Files
scylladb/auth/permissions_cache.hh
Jesse Haber-Kucharsky 5be16247cc auth: Decouple authorization and role management
auth: Decouple authorization and role management

Access control in Scylla consists of three main modules: authentication,
authorization, and role-management.

Each of these modules is intended to be interchangeable with alternative
implementations. The `auth::service` class composes these modules
together to perform all access-control functionality, including caching.

This architecture implies two main properties of the individual
access-control modules:

- Independence of modules. An implementation of authentication should
  have no dependence or knowledge of authorization or role-management,
  for example.

- Simplicity of implementing the interface. Functionality that is common
  to all implementations should not have to be duplicated in each
  implementation. The abstract interface for a module should capture
  only the differences between particular implementations.

Previously, the authorization interface depended on an instance of
`auth::service` for certain operations, since it required aggregation
over all the roles granted to a particular role or required checking if
a given role had superuser.

This change decouples authorization entirely from role-management: the
authorizer now manages only permissions granted directly to a role, and
not those inherited through other roles.

When a query needs to be authorized, `auth::service::get_permissions`
first uses the role manager to check if the role has superuser. Then, it
aggregates calls to `auth::authorizer::authorize` for each role granted
to the role (again, from the role-manager) to determine the sum-total
permission set. This information is cached for future queries.

This structure allows for easier error handling and
management (something I hope to improve in the future for both the
authorizer and authenticator interfaces), easier system testing, easier
implementation of the abstract interfaces, and clearer system
boundaries (so the code is easier to grok).

Some authorizers, like the "TransitionalAuthorizer", grant permissions
to anonymous users. Therefore, we could not unconditionally authorize an
empty permission set in `auth::service` for anonymous users. To account
for this, the interface of the authorizer has changed to accept an
optional name in `authorize`.

One additional notable change to the authorizer is the
`auth::authorizer::list`: previously, the filtering happened at the CQL
query layer and depended on the roles granted to the role in question.
I've changed the function to simply query for all roles and I do the
filtering in `auth::system` in-memory with the STL. This was necessary
to allow the authorizer to be decoupled from role-management. This
function is only called for LIST PERMISSIONS (so performance is not a
concern), and it significantly reduces demand on the implementation.

Finally, we unconditionally create a user in `cql_test_env` since
authorization requires its existence.
2018-02-14 14:15:59 -05:00

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/*
* Copyright (C) 2017 ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla 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 Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <chrono>
#include <experimental/string_view>
#include <functional>
#include <iostream>
#include <optional>
#include <utility>
#include <seastar/core/future.hh>
#include <seastar/core/shared_ptr.hh>
#include <seastar/core/sstring.hh>
#include "auth/authenticated_user.hh"
#include "auth/permission.hh"
#include "auth/resource.hh"
#include "auth/role_or_anonymous.hh"
#include "log.hh"
#include "stdx.hh"
#include "utils/hash.hh"
#include "utils/loading_cache.hh"
namespace std {
inline std::ostream& operator<<(std::ostream& os, const pair<auth::role_or_anonymous, auth::resource>& p) {
os << "{role: " << p.first << ", resource: " << p.second << "}";
return os;
}
}
namespace db {
class config;
}
namespace auth {
class service;
struct permissions_cache_config final {
static permissions_cache_config from_db_config(const db::config&);
std::size_t max_entries;
std::chrono::milliseconds validity_period;
std::chrono::milliseconds update_period;
};
class permissions_cache final {
using cache_type = utils::loading_cache<
std::pair<role_or_anonymous, resource>,
permission_set,
utils::loading_cache_reload_enabled::yes,
utils::simple_entry_size<permission_set>,
utils::tuple_hash>;
using key_type = typename cache_type::key_type;
cache_type _cache;
public:
explicit permissions_cache(const permissions_cache_config&, service&, logging::logger&);
future <> stop() {
return _cache.stop();
}
future<permission_set> get(const role_or_anonymous&, const resource&);
};
}