--- /dev/null
+/*
+ Unix SMB/CIFS implementation.
+
+ ldb database library - Extended match rules
+
+ Copyright (C) 2014 Samuel Cabrero <samuelcabrero@kernevil.me>
+
+ 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/>.
+*/
+
+#include "includes.h"
+#include <ldb_module.h>
+#include "dsdb/samdb/samdb.h"
+#include "ldb_matching_rules.h"
+
+static int ldb_eval_transitive_filter_helper(TALLOC_CTX *mem_ctx,
+ struct ldb_context *ldb,
+ const char *attr,
+ const struct dsdb_dn *dn_to_match,
+ const char *dn_oid,
+ struct dsdb_dn *to_visit,
+ struct dsdb_dn **visited,
+ unsigned int *visited_count,
+ bool *matched)
+{
+ TALLOC_CTX *tmp_ctx;
+ int ret, i, j;
+ struct ldb_result *res;
+ struct ldb_message *msg;
+ struct ldb_message_element *el;
+ const char *attrs[] = { attr, NULL };
+
+ tmp_ctx = talloc_new(mem_ctx);
+ if (tmp_ctx == NULL) {
+ return LDB_ERR_OPERATIONS_ERROR;
+ }
+
+ /*
+ * Fetch the entry to_visit
+ *
+ * NOTE: This is a new LDB search from the TOP of the module
+ * stack. This means that this search runs the whole stack
+ * from top to bottom.
+ *
+ * This may seem to be in-efficient, but it is also the only
+ * way to ensure that the ACLs for this search are applied
+ * correctly.
+ *
+ * Note also that we don't have the original request
+ * here, so we can not apply controls or timeouts here.
+ */
+ ret = dsdb_search_dn(ldb, tmp_ctx, &res, to_visit->dn, attrs, 0);
+ if (ret != LDB_SUCCESS) {
+ talloc_free(tmp_ctx);
+ return ret;
+ }
+ if (res->count != 1) {
+ talloc_free(tmp_ctx);
+ return LDB_ERR_OPERATIONS_ERROR;
+ }
+ msg = res->msgs[0];
+
+ /* Fetch the attribute to match from the entry being visited */
+ el = ldb_msg_find_element(msg, attr);
+ if (el == NULL) {
+ /* This entry does not have the attribute to match */
+ talloc_free(tmp_ctx);
+ *matched = false;
+ return LDB_SUCCESS;
+ }
+
+ /*
+ * If the value to match is present in the attribute values of the
+ * current entry being visited, set matched to true and return OK
+ */
+ for (i=0; i<el->num_values; i++) {
+ struct dsdb_dn *dn;
+ dn = dsdb_dn_parse(tmp_ctx, ldb, &el->values[i], dn_oid);
+ if (dn == NULL) {
+ talloc_free(tmp_ctx);
+ *matched = false;
+ return LDB_ERR_INVALID_DN_SYNTAX;
+ }
+
+ if (ldb_dn_compare(dn_to_match->dn, dn->dn) == 0) {
+ talloc_free(tmp_ctx);
+ *matched = true;
+ return LDB_SUCCESS;
+ }
+ }
+
+ /*
+ * If arrived here, the value to match is not in the values of the
+ * entry being visited. Add the entry being visited (to_visit)
+ * to the visited array. The array is (re)allocated in the parent
+ * memory context.
+ */
+ if (visited == NULL) {
+ visited = talloc_array(mem_ctx, struct dsdb_dn *, 1);
+ if (visited == NULL) {
+ talloc_free(tmp_ctx);
+ return LDB_ERR_OPERATIONS_ERROR;
+ }
+ visited[0] = to_visit;
+ (*visited_count) = 1;
+ } else {
+ visited = talloc_realloc(mem_ctx, visited, struct dsdb_dn *,
+ (*visited_count) + 1);
+ if (visited == NULL) {
+ talloc_free(tmp_ctx);
+ return LDB_ERR_OPERATIONS_ERROR;
+ }
+ visited[(*visited_count)] = to_visit;
+ (*visited_count)++;
+ }
+
+ /*
+ * steal to_visit into visited array context, as it has to live until
+ * the array is freed.
+ */
+ talloc_steal(visited, to_visit);
+
+ /*
+ * Iterate over the values of the attribute of the entry being
+ * visited (to_visit) and follow them, calling this function
+ * recursively.
+ * If the value is in the visited array, skip it.
+ * Otherwise, follow the link and visit it.
+ */
+ for (i=0; i<el->num_values; i++) {
+ struct dsdb_dn *next_to_visit;
+ bool skip = false;
+
+ next_to_visit = dsdb_dn_parse(tmp_ctx, ldb, &el->values[i], dn_oid);
+ if (next_to_visit == NULL) {
+ talloc_free(tmp_ctx);
+ *matched = false;
+ return LDB_ERR_INVALID_DN_SYNTAX;
+ }
+
+ /*
+ * If the value is already in the visited array, skip it.
+ * Note the last element of the array is ignored because it is
+ * the current entry DN.
+ */
+ for (j=0; j < (*visited_count) - 1; j++) {
+ struct dsdb_dn *visited_dn = visited[j];
+ if (ldb_dn_compare(visited_dn->dn,
+ next_to_visit->dn) == 0) {
+ skip = true;
+ break;
+ }
+ }
+ if (skip) {
+ talloc_free(next_to_visit);
+ continue;
+ }
+
+ /* If the value is not in the visited array, evaluate it */
+ ret = ldb_eval_transitive_filter_helper(tmp_ctx, ldb, attr,
+ dn_to_match, dn_oid,
+ next_to_visit,
+ visited, visited_count,
+ matched);
+ if (ret != LDB_SUCCESS) {
+ talloc_free(tmp_ctx);
+ return ret;
+ }
+ if (*matched) {
+ talloc_free(tmp_ctx);
+ return LDB_SUCCESS;
+ }
+ }
+
+ talloc_free(tmp_ctx);
+ *matched = false;
+ return LDB_SUCCESS;
+}
+
+/*
+ * This function parses the linked attribute value to match, whose syntax
+ * will be one of the different DN syntaxes, into a ldb_dn struct.
+ */
+static int ldb_eval_transitive_filter(TALLOC_CTX *mem_ctx,
+ struct ldb_context *ldb,
+ const char *attr,
+ const struct ldb_val *value_to_match,
+ struct dsdb_dn *current_object_dn,
+ bool *matched)
+{
+ const struct dsdb_schema *schema;
+ const struct dsdb_attribute *schema_attr;
+ struct dsdb_dn *dn_to_match;
+ const char *dn_oid;
+ unsigned int count;
+
+ schema = dsdb_get_schema(ldb, mem_ctx);
+ if (schema == NULL) {
+ return LDB_ERR_OPERATIONS_ERROR;
+ }
+
+ schema_attr = dsdb_attribute_by_lDAPDisplayName(schema, attr);
+ if (schema_attr == NULL) {
+ return LDB_ERR_NO_SUCH_ATTRIBUTE;
+ }
+
+ /* This is the DN syntax of the attribute being matched */
+ dn_oid = schema_attr->syntax->ldap_oid;
+
+ /*
+ * Build a ldb_dn struct holding the value to match, which is the
+ * value entered in the search filter
+ */
+ dn_to_match = dsdb_dn_parse(mem_ctx, ldb, value_to_match, dn_oid);
+ if (dn_to_match == NULL) {
+ *matched = false;
+ return LDB_ERR_INVALID_DN_SYNTAX;
+ }
+
+ return ldb_eval_transitive_filter_helper(mem_ctx, ldb, attr,
+ dn_to_match, dn_oid,
+ current_object_dn,
+ NULL, &count, matched);
+}
+
+/*
+ * This rule provides recursive search of a link attribute
+ *
+ * Documented in [MS-ADTS] section 3.1.1.3.4.4.3 LDAP_MATCHING_RULE_TRANSITIVE_EVAL
+ * This allows a search filter such as:
+ *
+ * member:1.2.840.113556.1.4.1941:=cn=user,cn=users,dc=samba,dc=example,dc=com
+ *
+ * This searches not only the member attribute, but also any member
+ * attributes that point at an object with this member in them. All the
+ * various DN syntax types are supported, not just plain DNs.
+ *
+ */
+static int ldb_comparator_trans(struct ldb_context *ldb,
+ const char *oid,
+ const struct ldb_message *msg,
+ const char *attribute_to_match,
+ const struct ldb_val *value_to_match,
+ bool *matched)
+{
+ const struct dsdb_schema *schema;
+ const struct dsdb_attribute *schema_attr;
+ struct ldb_dn *msg_dn;
+ struct dsdb_dn *dsdb_msg_dn;
+ TALLOC_CTX *tmp_ctx;
+ int ret;
+
+ tmp_ctx = talloc_new(ldb);
+ if (tmp_ctx == NULL) {
+ return LDB_ERR_OPERATIONS_ERROR;
+ }
+
+ /*
+ * If the target attribute to match is not a linked attribute, then
+ * the filter evaluates to undefined
+ */
+ schema = dsdb_get_schema(ldb, tmp_ctx);
+ if (schema == NULL) {
+ talloc_free(tmp_ctx);
+ return LDB_ERR_OPERATIONS_ERROR;
+ }
+
+ schema_attr = dsdb_attribute_by_lDAPDisplayName(schema, attribute_to_match);
+ if (schema_attr == NULL) {
+ talloc_free(tmp_ctx);
+ return LDB_ERR_NO_SUCH_ATTRIBUTE;
+ }
+
+ /*
+ * This extended match filter is only valid for linked attributes,
+ * following the MS definition (the schema attribute has a linkID
+ * defined). See dochelp request 114111212024789 on cifs-protocols
+ * mailing list.
+ */
+ if (schema_attr->linkID == 0) {
+ talloc_free(tmp_ctx);
+ return LDB_ERR_INAPPROPRIATE_MATCHING;
+ }
+
+ /* Duplicate original msg dn as the msg must not be modified */
+ msg_dn = ldb_dn_copy(tmp_ctx, msg->dn);
+ if (msg_dn == NULL) {
+ talloc_free(tmp_ctx);
+ return LDB_ERR_OPERATIONS_ERROR;
+ }
+
+ /*
+ * Build a dsdb dn from the message copied DN, which should be a plain
+ * DN syntax.
+ */
+ dsdb_msg_dn = dsdb_dn_construct(tmp_ctx, msg_dn, data_blob_null,
+ LDB_SYNTAX_DN);
+ if (dsdb_msg_dn == NULL) {
+ *matched = false;
+ return LDB_ERR_INVALID_DN_SYNTAX;
+ }
+
+ ret = ldb_eval_transitive_filter(tmp_ctx, ldb,
+ attribute_to_match,
+ value_to_match,
+ dsdb_msg_dn, matched);
+ talloc_free(tmp_ctx);
+ return ret;
+}
+
+
+int ldb_register_samba_matching_rules(struct ldb_context *ldb)
+{
+ struct ldb_extended_match_rule *transitive_eval;
+ int ret;
+
+ transitive_eval = talloc_zero(ldb, struct ldb_extended_match_rule);
+ transitive_eval->oid = SAMBA_LDAP_MATCH_RULE_TRANSITIVE_EVAL;
+ transitive_eval->callback = ldb_comparator_trans;
+ ret = ldb_register_extended_match_rule(ldb, transitive_eval);
+ if (ret != LDB_SUCCESS) {
+ talloc_free(transitive_eval);
+ return ret;
+ }
+
+ return LDB_SUCCESS;
+}
git.samba.org / obnox / samba / samba-obnox.git / commitdiff