s4:dsdb: split extended_dn into extended_dn_in, extended_dn_out and extended_dn_store.

By splitting the module, the extended_dn_in and extended_dn_store
moudles can use extended_dn_out to actually get the extended DN.  This
avoids code duplication.

The extended_dn_out module also contains a client implementation of
the OpenLDAP dereference control (draft-masarati-ldap-deref-00).

This also introduces a new control
'DSDB_CONTROL_DN_STORAGE_FORMAT_OID' to ask the extended_dn_out module
to return whatever the 'storage format' is.  This allows us to work
with both OpenLDAP (which performs a dereference at run time) and LDB
(which stores the GUID and SID on disk).

Signed-off-by: Stefan Metzmacher <metze@samba.org>

1 files changed, 431 insertions, 0 deletions

diff --git a/source4/dsdb/samdb/ldb_modules/extended_dn_store.c b/source4/dsdb/samdb/ldb_modules/extended_dn_store.c
new file mode 100644
index 0000000000..4f4e9d0fd7
--- /dev/null
+++ b/source4/dsdb/samdb/ldb_modules/extended_dn_store.c
@@ -0,0 +1,431 @@
+/* 
+   ldb database library
+
+   Copyright (C) Simo Sorce 2005-2008
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2007-2008
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+   
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+   
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+ *  Name: ldb
+ *
+ *  Component: ldb extended dn control module
+ *
+ *  Description: this module builds a special dn for returned search
+ *  results nad creates the special DN in the backend store for new
+ *  values.
+ *
+ *  This also has the curious result that we convert <SID=S-1-2-345>
+ *  in an attribute value into a normal DN for the rest of the stack
+ *  to process
+ *
+ *  Authors: Simo Sorce
+ *           Andrew Bartlett
+ */
+
+#include "includes.h"
+#include "ldb/include/ldb.h"
+#include "ldb/include/ldb_errors.h"
+#include "ldb/include/ldb_private.h"
+#include "librpc/gen_ndr/ndr_misc.h"
+#include "dsdb/samdb/samdb.h"
+#include "libcli/security/security.h"
+
+#include <time.h>
+
+struct extended_dn_replace_list {
+	struct extended_dn_replace_list *next;
+	struct ldb_dn *dn;
+	TALLOC_CTX *mem_ctx;
+	struct ldb_val *replace_dn;
+	struct extended_dn_context *ac;
+	struct ldb_request *search_req;
+};
+
+
+struct extended_dn_context {
+	const struct dsdb_schema *schema;
+	struct ldb_module *module;
+	struct ldb_request *req;
+	struct ldb_request *new_req;
+
+	struct extended_dn_replace_list *ops;
+	struct extended_dn_replace_list *cur;
+};
+
+
+static struct extended_dn_context *extended_dn_context_init(struct ldb_module *module,
+							    struct ldb_request *req)
+{
+	struct extended_dn_context *ac;
+
+	ac = talloc_zero(req, struct extended_dn_context);
+	if (ac == NULL) {
+		ldb_oom(module->ldb);
+		return NULL;
+	}
+
+	ac->schema = dsdb_get_schema(module->ldb);
+	ac->module = module;
+	ac->req = req;
+
+	return ac;
+}
+
+/* An extra layer of indirection because LDB does not allow the original request to be altered */
+
+static int extended_final_callback(struct ldb_request *req, struct ldb_reply *ares)
+{
+	int ret = LDB_ERR_OPERATIONS_ERROR;
+	struct extended_dn_context *ac;
+	ac = talloc_get_type(req->context, struct extended_dn_context);
+
+	if (ares->error != LDB_SUCCESS) {
+		ret = ldb_module_done(ac->req, ares->controls,
+				      ares->response, ares->error);
+	} else {
+		switch (ares->type) {
+		case LDB_REPLY_ENTRY:
+			
+			ret = ldb_module_send_entry(ac->req, ares->message, ares->controls);
+			break;
+		case LDB_REPLY_REFERRAL:
+			
+			ret = ldb_module_send_referral(ac->req, ares->referral);
+			break;
+		case LDB_REPLY_DONE:
+			
+			ret = ldb_module_done(ac->req, ares->controls,
+					      ares->response, ares->error);
+			break;
+		}
+	}
+	return ret;
+}
+
+static int extended_replace_dn(struct ldb_request *req, struct ldb_reply *ares)
+{
+	struct extended_dn_replace_list *os = talloc_get_type(req->context, 
+							   struct extended_dn_replace_list);
+
+	if (!ares) {
+		return ldb_module_done(os->ac->req, NULL, NULL,
+					LDB_ERR_OPERATIONS_ERROR);
+	}
+	if (ares->error == LDB_ERR_NO_SUCH_OBJECT) {
+		/* Don't worry too much about dangling references */
+
+		ldb_reset_err_string(os->ac->module->ldb);
+		if (os->next) {
+			struct extended_dn_replace_list *next;
+
+			next = os->next;
+
+			talloc_free(os);
+
+			os = next;
+			return ldb_next_request(os->ac->module, next->search_req);
+		} else {
+			/* Otherwise, we are done - let's run the
+			 * request now we have swapped the DNs for the
+			 * full versions */
+			return ldb_next_request(os->ac->module, os->ac->req);
+		}
+	}
+	if (ares->error != LDB_SUCCESS) {
+		return ldb_module_done(os->ac->req, ares->controls,
+					ares->response, ares->error);
+	}
+
+	/* Only entries are interesting, and we only want the olddn */
+	switch (ares->type) {
+	case LDB_REPLY_ENTRY:
+	{
+		/* This *must* be the right DN, as this is a base
+		 * search.  We can't check, as it could be an extended
+		 * DN, so a module below will resolve it */
+		struct ldb_dn *dn = ares->message->dn;
+
+		/* Replace the DN with the extended version of the DN
+		 * (ie, add SID and GUID) */
+		*os->replace_dn = data_blob_string_const(
+			ldb_dn_get_extended_linearized(os->mem_ctx, 
+						       dn, 1));
+		if (os->replace_dn->data == NULL) {
+			return ldb_module_done(os->ac->req, NULL, NULL,
+						LDB_ERR_OPERATIONS_ERROR);
+		}
+		break;
+	}
+	case LDB_REPLY_REFERRAL:
+		/* ignore */
+		break;
+
+	case LDB_REPLY_DONE:
+
+		talloc_free(ares);
+		
+		/* Run the next search */
+
+		if (os->next) {
+			struct extended_dn_replace_list *next;
+
+			next = os->next;
+
+			talloc_free(os);
+
+			os = next;
+			return ldb_next_request(os->ac->module, next->search_req);
+		} else {
+			/* Otherwise, we are done - let's run the
+			 * request now we have swapped the DNs for the
+			 * full versions */
+			return ldb_next_request(os->ac->module, os->ac->new_req);
+		}
+	}
+
+	talloc_free(ares);
+	return LDB_SUCCESS;
+}
+
+/* We have a 'normal' DN in the inbound request.  We need to find out
+ * what the GUID and SID are on the DN it points to, so we can
+ * construct an extended DN for storage.
+ *
+ * This creates a list of DNs to look up, and the plain DN to replace
+ */
+
+static int extended_store_replace(struct extended_dn_context *ac,
+				  TALLOC_CTX *callback_mem_ctx,
+				  struct ldb_val *plain_dn)
+{
+	int ret;
+	struct extended_dn_replace_list *os;
+	static const char *attrs[] = {
+		"objectSid",
+		"objectGUID",
+		NULL
+	};
+
+	os = talloc_zero(ac, struct extended_dn_replace_list);
+	if (!os) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	os->ac = ac;
+	
+	os->mem_ctx = callback_mem_ctx;
+
+	os->dn = ldb_dn_from_ldb_val(os, ac->module->ldb, plain_dn);
+	if (!os->dn || !ldb_dn_validate(os->dn)) {
+		talloc_free(os);
+		ldb_asprintf_errstring(ac->module->ldb, 
+				       "could not parse %.*s as a DN", (int)plain_dn->length, plain_dn->data);
+		return LDB_ERR_INVALID_DN_SYNTAX;
+	}
+
+	os->replace_dn = plain_dn;
+
+	/* The search request here might happen to be for an
+	 * 'extended' style DN, such as <GUID=abced...>.  The next
+	 * module in the stack will convert this into a normal DN for
+	 * processing */
+	ret = ldb_build_search_req(&os->search_req,
+				   ac->module->ldb, os, os->dn, LDB_SCOPE_BASE, NULL, 
+				   attrs, NULL, os, extended_replace_dn,
+				   ac->req);
+
+	if (ret != LDB_SUCCESS) {
+		talloc_free(os);
+		return ret;
+	}
+
+	ret = ldb_request_add_control(os->search_req,
+				      DSDB_CONTROL_DN_STORAGE_FORMAT_OID,
+				      true, NULL);
+	if (ret != LDB_SUCCESS) {
+		talloc_free(os);
+		return ret;
+	}
+
+	if (ac->ops) {
+		ac->cur->next = os;
+	} else {
+		ac->ops = os;
+	}
+	ac->cur = os;
+
+	return LDB_SUCCESS;
+}
+
+
+/* add */
+static int extended_dn_add(struct ldb_module *module, struct ldb_request *req)
+{
+	struct extended_dn_context *ac;
+	int ret;
+	int i, j;
+
+	if (ldb_dn_is_special(req->op.add.message->dn)) {
+		/* do not manipulate our control entries */
+		return ldb_next_request(module, req);
+	}
+
+	ac = extended_dn_context_init(module, req);
+	if (!ac) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	if (!ac->schema) {
+		/* without schema, this doesn't make any sense */
+		talloc_free(ac);
+		return ldb_next_request(module, req);
+	}
+
+	for (i=0; i < req->op.add.message->num_elements; i++) {
+		const struct ldb_message_element *el = &req->op.add.message->elements[i];
+		const struct dsdb_attribute *schema_attr
+			= dsdb_attribute_by_lDAPDisplayName(ac->schema, el->name);
+		if (!schema_attr) {
+			continue;
+		}
+
+		/* We only setup an extended DN GUID on these particular DN objects */
+		if (strcmp(schema_attr->attributeSyntax_oid, "2.5.5.1") != 0) {
+			continue;
+		}
+
+		/* Before we setup a procedure to modify the incoming message, we must copy it */
+		if (!ac->new_req) {
+			struct ldb_message *msg = ldb_msg_copy(ac, req->op.add.message);
+			if (!msg) {
+				ldb_oom(module->ldb);
+				return LDB_ERR_OPERATIONS_ERROR;
+			}
+		   
+			ret = ldb_build_add_req(&ac->new_req, module->ldb, ac, msg, req->controls, ac, extended_final_callback, req);
+			if (ret != LDB_SUCCESS) {
+				return ret;
+			}
+		}
+		/* Re-calculate el */
+		el = &ac->new_req->op.add.message->elements[i];
+		for (j = 0; j < el->num_values; j++) {
+			ret = extended_store_replace(ac, ac->new_req->op.add.message->elements, &el->values[j]);
+			if (ret != LDB_SUCCESS) {
+				return ret;
+			}
+		}
+	}
+
+	/* if DNs were set continue */
+	if (ac->ops == NULL) {
+		talloc_free(ac);
+		return ldb_next_request(module, req);
+	}
+
+	/* start with the searches */
+	return ldb_next_request(module, ac->ops->search_req);
+}
+
+/* modify */
+static int extended_dn_modify(struct ldb_module *module, struct ldb_request *req)
+{
+	/* Look over list of modifications */
+	/* Find if any are for linked attributes */
+	/* Determine the effect of the modification */
+	/* Apply the modify to the linked entry */
+
+	int i, j;
+	struct extended_dn_context *ac;
+	int ret;
+
+	if (ldb_dn_is_special(req->op.mod.message->dn)) {
+		/* do not manipulate our control entries */
+		return ldb_next_request(module, req);
+	}
+
+	ac = extended_dn_context_init(module, req);
+	if (!ac) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	if (!ac->schema) {
+		/* without schema, this doesn't make any sense */
+		return ldb_next_request(module, req);
+	}
+
+	for (i=0; i < req->op.mod.message->num_elements; i++) {
+		const struct ldb_message_element *el = &req->op.mod.message->elements[i];
+		const struct dsdb_attribute *schema_attr
+			= dsdb_attribute_by_lDAPDisplayName(ac->schema, el->name);
+		if (!schema_attr) {
+			continue;
+		}
+
+		/* We only setup an extended DN GUID on these particular DN objects */
+		if (strcmp(schema_attr->attributeSyntax_oid, "2.5.5.1") != 0) {
+			continue;
+		}
+		
+		/* Before we setup a procedure to modify the incoming message, we must copy it */
+		if (!ac->new_req) {
+			struct ldb_message *msg = ldb_msg_copy(ac, req->op.mod.message);
+			if (!msg) {
+				ldb_oom(module->ldb);
+				return LDB_ERR_OPERATIONS_ERROR;
+			}
+		   
+			ret = ldb_build_mod_req(&ac->new_req, module->ldb, ac, msg, req->controls, ac, extended_final_callback, req);
+			if (ret != LDB_SUCCESS) {
+				return ret;
+			}
+		}
+		/* Re-calculate el */
+		el = &ac->new_req->op.mod.message->elements[i];
+		/* For each value being added, we need to setup the lookups to fill in the extended DN */
+		for (j = 0; j < el->num_values; j++) {
+			struct ldb_dn *dn = ldb_dn_from_ldb_val(ac, module->ldb, &el->values[j]);
+			if (!dn || !ldb_dn_validate(dn)) {
+				ldb_asprintf_errstring(module->ldb, 
+						       "could not parse attribute %s as a DN", el->name);
+				return LDB_ERR_INVALID_DN_SYNTAX;
+			}
+			if (((el->flags & LDB_FLAG_MOD_MASK) == LDB_FLAG_MOD_DELETE) && !ldb_dn_has_extended(dn)) {
+				/* NO need to figure this DN out, it's going to be deleted anyway */
+				continue;
+			}
+			ret = extended_store_replace(ac, req->op.mod.message->elements, &el->values[j]);
+			if (ret != LDB_SUCCESS) {
+				return ret;
+			}
+		}
+	}
+
+	/* if DNs were set continue */
+	if (ac->ops == NULL) {
+		talloc_free(ac);
+		return ldb_next_request(module, req);
+	}
+
+	/* start with the searches */
+	return ldb_next_request(module, ac->ops->search_req);
+}
+
+_PUBLIC_ const struct ldb_module_ops ldb_extended_dn_store_module_ops = {
+	.name		   = "extended_dn_store",
+	.add               = extended_dn_add,
+	.modify            = extended_dn_modify,
+};