make accept_security_context() more compatible with how Samba3 (and

similarly built clients) behave.

This is better than just ignoring the checksum, if it isn't the GSSAPI
checksum.  (Samba4 clients in Samba3 mode use more than just the MD5
checksum, and will use a signed AES checksum if available.  Actual
samba3 may well do the same in future, against a suitable KDC).

Also a change for easier debugging of checksum issues.

Andrew Bartlett
(This used to be commit 120374f5f9e9af0653a26e0308e4bfdabbcaa3f3)

1 files changed, 42 insertions, 9 deletions

diff --git a/source4/heimdal/lib/gssapi/accept_sec_context.c b/source4/heimdal/lib/gssapi/accept_sec_context.c
index 9ca60a6cdd..afca449c5c 100644
--- a/source4/heimdal/lib/gssapi/accept_sec_context.c
+++ b/source4/heimdal/lib/gssapi/accept_sec_context.c
@@ -371,15 +371,48 @@ gsskrb5_acceptor_start
 	    return ret;
 	}
 
-	ret = gssapi_krb5_verify_8003_checksum(minor_status,
-					       input_chan_bindings,
-					       authenticator->cksum,
-					       &flags,
-					       &(*context_handle)->fwd_data);
-	krb5_free_authenticator(gssapi_krb5_context, &authenticator);
-	if (ret) {
-	    return ret;
-	}
+        if (authenticator->cksum->cksumtype == CKSUMTYPE_GSSAPI) {
+            ret = gssapi_krb5_verify_8003_checksum(minor_status,
+                                                   input_chan_bindings,
+                                                   authenticator->cksum,
+                                                   &flags,
+                                                   &(*context_handle)->fwd_data);
+
+	    krb5_free_authenticator(gssapi_krb5_context, &authenticator);
+	    if (ret) {
+		return ret;
+	    }
+        } else {
+	    krb5_crypto crypto;
+
+	    kret = krb5_crypto_init(gssapi_krb5_context, 
+				   (*context_handle)->auth_context->keyblock, 
+				   0, &crypto);
+	    if(kret) {
+		krb5_free_authenticator(gssapi_krb5_context, &authenticator);
+
+		ret = GSS_S_FAILURE;
+		*minor_status = kret;
+		gssapi_krb5_set_error_string ();
+		return ret;
+	    }
+
+	    /* Windows accepts Samba3's use of a kerberos, 
+	       rather than GSSAPI checksum here */
+	    kret = krb5_verify_checksum(gssapi_krb5_context,
+					crypto, KRB5_KU_AP_REQ_AUTH_CKSUM, NULL, 0,
+					authenticator->cksum);
+	    krb5_free_authenticator(gssapi_krb5_context, &authenticator);
+
+	    if(kret) {
+		ret = GSS_S_FAILURE;
+		*minor_status = kret;
+		gssapi_krb5_set_error_string ();
+		return ret;
+	    }
+
+	    flags = GSS_C_MUTUAL_FLAG | GSS_C_REPLAY_FLAG | GSS_C_SEQUENCE_FLAG;
+        }
     }
     
     if(flags & GSS_C_MUTUAL_FLAG) {