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ServiceAuthorizationManager.CheckAccess Method

  • Reference

Definition

Namespace:
System.ServiceModel
Assembly:
System.ServiceModel.dll

Checks authorization for the given operation context and optional message.

Overloads

CheckAccess(OperationContext)

Checks authorization for the given operation context.
CheckAccess(OperationContext, Message)

Checks authorization for the given operation context when access to a message is required.

CheckAccess(OperationContext)

Checks authorization for the given operation context.

public:
 virtual bool CheckAccess(System::ServiceModel::OperationContext ^ operationContext);
public virtual bool CheckAccess (System.ServiceModel.OperationContext operationContext);
abstract member CheckAccess : System.ServiceModel.OperationContext -> bool
override this.CheckAccess : System.ServiceModel.OperationContext -> bool
Public Overridable Function CheckAccess (operationContext As OperationContext) As Boolean

Parameters

operationContext
OperationContext

The OperationContext.

Returns

Boolean

true if access is granted; otherwise, false. The default is true.

Examples

The following code shows how to override this method to enforce custom access control requirements.

public class myServiceAuthorizationManager : ServiceAuthorizationManager
{
    // Override the CheckAccess method to enforce access control requirements.
    public override bool CheckAccess(OperationContext operationContext)
    {
        AuthorizationContext authContext =
        operationContext.ServiceSecurityContext.AuthorizationContext;
        if (authContext.ClaimSets == null) return false;
        if (authContext.ClaimSets.Count != 1) return false;
        ClaimSet myClaimSet = authContext.ClaimSets[0];
        if (!IssuedBySTS_B(myClaimSet)) return false;
        if (myClaimSet.Count != 1) return false;
        Claim myClaim = myClaimSet[0];
        if (myClaim.ClaimType ==
          "http://www.tmpuri.org:accessAuthorized")
        {
            string resource = myClaim.Resource as string;
            if (resource == null) return false;
            if (resource != "true") return false;
            return true;
        }
        else
        {
            return false;
        }
    }

    // This helper method checks whether SAML Token was issued by STS-B.
    // It compares the Thumbprint Claim of the Issuer against the
    // Certificate of STS-B.
    private bool IssuedBySTS_B(ClaimSet myClaimSet)
    {
        ClaimSet issuerClaimSet = myClaimSet.Issuer;
        if (issuerClaimSet == null) return false;
        if (issuerClaimSet.Count != 1) return false;
        Claim issuerClaim = issuerClaimSet[0];
        if (issuerClaim.ClaimType != ClaimTypes.Thumbprint)
            return false;
        if (issuerClaim.Resource == null) return false;
        byte[] claimThumbprint = (byte[])issuerClaim.Resource;
        // It is assumed that stsB_Certificate is a variable of type
        // X509Certificate2 that is initialized with the Certificate of
        // STS-B.
        X509Certificate2 stsB_Certificate = GetStsBCertificate();
        byte[] certThumbprint = stsB_Certificate.GetCertHash();
        if (claimThumbprint.Length != certThumbprint.Length)
            return false;
        for (int i = 0; i < claimThumbprint.Length; i++)
        {
            if (claimThumbprint[i] != certThumbprint[i]) return false;
        }
        return true;
    }

Public Class myServiceAuthorizationManager
    Inherits ServiceAuthorizationManager

    ' Override the CheckAccess method to enforce access control requirements.
    Public Overloads Overrides Function CheckAccess(ByVal operationContext As OperationContext) As Boolean
        Dim authContext = operationContext.ServiceSecurityContext.AuthorizationContext
        If authContext.ClaimSets Is Nothing Then
            Return False
        End If

        If authContext.ClaimSets.Count <> 1 Then
            Return False
        End If

        Dim myClaimSet = authContext.ClaimSets(0)
        If Not IssuedBySTS_B(myClaimSet) Then
            Return False
        End If
        If myClaimSet.Count <> 1 Then
            Return False
        End If
        Dim myClaim = myClaimSet(0)
        If myClaim.ClaimType = "http://www.tmpuri.org:accessAuthorized" Then
            Dim resource = TryCast(myClaim.Resource, String)
            If resource Is Nothing Then
                Return False
            End If
            If resource <> "true" Then
                Return False
            End If
            Return True
        Else
            Return False
        End If
    End Function

    ' This helper method checks whether SAML Token was issued by STS-B.     
    ' It compares the Thumbprint Claim of the Issuer against the 
    ' Certificate of STS-B. 
    Private Function IssuedBySTS_B(ByVal myClaimSet As ClaimSet) As Boolean
        Dim issuerClaimSet = myClaimSet.Issuer
        If issuerClaimSet Is Nothing Then
            Return False
        End If
        If issuerClaimSet.Count <> 1 Then
            Return False
        End If
        Dim issuerClaim = issuerClaimSet(0)
        If issuerClaim.ClaimType <> ClaimTypes.Thumbprint Then
            Return False
        End If
        If issuerClaim.Resource Is Nothing Then
            Return False
        End If
        Dim claimThumbprint() = CType(issuerClaim.Resource, Byte())
        ' It is assumed that stsB_Certificate is a variable of type 
        ' X509Certificate2 that is initialized with the Certificate of 
        ' STS-B.
        Dim stsB_Certificate = GetStsBCertificate()
        Dim certThumbprint() = stsB_Certificate.GetCertHash()
        If claimThumbprint.Length <> certThumbprint.Length Then
            Return False
        End If
        For i = 0 To claimThumbprint.Length - 1
            If claimThumbprint(i) <> certThumbprint(i) Then
                Return False
            End If
        Next i
        Return True
    End Function

Remarks

In general, applications should override CheckAccessCore instead of this method.

Override CheckAccess if the application associates or introduces a different set of policies for the resulting ServiceSecurityContext or provide a different policy evaluation (chaining) model.

This method is responsible for calling CheckAccessCore.

Applies to

CheckAccess(OperationContext, Message)

Checks authorization for the given operation context when access to a message is required.

public:
 virtual bool CheckAccess(System::ServiceModel::OperationContext ^ operationContext, System::ServiceModel::Channels::Message ^ % message);
public virtual bool CheckAccess (System.ServiceModel.OperationContext operationContext, ref System.ServiceModel.Channels.Message message);
abstract member CheckAccess : System.ServiceModel.OperationContext * Message -> bool
override this.CheckAccess : System.ServiceModel.OperationContext * Message -> bool
Public Overridable Function CheckAccess (operationContext As OperationContext, ByRef message As Message) As Boolean

Parameters

operationContext
OperationContext

The OperationContext.

message
Message

The Message to be examined to determine authorization.

Returns

Boolean

true if access is granted; otherwise, false. The default is true.

Examples

The following code shows how to override this method to enforce custom access control requirements that require access to the message body.

public class myService_M_AuthorizationManager : ServiceAuthorizationManager
{
    // set max size for message
    int someMaxSize = 16000;
    protected override bool CheckAccessCore(OperationContext operationContext, ref Message message)
    {
        bool accessAllowed = false;
        MessageBuffer requestBuffer = message.CreateBufferedCopy(someMaxSize);

        // do access checks using the message parameter value and set accessAllowed appropriately
        if (accessAllowed)
        {
            // replace incoming message with fresh copy since accessing the message consumes it
            message = requestBuffer.CreateMessage();
        }
        return accessAllowed;
    }
}

Public Class myService_M_AuthorizationManager
    Inherits ServiceAuthorizationManager

    ' set max size for message
    Private someMaxSize As Integer = 16000

    Public Overrides Function CheckAccess(ByVal operationContext As OperationContext, _
                                          ByRef message As Message) As Boolean
        Dim accessAllowed = False
        Dim requestBuffer = Message.CreateBufferedCopy(someMaxSize)

        ' do access checks using the message parameter value and set accessAllowed appropriately
        If accessAllowed Then
            ' replace incoming message with fresh copy since accessing the message consumes it
            Message = requestBuffer.CreateMessage()
        End If
        Return accessAllowed
    End Function
End Class

Remarks

In general, applications should override CheckAccessCore instead of this method, which should only be used if the authorization decision depends on the message body. Because of performance issues, if possible you should redesign your application so that the authorization decision does not require access to the message body.

Override this method if the application associates or introduces a different set of policies for the resulting ServiceSecurityContext and Message or provide a different policy evaluation (chaining) model.

This method is responsible for calling CheckAccessCore.

Applies to