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ATT reference implementation of XACML PDP engine
/*
*
* Copyright (c) 2013,2019 AT&T Knowledge Ventures
* SPDX-License-Identifier: MIT
*/
package com.att.research.xacmlatt.pdp.std.functions;
import java.util.List;
import com.att.research.xacml.api.AttributeValue;
import com.att.research.xacml.api.Identifier;
import com.att.research.xacml.std.StdStatus;
import com.att.research.xacml.std.StdStatusCode;
import com.att.research.xacml.std.datatypes.DataTypes;
import com.att.research.xacmlatt.pdp.eval.EvaluationContext;
import com.att.research.xacmlatt.pdp.policy.ExpressionResult;
import com.att.research.xacmlatt.pdp.policy.FunctionArgument;
/**
* FunctionDefinitionLogical extends {@link com.att.research.xacmlatt.pdp.std.functions.FunctionDefinitionHomogeneousSimple} to
* implement the XACML Logic predicates as functions taking zero, one, or multiple arguments of type Boolean and returning a Boolean.
*
* In the first implementation of XACML we had separate files for each XACML Function.
* This release combines multiple Functions in fewer files to minimize code duplication.
* This file supports the following XACML codes:
* or
* and
* n-of
* not
*
* @author glenngriffin
* @version $Revision: 1.1 $
*
*/
public class FunctionDefinitionLogical extends FunctionDefinitionHomogeneousSimple {
/**
* List of Logical Operations types
*
* @author glenngriffin
*
*/
public enum OPERATION {OR, AND, N_OF, NOT}
// the operation that this instance is being asked to do
private final OPERATION operation;
public FunctionDefinitionLogical(Identifier idIn, OPERATION op) {
super(idIn, DataTypes.DT_BOOLEAN, DataTypes.DT_BOOLEAN, null);
operation = op;
}
@Override
public ExpressionResult evaluate(EvaluationContext evaluationContext, List arguments) {
switch (operation) {
case OR:
if (arguments == null || arguments.size() == 0) {
return ER_FALSE;
}
try {
// evaluate the arguments one at a time and abort on the first true
for (int i = 0; i < arguments.size(); i++) {
ConvertedArgument argument = new ConvertedArgument(arguments.get(i), this.getDataTypeArgs(), false);
if ( ! argument.isOk()) {
// return a decorated message
return ExpressionResult.newError(getFunctionStatus(argument.getStatus()));
}
if (argument.getValue() == true) {
return ER_TRUE;
}
}
} catch (Exception e) {
String message = e.getMessage();
if (e.getCause() != null) {
message = e.getCause().getMessage();
}
return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, this.getShortFunctionId() + " " + message));
}
return ER_FALSE;
case AND:
if (arguments == null || arguments.size() == 0) {
return ER_TRUE;
}
try {
// evaluate the arguments one at a time and abort on the first false
for (int i = 0; i < arguments.size(); i++) {
ConvertedArgument argument = new ConvertedArgument(arguments.get(i), this.getDataTypeArgs(), false);
if ( ! argument.isOk()) {
return ExpressionResult.newError(getFunctionStatus(argument.getStatus()));
}
if (argument.getValue() == false) {
return ER_FALSE;
}
}
} catch (Exception e) {
String message = e.getMessage();
if (e.getCause() != null) {
message = e.getCause().getMessage();
}
return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, this.getShortFunctionId() + " " + message));
}
return ER_TRUE;
case N_OF:
Integer argumentCountNeeded;
int trueArgumentsSeen = 0;
if (arguments == null || arguments.size() == 0) {
return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, this.getShortFunctionId() + " Expected 1 argument, got 0"));
}
try {
//
// Special case:
// The first argument in the list (an Integer) is not homogeneous with the rest of the arguments (Booleans).
// While this is technically not a FunctionDefinitionHomogeneousSimple type of object, we derive from that class anyway
// so that we can take advantage of the validateArgument() method in that class.
// Unfortunately we cannot re-use that same code (because of generics - it gets messy) for the Integer argument.
// The following code essentially does the same job as validateArgument() on the first argument in the list.
//
// first arg is the number of remaining arguments that must be TRUE
if (arguments.get(0) == null) {
return ER_TRUE;
}
if ( ! arguments.get(0).getStatus().isOk()) {
return ExpressionResult.newError(getFunctionStatus(arguments.get(0).getStatus()));
}
if (arguments.get(0).isBag()) {
return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, this.getShortFunctionId() + " Expected a simple value, saw a bag"));
}
AttributeValue attributeValue = arguments.get(0).getValue();
if (attributeValue == null) {
// assume this is the same as "first argument is 0"
return ER_TRUE;
}
argumentCountNeeded = DataTypes.DT_INTEGER.convert(attributeValue.getValue()).intValue();
if (argumentCountNeeded == 0) {
return ER_TRUE;
}
if (arguments.size() - 1 < argumentCountNeeded) {
// return a non-OK status to signal indeterminate
return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, this.getShortFunctionId() +
" Expected " + argumentCountNeeded + " arguments but only " +
(arguments.size() - 1) + " arguments in list after the count"));
}
for (int i = 1; i < arguments.size(); i++) {
ConvertedArgument argument = new ConvertedArgument(arguments.get(i), this.getDataTypeArgs(), false);
if ( ! argument.isOk()) {
return ExpressionResult.newError(getFunctionStatus(argument.getStatus()));
}
if ((argument.getValue()) == true) {
trueArgumentsSeen++;
if (trueArgumentsSeen >= argumentCountNeeded) {
return ER_TRUE;
}
}
// if we cannot reach the goal, stop now.
// remaining entries to be looked at = list size - i - 1, which is the most additional TRUEs that we could get.
if ( (arguments.size() - i - 1) + trueArgumentsSeen < argumentCountNeeded) {
// do not evaluate remaining entries
return ER_FALSE;
}
}
// did not reach our goal
return ER_FALSE;
} catch (Exception e) {
String message = e.getMessage();
if (e.getCause() != null) {
message = e.getCause().getMessage();
}
return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, this.getShortFunctionId() + " " + message));
}
case NOT:
if (arguments == null || arguments.size() != 1) {
return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, this.getShortFunctionId() + " Expected 1 argument, got " +
((arguments == null) ? "null" : arguments.size()) ) );
}
try {
ConvertedArgument argument = new ConvertedArgument(arguments.get(0), this.getDataTypeArgs(), false);
if ( ! argument.isOk()) {
return ExpressionResult.newError(getFunctionStatus(argument.getStatus()));
}
if (argument.getValue() == true) {
return ER_FALSE;
} else {
return ER_TRUE;
}
} catch (Exception e) {
String message = e.getMessage();
if (e.getCause() != null) {
message = e.getCause().getMessage();
}
return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, this.getShortFunctionId() + " " + message));
}
}
// all cases should have been covered by above - should never get here
return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, this.getShortFunctionId() + " Could not evaluate Logical function " + operation));
}
}