1 files changed, 535 insertions, 0 deletions
diff --git a/source4/dsdb/samdb/ldb_modules/kludge_acl.c b/source4/dsdb/samdb/ldb_modules/kludge_acl.c
new file mode 100644
index 0000000000..0b5994bb88
--- /dev/null
+++ b/source4/dsdb/samdb/ldb_modules/kludge_acl.c
@@ -0,0 +1,535 @@
+/* 
+   ldb database library
+
+   Copyright (C) Andrew Bartlett 2005
+   Copyright (C) Simo Sorce 2006-2008
+
+    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 kludge ACL module
+ *
+ *  Description: Simple module to enforce a simple form of access
+ *               control, sufficient for securing a default Samba4 
+ *               installation.
+ *
+ *  Author: Andrew Bartlett
+ */
+
+#include "includes.h"
+#include "ldb_module.h"
+#include "auth/auth.h"
+#include "libcli/security/security.h"
+#include "dsdb/samdb/samdb.h"
+
+/* Kludge ACL rules:
+ *
+ * - System can read passwords
+ * - Administrators can write anything
+ * - Users can read anything that is not a password
+ *
+ */
+
+struct kludge_private_data {
+	const char **password_attrs;
+};
+
+static enum security_user_level what_is_user(struct ldb_module *module) 
+{
+	struct ldb_context *ldb = ldb_module_get_ctx(module);
+	struct auth_session_info *session_info
+		= (struct auth_session_info *)ldb_get_opaque(ldb, "sessionInfo");
+	return security_session_user_level(session_info);
+}
+
+static const char *user_name(TALLOC_CTX *mem_ctx, struct ldb_module *module) 
+{
+	struct ldb_context *ldb = ldb_module_get_ctx(module);
+	struct auth_session_info *session_info
+		= (struct auth_session_info *)ldb_get_opaque(ldb, "sessionInfo");
+	if (!session_info) {
+		return "UNKNOWN (NULL)";
+	}
+	
+	return talloc_asprintf(mem_ctx, "%s\\%s",
+			       session_info->server_info->domain_name,
+			       session_info->server_info->account_name);
+}
+
+/* search */
+struct kludge_acl_context {
+
+	struct ldb_module *module;
+	struct ldb_request *req;
+
+	enum security_user_level user_type;
+	bool allowedAttributes;
+	bool allowedAttributesEffective;
+	bool allowedChildClasses;
+	bool allowedChildClassesEffective;
+	const char * const *attrs;
+};
+
+/* read all objectClasses */
+
+static int kludge_acl_allowedAttributes(struct ldb_context *ldb, struct ldb_message *msg,
+					const char *attrName) 
+{
+	struct ldb_message_element *oc_el;
+	struct ldb_message_element *allowedAttributes;
+	const struct dsdb_schema *schema = dsdb_get_schema(ldb);
+	TALLOC_CTX *mem_ctx;
+	const char **objectclass_list, **attr_list;
+	int i, ret;
+
+ 	/* If we don't have a schema yet, we can't do anything... */
+	if (schema == NULL) {
+		return LDB_SUCCESS;
+	}
+
+	/* Must remove any existing attribute, or else confusion reins */
+	ldb_msg_remove_attr(msg, attrName);
+	ret = ldb_msg_add_empty(msg, attrName, 0, &allowedAttributes);
+	if (ret != LDB_SUCCESS) {
+		return ret;
+	}
+	
+	mem_ctx = talloc_new(msg);
+	if (!mem_ctx) {
+		ldb_oom(ldb);
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	/* To ensure that oc_el is valid, we must look for it after 
+	   we alter the element array in ldb_msg_add_empty() */
+	oc_el = ldb_msg_find_element(msg, "objectClass");
+	
+	objectclass_list = talloc_array(mem_ctx, const char *, oc_el->num_values + 1);
+	if (!objectclass_list) {
+		ldb_oom(ldb);
+		talloc_free(mem_ctx);
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	for (i=0; oc_el && i < oc_el->num_values; i++) {
+		objectclass_list[i] = (const char *)oc_el->values[i].data;
+	}
+	objectclass_list[i] = NULL;
+
+	attr_list = dsdb_full_attribute_list(mem_ctx, schema, objectclass_list, DSDB_SCHEMA_ALL);
+	if (!attr_list) {
+		ldb_asprintf_errstring(ldb, "kludge_acl: Failed to get list of attributes create %s attribute", attrName);
+		talloc_free(mem_ctx);
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	for (i=0; attr_list && attr_list[i]; i++) {
+		ldb_msg_add_string(msg, attrName, attr_list[i]);
+	}
+	talloc_free(mem_ctx);
+	return LDB_SUCCESS;
+
+}
+/* read all objectClasses */
+
+static int kludge_acl_childClasses(struct ldb_context *ldb, struct ldb_message *msg,
+				   const char *attrName) 
+{
+	struct ldb_message_element *oc_el;
+	struct ldb_message_element *allowedClasses;
+	const struct dsdb_schema *schema = dsdb_get_schema(ldb);
+	const struct dsdb_class *sclass;
+	int i, j, ret;
+
+ 	/* If we don't have a schema yet, we can't do anything... */
+	if (schema == NULL) {
+		return LDB_SUCCESS;
+	}
+
+	/* Must remove any existing attribute, or else confusion reins */
+	ldb_msg_remove_attr(msg, attrName);
+	ret = ldb_msg_add_empty(msg, attrName, 0, &allowedClasses);
+	if (ret != LDB_SUCCESS) {
+		return ret;
+	}
+	
+	/* To ensure that oc_el is valid, we must look for it after 
+	   we alter the element array in ldb_msg_add_empty() */
+	oc_el = ldb_msg_find_element(msg, "objectClass");
+
+	for (i=0; oc_el && i < oc_el->num_values; i++) {
+		sclass = dsdb_class_by_lDAPDisplayName(schema, (const char *)oc_el->values[i].data);
+		if (!sclass) {
+			/* We don't know this class?  what is going on? */
+			continue;
+		}
+
+		for (j=0; sclass->possibleInferiors && sclass->possibleInferiors[j]; j++) {
+			ldb_msg_add_string(msg, attrName, sclass->possibleInferiors[j]);
+		}
+	}
+		
+	if (allowedClasses->num_values > 1) {
+		qsort(allowedClasses->values, 
+		      allowedClasses->num_values, 
+		      sizeof(*allowedClasses->values),
+		      (comparison_fn_t)data_blob_cmp);
+	
+		for (i=1 ; i < allowedClasses->num_values; i++) {
+
+			struct ldb_val *val1 = &allowedClasses->values[i-1];
+			struct ldb_val *val2 = &allowedClasses->values[i];
+			if (data_blob_cmp(val1, val2) == 0) {
+				memmove(val1, val2, (allowedClasses->num_values - i) * sizeof( struct ldb_val)); 
+				allowedClasses->num_values--;
+				i--;
+			}
+		}
+	}
+
+	return LDB_SUCCESS;
+
+}
+
+/* find all attributes allowed by all these objectClasses */
+
+static int kludge_acl_callback(struct ldb_request *req, struct ldb_reply *ares)
+{
+	struct ldb_context *ldb;
+	struct kludge_acl_context *ac;
+	struct kludge_private_data *data;
+	int i, ret;
+
+	ac = talloc_get_type(req->context, struct kludge_acl_context);
+	data = talloc_get_type(ldb_module_get_private(ac->module), struct kludge_private_data);
+	ldb = ldb_module_get_ctx(ac->module);
+
+	if (!ares) {
+		return ldb_module_done(ac->req, NULL, NULL,
+					LDB_ERR_OPERATIONS_ERROR);
+	}
+	if (ares->error != LDB_SUCCESS) {
+		return ldb_module_done(ac->req, ares->controls,
+					ares->response, ares->error);
+	}
+
+	switch (ares->type) {
+	case LDB_REPLY_ENTRY:
+		if (ac->allowedAttributes) {
+			ret = kludge_acl_allowedAttributes(ldb,
+						   ares->message,
+						   "allowedAttributes");
+			if (ret != LDB_SUCCESS) {
+				return ldb_module_done(ac->req, NULL, NULL, ret);
+			}
+		}
+		if (ac->allowedChildClasses) {
+			ret = kludge_acl_childClasses(ldb,
+						ares->message,
+						"allowedChildClasses");
+			if (ret != LDB_SUCCESS) {
+				return ldb_module_done(ac->req, NULL, NULL, ret);
+			}
+		}
+
+		if (data && data->password_attrs) /* if we are not initialized just get through */
+		{
+			switch (ac->user_type) {
+			case SECURITY_SYSTEM:
+				if (ac->allowedAttributesEffective) {
+					ret = kludge_acl_allowedAttributes(ldb, ares->message,
+									"allowedAttributesEffective");
+					if (ret != LDB_SUCCESS) {
+						return ldb_module_done(ac->req, NULL, NULL, ret);
+					}
+				}
+				if (ac->allowedChildClassesEffective) {
+					ret = kludge_acl_childClasses(ldb, ares->message,
+									"allowedChildClassesEffective");
+					if (ret != LDB_SUCCESS) {
+						return ldb_module_done(ac->req, NULL, NULL, ret);
+					}
+				}
+				break;
+
+			case SECURITY_ADMINISTRATOR:
+				if (ac->allowedAttributesEffective) {
+					ret = kludge_acl_allowedAttributes(ldb, ares->message,
+									"allowedAttributesEffective");
+					if (ret != LDB_SUCCESS) {
+						return ldb_module_done(ac->req, NULL, NULL, ret);
+					}
+				}
+				if (ac->allowedChildClassesEffective) {
+					ret = kludge_acl_childClasses(ldb, ares->message,
+									"allowedChildClassesEffective");
+					if (ret != LDB_SUCCESS) {
+						return ldb_module_done(ac->req, NULL, NULL, ret);
+					}
+				}
+				/* fall through */
+			default:
+				/* remove password attributes */
+				for (i = 0; data->password_attrs[i]; i++) {
+					ldb_msg_remove_attr(ares->message, data->password_attrs[i]);
+				}
+			}
+		}
+
+		if (ac->allowedAttributes ||
+		    ac->allowedAttributesEffective ||
+		    ac->allowedChildClasses ||
+		    ac->allowedChildClassesEffective) {
+
+			if (!ldb_attr_in_list(ac->attrs, "objectClass") &&
+		            !ldb_attr_in_list(ac->attrs, "*")) {
+
+				ldb_msg_remove_attr(ares->message,
+						    "objectClass");
+			}
+		}
+
+		return ldb_module_send_entry(ac->req, ares->message, ares->controls);
+
+	case LDB_REPLY_REFERRAL:
+		return ldb_module_send_referral(ac->req, ares->referral);
+
+	case LDB_REPLY_DONE:
+		return ldb_module_done(ac->req, ares->controls,
+					ares->response, LDB_SUCCESS);
+
+	}
+	return LDB_SUCCESS;
+}
+
+static int kludge_acl_search(struct ldb_module *module, struct ldb_request *req)
+{
+	struct ldb_context *ldb;
+	struct kludge_acl_context *ac;
+	struct ldb_request *down_req;
+	struct kludge_private_data *data;
+	const char * const *attrs;
+	int ret, i;
+	struct ldb_control *sd_control;
+	struct ldb_control **sd_saved_controls;
+
+	ldb = ldb_module_get_ctx(module);
+
+	ac = talloc(req, struct kludge_acl_context);
+	if (ac == NULL) {
+		ldb_oom(ldb);
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	data = talloc_get_type(ldb_module_get_private(module), struct kludge_private_data);
+
+	ac->module = module;
+	ac->req = req;
+	ac->user_type = what_is_user(module);
+	ac->attrs = req->op.search.attrs;
+
+	ac->allowedAttributes = ldb_attr_in_list(req->op.search.attrs, "allowedAttributes");
+
+	ac->allowedAttributesEffective = ldb_attr_in_list(req->op.search.attrs, "allowedAttributesEffective");
+
+	ac->allowedChildClasses = ldb_attr_in_list(req->op.search.attrs, "allowedChildClasses");
+
+	ac->allowedChildClassesEffective = ldb_attr_in_list(req->op.search.attrs, "allowedChildClassesEffective");
+
+	if (ac->allowedAttributes || ac->allowedAttributesEffective || ac->allowedChildClasses || ac->allowedChildClassesEffective) {
+		attrs = ldb_attr_list_copy_add(ac, req->op.search.attrs, "objectClass");
+	} else {
+		attrs = req->op.search.attrs;
+	}
+
+	/* replace any attributes in the parse tree that are private,
+	   so we don't allow a search for 'userPassword=penguin',
+	   just as we would not allow that attribute to be returned */
+	switch (ac->user_type) {
+	case SECURITY_SYSTEM:
+		break;
+	default:
+	/* FIXME: We should copy the tree and keep the original unmodified. */
+		/* remove password attributes */
+
+		if (!data || !data->password_attrs) {
+			break;
+		}
+		for (i = 0; data->password_attrs[i]; i++) {
+			ldb_parse_tree_attr_replace(req->op.search.tree,
+						    data->password_attrs[i],
+						    "kludgeACLredactedattribute");
+		}
+	}
+
+	ret = ldb_build_search_req_ex(&down_req,
+					ldb, ac,
+					req->op.search.base,
+					req->op.search.scope,
+					req->op.search.tree,
+					attrs,
+					req->controls,
+					ac, kludge_acl_callback,
+					req);
+	if (ret != LDB_SUCCESS) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	/* check if there's an SD_FLAGS control */
+	sd_control = ldb_request_get_control(down_req, LDB_CONTROL_SD_FLAGS_OID);
+	if (sd_control) {
+		/* save it locally and remove it from the list */
+		/* we do not need to replace them later as we
+		 * are keeping the original req intact */
+		if (!save_controls(sd_control, down_req, &sd_saved_controls)) {
+			return LDB_ERR_OPERATIONS_ERROR;
+		}
+	}
+
+	/* perform the search */
+	return ldb_next_request(module, down_req);
+}
+
+/* ANY change type */
+static int kludge_acl_change(struct ldb_module *module, struct ldb_request *req)
+{
+	struct ldb_context *ldb = ldb_module_get_ctx(module);
+	enum security_user_level user_type = what_is_user(module);
+	switch (user_type) {
+	case SECURITY_SYSTEM:
+	case SECURITY_ADMINISTRATOR:
+		return ldb_next_request(module, req);
+	default:
+		ldb_asprintf_errstring(ldb,
+				       "kludge_acl_change: "
+				       "attempted database modify not permitted. "
+				       "User %s is not SYSTEM or an administrator",
+				       user_name(req, module));
+		return LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS;
+	}
+}
+
+static int kludge_acl_extended(struct ldb_module *module, struct ldb_request *req)
+{
+	struct ldb_context *ldb = ldb_module_get_ctx(module);
+	enum security_user_level user_type;
+
+	/* allow everybody to read the sequence number */
+	if (strcmp(req->op.extended.oid,
+		   LDB_EXTENDED_SEQUENCE_NUMBER) == 0) {
+		return ldb_next_request(module, req);
+	}
+
+	user_type = what_is_user(module);
+
+	switch (user_type) {
+	case SECURITY_SYSTEM:
+	case SECURITY_ADMINISTRATOR:
+		return ldb_next_request(module, req);
+	default:
+		ldb_asprintf_errstring(ldb,
+				       "kludge_acl_change: "
+				       "attempted database modify not permitted. "
+				       "User %s is not SYSTEM or an administrator",
+				       user_name(req, module));
+		return LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS;
+	}
+}
+
+static int kludge_acl_init(struct ldb_module *module)
+{
+	struct ldb_context *ldb;
+	int ret, i;
+	TALLOC_CTX *mem_ctx = talloc_new(module);
+	static const char *attrs[] = { "passwordAttribute", NULL };
+	struct ldb_result *res;
+	struct ldb_message *msg;
+	struct ldb_message_element *password_attributes;
+
+	struct kludge_private_data *data;
+
+	ldb = ldb_module_get_ctx(module);
+
+	data = talloc(module, struct kludge_private_data);
+	if (data == NULL) {
+		ldb_oom(ldb);
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	data->password_attrs = NULL;
+	ldb_module_set_private(module, data);
+
+	if (!mem_ctx) {
+		ldb_oom(ldb);
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	ret = ldb_search(ldb, mem_ctx, &res,
+			 ldb_dn_new(mem_ctx, ldb, "@KLUDGEACL"),
+			 LDB_SCOPE_BASE, attrs, NULL);
+	if (ret != LDB_SUCCESS) {
+		goto done;
+	}
+	if (res->count == 0) {
+		goto done;
+	}
+
+	if (res->count > 1) {
+		talloc_free(mem_ctx);
+		return LDB_ERR_CONSTRAINT_VIOLATION;
+	}
+
+	msg = res->msgs[0];
+
+	password_attributes = ldb_msg_find_element(msg, "passwordAttribute");
+	if (!password_attributes) {
+		goto done;
+	}
+	data->password_attrs = talloc_array(data, const char *, password_attributes->num_values + 1);
+	if (!data->password_attrs) {
+		talloc_free(mem_ctx);
+		ldb_oom(ldb);
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+	for (i=0; i < password_attributes->num_values; i++) {
+		data->password_attrs[i] = (const char *)password_attributes->values[i].data;	
+		talloc_steal(data->password_attrs, password_attributes->values[i].data);
+	}
+	data->password_attrs[i] = NULL;
+
+	ret = ldb_mod_register_control(module, LDB_CONTROL_SD_FLAGS_OID);
+	if (ret != LDB_SUCCESS) {
+		ldb_debug(ldb, LDB_DEBUG_ERROR,
+			"partition: Unable to register control with rootdse!\n");
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+done:
+	talloc_free(mem_ctx);
+	return ldb_next_init(module);
+}
+
+_PUBLIC_ const struct ldb_module_ops ldb_kludge_acl_module_ops = {
+	.name		   = "kludge_acl",
+	.search            = kludge_acl_search,
+	.add               = kludge_acl_change,
+	.modify            = kludge_acl_change,
+	.del               = kludge_acl_change,
+	.rename            = kludge_acl_change,
+	.extended          = kludge_acl_extended,
+	.init_context	   = kludge_acl_init
+};