BitFlagsResource.java
/*
** Module : BitFlagsResource.java
** Abstract : security mgr plugin for the "bitflags" resource.
**
** Copyright (c) 2005-2023, Golden Code Development Corporation.
**
** -#- -I- --Date-- ------------------------------Description------------------------------------
** 001 GES 20200115 First version based on the NetResource implementation.
** GES 20200206 Moved code to StringHelper.
** 002 HC 20230427 Implemented management for file-system resource. This includes Admin and
** server directory changes.
** 003 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
*/
/*
** This program 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.
**
** This program 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 Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
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*/
package com.goldencode.p2j.security;
import com.goldencode.p2j.directory.*;
import com.goldencode.p2j.util.logging.*;
import java.util.*;
import java.util.Collections;
import java.util.LinkedList;
import java.util.logging.*;
/**
* Implements the "bitFlags" resource. This can be used to protect any resource whose
* rights can be represented by a small set of flags:
* <ul>
* <li> create - a runtime instance of the resource can be created
* <li> delete - an existing runtime instance can be destroyed
* <li> read - the state or data associated with an existing runtime instance can be accessed
* <li> write - the state or data associated with an existing runtime instance can be modified
* <li> denied - no access is allowed (overrides any other access flags)
* </ul>
* <p>
* Rights objects for this resource are made of one bitfield with 8 bits. The first four bits
* correspond to the create, delete, read and write respectively. There are 3 reserved bits.
* The last bit is for explicit denial of access. When printed, they are shown as
* {@code CDRW...N}.
* <p>
* Resource names will be namespaced using the subclass' resource type name. The naming approach
* is {@code /resource_type_name/instance_name}. Each different instance of a particular
* resource type will share the same type name but must have a unique, non-empty instance name.
*/
public abstract class BitFlagsResource
extends AbstractResource
implements BitFlagsConstants
{
/** Extended bits, if any */
private String[] extBits;
/** Logger. */
private static final CentralLogger LOG = CentralLogger.get(BitFlagsResource.class);
/**
* Constructor.
*/
public BitFlagsResource()
{
extBits = getExtendedBits();
}
/**
* Returns the plugin's resource type name as a string.
*
* @return The plugin's resource type name.
*/
public abstract String getTypeName();
/**
* Override the method to provide extended bit names to augment the default set of bits.
* The method must return either {@code null} for no extended bits or an array of length 1, 2, 3.
* An array of length 1 will carry name of bit 4, length 2 bits 4 and 5, and length 3 bits 4, 5 and 6.
*
* @return See above.
*/
public String[] getExtendedBits()
{
return null;
}
/**
* Returns an array of descriptions, one object per the plugin's access rights item.
* <p>
* This plugin uses one field of type BitField with three bits: read, write
* end execute.
*
* @return The descriptions, one per access rights item.
*/
public final Description[] describeRights()
{
List<String> bitNames = new LinkedList<>();
Collections.addAll(bitNames, "create", "delete", "read", "write", "denied");
if (extBits != null)
{
for (String bitName : extBits)
{
// insert the additional bits just before "denied"
bitNames.add(bitNames.size() - 1, bitName);
}
}
Description[] items = new Description[1];
items[0] = new Description(AttributeType.ATTR_BITFIELD, // string
true, // mandatory?
false, // variable size?
BITSET_SIZE, // size
"permissions", // text label
"bit set to ON enables access",
bitNames.toArray(new String[bitNames.size()]),
new BitSet(BITSET_SIZE)); // 3 unused bits
return items;
}
/**
* Converts from the persistent form of the plugin's rights to the specific in-memory
* type.
*
* @param rights
* An array of objects of proper types representing items in a set
* of access rights.
*
* @return The reference to the interface.
*/
public Rights getRightsInstance(Object[] rights)
{
return new BitFlagsRights(BitSetHelper.fromBitField((BitField)rights[0]));
}
/**
* Checks whether a given array of objects representing a set of access
* rights fields is acceptable.
* <p>This method returns <code>true</code> only if:
* <ul>
* <li>DENIED bit is not set, or
* <li>DENIED bit is set and no other bit is set.
* </ul>
*
* @param rights
* An array of objects of proper types representing items in a set of access rights.
*
* @return <code>true</code> if the array is acceptable for an instance of access rights.
*/
public boolean isRightsSetValid(Object[] rights)
{
if (rights.length != 1)
return false;
if (!rights[0].getClass().isInstance(new BitField(1)))
return false;
BitSet bs = BitSetHelper.fromBitField((BitField)rights[0]);
BitFlagsRights r = new BitFlagsRights(bs);
boolean denied = r.get(BIT_DENIED_ACCESS);
if (!denied)
return true;
boolean set = r.get(BIT_CREATE_ACCESS) ||
r.get(BIT_DELETE_ACCESS) ||
r.get(BIT_READ_ACCESS) ||
r.get(BIT_WRITE_ACCESS);
// check extended bits if any
if (!set && extBits != null)
{
for (int i = 0; i < Math.min(3, extBits.length); i++)
{
set = r.get(i + 4);
if (set)
{
break;
}
}
}
if (set)
return false;
return true;
}
/**
* Reports if CREATE is allowed for the given resource name.
*
* @param name
* Resource instance name.
*
* @return <code>true</code> if access is allowed.
*/
public boolean canCreate(String name)
{
return accessWorker(name, BIT_CREATE_ACCESS);
}
/**
* Reports if DELETE is allowed for the given resource name.
*
* @param name
* Resource instance name.
*
* @return <code>true</code> if access is allowed.
*/
public boolean canDelete(String name)
{
return accessWorker(name, BIT_DELETE_ACCESS);
}
/**
* Reports if READ is allowed for the given resource name.
*
* @param name
* Resource instance name.
*
* @return <code>true</code> if access is allowed.
*/
public boolean canRead(String name)
{
return accessWorker(name, BIT_READ_ACCESS);
}
/**
* Reports if WRITE is allowed for the given resource name.
*
* @param name
* Resource instance name.
*
* @return <code>true</code> if access is allowed.
*/
public boolean canWrite(String name)
{
return accessWorker(name, BIT_WRITE_ACCESS);
}
/**
* Implements generalized access rights check worker.
*
* @param name
* Resource instance name.
* @param bit
* The bit to check.
*
* @return <code>true</code> if access is allowed.
*/
public boolean accessWorker(String name, int bit)
{
// check to see if there is a cached decision
Boolean cached = sm.getCachedDecision(resourceIndex, name, bit);
if (cached != null)
{
return cached.booleanValue();
}
// initiate the ACL search
int handle = sm.openRightsSearch(resourceIndex, name, bit);
boolean isFinerLoggable = LOG.isLoggable(Level.FINER);
if (isFinerLoggable)
{
LOG.finer("Search open: resId " + resourceIndex + ", instance " +
name + ", bit " + bit + ", handle " + handle);
}
boolean decision = false;
BitFlagsRights rights = (BitFlagsRights) sm.getNextRights(handle);
if (rights == null)
{
// no rights defined for the name
if (isFinerLoggable)
{
LOG.finer("Search done: handle " + handle + ", no rights found for " +
name + ", cache false");
}
}
else
{
loop:
while (rights != null)
{
if (isFinerLoggable)
{
LOG.finer("Search next: handle " + handle + ", rights " + rights);
}
if (rights.get(BIT_DENIED_ACCESS))
{
// no access ends the search
break loop;
}
else if (rights.get(bit))
{
decision = true;
// allowed access, ends the search
break loop;
}
// try the next rights instance
rights = (BitFlagsRights) sm.getNextRights(handle);
}
if (isFinerLoggable)
{
LOG.finer("Search done: handle " + handle + ", decision " +
decision + ", cache true");
}
}
sm.closeRightsSearch(handle, decision, true);
return decision;
}
}