/* 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 java.util.Arrays;
import java.util.List;
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.context.SecurityContextHolder;
import org.springframework.util.Assert;
/**
* 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 = new PrincipalSid(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
if (authentication.getAuthorities().contains(requiredAuthority)) {
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");
}
public void setSidRetrievalStrategy(SidRetrievalStrategy sidRetrievalStrategy) {
Assert.notNull(sidRetrievalStrategy, "SidRetrievalStrategy required");
this.sidRetrievalStrategy = sidRetrievalStrategy;
}
}