s4-drsuapi: Use sam_ctx consistently in dcesrv_drsuapi_DsGetNCChanges()
[nivanova/samba-autobuild/.git] / source4 / rpc_server / drsuapi / getncchanges.c
index 6b961bcfc4c94bf6319fa58062b22b91f5db3913..1f9a35fb0b5b088f42b51cbc5e961fc664f41176 100644 (file)
 #include "libcli/security/session.h"
 #include "rpc_server/drsuapi/dcesrv_drsuapi.h"
 #include "rpc_server/dcerpc_server_proto.h"
+#include "rpc_server/common/sid_helper.h"
 #include "../libcli/drsuapi/drsuapi.h"
 #include "lib/util/binsearch.h"
 #include "lib/util/tsort.h"
 #include "auth/session.h"
 #include "dsdb/common/util.h"
+#include "lib/dbwrap/dbwrap.h"
+#include "lib/dbwrap/dbwrap_rbt.h"
+#include "librpc/gen_ndr/ndr_misc.h"
 
 /* state of a partially completed getncchanges call */
 struct drsuapi_getncchanges_state {
+       struct db_context *anc_cache;
        struct GUID *guids;
        uint32_t num_records;
        uint32_t num_processed;
        struct ldb_dn *ncRoot_dn;
+       struct GUID ncRoot_guid;
        bool is_schema_nc;
        uint64_t min_usn;
        uint64_t max_usn;
@@ -53,10 +59,17 @@ struct drsuapi_getncchanges_state {
        struct drsuapi_DsReplicaCursor2CtrEx *final_udv;
        struct drsuapi_DsReplicaLinkedAttribute *la_list;
        uint32_t la_count;
-       bool la_sorted;
+       struct la_for_sorting *la_sorted;
        uint32_t la_idx;
 };
 
+/* We must keep the GUIDs in NDR form for sorting */
+struct la_for_sorting {
+       struct drsuapi_DsReplicaLinkedAttribute *link;
+       uint8_t target_guid[16];
+        uint8_t source_guid[16];
+};
+
 static int drsuapi_DsReplicaHighWaterMark_cmp(const struct drsuapi_DsReplicaHighWaterMark *h1,
                                              const struct drsuapi_DsReplicaHighWaterMark *h2)
 {
@@ -81,7 +94,7 @@ static int drsuapi_DsReplicaHighWaterMark_cmp(const struct drsuapi_DsReplicaHigh
   build a DsReplicaObjectIdentifier from a ldb msg
  */
 static struct drsuapi_DsReplicaObjectIdentifier *get_object_identifier(TALLOC_CTX *mem_ctx,
-                                                                      struct ldb_message *msg)
+                                                                      const struct ldb_message *msg)
 {
        struct drsuapi_DsReplicaObjectIdentifier *identifier;
        struct dom_sid *sid;
@@ -117,39 +130,312 @@ static bool udv_filter(const struct drsuapi_DsReplicaCursorCtrEx *udv,
 {
        const struct drsuapi_DsReplicaCursor *c;
        if (udv == NULL) return false;
-       BINARY_ARRAY_SEARCH(udv->cursors, udv->count, source_dsa_invocation_id, 
+       BINARY_ARRAY_SEARCH(udv->cursors, udv->count, source_dsa_invocation_id,
                            originating_invocation_id, udv_compare, c);
        if (c && originating_usn <= c->highest_usn) {
                return true;
        }
        return false;
-       
 }
 
-static int attid_cmp(enum drsuapi_DsAttributeId a1, enum drsuapi_DsAttributeId a2)
+static int uint32_t_cmp(uint32_t a1, uint32_t a2)
 {
        if (a1 == a2) return 0;
-       return ((uint32_t)a1) > ((uint32_t)a2) ? 1 : -1;
+       return a1 > a2 ? 1 : -1;
+}
+
+static int uint32_t_ptr_cmp(uint32_t *a1, uint32_t *a2, void *unused)
+{
+       if (*a1 == *a2) return 0;
+       return *a1 > *a2 ? 1 : -1;
+}
+
+static WERROR getncchanges_attid_remote_to_local(const struct dsdb_schema *schema,
+                                                const struct dsdb_syntax_ctx *ctx,
+                                                enum drsuapi_DsAttributeId remote_attid_as_enum,
+                                                enum drsuapi_DsAttributeId *local_attid_as_enum,
+                                                const struct dsdb_attribute **_sa)
+{
+       WERROR werr;
+       const struct dsdb_attribute *sa = NULL;
+
+       if (ctx->pfm_remote == NULL) {
+               DEBUG(7, ("No prefixMap supplied, falling back to local prefixMap.\n"));
+               goto fail;
+       }
+
+       werr = dsdb_attribute_drsuapi_remote_to_local(ctx,
+                                                     remote_attid_as_enum,
+                                                     local_attid_as_enum,
+                                                     _sa);
+       if (!W_ERROR_IS_OK(werr)) {
+               DEBUG(3, ("WARNING: Unable to resolve remote attid, falling back to local prefixMap.\n"));
+               goto fail;
+       }
+
+       return werr;
+fail:
+
+       sa = dsdb_attribute_by_attributeID_id(schema, remote_attid_as_enum);
+       if (sa == NULL) {
+               return WERR_DS_DRA_SCHEMA_MISMATCH;
+       } else {
+               if (local_attid_as_enum != NULL) {
+                       *local_attid_as_enum = sa->attributeID_id;
+               }
+               if (_sa != NULL) {
+                       *_sa = sa;
+               }
+               return WERR_OK;
+       }
 }
 
 /*
-  check if an attribute is in a partial_attribute_set
+ * Similar to function in repl_meta_data without the extra
+ * dependencies.
  */
-static bool check_partial_attribute_set(const struct dsdb_attribute *sa,
-                                       struct drsuapi_DsPartialAttributeSet *pas)
+static WERROR get_parsed_dns_trusted(TALLOC_CTX *mem_ctx, struct ldb_message_element *el,
+                                 struct parsed_dn **pdn)
 {
-       enum drsuapi_DsAttributeId *result;
-       BINARY_ARRAY_SEARCH_V(pas->attids, pas->num_attids, (enum drsuapi_DsAttributeId)sa->attributeID_id,
-                             attid_cmp, result);
-       return result != NULL;
+       /* Here we get a list of 'struct parsed_dns' without the parsing */
+       int i;
+       *pdn = talloc_zero_array(mem_ctx, struct parsed_dn,
+                                el->num_values);
+       if (!*pdn) {
+               return WERR_DS_DRA_INTERNAL_ERROR;
+       }
+
+       for (i = 0; i < el->num_values; i++) {
+               (*pdn)[i].v = &el->values[i];
+       }
+
+       return WERR_OK;
 }
 
+static WERROR getncchanges_update_revealed_list(struct ldb_context *sam_ctx,
+                                               TALLOC_CTX *mem_ctx,
+                                               struct ldb_message **msg,
+                                               struct ldb_dn *object_dn,
+                                               const struct GUID *object_guid,
+                                               const struct dsdb_attribute *sa,
+                                               struct replPropertyMetaData1 *meta_data,
+                                               struct ldb_message *revealed_users)
+{
+       enum ndr_err_code ndr_err;
+       int ldb_err;
+       char *attr_str = NULL;
+       char *attr_hex = NULL;
+       DATA_BLOB attr_blob;
+       struct ldb_message_element *existing = NULL, *el_add = NULL, *el_del = NULL;
+       const char * const * secret_attributes = ldb_get_opaque(sam_ctx, "LDB_SECRET_ATTRIBUTE_LIST");
+
+       if (!ldb_attr_in_list(secret_attributes,
+                             sa->lDAPDisplayName)) {
+               return WERR_OK;
+       }
+
+
+       ndr_err = ndr_push_struct_blob(&attr_blob, mem_ctx, meta_data, (ndr_push_flags_fn_t)ndr_push_replPropertyMetaData1);
+       if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+               return WERR_DS_DRA_INTERNAL_ERROR;
+       }
+
+       attr_hex = hex_encode_talloc(mem_ctx, attr_blob.data, attr_blob.length);
+       if (attr_hex == NULL) {
+               return WERR_NOT_ENOUGH_MEMORY;
+       }
+
+       attr_str = talloc_asprintf(mem_ctx, "B:%zd:%s:%s", attr_blob.length*2, attr_hex, ldb_dn_get_linearized(object_dn));
+       if (attr_str == NULL) {
+               return WERR_NOT_ENOUGH_MEMORY;
+       }
+
+       existing = ldb_msg_find_element(revealed_users, "msDS-RevealedUsers");
+       if (existing != NULL) {
+               /* Replace the old value (if one exists) with the current one */
+               struct parsed_dn *link_dns;
+               struct parsed_dn *exact = NULL, *unused = NULL;
+               WERROR werr;
+               uint8_t attid[4];
+               DATA_BLOB partial_meta;
+
+               werr = get_parsed_dns_trusted(mem_ctx, existing, &link_dns);
+               if (!W_ERROR_IS_OK(werr)) {
+                       return werr;
+               }
+
+               /* Construct a partial metadata blob to match on in the DB */
+               SIVAL(attid, 0, sa->attributeID_id);
+               partial_meta.length = 4;
+               partial_meta.data = attid;
+
+               /* Binary search using GUID and attribute id for uniqueness */
+               ldb_err = parsed_dn_find(sam_ctx, link_dns, existing->num_values,
+                                        object_guid, object_dn,
+                                        partial_meta, 4,
+                                        &exact, &unused,
+                                        DSDB_SYNTAX_BINARY_DN, true);
+
+               if (ldb_err != LDB_SUCCESS) {
+                       DEBUG(0,(__location__ ": Failed parsed DN find - %s\n",
+                                ldb_errstring(sam_ctx)));
+                       return WERR_DS_DRA_INTERNAL_ERROR;
+               }
+
+               if (exact != NULL) {
+                       /* Perform some verification of the blob */
+                       struct replPropertyMetaData1 existing_meta_data;
+                       ndr_err = ndr_pull_struct_blob_all_noalloc(&exact->dsdb_dn->extra_part,
+                                                                  &existing_meta_data,
+                                                                  (ndr_pull_flags_fn_t)ndr_pull_replPropertyMetaData1);
+                       if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+                               return WERR_DS_DRA_INTERNAL_ERROR;
+                       }
+
+                       if (existing_meta_data.attid == sa->attributeID_id) {
+                               ldb_err = ldb_msg_add_empty(*msg, "msDS-RevealedUsers", LDB_FLAG_MOD_DELETE, &el_del);
+                               if (ldb_err != LDB_SUCCESS) {
+                                       return WERR_DS_DRA_INTERNAL_ERROR;
+                               }
+
+                               el_del->values = talloc_array((*msg)->elements, struct ldb_val, 1);
+                               if (el_del->values == NULL) {
+                                       return WERR_NOT_ENOUGH_MEMORY;
+                               }
+                               el_del->values[0] = *exact->v;
+                               el_del->num_values = 1;
+                       } else {
+                               return WERR_DS_DRA_INTERNAL_ERROR;
+                       }
+               }
+       }
+
+       ldb_err = ldb_msg_add_empty(*msg, "msDS-RevealedUsers", LDB_FLAG_MOD_ADD, &el_add);
+       if (ldb_err != LDB_SUCCESS) {
+               return WERR_DS_DRA_INTERNAL_ERROR;
+       }
+
+       el_add->values = talloc_array((*msg)->elements, struct ldb_val, 1);
+       if (el_add->values == NULL) {
+               return WERR_NOT_ENOUGH_MEMORY;
+
+       }
+
+       el_add->values[0] = data_blob_string_const(attr_str);
+       el_add->num_values = 1;
+
+       return WERR_OK;
+}
+
+/*
+ * This function filter attributes for build_object based on the
+ * uptodatenessvector and partial attribute set.
+ *
+ * Any secret attributes are forced here for REPL_SECRET, and audited at this
+ * point with msDS-RevealedUsers.
+ */
+static WERROR get_nc_changes_filter_attrs(struct drsuapi_DsReplicaObjectListItemEx *obj,
+                                         struct replPropertyMetaDataBlob md,
+                                         struct ldb_context *sam_ctx,
+                                         const struct ldb_message *msg,
+                                         const struct GUID *guid,
+                                         uint32_t *count,
+                                         uint64_t highest_usn,
+                                         const struct dsdb_attribute *rdn_sa,
+                                         struct dsdb_schema *schema,
+                                         struct drsuapi_DsReplicaCursorCtrEx *uptodateness_vector,
+                                         struct drsuapi_DsPartialAttributeSet *partial_attribute_set,
+                                         uint32_t *local_pas,
+                                         uint32_t *attids,
+                                         bool exop_secret,
+                                         struct ldb_message **revealed_list_msg,
+                                         struct ldb_message *existing_revealed_list_msg)
+{
+       uint32_t i, n;
+       WERROR werr;
+       for (n=i=0; i<md.ctr.ctr1.count; i++) {
+               const struct dsdb_attribute *sa;
+               bool force_attribute = false;
+
+               /* if the attribute has not changed, and it is not the
+                  instanceType then don't include it */
+               if (md.ctr.ctr1.array[i].local_usn < highest_usn &&
+                   !exop_secret &&
+                   md.ctr.ctr1.array[i].attid != DRSUAPI_ATTID_instanceType) continue;
+
+               /* don't include the rDN */
+               if (md.ctr.ctr1.array[i].attid == rdn_sa->attributeID_id) continue;
+
+               sa = dsdb_attribute_by_attributeID_id(schema, md.ctr.ctr1.array[i].attid);
+               if (!sa) {
+                       DEBUG(0,(__location__ ": Failed to find attribute in schema for attrid %u mentioned in replPropertyMetaData of %s\n",
+                                (unsigned int)md.ctr.ctr1.array[i].attid,
+                                ldb_dn_get_linearized(msg->dn)));
+                       return WERR_DS_DRA_INTERNAL_ERROR;
+               }
+
+               if (sa->linkID) {
+                       struct ldb_message_element *el;
+                       el = ldb_msg_find_element(msg, sa->lDAPDisplayName);
+                       if (el && el->num_values && dsdb_dn_is_upgraded_link_val(&el->values[0])) {
+                               /* don't send upgraded links inline */
+                               continue;
+                       }
+               }
+
+               if (exop_secret &&
+                   !dsdb_attr_in_rodc_fas(sa)) {
+                       force_attribute = true;
+                       DEBUG(4,("Forcing attribute %s in %s\n",
+                                sa->lDAPDisplayName, ldb_dn_get_linearized(msg->dn)));
+                       werr = getncchanges_update_revealed_list(sam_ctx, obj,
+                                                                revealed_list_msg,
+                                                                msg->dn, guid, sa,
+                                                                &md.ctr.ctr1.array[i],
+                                                                existing_revealed_list_msg);
+                       if (!W_ERROR_IS_OK(werr)) {
+                               return werr;
+                       }
+               }
+
+               /* filter by uptodateness_vector */
+               if (md.ctr.ctr1.array[i].attid != DRSUAPI_ATTID_instanceType &&
+                   !force_attribute &&
+                   udv_filter(uptodateness_vector,
+                              &md.ctr.ctr1.array[i].originating_invocation_id,
+                              md.ctr.ctr1.array[i].originating_usn)) {
+                       continue;
+               }
+
+               /* filter by partial_attribute_set */
+               if (partial_attribute_set && !force_attribute) {
+                       uint32_t *result = NULL;
+                       BINARY_ARRAY_SEARCH_V(local_pas, partial_attribute_set->num_attids, sa->attributeID_id,
+                                             uint32_t_cmp, result);
+                       if (result == NULL) {
+                               continue;
+                       }
+               }
+
+               obj->meta_data_ctr->meta_data[n].originating_change_time = md.ctr.ctr1.array[i].originating_change_time;
+               obj->meta_data_ctr->meta_data[n].version = md.ctr.ctr1.array[i].version;
+               obj->meta_data_ctr->meta_data[n].originating_invocation_id = md.ctr.ctr1.array[i].originating_invocation_id;
+               obj->meta_data_ctr->meta_data[n].originating_usn = md.ctr.ctr1.array[i].originating_usn;
+               attids[n] = md.ctr.ctr1.array[i].attid;
+
+               n++;
+       }
+
+       *count = n;
+
+       return WERR_OK;
+}
 
 /* 
   drsuapi_DsGetNCChanges for one object
 */
 static WERROR get_nc_changes_build_object(struct drsuapi_DsReplicaObjectListItemEx *obj,
-                                         struct ldb_message *msg,
+                                         const struct ldb_message *msg,
                                          struct ldb_context *sam_ctx,
                                          struct ldb_dn *ncRoot_dn,
                                          bool   is_schema_nc,
@@ -160,23 +446,32 @@ static WERROR get_nc_changes_build_object(struct drsuapi_DsReplicaObjectListItem
                                          struct drsuapi_DsPartialAttributeSet *partial_attribute_set,
                                          struct drsuapi_DsReplicaCursorCtrEx *uptodateness_vector,
                                          enum drsuapi_DsExtendedOperation extended_op,
-                                         bool force_object_return)
+                                         bool force_object_return,
+                                         uint32_t *local_pas,
+                                         struct ldb_dn *machine_dn,
+                                         const struct GUID *guid)
 {
        const struct ldb_val *md_value;
        uint32_t i, n;
        struct replPropertyMetaDataBlob md;
        uint32_t rid = 0;
+       int ldb_err;
        enum ndr_err_code ndr_err;
        uint32_t *attids;
        const char *rdn;
        const struct dsdb_attribute *rdn_sa;
+       uint64_t uSNChanged;
        unsigned int instanceType;
        struct dsdb_syntax_ctx syntax_ctx;
+       struct ldb_result *res = NULL;
+       WERROR werr;
+       int ret;
 
        /* make dsdb sytanx context for conversions */
        dsdb_syntax_ctx_init(&syntax_ctx, sam_ctx, schema);
        syntax_ctx.is_schema_nc = is_schema_nc;
 
+       uSNChanged = ldb_msg_find_attr_as_uint64(msg, "uSNChanged", 0);
        instanceType = ldb_msg_find_attr_as_uint(msg, "instanceType", 0);
        if (instanceType & INSTANCE_TYPE_IS_NC_HEAD) {
                obj->is_nc_prefix = true;
@@ -195,7 +490,7 @@ static WERROR get_nc_changes_build_object(struct drsuapi_DsReplicaObjectListItem
                }
        }
        obj->next_object = NULL;
-       
+
        md_value = ldb_msg_find_ldb_val(msg, "replPropertyMetaData");
        if (!md_value) {
                /* nothing to send */
@@ -207,12 +502,17 @@ static WERROR get_nc_changes_build_object(struct drsuapi_DsReplicaObjectListItem
                return WERR_OK;
        }
 
+       if (uSNChanged <= highest_usn) {
+               /* nothing to send */
+               return WERR_OK;
+       }
+
        ndr_err = ndr_pull_struct_blob(md_value, obj, &md,
                                       (ndr_pull_flags_fn_t)ndr_pull_replPropertyMetaDataBlob);
        if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
                return WERR_DS_DRA_INTERNAL_ERROR;
        }
-       
+
        if (md.version != 1) {
                return WERR_DS_DRA_INTERNAL_ERROR;
        }
@@ -225,7 +525,7 @@ static WERROR get_nc_changes_build_object(struct drsuapi_DsReplicaObjectListItem
 
        rdn_sa = dsdb_attribute_by_lDAPDisplayName(schema, rdn);
        if (rdn_sa == NULL) {
-               DEBUG(0,(__location__ ": Can't find dsds_attribute for rDN %s in %s\n", 
+               DEBUG(0,(__location__ ": Can't find dsds_attribute for rDN %s in %s\n",
                         rdn, ldb_dn_get_linearized(msg->dn)));
                return WERR_DS_DRA_INTERNAL_ERROR;
        }
@@ -235,68 +535,84 @@ static WERROR get_nc_changes_build_object(struct drsuapi_DsReplicaObjectListItem
 
        obj->object.identifier = get_object_identifier(obj, msg);
        if (obj->object.identifier == NULL) {
-               return WERR_NOMEM;
+               return WERR_NOT_ENOUGH_MEMORY;
        }
        dom_sid_split_rid(NULL, &obj->object.identifier->sid, NULL, &rid);
-       
-       obj->meta_data_ctr->meta_data = talloc_array(obj, struct drsuapi_DsReplicaMetaData, md.ctr.ctr1.count);
-       for (n=i=0; i<md.ctr.ctr1.count; i++) {
-               const struct dsdb_attribute *sa;
-               bool force_attribute = false;
 
-               /* if the attribute has not changed, and it is not the
-                  instanceType then don't include it */
-               if (md.ctr.ctr1.array[i].local_usn < highest_usn &&
-                   extended_op != DRSUAPI_EXOP_REPL_SECRET &&
-                   md.ctr.ctr1.array[i].attid != DRSUAPI_ATTID_instanceType) continue;
-
-               /* don't include the rDN */
-               if (md.ctr.ctr1.array[i].attid == rdn_sa->attributeID_id) continue;
+       obj->meta_data_ctr->meta_data = talloc_array(obj, struct drsuapi_DsReplicaMetaData, md.ctr.ctr1.count);
 
-               sa = dsdb_attribute_by_attributeID_id(schema, md.ctr.ctr1.array[i].attid);
-               if (!sa) {
-                       DEBUG(0,(__location__ ": Failed to find attribute in schema for attrid %u mentioned in replPropertyMetaData of %s\n", 
-                                (unsigned int)md.ctr.ctr1.array[i].attid, 
-                                ldb_dn_get_linearized(msg->dn)));
-                       return WERR_DS_DRA_INTERNAL_ERROR;              
+       if (extended_op == DRSUAPI_EXOP_REPL_SECRET) {
+               /* Get the existing revealed users for the destination */
+               struct ldb_message *revealed_list_msg = NULL;
+               struct ldb_message *existing_revealed_list_msg = NULL;
+               const char *machine_attrs[] = {
+                       "msDS-RevealedUsers",
+                       NULL
+               };
+
+               revealed_list_msg = ldb_msg_new(sam_ctx);
+               if (revealed_list_msg == NULL) {
+                       return WERR_NOT_ENOUGH_MEMORY;
                }
+               revealed_list_msg->dn = machine_dn;
 
-               if (sa->linkID) {
-                       struct ldb_message_element *el;
-                       el = ldb_msg_find_element(msg, sa->lDAPDisplayName);
-                       if (el && el->num_values && dsdb_dn_is_upgraded_link_val(&el->values[0])) {
-                               /* don't send upgraded links inline */
-                               continue;
-                       }
+               ret = ldb_transaction_start(sam_ctx);
+               if (ret != LDB_SUCCESS) {
+                       DEBUG(0,(__location__ ": Failed transaction start - %s\n",
+                                ldb_errstring(sam_ctx)));
+                       return WERR_DS_DRA_INTERNAL_ERROR;
                }
 
-               if (extended_op == DRSUAPI_EXOP_REPL_SECRET &&
-                   !dsdb_attr_in_rodc_fas(sa)) {
-                       force_attribute = true;
-                       DEBUG(4,("Forcing attribute %s in %s\n",
-                                sa->lDAPDisplayName, ldb_dn_get_linearized(msg->dn)));
+               ldb_err = dsdb_search_dn(sam_ctx, obj, &res, machine_dn, machine_attrs, DSDB_SEARCH_SHOW_EXTENDED_DN);
+               if (ldb_err != LDB_SUCCESS || res->count != 1) {
+                       ldb_transaction_cancel(sam_ctx);
+                       return WERR_DS_DRA_INTERNAL_ERROR;
                }
 
-               /* filter by uptodateness_vector */
-               if (md.ctr.ctr1.array[i].attid != DRSUAPI_ATTID_instanceType &&
-                   !force_attribute &&
-                   udv_filter(uptodateness_vector,
-                              &md.ctr.ctr1.array[i].originating_invocation_id, 
-                              md.ctr.ctr1.array[i].originating_usn)) {
-                       continue;
+               existing_revealed_list_msg = res->msgs[0];
+
+               werr = get_nc_changes_filter_attrs(obj, md, sam_ctx, msg,
+                                                  guid, &n, highest_usn,
+                                                  rdn_sa, schema,
+                                                  uptodateness_vector,
+                                                  partial_attribute_set, local_pas,
+                                                  attids,
+                                                  true,
+                                                  &revealed_list_msg,
+                                                  existing_revealed_list_msg);
+               if (!W_ERROR_IS_OK(werr)) {
+                       ldb_transaction_cancel(sam_ctx);
+                       return werr;
                }
 
-               /* filter by partial_attribute_set */
-               if (partial_attribute_set && !check_partial_attribute_set(sa, partial_attribute_set)) {
-                       continue;
+               if (revealed_list_msg != NULL) {
+                       ret = ldb_modify(sam_ctx, revealed_list_msg);
+                       if (ret != LDB_SUCCESS) {
+                               DEBUG(0,(__location__ ": Failed to alter revealed links - %s\n",
+                                        ldb_errstring(sam_ctx)));
+                               ldb_transaction_cancel(sam_ctx);
+                               return WERR_DS_DRA_INTERNAL_ERROR;
+                       }
                }
 
-               obj->meta_data_ctr->meta_data[n].originating_change_time = md.ctr.ctr1.array[i].originating_change_time;
-               obj->meta_data_ctr->meta_data[n].version = md.ctr.ctr1.array[i].version;
-               obj->meta_data_ctr->meta_data[n].originating_invocation_id = md.ctr.ctr1.array[i].originating_invocation_id;
-               obj->meta_data_ctr->meta_data[n].originating_usn = md.ctr.ctr1.array[i].originating_usn;
-               attids[n] = md.ctr.ctr1.array[i].attid;
-               n++;
+               ret = ldb_transaction_commit(sam_ctx);
+               if (ret != LDB_SUCCESS) {
+                       DEBUG(0,(__location__ ": Failed transaction commit - %s\n",
+                                ldb_errstring(sam_ctx)));
+                       return WERR_DS_DRA_INTERNAL_ERROR;
+               }
+       } else {
+               werr = get_nc_changes_filter_attrs(obj, md, sam_ctx, msg, guid,
+                                                  &n, highest_usn, rdn_sa,
+                                                  schema, uptodateness_vector,
+                                                  partial_attribute_set, local_pas,
+                                                  attids,
+                                                  false,
+                                                  NULL,
+                                                  NULL);
+               if (!W_ERROR_IS_OK(werr)) {
+                       return werr;
+               }
        }
 
        /* ignore it if its an empty change. Note that renames always
@@ -324,7 +640,7 @@ static WERROR get_nc_changes_build_object(struct drsuapi_DsReplicaObjectListItem
        obj->object.attribute_ctr.attributes = talloc_array(obj, struct drsuapi_DsReplicaAttribute,
                                                            obj->object.attribute_ctr.num_attributes);
        if (obj->object.attribute_ctr.attributes == NULL) {
-               return WERR_NOMEM;
+               return WERR_NOT_ENOUGH_MEMORY;
        }
 
        /*
@@ -333,9 +649,8 @@ static WERROR get_nc_changes_build_object(struct drsuapi_DsReplicaObjectListItem
         */
        for (i=0; i<obj->object.attribute_ctr.num_attributes; i++) {
                struct ldb_message_element *el;
-               WERROR werr;
                const struct dsdb_attribute *sa;
-       
+
                sa = dsdb_attribute_by_attributeID_id(schema, attids[i]);
                if (!sa) {
                        DEBUG(0,("Unable to find attributeID %u in schema\n", attids[i]));
@@ -400,10 +715,11 @@ static WERROR get_nc_changes_add_la(TALLOC_CTX *mem_ctx,
                                    struct ldb_context *sam_ctx,
                                    const struct dsdb_schema *schema,
                                    const struct dsdb_attribute *sa,
-                                   struct ldb_message *msg,
+                                   const struct ldb_message *msg,
                                    struct dsdb_dn *dsdb_dn,
                                    struct drsuapi_DsReplicaLinkedAttribute **la_list,
-                                   uint32_t *la_count)
+                                   uint32_t *la_count,
+                                   bool is_schema_nc)
 {
        struct drsuapi_DsReplicaLinkedAttribute *la;
        bool active;
@@ -475,7 +791,7 @@ static WERROR get_nc_changes_add_la(TALLOC_CTX *mem_ctx,
                        return WERR_OK;
                }
        }
-       la->attid = sa->attributeID_id;
+       la->attid = dsdb_attribute_get_attid(sa, is_schema_nc);
        la->flags = active?DRSUAPI_DS_LINKED_ATTRIBUTE_FLAG_ACTIVE:0;
 
        status = dsdb_get_extended_dn_uint32(dsdb_dn->dn, &la->meta_data.version, "RMD_VERSION");
@@ -524,17 +840,34 @@ static WERROR get_nc_changes_add_la(TALLOC_CTX *mem_ctx,
 static WERROR get_nc_changes_add_links(struct ldb_context *sam_ctx,
                                       TALLOC_CTX *mem_ctx,
                                       struct ldb_dn *ncRoot_dn,
+                                      bool is_schema_nc,
                                       struct dsdb_schema *schema,
                                       uint64_t highest_usn,
                                       uint32_t replica_flags,
-                                      struct ldb_message *msg,
+                                      const struct ldb_message *msg,
                                       struct drsuapi_DsReplicaLinkedAttribute **la_list,
                                       uint32_t *la_count,
                                       struct drsuapi_DsReplicaCursorCtrEx *uptodateness_vector)
 {
        unsigned int i;
-       TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
-       uint64_t uSNChanged = ldb_msg_find_attr_as_int(msg, "uSNChanged", -1);
+       TALLOC_CTX *tmp_ctx = NULL;
+       uint64_t uSNChanged = ldb_msg_find_attr_as_uint64(msg, "uSNChanged", 0);
+       bool is_critical = ldb_msg_find_attr_as_bool(msg, "isCriticalSystemObject", false);
+
+       if (replica_flags & DRSUAPI_DRS_CRITICAL_ONLY) {
+               if (!is_critical) {
+                       return WERR_OK;
+               }
+       }
+
+       if (uSNChanged <= highest_usn) {
+               return WERR_OK;
+       }
+
+       tmp_ctx = talloc_new(mem_ctx);
+       if (tmp_ctx == NULL) {
+               return WERR_NOT_ENOUGH_MEMORY;
+       }
 
        for (i=0; i<msg->num_elements; i++) {
                struct ldb_message_element *el = &msg->elements[i];
@@ -557,8 +890,10 @@ static WERROR get_nc_changes_add_links(struct ldb_context *sam_ctx,
                for (j=0; j<el->num_values; j++) {
                        struct dsdb_dn *dsdb_dn;
                        uint64_t local_usn;
-                       NTSTATUS status;
+                       uint64_t originating_usn;
+                       NTSTATUS status, status2;
                        WERROR werr;
+                       struct GUID originating_invocation_id;
 
                        dsdb_dn = dsdb_dn_parse(tmp_ctx, sam_ctx, &el->values[j], sa->syntax->ldap_oid);
                        if (dsdb_dn == NULL) {
@@ -583,12 +918,28 @@ static WERROR get_nc_changes_add_links(struct ldb_context *sam_ctx,
                                return WERR_DS_DRA_INTERNAL_ERROR;
                        }
 
-                       if (local_usn < highest_usn) {
+                       if (local_usn <= highest_usn) {
                                continue;
                        }
 
-                       werr = get_nc_changes_add_la(mem_ctx, sam_ctx, schema, sa, msg,
-                                                    dsdb_dn, la_list, la_count);
+                       status = dsdb_get_extended_dn_guid(dsdb_dn->dn,
+                                                          &originating_invocation_id,
+                                                          "RMD_INVOCID");
+                       status2 = dsdb_get_extended_dn_uint64(dsdb_dn->dn,
+                                                             &originating_usn,
+                                                             "RMD_ORIGINATING_USN");
+
+                       if (NT_STATUS_IS_OK(status) && NT_STATUS_IS_OK(status2)) {
+                               if (udv_filter(uptodateness_vector,
+                                              &originating_invocation_id,
+                                              originating_usn)) {
+                                       continue;
+                               }
+                       }
+
+                       werr = get_nc_changes_add_la(mem_ctx, sam_ctx, schema,
+                                                    sa, msg, dsdb_dn, la_list,
+                                                    la_count, is_schema_nc);
                        if (!W_ERROR_IS_OK(werr)) {
                                talloc_free(tmp_ctx);
                                return werr;
@@ -619,75 +970,36 @@ static WERROR get_nc_changes_udv(struct ldb_context *sam_ctx,
                         ldb_dn_get_linearized(ncRoot_dn), ldb_errstring(sam_ctx)));
                return WERR_DS_DRA_INTERNAL_ERROR;
        }
-       
+
        return WERR_OK;
 }
 
 
 /* comparison function for linked attributes - see CompareLinks() in
  * MS-DRSR section 4.1.10.5.17 */
-static int linked_attribute_compare(const struct drsuapi_DsReplicaLinkedAttribute *la1,
-                                   const struct drsuapi_DsReplicaLinkedAttribute *la2,
-                                   struct ldb_context *sam_ctx)
+static int linked_attribute_compare(const struct la_for_sorting *la1,
+                                   const struct la_for_sorting *la2,
+                                   void *opaque)
 {
        int c;
-       WERROR werr;
-       TALLOC_CTX *tmp_ctx;
-       const struct dsdb_schema *schema;
-       const struct dsdb_attribute *schema_attrib;
-       struct dsdb_dn *dn1, *dn2;
-       struct GUID guid1, guid2;
-       NTSTATUS status;
-
-       c = GUID_compare(&la1->identifier->guid,
-                        &la2->identifier->guid);
-       if (c != 0) return c;
-
-       if (la1->attid != la2->attid) {
-               return la1->attid < la2->attid? -1:1;
-       }
-
-       if ((la1->flags & DRSUAPI_DS_LINKED_ATTRIBUTE_FLAG_ACTIVE) !=
-           (la2->flags & DRSUAPI_DS_LINKED_ATTRIBUTE_FLAG_ACTIVE)) {
-               return (la1->flags & DRSUAPI_DS_LINKED_ATTRIBUTE_FLAG_ACTIVE)? 1:-1;
+       c = memcmp(la1->source_guid,
+                  la2->source_guid, sizeof(la2->source_guid));
+       if (c != 0) {
+               return c;
        }
 
-       /* we need to get the target GUIDs to compare */
-       tmp_ctx = talloc_new(sam_ctx);
-
-       schema = dsdb_get_schema(sam_ctx, tmp_ctx);
-       schema_attrib = dsdb_attribute_by_attributeID_id(schema, la1->attid);
-
-       werr = dsdb_dn_la_from_blob(sam_ctx, schema_attrib, schema, tmp_ctx, la1->value.blob, &dn1);
-       if (!W_ERROR_IS_OK(werr)) {
-               DEBUG(0,(__location__ ": Bad la1 blob in sort\n"));
-               talloc_free(tmp_ctx);
-               return 0;
+       if (la1->link->attid != la2->link->attid) {
+               return la1->link->attid < la2->link->attid? -1:1;
        }
 
-       werr = dsdb_dn_la_from_blob(sam_ctx, schema_attrib, schema, tmp_ctx, la2->value.blob, &dn2);
-       if (!W_ERROR_IS_OK(werr)) {
-               DEBUG(0,(__location__ ": Bad la2 blob in sort\n"));
-               talloc_free(tmp_ctx);
-               return 0;
+       if ((la1->link->flags & DRSUAPI_DS_LINKED_ATTRIBUTE_FLAG_ACTIVE) !=
+           (la2->link->flags & DRSUAPI_DS_LINKED_ATTRIBUTE_FLAG_ACTIVE)) {
+               return (la1->link->flags &
+                       DRSUAPI_DS_LINKED_ATTRIBUTE_FLAG_ACTIVE)? 1:-1;
        }
 
-       status = dsdb_get_extended_dn_guid(dn1->dn, &guid1, "GUID");
-       if (!NT_STATUS_IS_OK(status)) {
-               DEBUG(0,(__location__ ": Bad la1 guid in sort\n"));
-               talloc_free(tmp_ctx);
-               return 0;
-       }
-       status = dsdb_get_extended_dn_guid(dn2->dn, &guid2, "GUID");
-       if (!NT_STATUS_IS_OK(status)) {
-               DEBUG(0,(__location__ ": Bad la2 guid in sort\n"));
-               talloc_free(tmp_ctx);
-               return 0;
-       }
-
-       talloc_free(tmp_ctx);
-
-       return GUID_compare(&guid1, &guid2);
+       return memcmp(la1->target_guid,
+                     la2->target_guid, sizeof(la2->target_guid));
 }
 
 struct drsuapi_changed_objects {
@@ -696,16 +1008,6 @@ struct drsuapi_changed_objects {
        uint64_t usn;
 };
 
-/*
-  sort the objects we send by tree order
- */
-static int site_res_cmp_anc_order(struct drsuapi_changed_objects *m1,
-                                 struct drsuapi_changed_objects *m2,
-                                 struct drsuapi_getncchanges_state *getnc_state)
-{
-       return ldb_dn_compare(m2->dn, m1->dn);
-}
-
 /*
   sort the objects we send first by uSNChanged
  */
@@ -814,129 +1116,30 @@ static WERROR getncchanges_rid_alloc(struct drsuapi_bind_state *b_state,
        }
 
        ret = ldb_extended(ldb, DSDB_EXTENDED_ALLOCATE_RID_POOL, exop, &ext_res);
-       if (ret != LDB_SUCCESS) {
-               DEBUG(0,(__location__ ": Failed extended allocation RID pool operation - %s\n",
-                        ldb_errstring(ldb)));
-               ldb_transaction_cancel(ldb);
-               return WERR_DS_DRA_INTERNAL_ERROR;
-       }
-
-       ret = ldb_transaction_commit(ldb);
-       if (ret != LDB_SUCCESS) {
-               DEBUG(0,(__location__ ": Failed transaction commit - %s\n",
-                        ldb_errstring(ldb)));
-               return WERR_DS_DRA_INTERNAL_ERROR;
-       }
-
-       talloc_free(ext_res);
-
-       DEBUG(2,("Allocated RID pool for server %s\n",
-                GUID_string(mem_ctx, &req10->destination_dsa_guid)));
-
-       ctr6->extended_ret = DRSUAPI_EXOP_ERR_SUCCESS;
-
-       return WERR_OK;
-}
-
-/*
-  return an array of SIDs from a ldb_message given an attribute name
-  assumes the SIDs are in extended DN format
- */
-static WERROR samdb_result_sid_array_dn(struct ldb_context *sam_ctx,
-                                       struct ldb_message *msg,
-                                       TALLOC_CTX *mem_ctx,
-                                       const char *attr,
-                                       const struct dom_sid ***sids)
-{
-       struct ldb_message_element *el;
-       unsigned int i;
-
-       el = ldb_msg_find_element(msg, attr);
-       if (!el) {
-               *sids = NULL;
-               return WERR_OK;
-       }
-
-       (*sids) = talloc_array(mem_ctx, const struct dom_sid *, el->num_values + 1);
-       W_ERROR_HAVE_NO_MEMORY(*sids);
-
-       for (i=0; i<el->num_values; i++) {
-               struct ldb_dn *dn = ldb_dn_from_ldb_val(mem_ctx, sam_ctx, &el->values[i]);
-               NTSTATUS status;
-               struct dom_sid *sid;
-
-               sid = talloc(*sids, struct dom_sid);
-               W_ERROR_HAVE_NO_MEMORY(sid);
-               status = dsdb_get_extended_dn_sid(dn, sid, "SID");
-               if (!NT_STATUS_IS_OK(status)) {
-                       return WERR_INTERNAL_DB_CORRUPTION;
-               }
-               (*sids)[i] = sid;
-       }
-       (*sids)[i] = NULL;
-
-       return WERR_OK;
-}
-
-
-/*
-  return an array of SIDs from a ldb_message given an attribute name
-  assumes the SIDs are in NDR form
- */
-static WERROR samdb_result_sid_array_ndr(struct ldb_context *sam_ctx,
-                                        struct ldb_message *msg,
-                                        TALLOC_CTX *mem_ctx,
-                                        const char *attr,
-                                        const struct dom_sid ***sids)
-{
-       struct ldb_message_element *el;
-       unsigned int i;
-
-       el = ldb_msg_find_element(msg, attr);
-       if (!el) {
-               *sids = NULL;
-               return WERR_OK;
+       if (ret != LDB_SUCCESS) {
+               DEBUG(0,(__location__ ": Failed extended allocation RID pool operation - %s\n",
+                        ldb_errstring(ldb)));
+               ldb_transaction_cancel(ldb);
+               return WERR_DS_DRA_INTERNAL_ERROR;
        }
 
-       (*sids) = talloc_array(mem_ctx, const struct dom_sid *, el->num_values + 1);
-       W_ERROR_HAVE_NO_MEMORY(*sids);
+       ret = ldb_transaction_commit(ldb);
+       if (ret != LDB_SUCCESS) {
+               DEBUG(0,(__location__ ": Failed transaction commit - %s\n",
+                        ldb_errstring(ldb)));
+               return WERR_DS_DRA_INTERNAL_ERROR;
+       }
 
-       for (i=0; i<el->num_values; i++) {
-               enum ndr_err_code ndr_err;
-               struct dom_sid *sid;
+       talloc_free(ext_res);
 
-               sid = talloc(*sids, struct dom_sid);
-               W_ERROR_HAVE_NO_MEMORY(sid);
+       DEBUG(2,("Allocated RID pool for server %s\n",
+                GUID_string(mem_ctx, &req10->destination_dsa_guid)));
 
-               ndr_err = ndr_pull_struct_blob(&el->values[i], sid, sid,
-                                              (ndr_pull_flags_fn_t)ndr_pull_dom_sid);
-               if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
-                       return WERR_INTERNAL_DB_CORRUPTION;
-               }
-               (*sids)[i] = sid;
-       }
-       (*sids)[i] = NULL;
+       ctr6->extended_ret = DRSUAPI_EXOP_ERR_SUCCESS;
 
        return WERR_OK;
 }
 
-/*
-  see if any SIDs in list1 are in list2
- */
-static bool sid_list_match(const struct dom_sid **list1, const struct dom_sid **list2)
-{
-       unsigned int i, j;
-       /* do we ever have enough SIDs here to worry about O(n^2) ? */
-       for (i=0; list1[i]; i++) {
-               for (j=0; list2[j]; j++) {
-                       if (dom_sid_equal(list1[i], list2[j])) {
-                               return true;
-                       }
-               }
-       }
-       return false;
-}
-
 /*
   handle a DRSUAPI_EXOP_REPL_SECRET call
  */
@@ -945,17 +1148,21 @@ static WERROR getncchanges_repl_secret(struct drsuapi_bind_state *b_state,
                                       struct drsuapi_DsGetNCChangesRequest10 *req10,
                                       struct dom_sid *user_sid,
                                       struct drsuapi_DsGetNCChangesCtr6 *ctr6,
-                                      bool has_get_all_changes)
+                                      bool has_get_all_changes,
+                                      struct ldb_dn **machine_dn)
 {
        struct drsuapi_DsReplicaObjectIdentifier *ncRoot = req10->naming_context;
        struct ldb_dn *obj_dn = NULL;
+       struct ldb_dn *ntds_dn = NULL, *server_dn = NULL;
        struct ldb_dn *rodc_dn, *krbtgt_link_dn;
        int ret;
-       const char *rodc_attrs[] = { "msDS-KrbTgtLink", "msDS-NeverRevealGroup", "msDS-RevealOnDemandGroup", NULL };
+       const char *rodc_attrs[] = { "msDS-KrbTgtLink", "msDS-NeverRevealGroup", "msDS-RevealOnDemandGroup", "objectGUID", NULL };
        const char *obj_attrs[] = { "tokenGroups", "objectSid", "UserAccountControl", "msDS-KrbTgtLinkBL", NULL };
-       struct ldb_result *rodc_res, *obj_res;
+       struct ldb_result *rodc_res = NULL, *obj_res = NULL;
        const struct dom_sid **never_reveal_sids, **reveal_sids, **token_sids;
+       const struct dom_sid *object_sid = NULL;
        WERROR werr;
+       const struct dom_sid *additional_sids[] = { NULL, NULL };
 
        DEBUG(3,(__location__ ": DRSUAPI_EXOP_REPL_SECRET extended op on %s\n",
                 drs_ObjectIdentifier_to_string(mem_ctx, ncRoot)));
@@ -974,6 +1181,31 @@ static WERROR getncchanges_repl_secret(struct drsuapi_bind_state *b_state,
                return WERR_DS_DRA_SOURCE_DISABLED;
        }
 
+       /*
+        * Before we accept or deny, fetch the machine DN for the destination
+        * DSA GUID.
+        *
+        * If we are the RODC, we will check that this matches the SID.
+        */
+       ret = dsdb_find_dn_by_guid(b_state->sam_ctx_system, mem_ctx,
+                                  &req10->destination_dsa_guid, 0,
+                                  &ntds_dn);
+       if (ret != LDB_SUCCESS) {
+               goto failed;
+       }
+
+       server_dn = ldb_dn_get_parent(mem_ctx, ntds_dn);
+       if (server_dn == NULL) {
+               goto failed;
+       }
+
+       ret = samdb_reference_dn(b_state->sam_ctx_system, mem_ctx, server_dn,
+                                "serverReference", machine_dn);
+
+       if (ret != LDB_SUCCESS) {
+               goto failed;
+       }
+
        /*
         * In MS-DRSR.pdf 5.99 IsGetNCChangesPermissionGranted
         *
@@ -994,13 +1226,13 @@ static WERROR getncchanges_repl_secret(struct drsuapi_bind_state *b_state,
         * Which basically means that if you have GET_ALL_CHANGES rights (~== RWDC)
         * then you can do EXOP_REPL_SECRETS
         */
+       obj_dn = drs_ObjectIdentifier_to_dn(mem_ctx, b_state->sam_ctx_system, ncRoot);
+       if (!ldb_dn_validate(obj_dn)) goto failed;
+
        if (has_get_all_changes) {
                goto allowed;
        }
 
-       obj_dn = drs_ObjectIdentifier_to_dn(mem_ctx, b_state->sam_ctx_system, ncRoot);
-       if (!ldb_dn_validate(obj_dn)) goto failed;
-
        rodc_dn = ldb_dn_new_fmt(mem_ctx, b_state->sam_ctx_system, "<SID=%s>",
                                 dom_sid_string(mem_ctx, user_sid));
        if (!ldb_dn_validate(rodc_dn)) goto failed;
@@ -1014,11 +1246,21 @@ static WERROR getncchanges_repl_secret(struct drsuapi_bind_state *b_state,
        if (ret != LDB_SUCCESS || obj_res->count != 1) goto failed;
 
        /* if the object SID is equal to the user_sid, allow */
-       if (dom_sid_equal(user_sid,
-                         samdb_result_dom_sid(mem_ctx, obj_res->msgs[0], "objectSid"))) {
+       object_sid = samdb_result_dom_sid(mem_ctx, obj_res->msgs[0], "objectSid");
+       if (dom_sid_equal(user_sid, object_sid)) {
                goto allowed;
        }
 
+       additional_sids[0] = object_sid;
+
+       /*
+        * Must be an RODC account at this point, verify machine DN matches the
+        * SID account
+        */
+       if (ldb_dn_compare(rodc_res->msgs[0]->dn, *machine_dn) != 0) {
+               goto denied;
+       }
+
        /* an RODC is allowed to get its own krbtgt account secrets */
        krbtgt_link_dn = samdb_result_dn(b_state->sam_ctx_system, mem_ctx,
                                         rodc_res->msgs[0], "msDS-KrbTgtLink", NULL);
@@ -1051,8 +1293,14 @@ static WERROR getncchanges_repl_secret(struct drsuapi_bind_state *b_state,
                goto denied;
        }
 
+       /*
+        * The SID list needs to include itself as well as the tokenGroups.
+        *
+        * TODO determine if sIDHistory is required for this check
+        */
        werr = samdb_result_sid_array_ndr(b_state->sam_ctx_system, obj_res->msgs[0],
-                                        mem_ctx, "tokenGroups", &token_sids);
+                                         mem_ctx, "tokenGroups", &token_sids,
+                                         additional_sids, 1);
        if (!W_ERROR_IS_OK(werr) || token_sids==NULL) {
                goto denied;
        }
@@ -1072,12 +1320,12 @@ denied:
        DEBUG(2,(__location__ ": Denied single object with secret replication for %s by RODC %s\n",
                 ldb_dn_get_linearized(obj_dn), ldb_dn_get_linearized(rodc_res->msgs[0]->dn)));
        ctr6->extended_ret = DRSUAPI_EXOP_ERR_NONE;
-       return WERR_DS_DRA_ACCESS_DENIED;
+       return WERR_DS_DRA_SECRETS_DENIED;
 
 allowed:
        DEBUG(2,(__location__ ": Allowed single object with secret replication for %s by %s %s\n",
                 ldb_dn_get_linearized(obj_dn), has_get_all_changes?"RWDC":"RODC",
-                ldb_dn_get_linearized(rodc_res->msgs[0]->dn)));
+                ldb_dn_get_linearized(*machine_dn)));
        ctr6->extended_ret = DRSUAPI_EXOP_ERR_SUCCESS;
        req10->highwatermark.highest_usn = 0;
        return WERR_OK;
@@ -1089,7 +1337,6 @@ failed:
        return WERR_DS_DRA_BAD_DN;
 }
 
-
 /*
   handle a DRSUAPI_EXOP_REPL_OBJ call
  */
@@ -1214,11 +1461,13 @@ static WERROR getncchanges_change_master(struct drsuapi_bind_state *b_state,
  */
 static WERROR dcesrv_drsuapi_is_reveal_secrets_request(struct drsuapi_bind_state *b_state,
                                                       struct drsuapi_DsGetNCChangesRequest10 *req10,
+                                                      struct dsdb_schema_prefixmap *pfm_remote,
                                                       bool *is_secret_request)
 {
        enum drsuapi_DsExtendedOperation exop;
        uint32_t i;
        struct dsdb_schema *schema;
+       struct dsdb_syntax_ctx syntax_ctx;
 
        *is_secret_request = true;
 
@@ -1252,14 +1501,24 @@ static WERROR dcesrv_drsuapi_is_reveal_secrets_request(struct drsuapi_bind_state
        }
 
        schema = dsdb_get_schema(b_state->sam_ctx, NULL);
+       dsdb_syntax_ctx_init(&syntax_ctx, b_state->sam_ctx, schema);
+       syntax_ctx.pfm_remote = pfm_remote;
 
        /* check the attributes they asked for */
        for (i=0; i<req10->partial_attribute_set->num_attids; i++) {
                const struct dsdb_attribute *sa;
-               sa = dsdb_attribute_by_attributeID_id(schema, req10->partial_attribute_set->attids[i]);
-               if (sa == NULL) {
-                       return WERR_DS_DRA_SCHEMA_MISMATCH;
+               WERROR werr = getncchanges_attid_remote_to_local(schema,
+                                                                &syntax_ctx,
+                                                                req10->partial_attribute_set->attids[i],
+                                                                NULL,
+                                                                &sa);
+
+               if (!W_ERROR_IS_OK(werr)) {
+                       DEBUG(0,(__location__": attid 0x%08X not found: %s\n",
+                                req10->partial_attribute_set->attids[i], win_errstr(werr)));
+                       return werr;
                }
+
                if (!dsdb_attr_in_rodc_fas(sa)) {
                        *is_secret_request = true;
                        return WERR_OK;
@@ -1270,10 +1529,18 @@ static WERROR dcesrv_drsuapi_is_reveal_secrets_request(struct drsuapi_bind_state
                /* check the extended attributes they asked for */
                for (i=0; i<req10->partial_attribute_set_ex->num_attids; i++) {
                        const struct dsdb_attribute *sa;
-                       sa = dsdb_attribute_by_attributeID_id(schema, req10->partial_attribute_set_ex->attids[i]);
-                       if (sa == NULL) {
-                               return WERR_DS_DRA_SCHEMA_MISMATCH;
+                       WERROR werr = getncchanges_attid_remote_to_local(schema,
+                                                                        &syntax_ctx,
+                                                                        req10->partial_attribute_set_ex->attids[i],
+                                                                        NULL,
+                                                                        &sa);
+
+                       if (!W_ERROR_IS_OK(werr)) {
+                               DEBUG(0,(__location__": attid 0x%08X not found: %s\n",
+                                        req10->partial_attribute_set_ex->attids[i], win_errstr(werr)));
+                               return werr;
                        }
+
                        if (!dsdb_attr_in_rodc_fas(sa)) {
                                *is_secret_request = true;
                                return WERR_OK;
@@ -1291,11 +1558,13 @@ static WERROR dcesrv_drsuapi_is_reveal_secrets_request(struct drsuapi_bind_state
  */
 static WERROR dcesrv_drsuapi_is_gc_pas_request(struct drsuapi_bind_state *b_state,
                                               struct drsuapi_DsGetNCChangesRequest10 *req10,
+                                              struct dsdb_schema_prefixmap *pfm_remote,
                                               bool *is_gc_pas_request)
 {
        enum drsuapi_DsExtendedOperation exop;
        uint32_t i;
        struct dsdb_schema *schema;
+       struct dsdb_syntax_ctx syntax_ctx;
 
        exop = req10->extended_op;
 
@@ -1320,14 +1589,24 @@ static WERROR dcesrv_drsuapi_is_gc_pas_request(struct drsuapi_bind_state *b_stat
        }
 
        schema = dsdb_get_schema(b_state->sam_ctx, NULL);
+       dsdb_syntax_ctx_init(&syntax_ctx, b_state->sam_ctx, schema);
+       syntax_ctx.pfm_remote = pfm_remote;
 
        /* check the attributes they asked for */
        for (i=0; i<req10->partial_attribute_set->num_attids; i++) {
                const struct dsdb_attribute *sa;
-               sa = dsdb_attribute_by_attributeID_id(schema, req10->partial_attribute_set->attids[i]);
-               if (sa == NULL) {
-                       return WERR_DS_DRA_SCHEMA_MISMATCH;
+               WERROR werr = getncchanges_attid_remote_to_local(schema,
+                                                                &syntax_ctx,
+                                                                req10->partial_attribute_set->attids[i],
+                                                                NULL,
+                                                                &sa);
+
+               if (!W_ERROR_IS_OK(werr)) {
+                       DEBUG(0,(__location__": attid 0x%08X not found: %s\n",
+                                req10->partial_attribute_set->attids[i], win_errstr(werr)));
+                       return werr;
                }
+
                if (!sa->isMemberOfPartialAttributeSet) {
                        *is_gc_pas_request = false;
                        return WERR_OK;
@@ -1338,10 +1617,18 @@ static WERROR dcesrv_drsuapi_is_gc_pas_request(struct drsuapi_bind_state *b_stat
                /* check the extended attributes they asked for */
                for (i=0; i<req10->partial_attribute_set_ex->num_attids; i++) {
                        const struct dsdb_attribute *sa;
-                       sa = dsdb_attribute_by_attributeID_id(schema, req10->partial_attribute_set_ex->attids[i]);
-                       if (sa == NULL) {
-                               return WERR_DS_DRA_SCHEMA_MISMATCH;
+                       WERROR werr = getncchanges_attid_remote_to_local(schema,
+                                                                        &syntax_ctx,
+                                                                        req10->partial_attribute_set_ex->attids[i],
+                                                                        NULL,
+                                                                        &sa);
+
+                       if (!W_ERROR_IS_OK(werr)) {
+                               DEBUG(0,(__location__": attid 0x%08X not found: %s\n",
+                                        req10->partial_attribute_set_ex->attids[i], win_errstr(werr)));
+                               return werr;
                        }
+
                        if (!sa->isMemberOfPartialAttributeSet) {
                                *is_gc_pas_request = false;
                                return WERR_OK;
@@ -1401,18 +1688,19 @@ static WERROR getncchanges_collect_objects(struct drsuapi_bind_state *b_state,
        int ret;
        char* search_filter;
        enum ldb_scope scope = LDB_SCOPE_SUBTREE;
-       //const char *extra_filter;
        struct drsuapi_getncchanges_state *getnc_state = b_state->getncchanges_state;
+       bool critical_only = false;
+
+       if (req10->replica_flags & DRSUAPI_DRS_CRITICAL_ONLY) {
+               critical_only = true;
+       }
 
        if (req10->extended_op == DRSUAPI_EXOP_REPL_OBJ ||
            req10->extended_op == DRSUAPI_EXOP_REPL_SECRET) {
                scope = LDB_SCOPE_BASE;
+               critical_only = false;
        }
 
-       //extra_filter = lpcfg_parm_string(dce_call->conn->dce_ctx->lp_ctx, NULL, "drs", "object filter");
-
-       //getnc_state->min_usn = req10->highwatermark.highest_usn;
-
        /* Construct response. */
        search_filter = talloc_asprintf(mem_ctx,
                                        "(uSNChanged>=%llu)",
@@ -1422,7 +1710,7 @@ static WERROR getncchanges_collect_objects(struct drsuapi_bind_state *b_state,
                search_filter = talloc_asprintf(mem_ctx, "(&%s(%s))", search_filter, extra_filter);
        }
 
-       if (req10->replica_flags & DRSUAPI_DRS_CRITICAL_ONLY) {
+       if (critical_only) {
                search_filter = talloc_asprintf(mem_ctx,
                                                "(&%s(isCriticalSystemObject=TRUE))",
                                                search_filter);
@@ -1596,7 +1884,7 @@ static WERROR getncchanges_collect_objects_exop(struct drsuapi_bind_state *b_sta
                                                     (*search_res)->count);
                if ((*search_res)->msgs == NULL) {
                        TALLOC_FREE(frame);
-                       return WERR_NOMEM;
+                       return WERR_NOT_ENOUGH_MEMORY;
                }
 
 
@@ -1617,6 +1905,95 @@ static WERROR getncchanges_collect_objects_exop(struct drsuapi_bind_state *b_sta
        }
 }
 
+static void dcesrv_drsuapi_update_highwatermark(const struct ldb_message *msg,
+                                               uint64_t max_usn,
+                                               struct drsuapi_DsReplicaHighWaterMark *hwm)
+{
+       uint64_t uSN = ldb_msg_find_attr_as_uint64(msg, "uSNChanged", 0);
+
+       if (uSN > max_usn) {
+               /*
+                * Only report the max_usn we had at the start
+                * of the replication cycle.
+                *
+                * If this object has changed lately we better
+                * let the destination dsa refetch the change.
+                * This is better than the risk of loosing some
+                * objects or linked attributes.
+                */
+               return;
+       }
+
+       if (uSN <= hwm->tmp_highest_usn) {
+               return;
+       }
+
+       hwm->tmp_highest_usn = uSN;
+       hwm->reserved_usn = 0;
+}
+
+static WERROR dcesrv_drsuapi_anc_cache_add(struct db_context *anc_cache,
+                                          const struct GUID *guid)
+{
+       enum ndr_err_code ndr_err;
+       uint8_t guid_buf[16] = { 0, };
+       DATA_BLOB b = {
+               .data = guid_buf,
+               .length = sizeof(guid_buf),
+       };
+       TDB_DATA key = {
+               .dptr = b.data,
+               .dsize = b.length,
+       };
+       TDB_DATA val = {
+               .dptr = NULL,
+               .dsize = 0,
+       };
+       NTSTATUS status;
+
+       ndr_err = ndr_push_struct_into_fixed_blob(&b, guid,
+                       (ndr_push_flags_fn_t)ndr_push_GUID);
+       if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+               return WERR_DS_DRA_INTERNAL_ERROR;
+       }
+
+       status = dbwrap_store(anc_cache, key, val, TDB_REPLACE);
+       if (!NT_STATUS_IS_OK(status)) {
+               return WERR_DS_DRA_INTERNAL_ERROR;
+       }
+
+       return WERR_OK;
+}
+
+static WERROR dcesrv_drsuapi_anc_cache_exists(struct db_context *anc_cache,
+                                             const struct GUID *guid)
+{
+       enum ndr_err_code ndr_err;
+       uint8_t guid_buf[16] = { 0, };
+       DATA_BLOB b = {
+               .data = guid_buf,
+               .length = sizeof(guid_buf),
+       };
+       TDB_DATA key = {
+               .dptr = b.data,
+               .dsize = b.length,
+       };
+       bool exists;
+
+       ndr_err = ndr_push_struct_into_fixed_blob(&b, guid,
+                       (ndr_push_flags_fn_t)ndr_push_GUID);
+       if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
+               return WERR_DS_DRA_INTERNAL_ERROR;
+       }
+
+       exists = dbwrap_exists(anc_cache, key);
+       if (!exists) {
+               return WERR_OBJECT_NOT_FOUND;
+       }
+
+       return WERR_OBJECT_NAME_EXISTS;
+}
+
 /* 
   drsuapi_DsGetNCChanges
 
@@ -1627,7 +2004,7 @@ WERROR dcesrv_drsuapi_DsGetNCChanges(struct dcesrv_call_state *dce_call, TALLOC_
 {
        struct drsuapi_DsReplicaObjectIdentifier *ncRoot;
        int ret;
-       uint32_t i;
+       uint32_t i, k;
        struct dsdb_schema *schema;
        struct drsuapi_DsReplicaOIDMapping_Ctr *ctr;
        struct drsuapi_DsReplicaObjectListItemEx **currentObject;
@@ -1635,7 +2012,7 @@ WERROR dcesrv_drsuapi_DsGetNCChanges(struct dcesrv_call_state *dce_call, TALLOC_
        DATA_BLOB session_key;
        WERROR werr;
        struct dcesrv_handle *h;
-       struct drsuapi_bind_state *b_state;     
+       struct drsuapi_bind_state *b_state;
        struct drsuapi_getncchanges_state *getnc_state;
        struct drsuapi_DsGetNCChangesRequest10 *req10;
        uint32_t options;
@@ -1645,7 +2022,7 @@ WERROR dcesrv_drsuapi_DsGetNCChanges(struct dcesrv_call_state *dce_call, TALLOC_
        uint32_t link_total = 0;
        uint32_t link_given = 0;
        struct ldb_dn *search_dn = NULL;
-       bool am_rodc, null_scope=false;
+       bool am_rodc;
        enum security_user_level security_level;
        struct ldb_context *sam_ctx;
        struct dom_sid *user_sid;
@@ -1658,10 +2035,15 @@ WERROR dcesrv_drsuapi_DsGetNCChanges(struct dcesrv_call_state *dce_call, TALLOC_
        bool has_get_all_changes = false;
        struct GUID invocation_id;
        static const struct drsuapi_DsReplicaLinkedAttribute no_linked_attr;
+       struct dsdb_schema_prefixmap *pfm_remote = NULL;
+       bool full = true;
+       uint32_t *local_pas = NULL;
+       struct ldb_dn *machine_dn = NULL; /* Only used for REPL SECRET EXOP */
 
        DCESRV_PULL_HANDLE_WERR(h, r->in.bind_handle, DRSUAPI_BIND_HANDLE);
        b_state = h->data;
 
+       /* sam_ctx_system is not present for non-administrator users */
        sam_ctx = b_state->sam_ctx_system?b_state->sam_ctx_system:b_state->sam_ctx;
 
        invocation_id = *(samdb_ntds_invocation_id(sam_ctx));
@@ -1692,7 +2074,7 @@ WERROR dcesrv_drsuapi_DsGetNCChanges(struct dcesrv_call_state *dce_call, TALLOC_
        case 8:
                req10 = getncchanges_map_req8(mem_ctx, &r->in.req->req8);
                if (req10 == NULL) {
-                       return WERR_NOMEM;
+                       return WERR_NOT_ENOUGH_MEMORY;
                }
                break;
        case 10:
@@ -1717,7 +2099,7 @@ WERROR dcesrv_drsuapi_DsGetNCChanges(struct dcesrv_call_state *dce_call, TALLOC_
        if (samdb_ntds_options(sam_ctx, &options) != LDB_SUCCESS) {
                return WERR_DS_DRA_INTERNAL_ERROR;
        }
-       
+
        if ((options & DS_NTDSDSA_OPT_DISABLE_OUTBOUND_REPL) &&
            !(req10->replica_flags & DRSUAPI_DRS_SYNC_FORCED)) {
                return WERR_DS_DRA_SOURCE_DISABLED;
@@ -1726,7 +2108,7 @@ WERROR dcesrv_drsuapi_DsGetNCChanges(struct dcesrv_call_state *dce_call, TALLOC_
        user_sid = &dce_call->conn->auth_state.session_info->security_token->sids[PRIMARY_USER_SID_INDEX];
 
        /* all clients must have GUID_DRS_GET_CHANGES */
-       werr = drs_security_access_check_nc_root(b_state->sam_ctx,
+       werr = drs_security_access_check_nc_root(sam_ctx,
                                                 mem_ctx,
                                                 dce_call->conn->auth_state.session_info->security_token,
                                                 req10->naming_context,
@@ -1735,14 +2117,40 @@ WERROR dcesrv_drsuapi_DsGetNCChanges(struct dcesrv_call_state *dce_call, TALLOC_
                return werr;
        }
 
+       if (dsdb_functional_level(sam_ctx) >= DS_DOMAIN_FUNCTION_2008) {
+               full = req10->partial_attribute_set == NULL &&
+                      req10->partial_attribute_set_ex == NULL;
+       } else {
+               full = (options & DRSUAPI_DRS_WRIT_REP) != 0;
+       }
+
+       werr = dsdb_schema_pfm_from_drsuapi_pfm(&req10->mapping_ctr, true,
+                                               mem_ctx, &pfm_remote, NULL);
+
+       /* We were supplied a partial attribute set, without the prefix map! */
+       if (!full && !W_ERROR_IS_OK(werr)) {
+               if (req10->mapping_ctr.num_mappings == 0) {
+                       /*
+                        * Despite the fact MS-DRSR specifies that this shouldn't
+                        * happen, Windows RODCs will in fact not provide a prefixMap.
+                        */
+                       DEBUG(5,(__location__ ": Failed to provide a remote prefixMap,"
+                                " falling back to local prefixMap\n"));
+               } else {
+                       DEBUG(0,(__location__ ": Failed to decode remote prefixMap: %s\n",
+                                win_errstr(werr)));
+                       return werr;
+               }
+       }
+
        /* allowed if the GC PAS and client has
           GUID_DRS_GET_FILTERED_ATTRIBUTES */
-       werr = dcesrv_drsuapi_is_gc_pas_request(b_state, req10, &is_gc_pas_request);
+       werr = dcesrv_drsuapi_is_gc_pas_request(b_state, req10, pfm_remote, &is_gc_pas_request);
        if (!W_ERROR_IS_OK(werr)) {
                return werr;
        }
        if (is_gc_pas_request) {
-               werr = drs_security_access_check_nc_root(b_state->sam_ctx,
+               werr = drs_security_access_check_nc_root(sam_ctx,
                                                         mem_ctx,
                                                         dce_call->conn->auth_state.session_info->security_token,
                                                         req10->naming_context,
@@ -1752,18 +2160,23 @@ WERROR dcesrv_drsuapi_DsGetNCChanges(struct dcesrv_call_state *dce_call, TALLOC_
                }
        }
 
-       werr = dcesrv_drsuapi_is_reveal_secrets_request(b_state, req10, &is_secret_request);
+       werr = dcesrv_drsuapi_is_reveal_secrets_request(b_state, req10,
+                                                       pfm_remote,
+                                                       &is_secret_request);
        if (!W_ERROR_IS_OK(werr)) {
                return werr;
        }
-       if (is_secret_request && req10->extended_op != DRSUAPI_EXOP_REPL_SECRET) {
-               werr = drs_security_access_check_nc_root(b_state->sam_ctx,
+       if (is_secret_request) {
+               werr = drs_security_access_check_nc_root(sam_ctx,
                                                         mem_ctx,
                                                         dce_call->conn->auth_state.session_info->security_token,
                                                         req10->naming_context,
                                                         GUID_DRS_GET_ALL_CHANGES);
                if (!W_ERROR_IS_OK(werr)) {
-                       return werr;
+                       /* Only bail if this is not a EXOP_REPL_SECRET */
+                       if (req10->extended_op != DRSUAPI_EXOP_REPL_SECRET) {
+                               return werr;
+                       }
                } else {
                        has_get_all_changes = true;
                }
@@ -1784,7 +2197,7 @@ allowed:
        if (req10->replica_flags & DRSUAPI_DRS_FULL_SYNC_PACKET) {
                /* Ignore the _in_ uptpdateness vector*/
                req10->uptodateness_vector = NULL;
-       } 
+       }
 
        if (GUID_all_zero(&req10->source_dsa_invocation_id)) {
                req10->source_dsa_invocation_id = invocation_id;
@@ -1830,14 +2243,28 @@ allowed:
        if (getnc_state == NULL) {
                getnc_state = talloc_zero(b_state, struct drsuapi_getncchanges_state);
                if (getnc_state == NULL) {
-                       return WERR_NOMEM;
+                       return WERR_NOT_ENOUGH_MEMORY;
                }
                b_state->getncchanges_state = getnc_state;
                getnc_state->ncRoot_dn = drs_ObjectIdentifier_to_dn(getnc_state, sam_ctx, ncRoot);
+               if (getnc_state->ncRoot_dn == NULL) {
+                       return WERR_NOT_ENOUGH_MEMORY;
+               }
+
+               ret = dsdb_find_guid_by_dn(b_state->sam_ctx,
+                                          getnc_state->ncRoot_dn,
+                                          &getnc_state->ncRoot_guid);
+               if (ret != LDB_SUCCESS) {
+                       DEBUG(0,(__location__ ": Failed to find GUID of ncRoot_dn %s\n",
+                                ldb_dn_get_linearized(getnc_state->ncRoot_dn)));
+                       return WERR_DS_DRA_INTERNAL_ERROR;
+               }
+               ncRoot->guid = getnc_state->ncRoot_guid;
 
                /* find out if we are to replicate Schema NC */
-               ret = ldb_dn_compare(getnc_state->ncRoot_dn,
-                                    ldb_get_schema_basedn(b_state->sam_ctx));
+               ret = ldb_dn_compare_base(ldb_get_schema_basedn(sam_ctx),
+                                         getnc_state->ncRoot_dn);
+
                getnc_state->is_schema_nc = (0 == ret);
 
                if (req10->extended_op != DRSUAPI_EXOP_NONE) {
@@ -1864,7 +2291,8 @@ allowed:
                        werr = getncchanges_repl_secret(b_state, mem_ctx, req10,
                                                        user_sid,
                                                        &r->out.ctr->ctr6,
-                                                       has_get_all_changes);
+                                                       has_get_all_changes,
+                                                       &machine_dn);
                        r->out.result = werr;
                        W_ERROR_NOT_OK_RETURN(werr);
                        break;
@@ -1910,11 +2338,13 @@ allowed:
                return WERR_DS_DRA_INVALID_PARAMETER;
        }
 
+       ncRoot->guid = getnc_state->ncRoot_guid;
+
        /* we need the session key for encrypting password attributes */
        status = dcesrv_inherited_session_key(dce_call->conn, &session_key);
        if (!NT_STATUS_IS_OK(status)) {
                DEBUG(0,(__location__ ": Failed to get session key\n"));
-               return WERR_DS_DRA_INTERNAL_ERROR;              
+               return WERR_DS_DRA_INTERNAL_ERROR;
        }
 
        /* 
@@ -1924,16 +2354,46 @@ allowed:
        if (getnc_state->guids == NULL) {
                const char *extra_filter;
                struct ldb_result *search_res = NULL;
+               static const struct drsuapi_DsReplicaCursorCtrEx empty_udv;
+               const struct drsuapi_DsReplicaCursorCtrEx *udv = NULL;
 
                extra_filter = lpcfg_parm_string(dce_call->conn->dce_ctx->lp_ctx, NULL, "drs", "object filter");
 
-               getnc_state->min_usn = req10->highwatermark.highest_usn;
+               if (req10->extended_op == DRSUAPI_EXOP_NONE) {
+                       if (req10->uptodateness_vector != NULL) {
+                               udv = req10->uptodateness_vector;
+                       } else {
+                               udv = &empty_udv;
+                       }
+
+                       getnc_state->min_usn = req10->highwatermark.highest_usn;
+                       for (i = 0; i < udv->count; i++) {
+                               bool match;
+                               const struct drsuapi_DsReplicaCursor *cur =
+                                       &udv->cursors[i];
+
+                               match = GUID_equal(&invocation_id,
+                                                  &cur->source_dsa_invocation_id);
+                               if (!match) {
+                                       continue;
+                               }
+                               if (cur->highest_usn > getnc_state->min_usn) {
+                                       getnc_state->min_usn = cur->highest_usn;
+                               }
+                               break;
+                       }
+               } else {
+                       /* We do not want REPL_SECRETS or REPL_SINGLE to return empty-handed */
+                       udv = &empty_udv;
+                       getnc_state->min_usn = 0;
+               }
+
                getnc_state->max_usn = getnc_state->min_usn;
 
                getnc_state->final_udv = talloc_zero(getnc_state,
                                        struct drsuapi_DsReplicaCursor2CtrEx);
                if (getnc_state->final_udv == NULL) {
-                       return WERR_NOMEM;
+                       return WERR_NOT_ENOUGH_MEMORY;
                }
                werr = get_nc_changes_udv(sam_ctx, getnc_state->ncRoot_dn,
                                          getnc_state->final_udv);
@@ -1976,11 +2436,6 @@ allowed:
                /* RID_ALLOC returns 3 objects in a fixed order */
                if (req10->extended_op == DRSUAPI_EXOP_FSMO_RID_ALLOC) {
                        /* Do nothing */
-               } else if (req10->replica_flags & DRSUAPI_DRS_GET_ANC) {
-                       LDB_TYPESAFE_QSORT(changes,
-                                          getnc_state->num_records,
-                                          getnc_state,
-                                          site_res_cmp_anc_order);
                } else {
                        LDB_TYPESAFE_QSORT(changes,
                                           getnc_state->num_records,
@@ -2003,6 +2458,15 @@ allowed:
 
                talloc_free(search_res);
                talloc_free(changes);
+
+               if (req10->extended_op != DRSUAPI_EXOP_NONE) {
+                       /* Do nothing */
+               } else if (req10->replica_flags & DRSUAPI_DRS_GET_ANC) {
+                       getnc_state->anc_cache = db_open_rbt(getnc_state);
+                       if (getnc_state->anc_cache == NULL) {
+                               return WERR_NOT_ENOUGH_MEMORY;
+                       }
+               }
        }
 
        if (req10->uptodateness_vector) {
@@ -2020,14 +2484,10 @@ allowed:
        }
 
        r->out.ctr->ctr6.naming_context = talloc(mem_ctx, struct drsuapi_DsReplicaObjectIdentifier);
-       *r->out.ctr->ctr6.naming_context = *ncRoot;
-
-       if (dsdb_find_guid_by_dn(sam_ctx, getnc_state->ncRoot_dn,
-                                &r->out.ctr->ctr6.naming_context->guid) != LDB_SUCCESS) {
-               DEBUG(0,(__location__ ": Failed to find GUID of ncRoot_dn %s\n",
-                        ldb_dn_get_linearized(getnc_state->ncRoot_dn)));
-               return WERR_DS_DRA_INTERNAL_ERROR;
+       if (r->out.ctr->ctr6.naming_context == NULL) {
+               return WERR_NOT_ENOUGH_MEMORY;
        }
+       *r->out.ctr->ctr6.naming_context = *ncRoot;
 
        /* find the SID if there is one */
        dsdb_find_sid_by_dn(sam_ctx, getnc_state->ncRoot_dn, &r->out.ctr->ctr6.naming_context->sid);
@@ -2068,13 +2528,36 @@ allowed:
         * 10 seconds by default.
         */
        max_wait = lpcfg_parm_int(dce_call->conn->dce_ctx->lp_ctx, NULL, "drs", "max work time", 10);
+
+       if (req10->partial_attribute_set != NULL) {
+               struct dsdb_syntax_ctx syntax_ctx;
+               uint32_t j = 0;
+
+               dsdb_syntax_ctx_init(&syntax_ctx, sam_ctx, schema);
+               syntax_ctx.pfm_remote = pfm_remote;
+
+               local_pas = talloc_array(b_state, uint32_t, req10->partial_attribute_set->num_attids);
+
+               for (j = 0; j < req10->partial_attribute_set->num_attids; j++) {
+                       getncchanges_attid_remote_to_local(schema,
+                                                          &syntax_ctx,
+                                                          req10->partial_attribute_set->attids[j],
+                                                          (enum drsuapi_DsAttributeId *)&local_pas[j],
+                                                          NULL);
+               }
+
+               LDB_TYPESAFE_QSORT(local_pas,
+                                  req10->partial_attribute_set->num_attids,
+                                  NULL,
+                                  uint32_t_ptr_cmp);
+       }
+
        for (i=getnc_state->num_processed;
             i<getnc_state->num_records &&
-                    !null_scope &&
                     (r->out.ctr->ctr6.object_count < max_objects)
                     && !max_wait_reached;
            i++) {
-               int uSN;
+               struct drsuapi_DsReplicaObjectListItemEx *new_objs = NULL;
                struct drsuapi_DsReplicaObjectListItemEx *obj;
                struct ldb_message *msg;
                static const char * const msg_attrs[] = {
@@ -2086,6 +2569,7 @@ allowed:
                                            NULL };
                struct ldb_result *msg_res;
                struct ldb_dn *msg_dn;
+               const struct GUID *next_anc_guid = NULL;
 
                obj = talloc_zero(mem_ctx, struct drsuapi_DsReplicaObjectListItemEx);
                W_ERROR_HAVE_NO_MEMORY(obj);
@@ -2094,8 +2578,13 @@ allowed:
                W_ERROR_HAVE_NO_MEMORY(msg_dn);
 
 
-               /* by re-searching here we avoid having a lot of full
-                * records in memory between calls to getncchanges
+               /*
+                * by re-searching here we avoid having a lot of full
+                * records in memory between calls to getncchanges.
+                *
+                * We expect that we may get some objects that vanish
+                * (tombstone expunge) between the first and second
+                * check.
                 */
                ret = drsuapi_search_with_extended_dn(sam_ctx, obj, &msg_res,
                                                      msg_dn,
@@ -2109,8 +2598,36 @@ allowed:
                        continue;
                }
 
+               if (msg_res->count == 0) {
+                       DEBUG(1,("getncchanges: got LDB_SUCCESS but failed"
+                                "to get any results in fetch of DN "
+                                "%s (race with tombstone expunge?)\n",
+                                ldb_dn_get_extended_linearized(obj,
+                                                               msg_dn, 1)));
+                       talloc_free(obj);
+                       continue;
+               }
+
                msg = msg_res->msgs[0];
 
+               /*
+                * If it has already been added as an ancestor of
+                * an object, we don't need to do anything more,
+                * as we've already added the links.
+                */
+               if (getnc_state->anc_cache != NULL) {
+                       werr = dcesrv_drsuapi_anc_cache_exists(getnc_state->anc_cache,
+                                                              &getnc_state->guids[i]);
+                       if (W_ERROR_EQUAL(werr, WERR_OBJECT_NAME_EXISTS)) {
+                               dcesrv_drsuapi_update_highwatermark(msg,
+                                               getnc_state->max_usn,
+                                               &r->out.ctr->ctr6.new_highwatermark);
+                               /* no attributes to send */
+                               talloc_free(obj);
+                               continue;
+                       }
+               }
+
                max_wait_reached = (time(NULL) - start > max_wait);
 
                werr = get_nc_changes_build_object(obj, msg,
@@ -2121,13 +2638,16 @@ allowed:
                                                   req10->partial_attribute_set,
                                                   req10->uptodateness_vector,
                                                   req10->extended_op,
-                                                  max_wait_reached);
+                                                  max_wait_reached,
+                                                  local_pas, machine_dn,
+                                                  &getnc_state->guids[i]);
                if (!W_ERROR_IS_OK(werr)) {
                        return werr;
                }
 
                werr = get_nc_changes_add_links(sam_ctx, getnc_state,
                                                getnc_state->ncRoot_dn,
+                                               getnc_state->is_schema_nc,
                                                schema, getnc_state->min_usn,
                                                req10->replica_flags,
                                                msg,
@@ -2138,23 +2658,9 @@ allowed:
                        return werr;
                }
 
-               uSN = ldb_msg_find_attr_as_int(msg, "uSNChanged", -1);
-               if (uSN > getnc_state->max_usn) {
-                       /*
-                        * Only report the max_usn we had at the start
-                        * of the replication cycle.
-                        *
-                        * If this object has changed lately we better
-                        * let the destination dsa refetch the change.
-                        * This is better than the risk of loosing some
-                        * objects or linked attributes.
-                        */
-                       uSN = 0;
-               }
-               if (uSN > r->out.ctr->ctr6.new_highwatermark.tmp_highest_usn) {
-                       r->out.ctr->ctr6.new_highwatermark.tmp_highest_usn = uSN;
-                       r->out.ctr->ctr6.new_highwatermark.reserved_usn = 0;
-               }
+               dcesrv_drsuapi_update_highwatermark(msg,
+                                       getnc_state->max_usn,
+                                       &r->out.ctr->ctr6.new_highwatermark);
 
                if (obj->meta_data_ctr == NULL) {
                        DEBUG(8,(__location__ ": getncchanges skipping send of object %s\n",
@@ -2164,10 +2670,149 @@ allowed:
                        continue;
                }
 
-               r->out.ctr->ctr6.object_count++;
-               
-               *currentObject = obj;
-               currentObject = &obj->next_object;
+               new_objs = obj;
+
+               if (getnc_state->anc_cache != NULL) {
+                       werr = dcesrv_drsuapi_anc_cache_add(getnc_state->anc_cache,
+                                                           &getnc_state->guids[i]);
+                       if (!W_ERROR_IS_OK(werr)) {
+                               return werr;
+                       }
+
+                       next_anc_guid = obj->parent_object_guid;
+               }
+
+               while (next_anc_guid != NULL) {
+                       struct drsuapi_DsReplicaObjectListItemEx *anc_obj = NULL;
+                       struct ldb_message *anc_msg = NULL;
+                       struct ldb_result *anc_res = NULL;
+                       struct ldb_dn *anc_dn = NULL;
+
+                       werr = dcesrv_drsuapi_anc_cache_exists(getnc_state->anc_cache,
+                                                              next_anc_guid);
+                       if (W_ERROR_EQUAL(werr, WERR_OBJECT_NAME_EXISTS)) {
+                               /*
+                                * We don't need to send it twice.
+                                */
+                               break;
+                       }
+                       if (W_ERROR_IS_OK(werr)) {
+                               return WERR_INTERNAL_ERROR;
+                       }
+                       if (!W_ERROR_EQUAL(werr, WERR_OBJECT_NOT_FOUND)) {
+                               return werr;
+                       }
+                       werr = WERR_OK;
+
+                       anc_obj = talloc_zero(mem_ctx,
+                                       struct drsuapi_DsReplicaObjectListItemEx);
+                       if (anc_obj == NULL) {
+                               return WERR_NOT_ENOUGH_MEMORY;
+                       }
+
+                       anc_dn = ldb_dn_new_fmt(anc_obj, sam_ctx, "<GUID=%s>",
+                                       GUID_string(anc_obj, next_anc_guid));
+                       if (anc_dn == NULL) {
+                               return WERR_NOT_ENOUGH_MEMORY;
+                       }
+
+                       ret = drsuapi_search_with_extended_dn(sam_ctx, anc_obj,
+                                                             &anc_res, anc_dn,
+                                                             LDB_SCOPE_BASE,
+                                                             msg_attrs, NULL);
+                       if (ret != LDB_SUCCESS) {
+                               const char *anc_str = NULL;
+                               const char *obj_str = NULL;
+
+                               anc_str = ldb_dn_get_extended_linearized(anc_obj,
+                                                                        anc_dn,
+                                                                        1);
+                               obj_str = ldb_dn_get_extended_linearized(anc_obj,
+                                                                        msg->dn,
+                                                                        1),
+
+                               DBG_ERR("getncchanges: failed to fetch ANC "
+                                       "DN %s for DN %s - %s\n",
+                                       anc_str, obj_str,
+                                       ldb_errstring(sam_ctx));
+                               return WERR_DS_DRA_INCONSISTENT_DIT;
+                       }
+
+                       anc_msg = anc_res->msgs[0];
+
+                       werr = get_nc_changes_build_object(anc_obj, anc_msg,
+                                                          sam_ctx,
+                                                          getnc_state->ncRoot_dn,
+                                                          getnc_state->is_schema_nc,
+                                                          schema, &session_key,
+                                                          getnc_state->min_usn,
+                                                          req10->replica_flags,
+                                                          req10->partial_attribute_set,
+                                                          req10->uptodateness_vector,
+                                                          req10->extended_op,
+                                                          false, /* force_object_return */
+                                                          local_pas,
+                                                          machine_dn,
+                                                          next_anc_guid);
+                       if (!W_ERROR_IS_OK(werr)) {
+                               return werr;
+                       }
+
+                       werr = get_nc_changes_add_links(sam_ctx, getnc_state,
+                                                       getnc_state->ncRoot_dn,
+                                                       getnc_state->is_schema_nc,
+                                                       schema, getnc_state->min_usn,
+                                                       req10->replica_flags,
+                                                       anc_msg,
+                                                       &getnc_state->la_list,
+                                                       &getnc_state->la_count,
+                                                       req10->uptodateness_vector);
+                       if (!W_ERROR_IS_OK(werr)) {
+                               return werr;
+                       }
+
+                       /*
+                        * Regardless of if we actually use it or not,
+                        * we add it to the cache so we don't look at it again
+                        */
+                       werr = dcesrv_drsuapi_anc_cache_add(getnc_state->anc_cache,
+                                                           next_anc_guid);
+                       if (!W_ERROR_IS_OK(werr)) {
+                               return werr;
+                       }
+
+                       /*
+                        * Any ancestors which are below the highwatermark
+                        * or uptodateness_vector shouldn't be added,
+                        * but we still look further up the
+                        * tree for ones which have been changed recently.
+                        */
+                       if (anc_obj->meta_data_ctr != NULL) {
+                               /*
+                                * prepend it to the list
+                                */
+                               anc_obj->next_object = new_objs;
+                               new_objs = anc_obj;
+                       }
+
+                       anc_msg = NULL;
+                       TALLOC_FREE(anc_res);
+                       TALLOC_FREE(anc_dn);
+
+                       /*
+                        * We may need to resolve more...
+                        */
+                       next_anc_guid = anc_obj->parent_object_guid;
+               }
+
+               *currentObject = new_objs;
+               while (new_objs != NULL) {
+                       r->out.ctr->ctr6.object_count += 1;
+                       if (new_objs->next_object == NULL) {
+                               currentObject = &new_objs->next_object;
+                       }
+                       new_objs = new_objs->next_object;
+               }
 
                DEBUG(8,(__location__ ": replicating object %s\n", ldb_dn_get_linearized(msg->dn)));
 
@@ -2180,8 +2825,6 @@ allowed:
 
        getnc_state->num_processed = i;
 
-       r->out.ctr->ctr6.nc_object_count = getnc_state->num_records;
-
        /* the client can us to call UpdateRefs on its behalf to
           re-establish monitoring of the NC */
        if ((req10->replica_flags & (DRSUAPI_DRS_ADD_REF | DRSUAPI_DRS_REF_GCSPN)) &&
@@ -2190,10 +2833,10 @@ allowed:
                DEBUG(3,("UpdateRefs on getncchanges for %s\n",
                         GUID_string(mem_ctx, &req10->destination_dsa_guid)));
                ureq.naming_context = ncRoot;
-               ureq.dest_dsa_dns_name = samdb_ntds_msdcs_dns_name(b_state->sam_ctx, mem_ctx,
+               ureq.dest_dsa_dns_name = samdb_ntds_msdcs_dns_name(sam_ctx, mem_ctx,
                                                                   &req10->destination_dsa_guid);
                if (!ureq.dest_dsa_dns_name) {
-                       return WERR_NOMEM;
+                       return WERR_NOT_ENOUGH_MEMORY;
                }
                ureq.dest_dsa_guid = req10->destination_dsa_guid;
                ureq.options = DRSUAPI_DRS_ADD_REF |
@@ -2205,7 +2848,9 @@ allowed:
                   to send notifies using the GC SPN */
                ureq.options |= (req10->replica_flags & DRSUAPI_DRS_REF_GCSPN);
 
-               werr = drsuapi_UpdateRefs(b_state, mem_ctx, &ureq);
+               werr = drsuapi_UpdateRefs(dce_call->msg_ctx,
+                                         dce_call->event_ctx, b_state,
+                                         mem_ctx, &ureq);
                if (!W_ERROR_IS_OK(werr)) {
                        DEBUG(0,(__location__ ": Failed UpdateRefs on %s for %s in DsGetNCChanges - %s\n",
                                 drs_ObjectIdentifier_to_string(mem_ctx, ncRoot), ureq.dest_dsa_dns_name,
@@ -2231,17 +2876,76 @@ allowed:
                r->out.ctr->ctr6.more_data = true;
        } else {
                /* sort the whole array the first time */
-               if (!getnc_state->la_sorted) {
-                       LDB_TYPESAFE_QSORT(getnc_state->la_list, getnc_state->la_count,
-                                          sam_ctx, linked_attribute_compare);
-                       getnc_state->la_sorted = true;
+               if (getnc_state->la_sorted == NULL) {
+                       int j;
+                       struct la_for_sorting *guid_array = talloc_array(getnc_state, struct la_for_sorting, getnc_state->la_count);
+                       if (guid_array == NULL) {
+                               DEBUG(0, ("Out of memory allocating %u linked attributes for sorting", getnc_state->la_count));
+                               return WERR_NOT_ENOUGH_MEMORY;
+                       }
+                       for (j = 0; j < getnc_state->la_count; j++) {
+                               /* we need to get the target GUIDs to compare */
+                               struct dsdb_dn *dn;
+                               const struct drsuapi_DsReplicaLinkedAttribute *la = &getnc_state->la_list[j];
+                               const struct dsdb_attribute *schema_attrib;
+                               const struct ldb_val *target_guid;
+                               DATA_BLOB source_guid;
+                               TALLOC_CTX *frame = talloc_stackframe();
+
+                               schema_attrib = dsdb_attribute_by_attributeID_id(schema, la->attid);
+
+                               werr = dsdb_dn_la_from_blob(sam_ctx, schema_attrib, schema, frame, la->value.blob, &dn);
+                               if (!W_ERROR_IS_OK(werr)) {
+                                       DEBUG(0,(__location__ ": Bad la blob in sort\n"));
+                                       TALLOC_FREE(frame);
+                                       return werr;
+                               }
+
+                               /* Extract the target GUID in NDR form */
+                               target_guid = ldb_dn_get_extended_component(dn->dn, "GUID");
+                               if (target_guid == NULL
+                                   || target_guid->length != sizeof(guid_array[0].target_guid)) {
+                                       status = NT_STATUS_OBJECT_NAME_NOT_FOUND;
+                               } else {
+                                       /* Repack the source GUID as NDR for sorting */
+                                       status = GUID_to_ndr_blob(&la->identifier->guid,
+                                                                 frame,
+                                                                 &source_guid);
+                               }
+
+                               if (!NT_STATUS_IS_OK(status)
+                                   || source_guid.length != sizeof(guid_array[0].source_guid)) {
+                                       DEBUG(0,(__location__ ": Bad la guid in sort\n"));
+                                       TALLOC_FREE(frame);
+                                       return ntstatus_to_werror(status);
+                               }
+
+                               guid_array[j].link = &getnc_state->la_list[j];
+                               memcpy(guid_array[j].target_guid, target_guid->data,
+                                      sizeof(guid_array[j].target_guid));
+                               memcpy(guid_array[j].source_guid, source_guid.data,
+                                      sizeof(guid_array[j].source_guid));
+                               TALLOC_FREE(frame);
+                       }
+
+                       LDB_TYPESAFE_QSORT(guid_array, getnc_state->la_count, NULL, linked_attribute_compare);
+                       getnc_state->la_sorted = guid_array;
                }
 
                link_count = getnc_state->la_count - getnc_state->la_idx;
                link_count = MIN(max_links, link_count);
 
                r->out.ctr->ctr6.linked_attributes_count = link_count;
-               r->out.ctr->ctr6.linked_attributes = getnc_state->la_list + getnc_state->la_idx;
+               r->out.ctr->ctr6.linked_attributes = talloc_array(r->out.ctr, struct drsuapi_DsReplicaLinkedAttribute, link_count);
+               if (r->out.ctr->ctr6.linked_attributes == NULL) {
+                       DEBUG(0, ("Out of memory allocating %u linked attributes for output", link_count));
+                       return WERR_NOT_ENOUGH_MEMORY;
+               }
+
+               for (k = 0; k < link_count; k++) {
+                       r->out.ctr->ctr6.linked_attributes[k]
+                               = *getnc_state->la_sorted[getnc_state->la_idx + k].link;
+               }
 
                getnc_state->la_idx += link_count;
                link_given = getnc_state->la_idx;
@@ -2251,6 +2955,22 @@ allowed:
                }
        }
 
+       if (req10->replica_flags & DRSUAPI_DRS_GET_NC_SIZE) {
+               /*
+                * TODO: This implementation is wrong
+                * we should find out the total number of
+                * objects and links in the whole naming context
+                * at the start of the cycle and return these
+                * values in each message.
+                *
+                * For now we keep our current strategy and return
+                * the number of objects for this cycle and the number
+                * of links we found so far during the cycle.
+                */
+               r->out.ctr->ctr6.nc_object_count = getnc_state->num_records;
+               r->out.ctr->ctr6.nc_linked_attributes_count = getnc_state->la_count;
+       }
+
        if (!r->out.ctr->ctr6.more_data) {
                talloc_steal(mem_ctx, getnc_state->la_list);