/* * Copyright (c) Contributors, http://opensimulator.org/ * See CONTRIBUTORS.TXT for a full list of copyright holders. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * Neither the name of the OpenSim Project nor the * names of its contributors may be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ using System; using System.Collections.Generic; namespace OpenSim.Framework { // ACL Class // Modelled after the structure of the Zend ACL Framework Library // with one key difference - the tree will search for all matching // permissions rather than just the first. Deny permissions will // override all others. #region ACL Core Class /// <summary> /// Access Control List Engine /// </summary> public class ACL { private Dictionary<string, Role> Roles = new Dictionary<string, Role>(); private Dictionary<string, Resource> Resources = new Dictionary<string, Resource>(); public ACL AddRole(Role role) { if (Roles.ContainsKey(role.Name)) throw new AlreadyContainsRoleException(role); Roles.Add(role.Name, role); return this; } public ACL AddResource(Resource resource) { Resources.Add(resource.Name, resource); return this; } public Permission HasPermission(string role, string resource) { if (!Roles.ContainsKey(role)) throw new KeyNotFoundException(); if (!Resources.ContainsKey(resource)) throw new KeyNotFoundException(); return Roles[role].RequestPermission(resource); } public ACL GrantPermission(string role, string resource) { if (!Roles.ContainsKey(role)) throw new KeyNotFoundException(); if (!Resources.ContainsKey(resource)) throw new KeyNotFoundException(); Roles[role].GivePermission(resource, Permission.Allow); return this; } public ACL DenyPermission(string role, string resource) { if (!Roles.ContainsKey(role)) throw new KeyNotFoundException(); if (!Resources.ContainsKey(resource)) throw new KeyNotFoundException(); Roles[role].GivePermission(resource, Permission.Deny); return this; } public ACL ResetPermission(string role, string resource) { if (!Roles.ContainsKey(role)) throw new KeyNotFoundException(); if (!Resources.ContainsKey(resource)) throw new KeyNotFoundException(); Roles[role].GivePermission(resource, Permission.None); return this; } } #endregion #region Exceptions /// <summary> /// Thrown when an ACL attempts to add a duplicate role. /// </summary> public class AlreadyContainsRoleException : Exception { protected Role m_role; public Role ErrorRole { get { return m_role; } } public AlreadyContainsRoleException(Role role) { m_role = role; } public override string ToString() { return "This ACL already contains a role called '" + m_role.Name + "'."; } } #endregion #region Roles and Resources /// <summary> /// Does this Role have permission to access a specified Resource? /// </summary> public enum Permission { Deny, None, Allow } ; /// <summary> /// A role class, for use with Users or Groups /// </summary> public class Role { private string m_name; private Role[] m_parents; private Dictionary<string, Permission> m_resources = new Dictionary<string, Permission>(); public string Name { get { return m_name; } } public Permission RequestPermission(string resource) { return RequestPermission(resource, Permission.None); } public Permission RequestPermission(string resource, Permission current) { // Deny permissions always override any others if (current == Permission.Deny) return current; Permission temp = Permission.None; // Pickup non-None permissions if (m_resources.ContainsKey(resource) && m_resources[resource] != Permission.None) temp = m_resources[resource]; if (m_parents != null) { foreach (Role parent in m_parents) { temp = parent.RequestPermission(resource, temp); } } return temp; } public void GivePermission(string resource, Permission perm) { m_resources[resource] = perm; } public Role(string name) { m_name = name; m_parents = null; } public Role(string name, Role[] parents) { m_name = name; m_parents = parents; } } public class Resource { private string m_name; public string Name { get { return m_name; } } public Resource(string name) { m_name = name; } } #endregion #region Tests internal class ACLTester { public ACLTester() { ACL acl = new ACL(); Role Guests = new Role("Guests"); acl.AddRole(Guests); Role[] parents = new Role[0]; parents[0] = Guests; Role JoeGuest = new Role("JoeGuest", parents); acl.AddRole(JoeGuest); Resource CanBuild = new Resource("CanBuild"); acl.AddResource(CanBuild); acl.GrantPermission("Guests", "CanBuild"); acl.HasPermission("JoeGuest", "CanBuild"); } } #endregion }