/*
* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.security.acls.domain;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.acls.model.Acl;
import org.springframework.security.acls.model.Sid;
import org.springframework.security.acls.model.SidRetrievalStrategy;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.AuthorityUtils;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.util.Assert;
import java.util.Arrays;
import java.util.List;
import java.util.Set;
/**
* Default implementation of {@link AclAuthorizationStrategy}.
* <p>
* Permission will be granted if at least one of the following conditions is true for the
* current principal.
* <ul>
* <li>is the owner (as defined by the ACL).</li>
* <li>holds the relevant system-wide {@link GrantedAuthority} injected into the
* constructor.</li>
* <li>has {@link BasePermission#ADMINISTRATION} permission (as defined by the ACL).</li>
* </ul>
*
* @author Ben Alex
*/
public class AclAuthorizationStrategyImpl implements AclAuthorizationStrategy {
// ~ Instance fields
// ================================================================================================
private final GrantedAuthority gaGeneralChanges;
private final GrantedAuthority gaModifyAuditing;
private final GrantedAuthority gaTakeOwnership;
private SidRetrievalStrategy sidRetrievalStrategy = new SidRetrievalStrategyImpl();
// ~ Constructors
// ===================================================================================================
/**
* Constructor. The only mandatory parameter relates to the system-wide
* {@link GrantedAuthority} instances that can be held to always permit ACL changes.
*
* @param auths the <code>GrantedAuthority</code>s that have special permissions
* (index 0 is the authority needed to change ownership, index 1 is the authority
* needed to modify auditing details, index 2 is the authority needed to change other
* ACL and ACE details) (required)
* <p>
* Alternatively, a single value can be supplied for all three permissions.
*/
public AclAuthorizationStrategyImpl(GrantedAuthority... auths) {
Assert.isTrue(auths != null && (auths.length == 3 || auths.length == 1),
"One or three GrantedAuthority instances required");
if (auths.length == 3) {
gaTakeOwnership = auths[0];
gaModifyAuditing = auths[1];
gaGeneralChanges = auths[2];
}
else {
gaTakeOwnership = gaModifyAuditing = gaGeneralChanges = auths[0];
}
}
// ~ Methods
// ========================================================================================================
public void securityCheck(Acl acl, int changeType) {
if ((SecurityContextHolder.getContext() == null)
|| (SecurityContextHolder.getContext().getAuthentication() == null)
|| !SecurityContextHolder.getContext().getAuthentication()
.isAuthenticated()) {
throw new AccessDeniedException(
"Authenticated principal required to operate with ACLs");
}
Authentication authentication = SecurityContextHolder.getContext()
.getAuthentication();
// Check if authorized by virtue of ACL ownership
Sid currentUser = createCurrentUser(authentication);
if (currentUser.equals(acl.getOwner())
&& ((changeType == CHANGE_GENERAL) || (changeType == CHANGE_OWNERSHIP))) {
return;
}
// Not authorized by ACL ownership; try via adminstrative permissions
GrantedAuthority requiredAuthority;
if (changeType == CHANGE_AUDITING) {
requiredAuthority = this.gaModifyAuditing;
}
else if (changeType == CHANGE_GENERAL) {
requiredAuthority = this.gaGeneralChanges;
}
else if (changeType == CHANGE_OWNERSHIP) {
requiredAuthority = this.gaTakeOwnership;
}
else {
throw new IllegalArgumentException("Unknown change type");
}
// Iterate this principal's authorities to determine right
Set<String> authorities = AuthorityUtils.authorityListToSet(authentication.getAuthorities());
if (authorities.contains(requiredAuthority.getAuthority())) {
return;
}
// Try to get permission via ACEs within the ACL
List<Sid> sids = sidRetrievalStrategy.getSids(authentication);
if (acl.isGranted(Arrays.asList(BasePermission.ADMINISTRATION), sids, false)) {
return;
}
throw new AccessDeniedException(
"Principal does not have required ACL permissions to perform requested operation");
}
/**
* Creates a principal-like sid from the authentication information.
*
* @param authentication the authentication information that can provide principal and
* thus the sid's id will be dependant on the value inside
* @return a sid with the ID taken from the authentication information
*/
protected Sid createCurrentUser(Authentication authentication) {
return new PrincipalSid(authentication);
}
public void setSidRetrievalStrategy(SidRetrievalStrategy sidRetrievalStrategy) {
Assert.notNull(sidRetrievalStrategy, "SidRetrievalStrategy required");
this.sidRetrievalStrategy = sidRetrievalStrategy;
}
}