/// <summary>
/// Match the target of this policy.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The retult evaluation of the policy target.</returns>
public TargetEvaluationValue Match(EvaluationContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
TargetEvaluationValue targetEvaluationValue = TargetEvaluationValue.Indeterminate;
context.Trace("Evaluating Target...");
context.AddIndent();
try
{
// Evaluate the policy target
targetEvaluationValue = TargetEvaluationValue.Match;
if (_target != null)
{
targetEvaluationValue = _target.Evaluate(context);
}
return(targetEvaluationValue);
}
finally
{
context.TraceContextValues();
context.RemoveIndent();
context.Trace("Target: {0}", targetEvaluationValue);
}
}
/// <summary>
/// Evaluates the policy set.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The decission result for this policy set.</returns>
public Decision Evaluate(EvaluationContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
context.Trace("Evaluating policySet: {0}", _policySet.Description);
context.CurrentPolicySet = this;
try
{
context.Trace("Evaluating Target...");
context.AddIndent();
// Evaluate the policy target
TargetEvaluationValue targetEvaluationValue = Match(context);
context.RemoveIndent();
context.Trace("Target: {0}", targetEvaluationValue);
ProcessTargetEvaluationValue(context, targetEvaluationValue);
context.Trace("PolicySet: {0}", _evaluationValue);
// If the policy evaluated to Deny or Permit add the obligations depending on its fulfill value.
ProcessObligations(context);
return(_evaluationValue);
}
finally
{
context.CurrentPolicySet = null;
}
}
/// <summary>
/// Evaluates the rule contents.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>A decission for this evalauation.</returns>
public Decision Evaluate(EvaluationContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
context.Trace("Evaluating rule: {0}", _rule.Description);
context.AddIndent();
context.CurrentRule = this;
try
{
// Validate the Target element
TargetEvaluationValue targetEvaluation = Match(context);
// If the target matches the conditions ar evaluated
EvaluationValue conditionEvaluation = EvaluationValue.True;
if (_rule.HasCondition)
{
// Evaluate the condition
conditionEvaluation = _condition.Evaluate(context);
}
else
{
context.Trace("Rule does not have a condition");
}
// Decite the final rule evaluation value
if (targetEvaluation == TargetEvaluationValue.Indeterminate || conditionEvaluation.IsIndeterminate)
{
_evaluationValue = Decision.Indeterminate;
}
else if (targetEvaluation == TargetEvaluationValue.Match && conditionEvaluation.BoolValue)
{
_evaluationValue = ((_rule.Effect == pol.Effect.Permit) ? Decision.Permit : Decision.Deny);
}
else if ((targetEvaluation == TargetEvaluationValue.NoMatch) ||
(targetEvaluation == TargetEvaluationValue.Match && !conditionEvaluation.BoolValue))
{
_evaluationValue = Decision.NotApplicable;
}
// Return the value
context.Trace("Rule: {0}", _evaluationValue);
return(_evaluationValue);
}
finally
{
context.RemoveIndent();
context.CurrentRule = null;
}
}
/// <summary>
/// The evaluation implementation in the pseudo-code described in the specification.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="rules">The policies that must be evaluated.</param>
/// <returns>The final decission for the combination of the rule evaluation.</returns>
public Decision Evaluate(EvaluationContext context, RuleCollection rules)
{
Decision decision = Decision.Indeterminate;
context.Trace("Evaluating rules...");
context.AddIndent();
try
{
foreach (Rule rule in rules)
{
decision = rule.Evaluate(context);
context.TraceContextValues();
if (decision == Decision.Deny)
{
decision = Decision.Deny;
return(decision);
}
if (decision == Decision.Permit)
{
decision = Decision.Permit;
return(decision);
}
if (decision == Decision.NotApplicable)
{
continue;
}
if (decision == Decision.Indeterminate)
{
decision = Decision.Indeterminate;
return(decision);
}
}
return(Decision.NotApplicable);
}
finally
{
context.Trace("Rule combination algorithm: {0}", decision.ToString());
context.RemoveIndent();
}
}
/// <summary>
/// Process the match result.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="targetEvaluationValue">The match evaluation result.</param>
private void ProcessTargetEvaluationValue(EvaluationContext context, TargetEvaluationValue targetEvaluationValue)
{
if (targetEvaluationValue == TargetEvaluationValue.Match)
{
try
{
context.Trace("Evaluating policies...");
context.AddIndent();
context.Trace("Policy combination algorithm: {0}", _policySet.PolicyCombiningAlgorithm);
// Evaluate all policies and apply rule combination
inf.IPolicyCombiningAlgorithm pca = EvaluationEngine.CreatePolicyCombiningAlgorithm(_policySet.PolicyCombiningAlgorithm);
if (pca == null)
{
throw new EvaluationException("the policy combining algorithm does not exists."); //TODO: resources
}
_evaluationValue = pca.Evaluate(context, _policies);
// Update the flags for general evaluation status.
context.TraceContextValues();
context.Trace("Policy combination algorithm: {0}", _evaluationValue.ToString());
}
finally
{
context.RemoveIndent();
}
}
else if (targetEvaluationValue == TargetEvaluationValue.NoMatch)
{
_evaluationValue = Decision.NotApplicable;
}
else if (targetEvaluationValue == TargetEvaluationValue.Indeterminate)
{
_evaluationValue = Decision.Indeterminate;
}
}
/// <summary>
/// Main evaluation method which is divided in two phases: Argument processing and
/// Function evaluation.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The result of the evaluation in an EvaluationValue instance.</returns>
public virtual EvaluationValue Evaluate(EvaluationContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
// Validate the function exists
context.Trace("Calling function: {0}", _applyBase.FunctionId);
inf.IFunction function = EvaluationEngine.GetFunction(_applyBase.FunctionId);
if (function == null)
{
context.Trace("ERR: function not found {0}", _applyBase.FunctionId);
context.ProcessingError = true;
return(EvaluationValue.Indeterminate);
}
// Process the arguments.
IFunctionParameterCollection arguments = ProcessArguments(context, new pol.IExpressionCollection((pol.IExpressionReadWriteCollection)_applyBase.Arguments));
// Call the function with the arguments processed.
EvaluationValue returnValue = EvaluationEngine.EvaluateFunction(context, function, arguments.ToArray());
return(returnValue);
}
/// <summary>
/// The evaluation implementation in the pseudo-code described in the specification.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="rules">The policies that must be evaluated.</param>
/// <returns>The final decission for the combination of the rule evaluation.</returns>
public Decision Evaluate( EvaluationContext context, RuleCollection rules )
{
Decision decision = Decision.Indeterminate;
context.Trace( "Evaluating rules..." );
context.AddIndent();
try
{
foreach( Rule rule in rules )
{
decision = rule.Evaluate( context );
context.TraceContextValues();
if( decision == Decision.Deny )
{
decision = Decision.Deny;
return decision;
}
if( decision == Decision.Permit )
{
decision = Decision.Permit;
return decision;
}
if( decision == Decision.NotApplicable )
{
continue;
}
if( decision == Decision.Indeterminate )
{
decision = Decision.Indeterminate;
return decision;
}
}
return Decision.NotApplicable;
}
finally
{
context.Trace( "Rule combination algorithm: {0}", decision.ToString() );
context.RemoveIndent();
}
}
/// <summary>
/// Process the obligations for the policy.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
private void ProcessObligations(EvaluationContext context)
{
_obligations = new pol.ObligationCollection();
if (_evaluationValue != Decision.Indeterminate &&
_evaluationValue != Decision.NotApplicable &&
_policySet.Obligations != null &&
_policySet.Obligations.Count != 0)
{
foreach (pol.ObligationElement obl in _policySet.Obligations)
{
if ((obl.FulfillOn == pol.Effect.Deny && _evaluationValue == Decision.Deny) ||
(obl.FulfillOn == pol.Effect.Permit && _evaluationValue == Decision.Permit))
{
context.Trace("Adding obligation: {0} ", obl.ObligationId);
_obligations.Add(obl);
}
}
// Get all obligations from child policies
foreach (IMatchEvaluable child in _policies)
{
IObligationsContainer oblig = child as IObligationsContainer;
if (oblig != null && oblig.Obligations != null)
{
foreach (pol.ObligationElement childObligation in oblig.Obligations)
{
if ((childObligation.FulfillOn == pol.Effect.Deny && _evaluationValue == Decision.Deny) ||
(childObligation.FulfillOn == pol.Effect.Permit && _evaluationValue == Decision.Permit))
{
_obligations.Add(childObligation);
}
}
}
}
}
}
/// <summary>
/// Resolves the attribute reference defined within the given match.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="match">The target item match.</param>
/// <param name="contextTargetItem">The context target item.</param>
/// <returns>The context attribute.</returns>
public static ctx.AttributeElement Resolve( EvaluationContext context, pol.TargetMatchBaseReadWrite match, ctx.TargetItemBase contextTargetItem )
{
ctx.AttributeElementReadWrite attribute = null;
if( match.AttributeReference is pol.AttributeDesignatorBase )
{
pol.AttributeDesignatorBase attrDesig = (pol.AttributeDesignatorBase)match.AttributeReference;
context.Trace( "Looking for attribute: {0}", attrDesig.AttributeId );
foreach( ctx.AttributeElementReadWrite tempAttribute in contextTargetItem.Attributes )
{
if( tempAttribute.Match( attrDesig ) )
{
attribute = tempAttribute;
break;
}
}
if( attribute == null )
{
context.Trace( "Attribute not found, loading searching an external repository" );
attribute = GetAttribute( context, attrDesig );
}
}
else if( match.AttributeReference is pol.AttributeSelectorElement )
{
pol.AttributeSelectorElement attrSelec = (pol.AttributeSelectorElement)match.AttributeReference;
ctx.ResourceContentElement content = (ctx.ResourceContentElement)((ctx.ResourceElement)contextTargetItem).ResourceContent;
if( content != null )
{
XmlDocument doc = context.ContextDocument.XmlDocument;
if( context.ContextDocument.XmlNamespaceManager == null )
{
context.ContextDocument.AddNamespaces( context.PolicyDocument.Namespaces );
}
string xpath = attrSelec.RequestContextPath;
try
{
XmlNode node = doc.DocumentElement.SelectSingleNode( xpath, context.ContextDocument.XmlNamespaceManager );
if( node != null )
{
attribute = new ctx.AttributeElement( null, attrSelec.DataType, null, null, node.InnerText, attrSelec.SchemaVersion );
}
}
catch( XPathException e )
{
context.Trace( Resource.TRACE_ERROR, e.Message );
context.ProcessingError = true;
}
}
}
if( attribute == null && match.AttributeReference.MustBePresent )
{
context.IsMissingAttribute = true;
context.AddMissingAttribute( match.AttributeReference );
}
if( attribute != null )
{
return new ctx.AttributeElement( attribute.AttributeId, attribute.DataType, attribute.Issuer, attribute.IssueInstant,
attribute.Value, attribute.SchemaVersion);
}
return null;
}
/// <summary>
/// Search for the attribute in the context target item using the attribute designator specified.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="attributeDesignator">The attribute designator instance.</param>
/// <param name="targetItem">The target item to search in.</param>
/// <returns>A bag value with the values of the attributes found.</returns>
public static BagValue FindAttribute( EvaluationContext context, pol.AttributeDesignatorBase attributeDesignator, ctx.TargetItemBase targetItem )
{
BagValue bag = new BagValue( GetDataType( attributeDesignator.DataType ) );
foreach( ctx.AttributeElement attribute in targetItem.Attributes )
{
if( attribute.Match( attributeDesignator ) )
{
context.Trace( "Adding target item attribute designator: {0}", attribute.ToString() );
bag.Add( attribute );
}
}
return bag;
}
/// <summary>
/// Evaluates the rule contents.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>A decission for this evalauation.</returns>
public Decision Evaluate( EvaluationContext context )
{
if (context == null) throw new ArgumentNullException("context");
context.Trace( "Evaluating rule: {0}", _rule.Description );
context.AddIndent();
context.CurrentRule = this;
try
{
// Validate the Target element
TargetEvaluationValue targetEvaluation = Match( context );
// If the target matches the conditions ar evaluated
EvaluationValue conditionEvaluation = EvaluationValue.True;
if( _rule.HasCondition )
{
// Evaluate the condition
conditionEvaluation = _condition.Evaluate( context );
}
else
{
context.Trace( "Rule does not have a condition" );
}
// Decite the final rule evaluation value
if( targetEvaluation == TargetEvaluationValue.Indeterminate || conditionEvaluation.IsIndeterminate )
{
_evaluationValue = Decision.Indeterminate;
}
else if( targetEvaluation == TargetEvaluationValue.Match && conditionEvaluation.BoolValue )
{
_evaluationValue = ((_rule.Effect == pol.Effect.Permit) ? Decision.Permit : Decision.Deny);
}
else if( ( targetEvaluation == TargetEvaluationValue.NoMatch ) ||
( targetEvaluation == TargetEvaluationValue.Match && !conditionEvaluation.BoolValue ) )
{
_evaluationValue = Decision.NotApplicable;
}
// Return the value
context.Trace( "Rule: {0}", _evaluationValue );
return _evaluationValue;
}
finally
{
context.RemoveIndent();
context.CurrentRule = null;
}
}
/// <summary>
/// Evaluates the target items and return wether the target applies to the context or not.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="targetItem">The target item in the context document.</param>
/// <returns></returns>
public TargetEvaluationValue Evaluate(EvaluationContext context, ctx.TargetItemBase targetItem)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (_targetItems.IsAny)
{
context.Trace("IsAny");
return(TargetEvaluationValue.Match);
}
_evaluationValue = TargetEvaluationValue.NoMatch;
//Match TargetItem
foreach (pol.TargetItemBase polItem in _targetItems.ItemsList)
{
foreach (pol.TargetMatchBase match in polItem.Match)
{
_evaluationValue = TargetEvaluationValue.NoMatch;
context.Trace("Using function: {0}", match.MatchId);
inf.IFunction matchFunction = EvaluationEngine.GetFunction(match.MatchId);
if (matchFunction == null)
{
context.Trace("ERR: function not found {0}", match.MatchId);
context.ProcessingError = true;
return(TargetEvaluationValue.Indeterminate);
}
if (matchFunction.Returns == null)
{
// Validates the function return value
context.Trace("ERR: The function '{0}' does not defines it's return value", match.MatchId);
context.ProcessingError = true;
return(TargetEvaluationValue.Indeterminate);
}
if (matchFunction.Returns != DataTypeDescriptor.Boolean)
{
context.Trace("ERR: Function does not return Boolean a value");
context.ProcessingError = true;
return(TargetEvaluationValue.Indeterminate);
}
ctx.AttributeElement attribute = EvaluationEngine.Resolve(context, match, targetItem);
if (attribute != null)
{
context.Trace("Attribute found, evaluating match function");
try
{
EvaluationValue returnValue = EvaluationEngine.EvaluateFunction(context, matchFunction, match.AttributeValue, attribute);
_evaluationValue = returnValue.BoolValue ? TargetEvaluationValue.Match : TargetEvaluationValue.NoMatch;
}
catch (EvaluationException e)
{
context.Trace(Resource.TRACE_ERROR, e.Message);
_evaluationValue = TargetEvaluationValue.Indeterminate;
}
}
// Validate MustBePresent
if (match.AttributeReference.MustBePresent)
{
if (context.IsMissingAttribute)
{
context.Trace("Attribute not found and must be present");
_evaluationValue = TargetEvaluationValue.Indeterminate;
}
}
// Do not iterate if the value was found
if (_evaluationValue != TargetEvaluationValue.Match)
{
break;
}
}
// Do not iterate if the value was found
if (_evaluationValue == TargetEvaluationValue.Match)
{
return(_evaluationValue);
}
}
return(_evaluationValue);
}
/// <summary>
/// Evaluates the variable into a value.
/// </summary>
/// <param name="context">The contex of the evaluation.</param>
/// <returns>The value of the function.</returns>
public EvaluationValue Evaluate( EvaluationContext context )
{
if (context == null) throw new ArgumentNullException("context");
context.Trace( "Evaluating variable" );
context.AddIndent();
try
{
if( _variableDefinition.Expression is pol.ApplyElement )
{
context.Trace( "Apply within condition." );
// There is a nested apply un this policy a new Apply will be created and also
// evaluated. It's return value will be used as the processed argument.
Apply _childApply = new Apply( (pol.ApplyElement)_variableDefinition.Expression );
// Evaluate the Apply
_value = _childApply.Evaluate( context );
context.TraceContextValues();
return _value;
}
else if( _variableDefinition.Expression is pol.FunctionElement )
{
throw new NotImplementedException( "FunctionElement" ); //TODO:
}
else if( _variableDefinition.Expression is pol.VariableReferenceElement )
{
pol.VariableReferenceElement variableRef = _variableDefinition.Expression as pol.VariableReferenceElement;
VariableDefinition variableDef = context.CurrentPolicy.VariableDefinition[ variableRef.VariableId ] as VariableDefinition;
context.TraceContextValues();
if( !variableDef.IsEvaluated )
{
return variableDef.Evaluate( context );
}
else
{
return variableDef.Value;
}
}
else if( _variableDefinition.Expression is pol.AttributeValueElementReadWrite )
{
// The AttributeValue does not need to be processed
context.Trace( "Attribute value {0}", _variableDefinition.Expression.ToString() );
pol.AttributeValueElementReadWrite att = (pol.AttributeValueElementReadWrite)_variableDefinition.Expression;
pol.AttributeValueElement attributeValue = new pol.AttributeValueElement( att.DataType, att.Contents, att.SchemaVersion );
_value = new EvaluationValue(
attributeValue.GetTypedValue( attributeValue.GetType( context ), 0 ),
attributeValue.GetType( context ) );
return _value;
}
else if( _variableDefinition.Expression is pol.AttributeDesignatorBase )
{
// Resolve the AttributeDesignator using the EvaluationEngine public methods.
context.Trace( "Processing attribute designator: {0}", _variableDefinition.Expression.ToString() );
pol.AttributeDesignatorBase attrDes = (pol.AttributeDesignatorBase)_variableDefinition.Expression;
BagValue bag = EvaluationEngine.Resolve( context, attrDes );
// If the attribute was not resolved by the EvaluationEngine search the
// attribute in the context document, also using the EvaluationEngine public
// methods.
if( bag.BagSize == 0 )
{
if( _variableDefinition.Expression is pol.SubjectAttributeDesignatorElement )
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute( context, attrDes );
if( attrib != null )
{
context.Trace( "Adding subject attribute designator: {0}", attrib.ToString() );
bag.Add( attrib );
}
}
else if( _variableDefinition.Expression is pol.ResourceAttributeDesignatorElement )
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute( context, attrDes );
if( attrib != null )
{
context.Trace( "Adding resource attribute designator {0}", attrib.ToString() );
bag.Add( attrib );
}
}
else if( _variableDefinition.Expression is pol.ActionAttributeDesignatorElement )
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute( context, attrDes );
if( attrib != null )
{
context.Trace( "Adding action attribute designator {0}", attrib.ToString() );
bag.Add( attrib );
}
}
else if( _variableDefinition.Expression is pol.EnvironmentAttributeDesignatorElement )
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute( context, attrDes );
if( attrib != null )
{
context.Trace( "Adding environment attribute designator {0}", attrib.ToString() );
bag.Add( attrib );
}
}
}
// If the argument was not found and the attribute must be present this is
// a MissingAttribute situation so set the flag. Otherwise add the attribute
// to the processed arguments.
if( bag.BagSize == 0 && attrDes.MustBePresent )
{
context.Trace( "Attribute is missing" );
context.IsMissingAttribute = true;
context.AddMissingAttribute( attrDes );
_value = EvaluationValue.Indeterminate;
}
else
{
_value = new EvaluationValue( bag, bag.GetType( context ) );
}
return _value;
}
else if( _variableDefinition.Expression is pol.AttributeSelectorElement )
{
// Resolve the XPath query using the EvaluationEngine public methods.
context.Trace( "Attribute selector" );
try
{
pol.AttributeSelectorElement attributeSelector = (pol.AttributeSelectorElement)_variableDefinition.Expression;
BagValue bag = EvaluationEngine.Resolve( context, attributeSelector );
if( bag.Elements.Count == 0 && attributeSelector.MustBePresent )
{
context.Trace( "Attribute is missing" );
context.IsMissingAttribute = true;
context.AddMissingAttribute( attributeSelector );
_value = EvaluationValue.Indeterminate;
}
else
{
_value = new EvaluationValue( bag, bag.GetType( context ) );
}
}
catch( EvaluationException e )
{
context.Trace( "ERR: {0}", e.Message );
context.ProcessingError = true;
_value = EvaluationValue.Indeterminate;
}
return _value;
}
throw new NotSupportedException( "internal error" );
}
finally
{
_isEvaluated = true;
context.RemoveIndent();
}
}
/// <summary>
/// Main evaluation method which is divided in two phases: Argument processing and
/// Function evaluation.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The result of the evaluation in an EvaluationValue instance.</returns>
public virtual EvaluationValue Evaluate( EvaluationContext context )
{
if (context == null) throw new ArgumentNullException("context");
// Validate the function exists
context.Trace( "Calling function: {0}", _applyBase.FunctionId );
inf.IFunction function = EvaluationEngine.GetFunction( _applyBase.FunctionId );
if( function == null )
{
context.Trace( "ERR: function not found {0}", _applyBase.FunctionId );
context.ProcessingError = true;
return EvaluationValue.Indeterminate;
}
// Process the arguments.
IFunctionParameterCollection arguments = ProcessArguments( context, new pol.IExpressionCollection( (pol.IExpressionReadWriteCollection)_applyBase.Arguments ) );
// Call the function with the arguments processed.
EvaluationValue returnValue = EvaluationEngine.EvaluateFunction( context, function, arguments.ToArray() );
return returnValue;
}
/// <summary>
/// Evaluates the target items and return wether the target applies to the context or not.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="targetItem">The target item in the context document.</param>
/// <returns></returns>
public TargetEvaluationValue Evaluate( EvaluationContext context, ctx.TargetItemBase targetItem )
{
if (context == null) throw new ArgumentNullException(nameof(context));
if (_targetItems.IsAny)
{
context.Trace("IsAny");
return TargetEvaluationValue.Match;
}
_evaluationValue = TargetEvaluationValue.NoMatch;
//Match TargetItem
foreach( pol.TargetItemBase polItem in _targetItems.ItemsList )
{
foreach( pol.TargetMatchBase match in polItem.Match )
{
_evaluationValue = TargetEvaluationValue.NoMatch;
context.Trace( "Using function: {0}", match.MatchId );
inf.IFunction matchFunction = EvaluationEngine.GetFunction( match.MatchId );
if( matchFunction == null )
{
context.Trace( "ERR: function not found {0}", match.MatchId );
context.ProcessingError = true;
return TargetEvaluationValue.Indeterminate;
}
if( matchFunction.Returns == null )
{
// Validates the function return value
context.Trace( "ERR: The function '{0}' does not defines it's return value", match.MatchId );
context.ProcessingError = true;
return TargetEvaluationValue.Indeterminate;
}
if( matchFunction.Returns != DataTypeDescriptor.Boolean )
{
context.Trace( "ERR: Function does not return Boolean a value" );
context.ProcessingError = true;
return TargetEvaluationValue.Indeterminate;
}
ctx.AttributeElement attribute = EvaluationEngine.Resolve( context, match, targetItem );
if( attribute != null )
{
context.Trace( "Attribute found, evaluating match function" );
try
{
EvaluationValue returnValue = EvaluationEngine.EvaluateFunction( context, matchFunction, match.AttributeValue, attribute );
_evaluationValue = returnValue.BoolValue ? TargetEvaluationValue.Match : TargetEvaluationValue.NoMatch;
}
catch( EvaluationException e )
{
context.Trace( Resource.TRACE_ERROR, e.Message );
_evaluationValue = TargetEvaluationValue.Indeterminate;
}
}
// Validate MustBePresent
if( match.AttributeReference.MustBePresent )
{
if( context.IsMissingAttribute )
{
context.Trace( "Attribute not found and must be present" );
_evaluationValue = TargetEvaluationValue.Indeterminate;
}
}
// Do not iterate if the value was found
if( _evaluationValue != TargetEvaluationValue.Match )
{
break;
}
}
// Do not iterate if the value was found
if( _evaluationValue == TargetEvaluationValue.Match )
{
return _evaluationValue;
}
}
return _evaluationValue;
}
/// <summary>
/// THe argument processing method resolves all the attribute designators, attribute
/// selectors. If there is an internal Apply it will be evaulated within this method.
/// </summary>
/// <remarks>All the processed arguments are converted into an IFunctionParameter instance
/// because this is the only value that can be used to call a function.</remarks>
/// <param name="context">The evaluation context instance.</param>
/// <param name="arguments">The arguments to process.</param>
/// <returns>A list of arguments ready to be used by a function.</returns>
private IFunctionParameterCollection ProcessArguments(EvaluationContext context, pol.IExpressionCollection arguments)
{
context.Trace("Processing arguments");
context.AddIndent();
// Create a list to return the processed values.
IFunctionParameterCollection processedArguments = new IFunctionParameterCollection();
// Iterate through the arguments, the IExpressionType is a mark interface
foreach (inf.IExpression arg in arguments)
{
if (arg is pol.ApplyElement)
{
context.Trace("Nested apply");
// There is a nested apply un this policy a new Apply will be created and also
// evaluated. It's return value will be used as the processed argument.
Apply _childApply = new Apply((pol.ApplyElement)arg);
// Evaluate the Apply
EvaluationValue retVal = _childApply.Evaluate(context);
context.TraceContextValues();
// If the results were Indeterminate the Indeterminate value will be placed in
// the processed arguments, later another method will validate the parameters
// and cancel the evaluation propperly.
if (!retVal.IsIndeterminate)
{
if (!context.IsMissingAttribute)
{
processedArguments.Add(retVal);
}
}
else
{
processedArguments.Add(retVal);
}
}
else if (arg is pol.FunctionElementReadWrite)
{
// Search for the function and place it in the processed arguments.
pol.FunctionElement functionId = new pol.FunctionElement(((pol.FunctionElementReadWrite)arg).FunctionId, ((pol.FunctionElementReadWrite)arg).SchemaVersion);
context.Trace("Function {0}", functionId.FunctionId);
inf.IFunction function = EvaluationEngine.GetFunction(functionId.FunctionId);
if (function == null)
{
context.Trace("ERR: function not found {0}", _applyBase.FunctionId);
context.ProcessingError = true;
processedArguments.Add(EvaluationValue.Indeterminate);
}
else
{
processedArguments.Add(function);
}
}
else if (arg is pol.VariableReferenceElement)
{
pol.VariableReferenceElement variableRef = arg as pol.VariableReferenceElement;
VariableDefinition variableDef = context.CurrentPolicy.VariableDefinition[variableRef.VariableId] as VariableDefinition;
context.TraceContextValues();
if (!variableDef.IsEvaluated)
{
processedArguments.Add(variableDef.Evaluate(context));
}
else
{
processedArguments.Add(variableDef.Value);
}
}
else if (arg is pol.AttributeValueElementReadWrite)
{
// The AttributeValue does not need to be processed
context.Trace("Attribute value {0}", arg.ToString());
processedArguments.Add(new pol.AttributeValueElement(((pol.AttributeValueElementReadWrite)arg).DataType, ((pol.AttributeValueElementReadWrite)arg).Contents, ((pol.AttributeValueElementReadWrite)arg).SchemaVersion));
}
else if (arg is pol.AttributeDesignatorBase)
{
// Resolve the AttributeDesignator using the EvaluationEngine public methods.
context.Trace("Processing attribute designator: {0}", arg.ToString());
pol.AttributeDesignatorBase attrDes = (pol.AttributeDesignatorBase)arg;
BagValue bag = EvaluationEngine.Resolve(context, attrDes);
// If the attribute was not resolved by the EvaluationEngine search the
// attribute in the context document, also using the EvaluationEngine public
// methods.
if (bag.BagSize == 0)
{
if (arg is pol.SubjectAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding subject attribute designator: {0}", attrib.ToString());
bag.Add(attrib);
break;
}
}
else if (arg is pol.ResourceAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding resource attribute designator {0}", attrib.ToString());
bag.Add(attrib);
}
}
else if (arg is pol.ActionAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding action attribute designator {0}", attrib.ToString());
bag.Add(attrib);
}
}
else if (arg is pol.EnvironmentAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding environment attribute designator {0}", attrib.ToString());
bag.Add(attrib);
}
}
}
// If the argument was not found and the attribute must be present this is
// a MissingAttribute situation so set the flag. Otherwise add the attribute
// to the processed arguments.
if (bag.BagSize == 0 && attrDes.MustBePresent)
{
context.Trace("Attribute is missing");
context.IsMissingAttribute = true;
context.AddMissingAttribute(attrDes);
}
else
{
processedArguments.Add(bag);
}
}
else if (arg is pol.AttributeSelectorElement)
{
// Resolve the XPath query using the EvaluationEngine public methods.
context.Trace("Attribute selector");
try
{
BagValue bag = EvaluationEngine.Resolve(context, (pol.AttributeSelectorElement)arg);
if (bag.Elements.Count == 0 && ((pol.AttributeSelectorElement)arg).MustBePresent)
{
context.Trace("Attribute is missing");
context.IsMissingAttribute = true;
context.AddMissingAttribute((pol.AttributeReferenceBase)arg);
}
else
{
processedArguments.Add(bag);
}
}
catch (EvaluationException e)
{
context.Trace(Resource.TRACE_ERROR, e.Message);
processedArguments.Add(EvaluationValue.Indeterminate);
context.ProcessingError = true;
}
}
}
context.RemoveIndent();
return(processedArguments);
}
/// <summary>
/// This method overrides the ApplyBase method in order to provide extra validations
/// required in the condition evaluation, for example the final return value should be a
/// boolean value.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The EvaluationValue with the results of the condition evaluation.</returns>
public override EvaluationValue Evaluate(EvaluationContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
context.Trace("Evaluating condition");
context.AddIndent();
try
{
// Iterate through the arguments, the IExpressionType is a mark interface
foreach (inf.IExpression arg in ApplyDefinition.Arguments)
{
if (arg is pol.ApplyElement)
{
context.Trace("Apply within condition.");
// There is a nested apply un this policy a new Apply will be created and also
// evaluated. It's return value will be used as the processed argument.
Apply _childApply = new Apply((pol.ApplyElement)arg);
// Evaluate the Apply
EvaluationValue retVal = _childApply.Evaluate(context);
return(retVal);
}
else if (arg is pol.FunctionElementReadWrite)
{
throw new NotImplementedException("FunctionElement"); //TODO:
}
else if (arg is pol.VariableReferenceElement)
{
pol.VariableReferenceElement variableRef = arg as pol.VariableReferenceElement;
VariableDefinition variableDef = context.CurrentPolicy.VariableDefinition[variableRef.VariableId] as VariableDefinition;
if (!variableDef.IsEvaluated)
{
return(variableDef.Evaluate(context));
}
else
{
return(variableDef.Value);
}
}
else if (arg is pol.AttributeValueElementReadWrite)
{
// The AttributeValue does not need to be processed
context.Trace("Attribute value {0}", arg.ToString());
pol.AttributeValueElement attributeValue = new pol.AttributeValueElement(((pol.AttributeValueElementReadWrite)arg).DataType, ((pol.AttributeValueElementReadWrite)arg).Contents, ((pol.AttributeValueElementReadWrite)arg).SchemaVersion);
return(new EvaluationValue(
attributeValue.GetTypedValue(attributeValue.GetType(context), 0),
attributeValue.GetType(context)));
}
else if (arg is pol.AttributeDesignatorBase)
{
// Returning an empty bag, since the condition is not supposed to work with a bag
context.Trace("Processing attribute designator: {0}", arg.ToString());
pol.AttributeDesignatorBase attrDes = (pol.AttributeDesignatorBase)arg;
BagValue bag = new BagValue(EvaluationEngine.GetDataType(attrDes.DataType));
return(new EvaluationValue(bag, bag.GetType(context)));
}
else if (arg is pol.AttributeSelectorElement)
{
// Returning an empty bag, since the condition is not supposed to work with a bag
context.Trace("Attribute selector");
pol.AttributeSelectorElement attrSel = (pol.AttributeSelectorElement)arg;
BagValue bag = new BagValue(EvaluationEngine.GetDataType(attrSel.DataType));
return(new EvaluationValue(bag, bag.GetType(context)));
}
}
throw new NotSupportedException("internal error");
}
finally
{
context.TraceContextValues();
context.RemoveIndent();
}
}
/// <summary>
/// Process the match result.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="targetEvaluationValue">The match evaluation result.</param>
private void ProcessTargetEvaluationValue(EvaluationContext context, TargetEvaluationValue targetEvaluationValue)
{
if (targetEvaluationValue == TargetEvaluationValue.Match)
{
try
{
context.Trace("Evaluating policies...");
context.AddIndent();
context.Trace("Policy combination algorithm: {0}", _policySet.PolicyCombiningAlgorithm);
// Evaluate all policies and apply rule combination
inf.IPolicyCombiningAlgorithm pca = EvaluationEngine.CreatePolicyCombiningAlgorithm(_policySet.PolicyCombiningAlgorithm);
if (pca == null)
{
throw new EvaluationException("the policy combining algorithm does not exists."); //TODO: resources
}
_evaluationValue = pca.Evaluate(context, _policies);
// Update the flags for general evaluation status.
context.TraceContextValues();
context.Trace("Policy combination algorithm: {0}", _evaluationValue.ToString());
}
finally
{
context.RemoveIndent();
}
}
else if (targetEvaluationValue == TargetEvaluationValue.NoMatch)
{
_evaluationValue = Decision.NotApplicable;
}
else if (targetEvaluationValue == TargetEvaluationValue.Indeterminate)
{
_evaluationValue = Decision.Indeterminate;
}
}
/// <summary>
/// Process the obligations for the policy.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
private void ProcessObligations(EvaluationContext context)
{
_obligations = new pol.ObligationCollection();
if (_evaluationValue != Decision.Indeterminate &&
_evaluationValue != Decision.NotApplicable &&
_policySet.Obligations != null &&
_policySet.Obligations.Count != 0)
{
foreach (pol.ObligationElement obl in _policySet.Obligations)
{
if ((obl.FulfillOn == pol.Effect.Deny && _evaluationValue == Decision.Deny) ||
(obl.FulfillOn == pol.Effect.Permit && _evaluationValue == Decision.Permit))
{
context.Trace("Adding obligation: {0} ", obl.ObligationId);
_obligations.Add(obl);
}
}
// Get all obligations from child policies
foreach (IMatchEvaluable child in _policies)
{
IObligationsContainer oblig = child as IObligationsContainer;
if (oblig != null && oblig.Obligations != null)
{
foreach (pol.ObligationElement childObligation in oblig.Obligations)
{
if ((childObligation.FulfillOn == pol.Effect.Deny && _evaluationValue == Decision.Deny) ||
(childObligation.FulfillOn == pol.Effect.Permit && _evaluationValue == Decision.Permit))
{
_obligations.Add(childObligation);
}
}
}
}
}
}
/// <summary>
/// Evaluates the policy set.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The decission result for this policy set.</returns>
public Decision Evaluate( EvaluationContext context )
{
if (context == null) throw new ArgumentNullException("context");
context.Trace( "Evaluating policySet: {0}", _policySet.Description );
context.CurrentPolicySet = this;
try
{
context.Trace( "Evaluating Target..." );
context.AddIndent();
// Evaluate the policy target
TargetEvaluationValue targetEvaluationValue = Match( context );
context.RemoveIndent();
context.Trace( "Target: {0}", targetEvaluationValue );
ProcessTargetEvaluationValue(context, targetEvaluationValue);
context.Trace( "PolicySet: {0}", _evaluationValue );
// If the policy evaluated to Deny or Permit add the obligations depending on its fulfill value.
ProcessObligations(context);
return _evaluationValue;
}
finally
{
context.CurrentPolicySet = null;
}
}
/// <summary>
/// Evaluates a function and also validates it's return value and parameter data types
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="functionInstance">The function to call</param>
/// <param name="arguments">The function arguments</param>
/// <returns>The return value of the function</returns>
public static EvaluationValue EvaluateFunction( EvaluationContext context, inf.IFunction functionInstance, params inf.IFunctionParameter[] arguments )
{
if (context == null) throw new ArgumentNullException("context");
// If the caller is in a missing attribute state the function should not be called
if( context.IsMissingAttribute )
{
context.Trace( "There's a missing attribute in the parameters" ); //TODO: resources
return EvaluationValue.Indeterminate;
}
else
{
// Validate function defined arguments
int functionArgumentIdx;
for( functionArgumentIdx = 0; functionArgumentIdx < functionInstance.Arguments.Length; functionArgumentIdx++ )
{
// Validate the value is not an Indeterminate value
if( arguments[ functionArgumentIdx ] is EvaluationValue &&
((EvaluationValue)arguments[ functionArgumentIdx ]).IsIndeterminate )
{
if( !context.IsMissingAttribute )
{
context.ProcessingError = true;
}
context.Trace( "There's a parameter with Indeterminate value" );
return EvaluationValue.Indeterminate;
}
// Compare the function and the value data type
if( ( ( functionInstance.Arguments[ functionArgumentIdx ] != arguments[ functionArgumentIdx ].GetType( context ) ) &&
( ( functionInstance.Arguments[ functionArgumentIdx ] != DataTypeDescriptor.Bag ) && (arguments[ functionArgumentIdx ] is BagValue) ) ) )
{
context.ProcessingError = true;
context.Trace( "There's a parameter with an invalid datatype" ); //TODO: resources
return EvaluationValue.Indeterminate;
}
}
//If the function supports variable arguments, the last datatype is used to validate the
//rest of the parameters
if( functionInstance.VarArgs )
{
functionArgumentIdx--;
for( int argumentValueIdx = functionArgumentIdx; argumentValueIdx < arguments.Length; argumentValueIdx++ )
{
// Validate the value is not an Indeterminate value
if( arguments[ argumentValueIdx ] is EvaluationValue && ((EvaluationValue)arguments[ argumentValueIdx ]).IsIndeterminate )
{
if( !context.IsMissingAttribute )
{
context.ProcessingError = true;
}
context.Trace( "There's a parameter with Indeterminate value" ); //TODO: resources
return EvaluationValue.Indeterminate;
}
// Compare the function and the value data type
if( ( functionInstance.Arguments[ functionArgumentIdx ] != arguments[ argumentValueIdx ].GetType( context ) ) &&
( (arguments[ argumentValueIdx ] is BagValue) && ( functionInstance.Arguments[ functionArgumentIdx ] != DataTypeDescriptor.Bag ) ) )
{
context.ProcessingError = true;
context.Trace( "There's a parameter with an invalid datatype" ); //TODO: resources
return EvaluationValue.Indeterminate;
}
}
}
StringBuilder sb = new StringBuilder();
// Call the function in a controlled evironment to capture any exception
try
{
sb.Append( functionInstance.Id );
sb.Append( "( " );
bool isFirst = true;
foreach( inf.IFunctionParameter param in arguments )
{
if( isFirst )
{
isFirst = false;
}
else
{
sb.Append( ", " );
}
sb.Append( param.ToString() );
}
sb.Append( " )" );
sb.Append( " = " );
EvaluationValue returnValue = functionInstance.Evaluate( context, arguments );
sb.Append( returnValue.ToString() );
context.Trace( sb.ToString() );
return returnValue;
}
catch( EvaluationException e )
{
context.Trace( sb.ToString() );
context.ProcessingError = true;
context.Trace( "Error: {0}", e.Message ); //TODO: resources
return EvaluationValue.Indeterminate;
}
}
}
/// <summary>
/// THe argument processing method resolves all the attribute designators, attribute
/// selectors. If there is an internal Apply it will be evaulated within this method.
/// </summary>
/// <remarks>All the processed arguments are converted into an IFunctionParameter instance
/// because this is the only value that can be used to call a function.</remarks>
/// <param name="context">The evaluation context instance.</param>
/// <param name="arguments">The arguments to process.</param>
/// <returns>A list of arguments ready to be used by a function.</returns>
private IFunctionParameterCollection ProcessArguments( EvaluationContext context, pol.IExpressionCollection arguments )
{
context.Trace( "Processing arguments" );
context.AddIndent();
// Create a list to return the processed values.
IFunctionParameterCollection processedArguments = new IFunctionParameterCollection();
// Iterate through the arguments, the IExpressionType is a mark interface
foreach( inf.IExpression arg in arguments )
{
if( arg is pol.ApplyElement )
{
context.Trace( "Nested apply" );
// There is a nested apply un this policy a new Apply will be created and also
// evaluated. It's return value will be used as the processed argument.
Apply _childApply = new Apply( (pol.ApplyElement)arg );
// Evaluate the Apply
EvaluationValue retVal = _childApply.Evaluate( context );
context.TraceContextValues();
// If the results were Indeterminate the Indeterminate value will be placed in
// the processed arguments, later another method will validate the parameters
// and cancel the evaluation propperly.
if( !retVal.IsIndeterminate )
{
if( !context.IsMissingAttribute )
{
processedArguments.Add( retVal );
}
}
else
{
processedArguments.Add( retVal );
}
}
else if( arg is pol.FunctionElementReadWrite )
{
// Search for the function and place it in the processed arguments.
pol.FunctionElement functionId = new pol.FunctionElement( ((pol.FunctionElementReadWrite)arg).FunctionId, ((pol.FunctionElementReadWrite)arg).SchemaVersion );
context.Trace( "Function {0}", functionId.FunctionId );
inf.IFunction function = EvaluationEngine.GetFunction( functionId.FunctionId );
if( function == null )
{
context.Trace( "ERR: function not found {0}", _applyBase.FunctionId );
context.ProcessingError = true;
processedArguments.Add( EvaluationValue.Indeterminate );
}
else
{
processedArguments.Add( function );
}
}
else if( arg is pol.VariableReferenceElement )
{
pol.VariableReferenceElement variableRef = arg as pol.VariableReferenceElement;
VariableDefinition variableDef = context.CurrentPolicy.VariableDefinition[ variableRef.VariableId ] as VariableDefinition;
context.TraceContextValues();
if( !variableDef.IsEvaluated )
{
processedArguments.Add( variableDef.Evaluate( context ) );
}
else
{
processedArguments.Add( variableDef.Value );
}
}
else if( arg is pol.AttributeValueElementReadWrite )
{
// The AttributeValue does not need to be processed
context.Trace( "Attribute value {0}", arg.ToString() );
processedArguments.Add( new pol.AttributeValueElement( ((pol.AttributeValueElementReadWrite)arg).DataType, ((pol.AttributeValueElementReadWrite)arg).Contents, ((pol.AttributeValueElementReadWrite)arg).SchemaVersion ));
}
else if( arg is pol.AttributeDesignatorBase )
{
// Resolve the AttributeDesignator using the EvaluationEngine public methods.
context.Trace( "Processing attribute designator: {0}", arg.ToString() );
pol.AttributeDesignatorBase attrDes = (pol.AttributeDesignatorBase)arg;
BagValue bag = EvaluationEngine.Resolve( context, attrDes );
// If the attribute was not resolved by the EvaluationEngine search the
// attribute in the context document, also using the EvaluationEngine public
// methods.
if( bag.BagSize == 0 )
{
if( arg is pol.SubjectAttributeDesignatorElement )
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute( context, attrDes );
if( attrib != null )
{
context.Trace( "Adding subject attribute designator: {0}", attrib.ToString() );
bag.Add( attrib );
break;
}
}
else if( arg is pol.ResourceAttributeDesignatorElement )
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute( context, attrDes );
if( attrib != null )
{
context.Trace( "Adding resource attribute designator {0}", attrib.ToString() );
bag.Add( attrib );
}
}
else if( arg is pol.ActionAttributeDesignatorElement )
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute( context, attrDes );
if( attrib != null )
{
context.Trace( "Adding action attribute designator {0}", attrib.ToString() );
bag.Add( attrib );
}
}
else if( arg is pol.EnvironmentAttributeDesignatorElement )
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute( context, attrDes );
if( attrib != null )
{
context.Trace( "Adding environment attribute designator {0}", attrib.ToString() );
bag.Add( attrib );
}
}
}
// If the argument was not found and the attribute must be present this is
// a MissingAttribute situation so set the flag. Otherwise add the attribute
// to the processed arguments.
if( bag.BagSize == 0 && attrDes.MustBePresent )
{
context.Trace( "Attribute is missing" );
context.IsMissingAttribute = true;
context.AddMissingAttribute( attrDes );
}
else
{
processedArguments.Add( bag );
}
}
else if( arg is pol.AttributeSelectorElement )
{
// Resolve the XPath query using the EvaluationEngine public methods.
context.Trace( "Attribute selector" );
try
{
BagValue bag = EvaluationEngine.Resolve( context, (pol.AttributeSelectorElement)arg );
if( bag.Elements.Count == 0 && ((pol.AttributeSelectorElement)arg).MustBePresent )
{
context.Trace( "Attribute is missing" );
context.IsMissingAttribute = true;
context.AddMissingAttribute( (pol.AttributeReferenceBase)arg );
}
else
{
processedArguments.Add( bag );
}
}
catch( EvaluationException e )
{
context.Trace( Resource.TRACE_ERROR, e.Message );
processedArguments.Add( EvaluationValue.Indeterminate );
context.ProcessingError = true;
}
}
}
context.RemoveIndent();
return processedArguments;
}
/// <summary>
/// This method overrides the ApplyBase method in order to provide extra validations
/// required in the condition evaluation, for example the final return value should be a
/// boolean value.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The EvaluationValue with the results of the condition evaluation.</returns>
public override EvaluationValue Evaluate( EvaluationContext context )
{
if (context == null) throw new ArgumentNullException("context");
EvaluationValue _evaluationValue = null;
context.Trace( "Evaluating condition..." );
context.AddIndent();
try
{
// Get the function instance
inf.IFunction function = EvaluationEngine.GetFunction( ApplyDefinition.FunctionId );
if( function == null )
{
context.Trace( "ERR: function not found {0}", ApplyDefinition.FunctionId );
context.ProcessingError = true;
return EvaluationValue.Indeterminate;
}
// Validates the function return value
if( function.Returns == null )
{
context.Trace( "The function '{0}' does not defines it's return value", ApplyDefinition.FunctionId );
_evaluationValue = EvaluationValue.Indeterminate;
context.ProcessingError = true;
}
else if( function.Returns != DataTypeDescriptor.Boolean )
{
context.Trace( "Function does not return Boolean a value" );
_evaluationValue = EvaluationValue.Indeterminate;
context.ProcessingError = true;
}
else
{
// Call the ApplyBase method to perform the evaluation.
_evaluationValue = base.Evaluate( context );
}
// Validate the results of the evaluation
if( _evaluationValue.IsIndeterminate )
{
context.Trace( "condition evaluated into {0}", _evaluationValue.ToString() );
return _evaluationValue;
}
if( !(_evaluationValue.Value is bool) )
{
context.Trace( "condition evaluated into {0}", _evaluationValue.ToString() );
return EvaluationValue.Indeterminate;
}
if( _evaluationValue.BoolValue )
{
context.Trace( "condition evaluated into {0}", _evaluationValue.ToString() );
return EvaluationValue.True;
}
else
{
// If the evaluation was false, validate if there was a missin attribute during
// evaluation and return an Indeterminate, otherwise return the False value.
if( context.IsMissingAttribute )
{
context.Trace( "condition evaluated into {0}", _evaluationValue.ToString() );
return EvaluationValue.Indeterminate;
}
else
{
context.Trace( "condition evaluated into {0}", _evaluationValue.ToString() );
return EvaluationValue.False;
}
}
}
finally
{
context.TraceContextValues();
context.RemoveIndent();
context.Trace( "Condition: {0}", _evaluationValue.ToString() );
}
}
/// <summary>
/// The evaluation implementation in the pseudo-code described in the specification.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="rules">The policies that must be evaluated.</param>
/// <returns>The final decission for the combination of the rule evaluation.</returns>
public Decision Evaluate(EvaluationContext context, RuleCollection rules)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
if (rules == null)
{
throw new ArgumentNullException("rules");
}
Decision decision = Decision.Indeterminate;
bool atLeastOneError = false;
bool potentialPermit = false;
bool atLeastOneDeny = false;
context.Trace("Evaluating rules...");
context.AddIndent();
try
{
foreach (Rule rule in rules)
{
decision = rule.Evaluate(context);
context.TraceContextValues();
if (decision == Decision.Deny)
{
atLeastOneDeny = true;
continue;
}
if (decision == Decision.Permit)
{
decision = Decision.Permit;
return(decision);
}
if (decision == Decision.NotApplicable)
{
continue;
}
if (decision == Decision.Indeterminate)
{
atLeastOneError = true;
if (rule.RuleDefinition.Effect == pol.Effect.Permit)
{
potentialPermit = true;
}
continue;
}
}
if (potentialPermit)
{
decision = Decision.Indeterminate;
return(decision);
}
if (atLeastOneDeny)
{
decision = Decision.Deny;
return(decision);
}
if (atLeastOneError)
{
decision = Decision.Indeterminate;
return(decision);
}
decision = Decision.NotApplicable;
return(decision);
}
finally
{
context.Trace("Rule combination algorithm: {0}", decision.ToString());
context.RemoveIndent();
}
}
/// <summary>
/// This method overrides the ApplyBase method in order to provide extra validations
/// required in the condition evaluation, for example the final return value should be a
/// boolean value.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The EvaluationValue with the results of the condition evaluation.</returns>
public override EvaluationValue Evaluate( EvaluationContext context )
{
if (context == null) throw new ArgumentNullException("context");
context.Trace( "Evaluating condition" );
context.AddIndent();
try
{
// Iterate through the arguments, the IExpressionType is a mark interface
foreach( inf.IExpression arg in ApplyDefinition.Arguments )
{
if( arg is pol.ApplyElement )
{
context.Trace( "Apply within condition." );
// There is a nested apply un this policy a new Apply will be created and also
// evaluated. It's return value will be used as the processed argument.
Apply _childApply = new Apply( (pol.ApplyElement)arg );
// Evaluate the Apply
EvaluationValue retVal = _childApply.Evaluate( context );
return retVal;
}
else if( arg is pol.FunctionElementReadWrite )
{
throw new NotImplementedException( "FunctionElement" ); //TODO:
}
else if( arg is pol.VariableReferenceElement )
{
pol.VariableReferenceElement variableRef = arg as pol.VariableReferenceElement;
VariableDefinition variableDef = context.CurrentPolicy.VariableDefinition[ variableRef.VariableId ] as VariableDefinition;
if( !variableDef.IsEvaluated )
{
return variableDef.Evaluate( context );
}
else
{
return variableDef.Value;
}
}
else if( arg is pol.AttributeValueElementReadWrite )
{
// The AttributeValue does not need to be processed
context.Trace( "Attribute value {0}", arg.ToString() );
pol.AttributeValueElement attributeValue = new pol.AttributeValueElement( ((pol.AttributeValueElementReadWrite)arg).DataType, ((pol.AttributeValueElementReadWrite)arg).Contents, ((pol.AttributeValueElementReadWrite)arg).SchemaVersion );
return new EvaluationValue(
attributeValue.GetTypedValue( attributeValue.GetType( context ), 0 ),
attributeValue.GetType( context ) );
}
else if( arg is pol.AttributeDesignatorBase )
{
// Returning an empty bag, since the condition is not supposed to work with a bag
context.Trace( "Processing attribute designator: {0}", arg.ToString() );
pol.AttributeDesignatorBase attrDes = (pol.AttributeDesignatorBase)arg;
BagValue bag = new BagValue( EvaluationEngine.GetDataType( attrDes.DataType ) );
return new EvaluationValue( bag, bag.GetType( context ) );
}
else if( arg is pol.AttributeSelectorElement )
{
// Returning an empty bag, since the condition is not supposed to work with a bag
context.Trace( "Attribute selector" );
pol.AttributeSelectorElement attrSel = (pol.AttributeSelectorElement)arg;
BagValue bag = new BagValue( EvaluationEngine.GetDataType( attrSel.DataType ) );
return new EvaluationValue( bag, bag.GetType( context ) );
}
}
throw new NotSupportedException( "internal error" );
}
finally
{
context.TraceContextValues();
context.RemoveIndent();
}
}
/// <summary>
/// Evaluates the policy.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The decission result for this policy.</returns>
public Decision Evaluate(EvaluationContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
context.Trace("Evaluating policy: {0}", _policy.Description);
context.AddIndent();
context.CurrentPolicy = this;
try
{
// Evaluate the variables
if (this._policy.SchemaVersion == XacmlVersion.Version20)
{
if (_variables == null)
{
context.Trace("Evaluating variables...");
_variables = new Hashtable();
foreach (pol.VariableDefinitionElement variableDef in _policy.VariableDefinitions.Values)
{
VariableDefinition variable = new VariableDefinition(variableDef);
_variables.Add(variableDef.Id, variable);
}
}
}
// Matches the target.
TargetEvaluationValue targetEvaluationValue = Match(context);
// If the target matches.
if (targetEvaluationValue == TargetEvaluationValue.Match)
{
context.Trace("Rule combination algorithm: {0}", _policy.RuleCombiningAlgorithm);
// Evaluate all rules and apply rule combination
inf.IRuleCombiningAlgorithm rca = EvaluationEngine.CreateRuleCombiningAlgorithm(_policy.RuleCombiningAlgorithm);
_evaluationValue = rca.Evaluate(context, _rules);
}
else if (targetEvaluationValue == TargetEvaluationValue.NoMatch)
{
_evaluationValue = Decision.NotApplicable;
}
else if (targetEvaluationValue == TargetEvaluationValue.Indeterminate)
{
_evaluationValue = Decision.Indeterminate;
}
context.Trace("Policy: {0}", _evaluationValue);
// Copy all the obligations.
_obligations = new pol.ObligationCollection();
if (_evaluationValue != Decision.Indeterminate &&
_evaluationValue != Decision.NotApplicable &&
_policy.Obligations != null && _policy.Obligations.Count != 0)
{
foreach (pol.ObligationElement obl in _policy.Obligations)
{
if ((obl.FulfillOn == pol.Effect.Deny && _evaluationValue == Decision.Deny) ||
(obl.FulfillOn == pol.Effect.Permit && _evaluationValue == Decision.Permit))
{
context.Trace("Adding obligation: {0} ", obl.ObligationId);
_obligations.Add(obl);
}
}
}
return(_evaluationValue);
}
finally
{
context.RemoveIndent();
context.CurrentPolicy = null;
}
}
/// <summary>
/// This method overrides the ApplyBase method in order to provide extra validations
/// required in the condition evaluation, for example the final return value should be a
/// boolean value.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The EvaluationValue with the results of the condition evaluation.</returns>
public override EvaluationValue Evaluate(EvaluationContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
EvaluationValue _evaluationValue = null;
context.Trace("Evaluating condition...");
context.AddIndent();
try
{
// Get the function instance
inf.IFunction function = EvaluationEngine.GetFunction(ApplyDefinition.FunctionId);
if (function == null)
{
context.Trace("ERR: function not found {0}", ApplyDefinition.FunctionId);
context.ProcessingError = true;
return(EvaluationValue.Indeterminate);
}
// Validates the function return value
if (function.Returns == null)
{
context.Trace("The function '{0}' does not defines it's return value", ApplyDefinition.FunctionId);
_evaluationValue = EvaluationValue.Indeterminate;
context.ProcessingError = true;
}
else if (function.Returns != DataTypeDescriptor.Boolean)
{
context.Trace("Function does not return Boolean a value");
_evaluationValue = EvaluationValue.Indeterminate;
context.ProcessingError = true;
}
else
{
// Call the ApplyBase method to perform the evaluation.
_evaluationValue = base.Evaluate(context);
}
// Validate the results of the evaluation
if (_evaluationValue.IsIndeterminate)
{
context.Trace("condition evaluated into {0}", _evaluationValue.ToString());
return(_evaluationValue);
}
if (!(_evaluationValue.Value is bool))
{
context.Trace("condition evaluated into {0}", _evaluationValue.ToString());
return(EvaluationValue.Indeterminate);
}
if (_evaluationValue.BoolValue)
{
context.Trace("condition evaluated into {0}", _evaluationValue.ToString());
return(EvaluationValue.True);
}
else
{
// If the evaluation was false, validate if there was a missin attribute during
// evaluation and return an Indeterminate, otherwise return the False value.
if (context.IsMissingAttribute)
{
context.Trace("condition evaluated into {0}", _evaluationValue.ToString());
return(EvaluationValue.Indeterminate);
}
else
{
context.Trace("condition evaluated into {0}", _evaluationValue.ToString());
return(EvaluationValue.False);
}
}
}
finally
{
context.TraceContextValues();
context.RemoveIndent();
context.Trace("Condition: {0}", _evaluationValue.ToString());
}
}
/// <summary>
/// Matches this target instance using the context document.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The results of the evaluation of this target.</returns>
public TargetEvaluationValue Evaluate( EvaluationContext context )
{
if (context == null) throw new ArgumentNullException("context");
// Set the default value.
_evaluationValue = TargetEvaluationValue.NoMatch;
// Resource
context.Trace( "Evaluating Resource..." );
context.AddIndent();
TargetEvaluationValue resourceEval = _resources.Evaluate( context, context.CurrentResource );
context.TraceContextValues();
context.Trace( "Target item result: {0}", resourceEval );
context.RemoveIndent();
// Action
context.Trace( "Evaluating Action..." );
context.AddIndent();
TargetEvaluationValue actionEval = _actions.Evaluate( context, context.ContextDocument.Request.Action );
context.TraceContextValues();
context.Trace( "Target item result: {0}", actionEval );
context.RemoveIndent();
context.Trace( "Evaluating Subjects..." );
context.AddIndent();
if( actionEval == TargetEvaluationValue.Match && resourceEval == TargetEvaluationValue.Match )
{
// Subjects
foreach( ctx.SubjectElement ctxSubject in context.ContextDocument.Request.Subjects )
{
context.Trace( "Evaluating Subject: {0}", ctxSubject.SubjectCategory );
// Subject
TargetEvaluationValue subjectEval = _subjects.Evaluate( context, ctxSubject );
context.TraceContextValues();
if( subjectEval == TargetEvaluationValue.Indeterminate )
{
_evaluationValue = TargetEvaluationValue.Indeterminate;
}
else if( subjectEval == TargetEvaluationValue.Match )
{
_evaluationValue = TargetEvaluationValue.Match;
context.RemoveIndent();
context.Trace( "Target item result: {0}", _evaluationValue );
return _evaluationValue;
}
}
context.RemoveIndent();
context.Trace( "Target item result: {0}", _evaluationValue );
return _evaluationValue;
}
else
{
context.Trace( "Actions or Resources does not Match so Subjects will not be evaluated" );
if( resourceEval == TargetEvaluationValue.Indeterminate || actionEval == TargetEvaluationValue.Indeterminate )
{
context.RemoveIndent();
return TargetEvaluationValue.Indeterminate;
}
else
{
context.RemoveIndent();
return TargetEvaluationValue.NoMatch;
}
}
}
/// <summary>
/// Evaluates the function.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="args">The function arguments.</param>
/// <returns>The result value of the function evaluation.</returns>
public override EvaluationValue Evaluate( EvaluationContext context, params inf.IFunctionParameter[] args )
{
if (context == null) throw new ArgumentNullException("context");
if (args == null) throw new ArgumentNullException("args");
try
{
if( GetAnyUriArgument( args, 0 ).Equals( GetAnyUriArgument( args, 1 ) ) )
{
return EvaluationValue.True;
}
else
{
return EvaluationValue.False;
}
}
catch( EvaluationException e )
{
context.Trace( Resource.TRACE_ERROR, e.Message );
return EvaluationValue.False;
}
}
/// <summary>
/// Evaluates the policy.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The decission result for this policy.</returns>
public Decision Evaluate( EvaluationContext context )
{
if (context == null) throw new ArgumentNullException("context");
context.Trace( "Evaluating policy: {0}", _policy.Description );
context.AddIndent();
context.CurrentPolicy = this;
try
{
// Evaluate the variables
if( this._policy.SchemaVersion == XacmlVersion.Version20 )
{
if( _variables == null )
{
context.Trace( "Evaluating variables..." );
_variables = new Hashtable();
foreach( pol.VariableDefinitionElement variableDef in _policy.VariableDefinitions.Values )
{
VariableDefinition variable = new VariableDefinition( variableDef );
_variables.Add( variableDef.Id, variable );
}
}
}
// Matches the target.
TargetEvaluationValue targetEvaluationValue = Match( context );
// If the target matches.
if( targetEvaluationValue == TargetEvaluationValue.Match )
{
context.Trace( "Rule combination algorithm: {0}", _policy.RuleCombiningAlgorithm );
// Evaluate all rules and apply rule combination
inf.IRuleCombiningAlgorithm rca = EvaluationEngine.CreateRuleCombiningAlgorithm( _policy.RuleCombiningAlgorithm );
_evaluationValue = rca.Evaluate( context, _rules );
}
else if( targetEvaluationValue == TargetEvaluationValue.NoMatch )
{
_evaluationValue = Decision.NotApplicable;
}
else if( targetEvaluationValue == TargetEvaluationValue.Indeterminate )
{
_evaluationValue = Decision.Indeterminate;
}
context.Trace( "Policy: {0}", _evaluationValue );
// Copy all the obligations.
_obligations = new pol.ObligationCollection();
if( _evaluationValue != Decision.Indeterminate &&
_evaluationValue != Decision.NotApplicable &&
_policy.Obligations != null && _policy.Obligations.Count != 0 )
{
foreach( pol.ObligationElement obl in _policy.Obligations )
{
if( ( obl.FulfillOn == pol.Effect.Deny && _evaluationValue == Decision.Deny ) ||
( obl.FulfillOn == pol.Effect.Permit && _evaluationValue == Decision.Permit ) )
{
context.Trace( "Adding obligation: {0} ", obl.ObligationId );
_obligations.Add( obl );
}
}
}
return _evaluationValue;
}
finally
{
context.RemoveIndent();
context.CurrentPolicy = null;
}
}
/// <summary>
/// The evaluation implementation in the pseudo-code described in the specification.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="rules">The policies that must be evaluated.</param>
/// <returns>The final decission for the combination of the rule evaluation.</returns>
public Decision Evaluate( EvaluationContext context, RuleCollection rules )
{
Decision decision = Decision.Indeterminate;
bool atLeastOneError = false;
bool potentialDeny = false;
bool atLeastOnePermit = false;
context.Trace( "Evaluating rules..." );
context.AddIndent();
try
{
foreach( Rule rule in rules )
{
decision = rule.Evaluate( context );
context.TraceContextValues();
if( decision == Decision.Deny )
{
decision = Decision.Deny;
return decision;
}
if( decision == Decision.Permit )
{
atLeastOnePermit = true;
continue;
}
if( decision == Decision.NotApplicable )
{
continue;
}
if( decision == Decision.Indeterminate )
{
atLeastOneError = true;
if( rule.RuleDefinition.Effect == pol.Effect.Deny )
{
potentialDeny = true;
}
continue;
}
}
if( potentialDeny )
{
decision = Decision.Indeterminate;
return decision;
}
if( atLeastOnePermit )
{
decision = Decision.Permit;
return decision;
}
if( atLeastOneError )
{
decision = Decision.Indeterminate;
return decision;
}
decision = Decision.NotApplicable;
return decision;
}
finally
{
context.Trace( "Rule combination algorithm: {0}", decision.ToString() );
context.RemoveIndent();
}
}
/// <summary>
/// Evaluates the variable into a value.
/// </summary>
/// <param name="context">The contex of the evaluation.</param>
/// <returns>The value of the function.</returns>
public EvaluationValue Evaluate(EvaluationContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
context.Trace("Evaluating variable");
context.AddIndent();
try
{
if (_variableDefinition.Expression is pol.ApplyElement)
{
context.Trace("Apply within condition.");
// There is a nested apply un this policy a new Apply will be created and also
// evaluated. It's return value will be used as the processed argument.
Apply _childApply = new Apply((pol.ApplyElement)_variableDefinition.Expression);
// Evaluate the Apply
_value = _childApply.Evaluate(context);
context.TraceContextValues();
return(_value);
}
else if (_variableDefinition.Expression is pol.FunctionElement)
{
throw new NotImplementedException("FunctionElement"); //TODO:
}
else if (_variableDefinition.Expression is pol.VariableReferenceElement)
{
pol.VariableReferenceElement variableRef = _variableDefinition.Expression as pol.VariableReferenceElement;
VariableDefinition variableDef = context.CurrentPolicy.VariableDefinition[variableRef.VariableId] as VariableDefinition;
context.TraceContextValues();
if (!variableDef.IsEvaluated)
{
return(variableDef.Evaluate(context));
}
else
{
return(variableDef.Value);
}
}
else if (_variableDefinition.Expression is pol.AttributeValueElementReadWrite)
{
// The AttributeValue does not need to be processed
context.Trace("Attribute value {0}", _variableDefinition.Expression.ToString());
pol.AttributeValueElementReadWrite att = (pol.AttributeValueElementReadWrite)_variableDefinition.Expression;
pol.AttributeValueElement attributeValue = new pol.AttributeValueElement(att.DataType, att.Contents, att.SchemaVersion);
_value = new EvaluationValue(
attributeValue.GetTypedValue(attributeValue.GetType(context), 0),
attributeValue.GetType(context));
return(_value);
}
else if (_variableDefinition.Expression is pol.AttributeDesignatorBase)
{
// Resolve the AttributeDesignator using the EvaluationEngine public methods.
context.Trace("Processing attribute designator: {0}", _variableDefinition.Expression.ToString());
pol.AttributeDesignatorBase attrDes = (pol.AttributeDesignatorBase)_variableDefinition.Expression;
BagValue bag = EvaluationEngine.Resolve(context, attrDes);
// If the attribute was not resolved by the EvaluationEngine search the
// attribute in the context document, also using the EvaluationEngine public
// methods.
if (bag.BagSize == 0)
{
if (_variableDefinition.Expression is pol.SubjectAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding subject attribute designator: {0}", attrib.ToString());
bag.Add(attrib);
}
}
else if (_variableDefinition.Expression is pol.ResourceAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding resource attribute designator {0}", attrib.ToString());
bag.Add(attrib);
}
}
else if (_variableDefinition.Expression is pol.ActionAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding action attribute designator {0}", attrib.ToString());
bag.Add(attrib);
}
}
else if (_variableDefinition.Expression is pol.EnvironmentAttributeDesignatorElement)
{
ctx.AttributeElement attrib = EvaluationEngine.GetAttribute(context, attrDes);
if (attrib != null)
{
context.Trace("Adding environment attribute designator {0}", attrib.ToString());
bag.Add(attrib);
}
}
}
// If the argument was not found and the attribute must be present this is
// a MissingAttribute situation so set the flag. Otherwise add the attribute
// to the processed arguments.
if (bag.BagSize == 0 && attrDes.MustBePresent)
{
context.Trace("Attribute is missing");
context.IsMissingAttribute = true;
context.AddMissingAttribute(attrDes);
_value = EvaluationValue.Indeterminate;
}
else
{
_value = new EvaluationValue(bag, bag.GetType(context));
}
return(_value);
}
else if (_variableDefinition.Expression is pol.AttributeSelectorElement)
{
// Resolve the XPath query using the EvaluationEngine public methods.
context.Trace("Attribute selector");
try
{
pol.AttributeSelectorElement attributeSelector = (pol.AttributeSelectorElement)_variableDefinition.Expression;
BagValue bag = EvaluationEngine.Resolve(context, attributeSelector);
if (bag.Elements.Count == 0 && attributeSelector.MustBePresent)
{
context.Trace("Attribute is missing");
context.IsMissingAttribute = true;
context.AddMissingAttribute(attributeSelector);
_value = EvaluationValue.Indeterminate;
}
else
{
_value = new EvaluationValue(bag, bag.GetType(context));
}
}
catch (EvaluationException e)
{
context.Trace("ERR: {0}", e.Message);
context.ProcessingError = true;
_value = EvaluationValue.Indeterminate;
}
return(_value);
}
throw new NotSupportedException("internal error");
}
finally
{
_isEvaluated = true;
context.RemoveIndent();
}
}
/// <summary>
/// Evaluate the context document using a specified policy
/// </summary>
/// <param name="contextDocument">The context document instance</param>
/// <returns>The response document.</returns>
public ctx.ResponseElement Evaluate( ctx.ContextDocument contextDocument )
{
EvaluationContext context = new EvaluationContext( this, null, contextDocument );
try
{
// Validates the configuration file was found.
if( ConfigurationRoot.Config != null )
{
// Search all the policies repositories to find a policy that matches the
// context document
pol.PolicyDocument policyDocument = null;
foreach( inf.IPolicyRepository policyRep in ConfigurationRoot.Config.PolicyRepositories )
{
if( policyDocument == null )
{
policyDocument = policyRep.Match( context );
}
else
{
throw new EvaluationException( Resource.ResourceManager[ Resource.MessageKey.exc_duplicated_policy_in_repository ] );
}
}
// If the policy was found evaluate the context document, otherwise use the
// Evaluate method to generate a Response context document.
if( policyDocument != null )
{
return Evaluate( policyDocument, contextDocument );
}
return Evaluate(null, null);
}
throw new EvaluationException(Resource.ResourceManager[ Resource.MessageKey.exc_configuration_file_not_found]);
}
catch( EvaluationException e )
{
context.Trace( Resource.TRACE_ERROR, e.Message );
}
return Evaluate(null, null);
}
/// <summary>
/// Verifies if the rule target matches
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The result of the Match process.</returns>
public TargetEvaluationValue Match( EvaluationContext context )
{
if (context == null) throw new ArgumentNullException("context");
TargetEvaluationValue targetEvaluationValue = TargetEvaluationValue.Indeterminate;
context.Trace( "Evaluating rule target" );
context.AddIndent();
try
{
// Evaluate the policy target
targetEvaluationValue = TargetEvaluationValue.Match;
if( _target != null )
{
targetEvaluationValue = _target.Evaluate( context );
context.TraceContextValues();
}
return targetEvaluationValue;
}
finally
{
context.RemoveIndent();
context.Trace( "Target: {0}", targetEvaluationValue );
}
}
/// <summary>
/// Evaluate the context document using a specified policy
/// </summary>
/// <param name="policyDocument">The policy instance</param>
/// <param name="contextDocument">The context document instance</param>
/// <returns>The response document</returns>
public ctx.ResponseElement Evaluate( pol.PolicyDocument policyDocument, ctx.ContextDocument contextDocument )
{
if (policyDocument == null) throw new ArgumentNullException("policyDocument");
if (contextDocument == null) throw new ArgumentNullException("contextDocument");
EvaluationContext context = new EvaluationContext( this, policyDocument, (ctx.ContextDocument)contextDocument ) ;
context.Trace( "Start evaluation" );
context.AddIndent();
if ( policyDocument == null || contextDocument == null )
{
// If a validation error was found a response is created with the syntax error message
ctx.ResponseElement response =
new ctx.ResponseElement(
new ctx.ResultElement[] {
new ctx.ResultElement(
null,
Decision.Indeterminate,
new ctx.StatusElement(
new ctx.StatusCodeElement( StatusCodes.ProcessingError, null, policyDocument.Version ),
null,
null, policyDocument.Version ),
null, policyDocument.Version ) },
policyDocument.Version );
return response;
}
// Check if both documents are valid
if( !policyDocument.IsValidDocument || !contextDocument.IsValidDocument )
{
// If a validation error was found a response is created with the syntax error message
ctx.ResponseElement response =
new ctx.ResponseElement(
new ctx.ResultElement[] {
new ctx.ResultElement(
null,
Decision.Indeterminate,
new ctx.StatusElement(
new ctx.StatusCodeElement( StatusCodes.SyntaxError, null, policyDocument.Version ),
null,
null, policyDocument.Version ),
null, policyDocument.Version ) },
policyDocument.Version );
return response;
}
// Create a new response
contextDocument.Response = new ctx.ResponseElement( (ctx.ResultElement[])null, policyDocument.Version );
try
{
// Create the evaluable policy intance
IMatchEvaluable policy = null;
if( policyDocument.PolicySet != null )
{
policy = new PolicySet( this, (pol.PolicySetElement)policyDocument.PolicySet );
}
else if( policyDocument.Policy != null )
{
policy = new Policy( (pol.PolicyElement)policyDocument.Policy );
}
// Evaluate the policy or policy set
if( policy != null )
{
// Creates the evaluable policy set
if( policy.AllResources.Count == 0 )
{
policy.AllResources.Add( "" );
}
string requestedResourceString = String.Empty;
Uri requestedResource = null;
foreach( ctx.ResourceElement resource in contextDocument.Request.Resources )
{
// Keep the requested resource
if( resource.IsHierarchical )
{
foreach( ctx.AttributeElement attribute in resource.Attributes )
{
if( attribute.AttributeId == ResourceElement.ResourceId )
{
if( context.PolicyDocument.Version == XacmlVersion.Version10 ||
context.PolicyDocument.Version == XacmlVersion.Version11 )
{
requestedResourceString = attribute.AttributeValues[0].Contents;
}
else
{
if( attribute.AttributeValues.Count > 1 )
{
throw new NotSupportedException( "resources contains a bag of values" );
}
requestedResourceString = attribute.AttributeValues[0].Contents;
}
}
}
if( !string.IsNullOrEmpty(requestedResourceString) )
{
requestedResource = new Uri( requestedResourceString );
}
}
// Iterate through the policy resources evaluating each resource in the context document request
foreach( string resourceName in policy.AllResources )
{
bool mustEvaluate;
if( resource.IsHierarchical )
{
//Validate if the resource is hierarchically desdendant or children
//of the requested resource
Uri policyResource = new Uri( resourceName );
if( !(mustEvaluate = requestedResource.Equals( policyResource ) ) )
{
// Perform the hierarchical evaluation
if( resource.ResourceScopeValue == ctx.ResourceScope.Children )
{
mustEvaluate = typ.AnyUri.IsChildrenOf( requestedResource, policyResource );
}
else if( resource.ResourceScopeValue == ctx.ResourceScope.Descendants )
{
mustEvaluate = typ.AnyUri.IsDescendantOf( requestedResource, policyResource );
}
}
if( mustEvaluate )
{
foreach( ctx.AttributeElementReadWrite attribute in context.CurrentResource.Attributes )
{
if( attribute.AttributeId == ResourceElement.ResourceId )
{
attribute.AttributeValues[0].Contents = resourceName;
break;
}
}
}
}
else
{
context.CurrentResource = resource;
mustEvaluate = true;
}
if( mustEvaluate )
{
// Evaluates the policy set
Decision decision = policy.Evaluate( context );
// Create a status code using the policy execution state
ctx.StatusCodeElement scode;
if( context.IsMissingAttribute )
{
scode = new ctx.StatusCodeElement(
StatusCodes.MissingAttribute, null, policyDocument.Version );
}
else if( context.ProcessingError )
{
scode = new ctx.StatusCodeElement(
StatusCodes.ProcessingError, null, policyDocument.Version );
}
else
{
scode = new ctx.StatusCodeElement(
StatusCodes.OK, null, policyDocument.Version );
}
//Stop the iteration if there is not a hierarchical request
if( !resource.IsHierarchical )
{
// Ussually when a single resource is requested the ResourceId is not specified in the result
IObligationsContainer oblig = policy as IObligationsContainer;
contextDocument.Response.Results.Add(
new ctx.ResultElement( "", decision,
new ctx.StatusElement( scode, "", "", policyDocument.Version ), oblig.Obligations, policyDocument.Version ) );
break;
}
else
{
// Adding a resource for each requested resource, using the resourceName as the resourceId of the result
IObligationsContainer oblig = policy as IObligationsContainer;
contextDocument.Response.Results.Add(
new ctx.ResultElement( resourceName, decision,
new ctx.StatusElement( scode, "", "", policyDocument.Version ), oblig.Obligations, policyDocument.Version ) );
}
} // if( mustEvaluate )
} // foreach( string resourceName in policy.AllResources )
}
} //if( policy != null )
}
catch( EvaluationException e )
{
// If a validation error was found a response is created with the syntax error message
contextDocument.Response =
new ctx.ResponseElement(
new ctx.ResultElement[] {
new ctx.ResultElement(
null,
Decision.Indeterminate,
new ctx.StatusElement(
new ctx.StatusCodeElement( StatusCodes.ProcessingError, null, policyDocument.Version ),
e.Message,
e.StackTrace, policyDocument.Version ),
null, policyDocument.Version ) },
policyDocument.Version );
}
return contextDocument.Response;
}
/// <summary>
/// Matches this target instance using the context document.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <returns>The results of the evaluation of this target.</returns>
public TargetEvaluationValue Evaluate(EvaluationContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
// Set the default value.
_evaluationValue = TargetEvaluationValue.NoMatch;
// Resource
context.Trace("Evaluating Resource...");
context.AddIndent();
TargetEvaluationValue resourceEval = _resources.Evaluate(context, context.CurrentResource);
context.TraceContextValues();
context.Trace("Target item result: {0}", resourceEval);
context.RemoveIndent();
// Action
context.Trace("Evaluating Action...");
context.AddIndent();
TargetEvaluationValue actionEval = _actions.Evaluate(context, context.ContextDocument.Request.Action);
context.TraceContextValues();
context.Trace("Target item result: {0}", actionEval);
context.RemoveIndent();
context.Trace("Evaluating Subjects...");
context.AddIndent();
if (actionEval == TargetEvaluationValue.Match && resourceEval == TargetEvaluationValue.Match)
{
// Subjects
foreach (ctx.SubjectElement ctxSubject in context.ContextDocument.Request.Subjects)
{
context.Trace("Evaluating Subject: {0}", ctxSubject.SubjectCategory);
// Subject
TargetEvaluationValue subjectEval = _subjects.Evaluate(context, ctxSubject);
context.TraceContextValues();
if (subjectEval == TargetEvaluationValue.Indeterminate)
{
_evaluationValue = TargetEvaluationValue.Indeterminate;
}
else if (subjectEval == TargetEvaluationValue.Match)
{
_evaluationValue = TargetEvaluationValue.Match;
context.RemoveIndent();
context.Trace("Target item result: {0}", _evaluationValue);
return(_evaluationValue);
}
}
context.RemoveIndent();
context.Trace("Target item result: {0}", _evaluationValue);
return(_evaluationValue);
}
else
{
context.Trace("Actions or Resources does not Match so Subjects will not be evaluated");
if (resourceEval == TargetEvaluationValue.Indeterminate || actionEval == TargetEvaluationValue.Indeterminate)
{
context.RemoveIndent();
return(TargetEvaluationValue.Indeterminate);
}
else
{
context.RemoveIndent();
return(TargetEvaluationValue.NoMatch);
}
}
}
/// <summary>
/// Resolves the AttributeSelector in the context document using the XPath sentence.
/// </summary>
/// <param name="context">The evaluation context instance.</param>
/// <param name="attributeSelector">The attribute selector.</param>
/// <returns>A bag of values with the contents of the node.</returns>
public static BagValue Resolve( EvaluationContext context, pol.AttributeSelectorElement attributeSelector )
{
BagValue bagValue = new BagValue( GetDataType( attributeSelector.DataType ) );
ctx.ResourceContentElement content = (ctx.ResourceContentElement)context.CurrentResource.ResourceContent;
if( content != null )
{
XmlDocument doc = context.ContextDocument.XmlDocument;
if( context.ContextDocument.XmlNamespaceManager == null )
{
context.ContextDocument.AddNamespaces( context.PolicyDocument.Namespaces );
}
try
{
string xpath = attributeSelector.RequestContextPath;
XmlNodeList nodeList = doc.DocumentElement.SelectNodes( xpath, context.ContextDocument.XmlNamespaceManager );
if( nodeList != null )
{
foreach( XmlNode node in nodeList )
{
pol.AttributeValueElement ave =
new pol.AttributeValueElement(
attributeSelector.DataType,
node.InnerText,
attributeSelector.SchemaVersion );
bagValue.Add( ave );
}
}
}
catch( XPathException e )
{
context.Trace( Resource.TRACE_ERROR, e.Message );
bagValue = new BagValue( GetDataType( attributeSelector.DataType ) );
}
}
return bagValue;
}
