auth: ldap: add permissions reload to unified cache

The LDAP server may change role-chain assignments without notifying
Scylla. As a result, effective permissions can change, so some form of
polling is required.

Currently, this is handled via cache expiration. However, the unified
cache is designed to be consistent and does not support expiration.
To provide an equivalent mechanism for LDAP, we will periodically
reload the permissions portion of the new cache at intervals matching
the previously configured expiration time.

auth/cache.cc

@@ -8,6 +8,7 @@
 
 #include "auth/cache.hh"
 #include "auth/common.hh"
+#include "auth/role_or_anonymous.hh"
 #include "auth/roles-metadata.hh"
 #include "cql3/query_processor.hh"
 #include "cql3/untyped_result_set.hh"
@@ -97,6 +98,23 @@ future<> cache::prune(const resource& r) {
     }
 }
 
+future<> cache::reload_all_permissions() noexcept {
+    SCYLLA_ASSERT(_permission_loader);
+    auto units = co_await get_units(_loading_sem, 1, _as);
+    const role_or_anonymous anon;
+    for (auto& [res, perms] : _anonymous_permissions) {
+        perms = co_await _permission_loader(anon, res);
+    }
+    for (auto& [role, entry] : _roles) {
+        auto& perms_cache = entry->cached_permissions;
+        auto r = role_or_anonymous(role);
+        for (auto& [res, perms] : perms_cache) {
+            perms = co_await _permission_loader(r, res);
+        }
+    }
+    logger.debug("Reloaded auth cache with {} entries", _roles.size());
+}
+
 future<lw_shared_ptr<cache::role_record>> cache::fetch_role(const role_name_t& role) const {
     auto rec = make_lw_shared<role_record>();
     rec->version = _current_version;

auth/cache.hh

@@ -55,6 +55,7 @@ public:
     void set_permission_loader(permission_loader_func loader);
     future<permission_set> get_permissions(const role_or_anonymous& role, const resource& r);
     future<> prune(const resource& r);
+    future<> reload_all_permissions() noexcept;
     future<> load_all();
     future<> load_roles(std::unordered_set<role_name_t> roles);
     static bool includes_table(const table_id&) noexcept;

auth/ldap_role_manager.cc

@@ -88,10 +88,16 @@ static const class_registrator<
 
 ldap_role_manager::ldap_role_manager(
         std::string_view query_template, std::string_view target_attr, std::string_view bind_name, std::string_view bind_password,
+        uint32_t permissions_update_interval_in_ms,
+        utils::observer<uint32_t>  permissions_update_interval_in_ms_observer,
         cql3::query_processor& qp, ::service::raft_group0_client& rg0c, ::service::migration_manager& mm, cache& cache)
         : _std_mgr(qp, rg0c, mm, cache), _group0_client(rg0c), _query_template(query_template), _target_attr(target_attr), _bind_name(bind_name)
         , _bind_password(bind_password)
-        , _connection_factory(bind(std::mem_fn(&ldap_role_manager::reconnect), std::ref(*this))) {
+        , _permissions_update_interval_in_ms(permissions_update_interval_in_ms)
+        , _permissions_update_interval_in_ms_observer(std::move(permissions_update_interval_in_ms_observer))
+        , _connection_factory(bind(std::mem_fn(&ldap_role_manager::reconnect), std::ref(*this)))
+        , _cache(cache)
+        , _cache_pruner(make_ready_future<>()) {
 }
 
 ldap_role_manager::ldap_role_manager(cql3::query_processor& qp, ::service::raft_group0_client& rg0c, ::service::migration_manager& mm, cache& cache)
@@ -100,6 +106,8 @@ ldap_role_manager::ldap_role_manager(cql3::query_processor& qp, ::service::raft_
             qp.db().get_config().ldap_attr_role(),
             qp.db().get_config().ldap_bind_dn(),
             qp.db().get_config().ldap_bind_passwd(),
+            qp.db().get_config().permissions_update_interval_in_ms(),
+            qp.db().get_config().permissions_update_interval_in_ms.observe([this] (const uint32_t& v) { _permissions_update_interval_in_ms = v; }),
             qp,
             rg0c,
             mm,
@@ -119,6 +127,22 @@ future<> ldap_role_manager::start() {
         return make_exception_future(
                 std::runtime_error(fmt::format("error getting LDAP server address from template {}", _query_template)));
     }
+    _cache_pruner = futurize_invoke([this] () -> future<> {
+        while (true) {
+            try {
+                co_await seastar::sleep_abortable(std::chrono::milliseconds(_permissions_update_interval_in_ms), _as);
+            } catch (const seastar::sleep_aborted&) {
+                co_return; // ignore
+            }
+            co_await _cache.container().invoke_on_all([] (cache& c) -> future<> {
+                try {
+                    co_await c.reload_all_permissions();
+                } catch (...) {
+                    mylog.warn("Cache reload all permissions failed: {}", std::current_exception());
+                }
+            });
+        }
+    });
     return _std_mgr.start();
 }
 
@@ -175,7 +199,11 @@ future<conn_ptr> ldap_role_manager::reconnect() {
 
 future<> ldap_role_manager::stop() {
     _as.request_abort();
-    return _std_mgr.stop().then([this] { return _connection_factory.stop(); });
+    return std::move(_cache_pruner).then([this] {
+        return _std_mgr.stop();
+    }).then([this] {
+        return _connection_factory.stop();
+    });
 }
 
 future<> ldap_role_manager::create(std::string_view name, const role_config& config, ::service::group0_batch& mc) {

auth/ldap_role_manager.hh

@@ -10,6 +10,7 @@
 #pragma once
 
 #include <seastar/core/abort_source.hh>
+#include <seastar/core/future.hh>
 #include <stdexcept>
 
 #include "ent/ldap/ldap_connection.hh"
@@ -34,14 +35,22 @@ class ldap_role_manager : public role_manager {
     seastar::sstring _target_attr; ///< LDAP entry attribute containing the Scylla role name.
     seastar::sstring _bind_name; ///< Username for LDAP simple bind.
     seastar::sstring _bind_password; ///< Password for LDAP simple bind.
+
+    uint32_t _permissions_update_interval_in_ms;
+    utils::observer<uint32_t> _permissions_update_interval_in_ms_observer;
+
     mutable ldap_reuser _connection_factory; // Potentially modified by query_granted().
     seastar::abort_source _as;
+    cache& _cache;
+    seastar::future<> _cache_pruner;
   public:
     ldap_role_manager(
             std::string_view query_template, ///< LDAP query template as described in Scylla documentation.
             std::string_view target_attr, ///< LDAP entry attribute containing the Scylla role name.
             std::string_view bind_name, ///< LDAP bind credentials.
             std::string_view bind_password, ///< LDAP bind credentials.
+            uint32_t permissions_update_interval_in_ms,
+            utils::observer<uint32_t> permissions_update_interval_in_ms_observer,
             cql3::query_processor& qp, ///< Passed to standard_role_manager.
             ::service::raft_group0_client& rg0c, ///< Passed to standard_role_manager.
             ::service::migration_manager& mm, ///< Passed to standard_role_manager.

test/ldap/role_manager_test.cc

@@ -284,6 +284,7 @@ auto make_ldap_manager(cql_test_env& env, sstring query_template = default_query
     };
     return std::unique_ptr<auth::ldap_role_manager, decltype(stop_role_manager)>(
             new auth::ldap_role_manager(query_template, /*target_attr=*/"cn", manager_dn, manager_password,
+                    env.db_config().permissions_update_interval_in_ms(), env.db_config().permissions_update_interval_in_ms.observe([] (const uint32_t& v) {}),
                     env.local_qp(), env.get_raft_group0_client(), env.migration_manager().local(), env.auth_cache().local()),
         std::move(stop_role_manager));
 }