[continued from previous message]

- private_data->sd_cached_blob = sd_element->values[0];
- talloc_steal(private_data, sd_element->values[0].data);
- } else {
- private_data->sd_cached_blob = ldb_val_dup(private_data,
- &sd_element->values[0]);
- if (private_data->sd_cached_blob.data == NULL) {
- TALLOC_FREE(*sd);
- return ldb_operr(ldb);
- }
+ private_data->sd_cached_blob = ldb_val_dup(private_data,
+ &sd_element->values[0]);
+ if (private_data->sd_cached_blob.data == NULL) {
+ TALLOC_FREE(*sd);
+ return ldb_operr(ldb);
}

talloc_unlink(private_data, private_data->sd_cached);
@@ -327,6 +510,23 @@
return LDB_SUCCESS;
}

+/* Check whether the attribute is a password attribute. */
+static bool attr_is_secret(const char *attr, const struct aclread_private *private_data)
+{
+ const char **found = NULL;
+
+ if (private_data->password_attrs == NULL) {
+ return false;
+ }
+
+ BINARY_ARRAY_SEARCH_V(private_data->password_attrs,
+ private_data->num_password_attrs,
+ attr,
+ ldb_attr_cmp,
+ found);
+ return found != NULL;
+}
+
/*
* Returns the access mask required to read a given attribute
*/
@@ -362,61 +562,59 @@
return access_mask;
}

-/* helper struct for traversing the attributes in the search-tree */
-struct parse_tree_aclread_ctx {
- struct aclread_context *ac;
- TALLOC_CTX *mem_ctx;
- struct dom_sid *sid;
- struct ldb_dn *dn;
- struct security_descriptor *sd;
- const struct dsdb_class *objectclass;
- bool suppress_result;
-};
-
/*
- * Checks that the user has sufficient access rights to view an attribute
+ * Checks that the user has sufficient access rights to view an attribute, else
+ * marks it as inaccessible.
*/
-static int check_attr_access_rights(TALLOC_CTX *mem_ctx, const char *attr_name,
- struct aclread_context *ac,
- struct security_descriptor *sd,
- const struct dsdb_class *objectclass,
- struct dom_sid *sid, struct ldb_dn *dn) +static int acl_redact_attr(TALLOC_CTX *mem_ctx,
+ struct ldb_message_element *el,
+ struct aclread_context *ac,
+ const struct aclread_private *private_data,
+ const struct ldb_message *msg,
+ const struct dsdb_schema *schema,
+ const struct security_descriptor *sd,
+ const struct dom_sid *sid,
+ const struct dsdb_class *objectclass)
{
int ret;
const struct dsdb_attribute *attr = NULL;
uint32_t access_mask;
struct ldb_context *ldb = ldb_module_get_ctx(ac->module);

- attr = dsdb_attribute_by_lDAPDisplayName(ac->schema, attr_name);
+ if (attr_is_secret(el->name, private_data)) {
+ ldb_msg_element_mark_inaccessible(el);
+ return LDB_SUCCESS;
+ }
+
+ /* Look up the attribute in the schema. */
+ attr = dsdb_attribute_by_lDAPDisplayName(schema, el->name);
if (!attr) {
ldb_debug_set(ldb,
- LDB_DEBUG_TRACE,
- "acl_read: %s cannot find attr[%s] in schema,"
- "ignoring\n",
- ldb_dn_get_linearized(dn), attr_name);
- return LDB_SUCCESS;
+ LDB_DEBUG_FATAL,
+ "acl_read: %s cannot find attr[%s] in schema\n", + ldb_dn_get_linearized(msg->dn), el->name);
+ return LDB_ERR_OPERATIONS_ERROR;
}

access_mask = get_attr_access_mask(attr, ac->sd_flags);
-
- /* the access-mask should be non-zero. Skip attribute otherwise */
if (access_mask == 0) {
DBG_ERR("Could not determine access mask for attribute %s\n",
- attr_name);
+ el->name);
+ ldb_msg_element_mark_inaccessible(el);
return LDB_SUCCESS;
}

+ /* We must check whether the user has rights to view the attribute. */ +
ret = acl_check_access_on_attribute(ac->module, mem_ctx, sd, sid,
access_mask, attr, objectclass);

if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
- return ret;
- }
-
- if (ret != LDB_SUCCESS) {
+ ldb_msg_element_mark_inaccessible(el);
+ } else if (ret != LDB_SUCCESS) {
ldb_debug_set(ldb, LDB_DEBUG_FATAL,
"acl_read: %s check attr[%s] gives %s - %s\n",
- ldb_dn_get_linearized(dn), attr_name,
+ ldb_dn_get_linearized(msg->dn), el->name,
ldb_strerror(ret), ldb_errstring(ldb));
return ret;
}
@@ -424,152 +622,112 @@
return LDB_SUCCESS;
}

-/*
- * Returns the attribute name for this particular level of a search operation - * parse-tree.
- */
-static const char * parse_tree_get_attr(struct ldb_parse_tree *tree)
+static int setup_access_check_context(struct aclread_context *ac,
+ const struct ldb_message *msg,
+ struct access_check_context *ctx)
{
- const char *attr = NULL;
-
- switch (tree->operation) {
- case LDB_OP_EQUALITY:
- case LDB_OP_GREATER:
- case LDB_OP_LESS:
- case LDB_OP_APPROX:
- attr = tree->u.equality.attr;
- break;
- case LDB_OP_SUBSTRING:
- attr = tree->u.substring.attr;
- break;
- case LDB_OP_PRESENT:
- attr = tree->u.present.attr;
- break;
- case LDB_OP_EXTENDED:
- attr = tree->u.extended.attr;
- break;
-
- /* we'll check LDB_OP_AND/_OR/_NOT children later on in the walk */
- default:
- break;
- }
- return attr;
-}
-
-/*
- * Checks a single attribute in the search parse-tree to make sure the user has
- * sufficient rights to view it.
- */
-static int parse_tree_check_attr_access(struct ldb_parse_tree *tree,
- void *private_context)
-{
- struct parse_tree_aclread_ctx *ctx = NULL;
- const char *attr_name = NULL;
int ret;
- static const char * const attrs_always_present[] = {
- "objectClass",
- "distinguishedName",
- "name",
- "objectGUID",
- NULL
- };
-
- ctx = (struct parse_tree_aclread_ctx *)private_context;

/*
- * we can skip any further checking if we already know that this object - * shouldn't be visible in this user's search
+ * Fetch the schema so we can check which attributes are
+ * considered confidential.
*/
- if (ctx->suppress_result) {
- return LDB_SUCCESS;
- }
+ if (ac->schema == NULL) {
+ struct ldb_context *ldb = ldb_module_get_ctx(ac->module);

- /* skip this level of the search-tree if it has no attribute to check */
- attr_name = parse_tree_get_attr(tree);
- if (attr_name == NULL) {
- return LDB_SUCCESS;
+ /* Cache the schema for later use. */
+ ac->schema = dsdb_get_schema(ldb, ac);
+
+ if (ac->schema == NULL) {
+ return ldb_error(ldb, LDB_ERR_OPERATIONS_ERROR,
+ "aclread_callback: Error obtaining schema.");
+ }
}

+ /* Fetch the object's security descriptor. */
+ ret = aclread_get_sd_from_ldb_message(ac, msg, &ctx->sd);
+ if (ret != LDB_SUCCESS) {
+ ldb_debug_set(ldb_module_get_ctx(ac->module), LDB_DEBUG_FATAL, + "acl_read: cannot get descriptor of %s: %s\n",
+ ldb_dn_get_linearized(msg->dn), ldb_strerror(ret));
+ return LDB_ERR_OPERATIONS_ERROR;
+ } else if (ctx->sd == NULL) {
+ ldb_debug_set(ldb_module_get_ctx(ac->module), LDB_DEBUG_FATAL, + "acl_read: cannot get descriptor of %s (attribute not found)\n",
+ ldb_dn_get_linearized(msg->dn));
+ return LDB_ERR_OPERATIONS_ERROR;
+ }
/*
- * If the search filter is checking for an attribute's presence, and the
- * attribute is always present, we can skip access rights checks. Every - * object has these attributes, and so there's no security reason to
- * hide their presence.
- * Note: the acl.py tests (e.g. test_search1()) rely on this exception. - * I.e. even if we lack Read Property (RP) rights for a child object, it
- * should still appear as a visible object in 'objectClass=*' searches, - * so long as we have List Contents (LC) rights for the object.
+ * Get the most specific structural object class for the ACL check
*/
- if (tree->operation == LDB_OP_PRESENT &&
- is_attr_in_list(attrs_always_present, attr_name)) {
- return LDB_SUCCESS;
+ ctx->objectclass = dsdb_get_structural_oc_from_msg(ac->schema, msg);
+ if (ctx->objectclass == NULL) {
+ ldb_asprintf_errstring(ldb_module_get_ctx(ac->module),
+ "acl_read: Failed to find a structural class for %s",
+ ldb_dn_get_linearized(msg->dn));
+ return LDB_ERR_OPERATIONS_ERROR;
}

- ret = check_attr_access_rights(ctx->mem_ctx, attr_name, ctx->ac,
- ctx->sd, ctx->objectclass, ctx->sid,
- ctx->dn);
-
- /*
- * if the user does not have the rights to view this attribute, then we - * should not return the object as a search result, i.e. act as if the - * object doesn't exist (for this particular user, at least)
- */
- if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
- ctx->suppress_result = true;
- return LDB_SUCCESS;
+ /* Fetch the object's SID. */
+ ret = samdb_result_dom_sid_buf(msg, "objectSid", &ctx->sid_buf);
+ if (ret == LDB_SUCCESS) {
+ ctx->sid = &ctx->sid_buf;
+ } else if (ret == LDB_ERR_NO_SUCH_ATTRIBUTE) {
+ /* This is expected. */
+ ctx->sid = NULL;
+ } else {
+ ldb_asprintf_errstring(ldb_module_get_ctx(ac->module),
+ "acl_read: Failed to parse objectSid as dom_sid for %s",
+ ldb_dn_get_linearized(msg->dn));
+ return ret;
}

- return ret;
+ return LDB_SUCCESS;
}

/*
- * Traverse the search-tree to check that the user has sufficient access rights
- * to view all the attributes.
+ * Whether this attribute was added to perform access checks and must be
+ * removed.
*/
-static int check_search_ops_access(struct aclread_context *ac,
- TALLOC_CTX *mem_ctx,
- struct security_descriptor *sd,
- const struct dsdb_class *objectclass,
- struct dom_sid *sid, struct ldb_dn *dn,
- bool *suppress_result)
+static bool should_remove_attr(const char *attr, const struct aclread_context *ac)
{
- int ret;
- struct parse_tree_aclread_ctx ctx = { 0 };
- struct ldb_parse_tree *tree = ac->req->op.search.tree;
+ if (ac->added_nTSecurityDescriptor &&
+ ldb_attr_cmp("nTSecurityDescriptor", attr) == 0)
+ {
+ return true;
+ }
+
+ if (ac->added_objectSid &&
+ ldb_attr_cmp("objectSid", attr) == 0)
+ {
+ return true;
+ }

- ctx.ac = ac;
- ctx.mem_ctx = mem_ctx;
- ctx.suppress_result = false;
- ctx.sid = sid;
- ctx.dn = dn;
- ctx.sd = sd;
- ctx.objectclass = objectclass;
+ if (ac->added_instanceType &&
+ ldb_attr_cmp("instanceType", attr) == 0)
+ {
+ return true;
+ }

- /* walk the search tree, checking each attribute as we go */
- ret = ldb_parse_tree_walk(tree, parse_tree_check_attr_access, &ctx);
+ if (ac->added_objectClass &&
+ ldb_attr_cmp("objectClass", attr) == 0)
+ {
+ return true;
+ }

- /* return whether this search result should be hidden to this user */
- *suppress_result = ctx.suppress_result;
- return ret;
+ return false;
}

static int aclread_callback(struct ldb_request *req, struct ldb_reply *ares)
{
- struct ldb_context *ldb;
struct aclread_context *ac;
- struct ldb_message *ret_msg;
+ struct aclread_private *private_data = NULL;
struct ldb_message *msg;
int ret;
- size_t num_of_attrs = 0;
- unsigned int i, k = 0;
- struct security_descriptor *sd = NULL;
- struct dom_sid *sid = NULL;
- TALLOC_CTX *tmp_ctx;
- const struct dsdb_class *objectclass;
- bool suppress_result = false;
+ unsigned int i;
+ struct access_check_context acl_ctx;

- ac = talloc_get_type(req->context, struct aclread_context);
- ldb = ldb_module_get_ctx(ac->module);
+ ac = talloc_get_type_abort(req->context, struct aclread_context);
if (!ares) {
return ldb_module_done(ac->req, NULL, NULL, LDB_ERR_OPERATIONS_ERROR );
}
@@ -577,36 +735,10 @@
return ldb_module_done(ac->req, ares->controls,
ares->response, ares->error);
}
- tmp_ctx = talloc_new(ac);
switch (ares->type) {
case LDB_REPLY_ENTRY:
msg = ares->message;
- ret = aclread_get_sd_from_ldb_message(ac, msg, &sd);
- if (ret != LDB_SUCCESS) {
- ldb_debug_set(ldb, LDB_DEBUG_FATAL,
- "acl_read: cannot get descriptor of %s: %s\n",
- ldb_dn_get_linearized(msg->dn), ldb_strerror(ret));
- ret = LDB_ERR_OPERATIONS_ERROR;
- goto fail;
- } else if (sd == NULL) {
- ldb_debug_set(ldb, LDB_DEBUG_FATAL,
- "acl_read: cannot get descriptor of %s (attribute not found)\n",
- ldb_dn_get_linearized(msg->dn));
- ret = LDB_ERR_OPERATIONS_ERROR;
- goto fail;
- }
- /*
- * Get the most specific structural object class for the ACL check
- */
- objectclass = dsdb_get_structural_oc_from_msg(ac->schema, msg); - if (objectclass == NULL) {
- ldb_asprintf_errstring(ldb, "acl_read: Failed to find a structural class for %s",
- ldb_dn_get_linearized(msg->dn)); - ret = LDB_ERR_OPERATIONS_ERROR;
- goto fail;
- }

- sid = samdb_result_dom_sid(tmp_ctx, msg, "objectSid");
if (!ldb_dn_is_null(msg->dn)) {
/*
* this is a real object, so we have
@@ -614,187 +746,90 @@
*/
ret = aclread_check_object_visible(ac, msg, req);
if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
- talloc_free(tmp_ctx);
return LDB_SUCCESS;
} else if (ret != LDB_SUCCESS) {
+ struct ldb_context *ldb = ldb_module_get_ctx(ac->module);
ldb_debug_set(ldb, LDB_DEBUG_FATAL,
"acl_read: %s check parent %s - %s\n",
ldb_dn_get_linearized(msg->dn),
ldb_strerror(ret),
ldb_errstring(ldb));
- goto fail;
+ return ldb_module_done(ac->req, NULL, NULL, ret);
}
}

/* for every element in the message check RP */
- for (i=0; i < msg->num_elements; i++) {
- const struct dsdb_attribute *attr;
- bool is_sd, is_objectsid, is_instancetype, is_objectclass;
- uint32_t access_mask;
- attr = dsdb_attribute_by_lDAPDisplayName(ac->schema,
- msg->elements[i].name);
- if (!attr) {
- ldb_debug_set(ldb, LDB_DEBUG_FATAL,
- "acl_read: %s cannot find attr[%s] in of schema\n",
- ldb_dn_get_linearized(msg->dn),
- msg->elements[i].name);
- ret = LDB_ERR_OPERATIONS_ERROR;
- goto fail;
- }
- is_sd = ldb_attr_cmp("nTSecurityDescriptor",
- msg->elements[i].name) == 0;
- is_objectsid = ldb_attr_cmp("objectSid",
- msg->elements[i].name) == 0;
- is_instancetype = ldb_attr_cmp("instanceType",
- msg->elements[i].name) == 0;
- is_objectclass = ldb_attr_cmp("objectClass",
- msg->elements[i].name) == 0;
- /* these attributes were added to perform access checks and must be removed */
- if (is_objectsid && ac->added_objectSid) {
- aclread_mark_inaccesslible(&msg->elements[i]); - continue;
- }
- if (is_instancetype && ac->added_instanceType) {
- aclread_mark_inaccesslible(&msg->elements[i]); - continue;
- }
- if (is_objectclass && ac->added_objectClass) {
- aclread_mark_inaccesslible(&msg->elements[i]); - continue;
- }
- if (is_sd && ac->added_nTSecurityDescriptor) {
- aclread_mark_inaccesslible(&msg->elements[i]); + for (i = 0; i < msg->num_elements; ++i) {
+ struct ldb_message_element *el = &msg->elements[i];
+
+ /* Remove attributes added to perform access checks. */ + if (should_remove_attr(el->name, ac)) {
+ ldb_msg_element_mark_inaccessible(el);
continue;
}

- access_mask = get_attr_access_mask(attr, ac->sd_flags); -
- if (access_mask == 0) {
- aclread_mark_inaccesslible(&msg->elements[i]); + if (acl_element_is_access_checked(el)) {
+ /* We will have already checked this attribute. */
continue;
}

- ret = acl_check_access_on_attribute(ac->module,
- tmp_ctx,
- sd,
- sid,
- access_mask,
- attr,
- objectclass);
-
/*
- * Dirsync control needs the replpropertymetadata attribute
- * so return it as it will be removed by the control
- * in anycase.
+ * We need to fetch the security descriptor to check
+ * this attribute.
*/
- if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
- bool in_search_filter;
+ break;
+ }

- /* check if attr is part of the search filter */
- in_search_filter = dsdb_attr_in_parse_tree(ac->req->op.search.tree,
- msg->elements[i].name);
-
- if (in_search_filter) {
-
- /*
- * We are doing dirysnc answers
- * and the object shouldn't be returned (normally)
- * but we will return it without replPropertyMetaData
- * so that the dirysync module will do what is needed
- * (remove the object if it is not deleted, or return
- * just the objectGUID if it's deleted).
- */
- if (ac->indirsync) {
- ldb_msg_remove_attr(msg, "replPropertyMetaData");
- break;
- } else {
-
- /* do not return this entry */ - talloc_free(tmp_ctx);
- return LDB_SUCCESS;
- }
- } else {
- aclread_mark_inaccesslible(&msg->elements[i]);
- }
- } else if (ret != LDB_SUCCESS) {
- ldb_debug_set(ldb, LDB_DEBUG_FATAL,
- "acl_read: %s check attr[%s] gives %s - %s\n",
- ldb_dn_get_linearized(msg->dn),
- msg->elements[i].name,
- ldb_strerror(ret),
- ldb_errstring(ldb));
- goto fail;
- }
+ if (i == msg->num_elements) {
+ /* All elements have been checked. */
+ goto reply_entry_done;
}

- /*
- * check access rights for the search attributes, as well as the
- * attribute values actually being returned
- */
- ret = check_search_ops_access(ac, tmp_ctx, sd, objectclass, sid,
- msg->dn, &suppress_result);
+ ret = setup_access_check_context(ac, msg, &acl_ctx);
if (ret != LDB_SUCCESS) {
- ldb_debug_set(ldb, LDB_DEBUG_FATAL,
- "acl_read: %s check search ops %s - %s\n",
- ldb_dn_get_linearized(msg->dn),
- ldb_strerror(ret), ldb_errstring(ldb));
- goto fail;
+ return ret;
}

- if (suppress_result) {
+ private_data = talloc_get_type_abort(ldb_module_get_private(ac->module),
+ struct aclread_private);

- /*
- * As per the above logic, we strip replPropertyMetaData
- * out of the msg so that the dirysync module will do
- * what is needed (return just the objectGUID if it's, - * deleted, or remove the object if it is not).
- */
- if (ac->indirsync) {
- ldb_msg_remove_attr(msg, "replPropertyMetaData");
- } else {
- talloc_free(tmp_ctx);
- return LDB_SUCCESS;
- }
- }
+ for (/* begin where we left off */; i < msg->num_elements; ++i) {
+ struct ldb_message_element *el = &msg->elements[i];

- for (i=0; i < msg->num_elements; i++) {
- if (!aclread_is_inaccessible(&msg->elements[i])) {
- num_of_attrs++;
- }
- }
- /*create a new message to return*/
- ret_msg = ldb_msg_new(ac->req);
- ret_msg->dn = msg->dn;
- talloc_steal(ret_msg, msg->dn);
- ret_msg->num_elements = num_of_attrs;
- if (num_of_attrs > 0) {
- ret_msg->elements = talloc_array(ret_msg,
- struct ldb_message_element,
- num_of_attrs);
- if (ret_msg->elements == NULL) {
- return ldb_oom(ldb);
+ /* Remove attributes added to perform access checks. */ + if (should_remove_attr(el->name, ac)) {
+ ldb_msg_element_mark_inaccessible(el);
+ continue;
}
- for (i=0; i < msg->num_elements; i++) {
- bool to_remove = aclread_is_inaccessible(&msg->elements[i]);
- if (!to_remove) {
- ret_msg->elements[k] = msg->elements[i];
- talloc_steal(ret_msg->elements, msg->elements[i].name);
- talloc_steal(ret_msg->elements, msg->elements[i].values);
- k++;
- }
+
+ if (acl_element_is_access_checked(el)) {
+ /* We will have already checked this attribute. */
+ continue;
}
+
/*
- * This should not be needed, but some modules
- * may allocate values on the wrong context...
+ * We need to check whether the attribute is secret,
+ * confidential, or access-controlled.
*/
- talloc_steal(ret_msg->elements, msg);
- } else {
- ret_msg->elements = NULL;
+ ret = acl_redact_attr(ac,
+ el,
+ ac,
+ private_data,
+ msg,
+ ac->schema,
+ acl_ctx.sd,
+ acl_ctx.sid,
+ acl_ctx.objectclass);
+ if (ret != LDB_SUCCESS) {
+ return ldb_module_done(ac->req, NULL, NULL, ret);
+ }
}
- talloc_free(tmp_ctx);
+
+ reply_entry_done:
+ ldb_msg_remove_inaccessible(msg);

ac->num_entries++;
- return ldb_module_send_entry(ac->req, ret_msg, ares->controls); + return ldb_module_send_entry(ac->req, msg, ares->controls);
case LDB_REPLY_REFERRAL:
return ldb_module_send_referral(ac->req, ares->referral);
case LDB_REPLY_DONE:
@@ -813,9 +848,6 @@

}
return LDB_SUCCESS;
-fail:
- talloc_free(tmp_ctx);
- return ldb_module_done(ac->req, NULL, NULL, ret);
}


@@ -825,8 +857,7 @@
int ret;
struct aclread_context *ac;
struct ldb_request *down_req;
- struct ldb_control *as_system = ldb_request_get_control(req, LDB_CONTROL_AS_SYSTEM_OID);
- uint32_t flags = ldb_req_get_custom_flags(req);
+ bool am_system;
struct ldb_result *res;
struct aclread_private *p;
bool need_sd = false;
@@ -843,11 +874,16 @@
ldb = ldb_module_get_ctx(module);
p = talloc_get_type(ldb_module_get_private(module), struct aclread_private);

+ am_system = ldb_request_get_control(req, LDB_CONTROL_AS_SYSTEM_OID) != NULL;
+ if (!am_system) {
+ am_system = dsdb_module_am_system(module);
+ }
+
/* skip access checks if we are system or system control is supplied
* or this is not LDAP server request */
if (!p || !p->enabled ||
- dsdb_module_am_system(module)
- || as_system || !is_untrusted) {
+ am_system ||
+ !is_untrusted) {
return ldb_next_request(module, req);
}
/* no checks on special dn */
@@ -861,15 +897,6 @@
}
ac->module = module;
ac->req = req;
- ac->schema = dsdb_get_schema(ldb, req);
- if (flags & DSDB_ACL_CHECKS_DIRSYNC_FLAG) {
- ac->indirsync = true;
- } else {
- ac->indirsync = false;
- }
- if (!ac->schema) {
- return ldb_operr(ldb);
- }

attrs = req->op.search.attrs;
if (attrs == NULL) {
@@ -926,7 +953,7 @@
ac->added_nTSecurityDescriptor = true;
}

- ac->attrs = req->op.search.attrs;
+ ac->am_administrator = dsdb_module_am_administrator(module);

/* check accessibility of base */
if (!ldb_dn_is_null(req->op.search.base)) {
@@ -970,19 +997,287 @@
return LDB_ERR_OPERATIONS_ERROR;
}

+ /*
+ * We provide 'ac' as the control value, which is then used by the
+ * callback to avoid double-work.
+ */
+ ret = ldb_request_add_control(down_req, DSDB_CONTROL_ACL_READ_OID, false, ac);
+ if (ret != LDB_SUCCESS) {
+ return ldb_error(ldb, ret,
+ "acl_read: Error adding acl_read control.");
+ }
+
return ldb_next_request(module, down_req);
}

+/*
+ * Here we mark inaccessible attributes known to be looked for in the
+ * filter. This only redacts attributes found in the search expression. If any + * extended attribute match rules examine different attributes without their own
+ * access control checks, a security bypass is possible.
+ */
+static int acl_redact_msg_for_filter(struct ldb_module *module, struct ldb_request *req, struct ldb_message *msg)
+{
+ struct ldb_context *ldb = ldb_module_get_ctx(module);
+ const struct aclread_private *private_data = NULL;
+ struct ldb_control *control = NULL;
+ struct aclread_context *ac = NULL;
+ struct access_check_context acl_ctx;
+ int ret;
+ unsigned i;
+
+ /*
+ * The private data contains a list of attributes which are to be
+ * considered secret.
+ */
+ private_data = talloc_get_type(ldb_module_get_private(module), struct aclread_private);
+ if (private_data == NULL) {
+ return ldb_error(ldb, LDB_ERR_OPERATIONS_ERROR,
+ "aclread_private data is missing");
+ }
+ if (!private_data->enabled) {
+ return LDB_SUCCESS;
+ }
+
+ control = ldb_request_get_control(req, DSDB_CONTROL_ACL_READ_OID);
+ if (control == NULL) {
+ /*
+ * We've bypassed the acl_read module for this request, and
+ * should skip redaction in this case.
+ */
+ return LDB_SUCCESS;
+ }
+
+ ac = talloc_get_type_abort(control->data, struct aclread_context);
+
+ if (!ac->got_tree_attrs) {
+ ret = ldb_parse_tree_collect_acl_attrs(module, ac, &ac->tree_attrs, req->op.search.tree);
+ if (ret != LDB_SUCCESS) {
+ return ret;
+ }
+ ac->got_tree_attrs = true;
+ }
+
+ for (i = 0; i < msg->num_elements; ++i) {
+ struct ldb_message_element *el = &msg->elements[i];
+
+ /* Is the attribute mentioned in the search expression? */
+ if (attr_in_vec(&ac->tree_attrs, el->name)) {
+ /*
+ * We need to fetch the security descriptor to check
+ * this element.
+ */
+ break;
+ }
+
+ /*
+ * This attribute is not in the search filter, so we can leave + * handling it till aclread_callback(), by which time we know
+ * this object is a match. This saves work checking ACLs if the + * search is unindexed and most objects don't match the filter. + */
+ }
+
+ if (i == msg->num_elements) {
+ /* All elements have been checked. */
+ return LDB_SUCCESS;
+ }
+
+ ret = setup_access_check_context(ac, msg, &acl_ctx);
+ if (ret != LDB_SUCCESS) {
+ return ret;
+ }
+
+ /* For every element in the message and the parse tree, check RP. */
+
+ for (/* begin where we left off */; i < msg->num_elements; ++i) {
+ struct ldb_message_element *el = &msg->elements[i];
+
+ /* Is the attribute mentioned in the search expression? */
+ if (!attr_in_vec(&ac->tree_attrs, el->name)) {
+ /*
+ * If not, leave it for later and check the next
+ * attribute.
+ */
+ continue;
+ }
+
+ /*
+ * We need to check whether the attribute is secret,
+ * confidential, or access-controlled.
+ */
+ ret = acl_redact_attr(ac,
+ el,
+ ac,
+ private_data,
+ msg,
+ ac->schema,
+ acl_ctx.sd,
+ acl_ctx.sid,
+ acl_ctx.objectclass);
+ if (ret != LDB_SUCCESS) {
+ return ret;
+ }
+
+ acl_element_mark_access_checked(el);
+ }
+
+ return LDB_SUCCESS;
+}
+
+static int ldb_attr_cmp_fn(const void *_a, const void *_b)
+{
+ const char * const *a = _a;
+ const char * const *b = _b;
+
+ return ldb_attr_cmp(*a, *b);
+}
+
static int aclread_init(struct ldb_module *module)
{
struct ldb_context *ldb = ldb_module_get_ctx(module);
+ unsigned int i, n, j;
+ TALLOC_CTX *mem_ctx = NULL;
+ int ret;
+ bool userPassword_support;
+ static const char * const attrs[] = { "passwordAttribute", NULL };
+ static const char * const secret_attrs[] = {
+ DSDB_SECRET_ATTRIBUTES
+ };
+ struct ldb_result *res;
+ struct ldb_message *msg;
+ struct ldb_message_element *password_attributes;
struct aclread_private *p = talloc_zero(module, struct aclread_private);
if (p == NULL) {
return ldb_module_oom(module);
}
p->enabled = lpcfg_parm_bool(ldb_get_opaque(ldb, "loadparm"), NULL, "acl", "search", true);
+
+ ret = ldb_mod_register_control(module, LDB_CONTROL_SD_FLAGS_OID);
+ if (ret != LDB_SUCCESS) {
+ ldb_debug(ldb, LDB_DEBUG_ERROR,
+ "acl_module_init: Unable to register sd_flags control with rootdse!\n");
+ return ldb_operr(ldb);
+ }
+
ldb_module_set_private(module, p);
- return ldb_next_init(module);
+
+ mem_ctx = talloc_new(module);
+ if (!mem_ctx) {
+ return ldb_oom(ldb);
+ }
+
+ ret = dsdb_module_search_dn(module, mem_ctx, &res,
+ ldb_dn_new(mem_ctx, ldb, "@KLUDGEACL"),
+ attrs,
+ DSDB_FLAG_NEXT_MODULE |
+ DSDB_FLAG_AS_SYSTEM,
+ 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;
+ }
+ p->password_attrs = talloc_array(p, const char *,
+ password_attributes->num_values +
+ ARRAY_SIZE(secret_attrs));
+ if (!p->password_attrs) {
+ talloc_free(mem_ctx);
+ return ldb_oom(ldb);
+ }
+
+ n = 0;
+ for (i=0; i < password_attributes->num_values; i++) {
+ p->password_attrs[n] = (const char *)password_attributes->values[i].data;
+ talloc_steal(p->password_attrs, password_attributes->values[i].data);
+ n++;
+ }
+
+ for (i=0; i < ARRAY_SIZE(secret_attrs); i++) {
+ bool found = false;
+
+ for (j=0; j < n; j++) {
+ if (strcasecmp(p->password_attrs[j], secret_attrs[i]) == 0) {
+ found = true;
+ break;
+ }
+ }
+
+ if (found) {
+ continue;
+ }
+
+ p->password_attrs[n] = talloc_strdup(p->password_attrs,
+ secret_attrs[i]);
+ if (p->password_attrs[n] == NULL) {
+ talloc_free(mem_ctx);
+ return ldb_oom(ldb);
+ }
+ n++;
+ }
+ p->num_password_attrs = n;
+
+ /* Sort the password attributes so we can use binary search. */
+ TYPESAFE_QSORT(p->password_attrs, p->num_password_attrs, ldb_attr_cmp_fn);
+
+ ret = ldb_register_redact_callback(ldb, acl_redact_msg_for_filter, module);
+ if (ret != LDB_SUCCESS) {
+ return ret;
+ }
+
+done:
+ talloc_free(mem_ctx);
+ ret = ldb_next_init(module);
+
+ if (ret != LDB_SUCCESS) {
+ return ret;
+ }
+
+ if (p->password_attrs != NULL) {
+ /*
+ * Check this after the modules have be initialised so we can
+ * actually read the backend DB.
+ */
+ userPassword_support = dsdb_user_password_support(module,
+ module,
+ NULL);
+ if (!userPassword_support) {
+ const char **found = NULL;
+
+ /*
+ * Remove the userPassword attribute, as it is not
+ * considered secret.
+ */
+ BINARY_ARRAY_SEARCH_V(p->password_attrs,
+ p->num_password_attrs,
+ "userPassword",
+ ldb_attr_cmp,
+ found);
+ if (found != NULL) {
+ size_t found_idx = found - p->password_attrs;
+
+ /* Shift following elements backwards by one. */
+ for (i = found_idx; i < p->num_password_attrs - 1; ++i) {
+ p->password_attrs[i] = p->password_attrs[i + 1];
+ }
+ --p->num_password_attrs;
+ }
+ }
+ }
+ return ret;
}

static const struct ldb_module_ops ldb_aclread_module_ops = {
diff -Nru samba-4.17.6+dfsg/source4/dsdb/samdb/ldb_modules/acl_util.c samba-4.17.7+dfsg/source4/dsdb/samdb/ldb_modules/acl_util.c
--- samba-4.17.6+dfsg/source4/dsdb/samdb/ldb_modules/acl_util.c 2022-08-08 17:15:39.548193500 +0300
+++ samba-4.17.7+dfsg/source4/dsdb/samdb/ldb_modules/acl_util.c 2023-03-20 12:03:44.507649400 +0300
@@ -97,8 +97,8 @@

int acl_check_access_on_attribute(struct ldb_module *module,
TALLOC_CTX *mem_ctx,
- struct security_descriptor *sd,
- struct dom_sid *rp_sid,
+ const struct security_descriptor *sd,
+ const struct dom_sid *rp_sid,
uint32_t access_mask,
const struct dsdb_attribute *attr,
const struct dsdb_class *objectclass)
@@ -298,7 +298,7 @@

sd_control = ldb_request_get_control(req, LDB_CONTROL_SD_FLAGS_OID);
if (sd_control != NULL && sd_control->data != NULL) {
- struct ldb_sd_flags_control *sdctr = (struct ldb_sd_flags_control *)sd_control->data;
+ struct ldb_sd_flags_control *sdctr = talloc_get_type_abort(sd_control->data, struct ldb_sd_flags_control);

sd_flags = sdctr->secinfo_flags;

diff -Nru samba-4.17.6+dfsg/source4/dsdb