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//-----------------------------------------------------------------------
// <copyright file="OAuthAuthorizationServer.cs" company="Andrew Arnott">
// Copyright (c) Andrew Arnott. All rights reserved.
// </copyright>
//-----------------------------------------------------------------------
namespace RelyingPartyLogic {
using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Web;
using DotNetOpenAuth.Messaging.Bindings;
using DotNetOpenAuth.OAuth2;
using DotNetOpenAuth.OAuth2.ChannelElements;
using DotNetOpenAuth.OAuth2.Messages;
/// <summary>
/// Provides OAuth 2.0 authorization server information to DotNetOpenAuth.
/// </summary>
public class OAuthAuthorizationServer : IAuthorizationServer {
private static readonly RSAParameters AsymmetricKey = CreateRSAKey();
private readonly INonceStore nonceStore = new NonceDbStore();
/// <summary>
/// Initializes a new instance of the <see cref="OAuthAuthorizationServer"/> class.
/// </summary>
public OAuthAuthorizationServer() {
this.CryptoKeyStore = new RelyingPartyApplicationDbStore();
}
#region IAuthorizationServer Members
public ICryptoKeyStore CryptoKeyStore { get; private set; }
/// <summary>
/// Gets the authorization code nonce store to use to ensure that authorization codes can only be used once.
/// </summary>
/// <value>The authorization code nonce store.</value>
public INonceStore VerificationCodeNonceStore {
get { return this.nonceStore; }
}
public RSACryptoServiceProvider CreateAccessTokenSigningCryptoServiceProvider() {
return CreateAsymmetricKeyServiceProvider();
}
/// <summary>
/// Gets the client with a given identifier.
/// </summary>
/// <param name="clientIdentifier">The client identifier.</param>
/// <returns>The client registration. Never null.</returns>
/// <exception cref="ArgumentException">Thrown when no client with the given identifier is registered with this authorization server.</exception>
public IConsumerDescription GetClient(string clientIdentifier) {
try {
return Database.DataContext.Clients.First(c => c.ClientIdentifier == clientIdentifier);
} catch (InvalidOperationException ex) {
throw new ArgumentOutOfRangeException("No client by that identifier.", ex);
}
}
/// <summary>
/// Determines whether a described authorization is (still) valid.
/// </summary>
/// <param name="authorization">The authorization.</param>
/// <returns>
/// <c>true</c> if the original authorization is still valid; otherwise, <c>false</c>.
/// </returns>
/// <remarks>
/// <para>When establishing that an authorization is still valid,
/// it's very important to only match on recorded authorizations that
/// meet these criteria:</para>
/// 1) The client identifier matches.
/// 2) The user account matches.
/// 3) The scope on the recorded authorization must include all scopes in the given authorization.
/// 4) The date the recorded authorization was issued must be <em>no later</em> that the date the given authorization was issued.
/// <para>One possible scenario is where the user authorized a client, later revoked authorization,
/// and even later reinstated authorization. This subsequent recorded authorization
/// would not satisfy requirement #4 in the above list. This is important because the revocation
/// the user went through should invalidate all previously issued tokens as a matter of
/// security in the event the user was revoking access in order to sever authorization on a stolen
/// account or piece of hardware in which the tokens were stored. </para>
/// </remarks>
public bool IsAuthorizationValid(IAuthorizationDescription authorization) {
return this.IsAuthorizationValid(authorization.Scope, authorization.ClientIdentifier, authorization.UtcIssued, authorization.User);
}
#endregion
public bool CanBeAutoApproved(EndUserAuthorizationRequest authorizationRequest) {
if (authorizationRequest == null) {
throw new ArgumentNullException("authorizationRequest");
}
// NEVER issue an auto-approval to a client that would end up getting an access token immediately
// (without a client secret), as that would allow ANY client to spoof an approved client's identity
// and obtain unauthorized access to user data.
if (authorizationRequest.ResponseType == EndUserAuthorizationResponseType.AuthorizationCode) {
// Never issue auto-approval if the client secret is blank, since that too makes it easy to spoof
// a client's identity and obtain unauthorized access.
var requestingClient = Database.DataContext.Clients.First(c => c.ClientIdentifier == authorizationRequest.ClientIdentifier);
if (!string.IsNullOrEmpty(requestingClient.ClientSecret)) {
return this.IsAuthorizationValid(
authorizationRequest.Scope,
authorizationRequest.ClientIdentifier,
DateTime.UtcNow,
HttpContext.Current.User.Identity.Name);
}
}
// Default to not auto-approving.
return false;
}
/// <summary>
/// Creates the asymmetric crypto service provider.
/// </summary>
/// <returns>An RSA crypto service provider.</returns>
/// <remarks>
/// Since <see cref="RSACryptoServiceProvider"/> are not thread-safe, one must be created for each thread.
/// In this sample we just create one for each incoming request. Be sure to call Dispose on them to release native handles.
/// </remarks>
internal static RSACryptoServiceProvider CreateAsymmetricKeyServiceProvider() {
var serviceProvider = new RSACryptoServiceProvider();
serviceProvider.ImportParameters(AsymmetricKey);
return serviceProvider;
}
/// <summary>
/// Creates the RSA key used by all the crypto service provider instances we create.
/// </summary>
/// <returns>RSA data that includes the private key.</returns>
private static RSAParameters CreateRSAKey() {
// As we generate a new random key, we need to set the UseMachineKeyStore flag so that this doesn't
// crash on IIS. For more information:
// http://social.msdn.microsoft.com/Forums/en-US/clr/thread/7ea48fd0-8d6b-43ed-b272-1a0249ae490f?prof=required
var cspParameters = new CspParameters();
cspParameters.Flags = CspProviderFlags.UseArchivableKey | CspProviderFlags.UseMachineKeyStore;
var asymmetricKey = new RSACryptoServiceProvider(cspParameters);
return asymmetricKey.ExportParameters(true);
}
private bool IsAuthorizationValid(HashSet<string> requestedScopes, string clientIdentifier, DateTime issuedUtc, string username) {
var grantedScopeStrings = from auth in Database.DataContext.ClientAuthorizations
where
auth.Client.ClientIdentifier == clientIdentifier &&
auth.CreatedOnUtc <= issuedUtc &&
(!auth.ExpirationDateUtc.HasValue || auth.ExpirationDateUtc.Value >= DateTime.UtcNow) &&
auth.User.AuthenticationTokens.Any(token => token.ClaimedIdentifier == username)
select auth.Scope;
if (!grantedScopeStrings.Any()) {
// No granted authorizations prior to the issuance of this token, so it must have been revoked.
// Even if later authorizations restore this client's ability to call in, we can't allow
// access tokens issued before the re-authorization because the revoked authorization should
// effectively and permanently revoke all access and refresh tokens.
return false;
}
var grantedScopes = new HashSet<string>(OAuthUtilities.ScopeStringComparer);
foreach (string scope in grantedScopeStrings) {
grantedScopes.UnionWith(OAuthUtilities.SplitScopes(scope));
}
return requestedScopes.IsSubsetOf(grantedScopes);
}
}
}
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