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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.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 {
internal static readonly RSAParameters AsymmetricKey;
private static readonly byte[] secret;
private readonly INonceStore nonceStore = new NonceDbStore();
static OAuthAuthorizationServer() {
// TODO: Replace this sample code with real code.
// For this sample, we just generate random secrets.
RandomNumberGenerator crypto = new RNGCryptoServiceProvider();
secret = new byte[16];
crypto.GetBytes(secret);
AsymmetricKey = new RSACryptoServiceProvider().ExportParameters(true);
}
/// <summary>
/// Initializes a new instance of the <see cref="OAuthAuthorizationServer"/> class.
/// </summary>
public OAuthAuthorizationServer() {
}
#region IAuthorizationServer Members
/// <summary>
/// Gets the secret used to symmetrically encrypt and sign authorization codes and refresh tokens.
/// </summary>
/// <value></value>
/// <remarks>
/// This secret should be kept strictly confidential in the authorization server(s)
/// and NOT shared with the resource server. Anyone with this secret can mint
/// tokens to essentially grant themselves access to anything they want.
/// </remarks>
public byte[] Secret {
get { return secret; }
}
/// <summary>
/// Gets the asymmetric private key to use for signing access tokens.
/// </summary>
/// <value></value>
/// <remarks>
/// The public key in the private/public key pair will be used by the resource
/// servers to validate that the access token is minted by a trusted authorization server.
/// </remarks>
public RSAParameters AccessTokenSigningPrivateKey {
get { return AsymmetricKey; }
}
/// <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; }
}
/// <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;
}
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.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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