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// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Security.Claims;
using System.Text;
using System.Text.Encodings.Web;
using System.Threading.Tasks;
using Microsoft.AspNetCore.DataProtection;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Microsoft.IdentityModel.Protocols.OpenIdConnect;
using Microsoft.IdentityModel.Tokens;
using Microsoft.Net.Http.Headers;
namespace Microsoft.AspNetCore.Authentication.JwtBearer
{
public class JwtBearerHandler : AuthenticationHandler<JwtBearerOptions>
{
private OpenIdConnectConfiguration _configuration;
public JwtBearerHandler(IOptionsMonitor<JwtBearerOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock)
: base(options, logger, encoder, clock)
{ }
/// <summary>
/// The handler calls methods on the events which give the application control at certain points where processing is occurring.
/// If it is not provided a default instance is supplied which does nothing when the methods are called.
/// </summary>
protected new JwtBearerEvents Events
{
get => (JwtBearerEvents)base.Events;
set => base.Events = value;
}
protected override Task<object> CreateEventsAsync() => Task.FromResult<object>(new JwtBearerEvents());
/// <summary>
/// Searches the 'Authorization' header for a 'Bearer' token. If the 'Bearer' token is found, it is validated using <see cref="TokenValidationParameters"/> set in the options.
/// </summary>
/// <returns></returns>
protected override async Task<AuthenticateResult> HandleAuthenticateAsync()
{
string token = null;
try
{
// Give application opportunity to find from a different location, adjust, or reject token
var messageReceivedContext = new MessageReceivedContext(Context, Scheme, Options);
// event can set the token
await Events.MessageReceived(messageReceivedContext);
if (messageReceivedContext.Result != null)
{
return messageReceivedContext.Result;
}
// If application retrieved token from somewhere else, use that.
token = messageReceivedContext.Token;
if (string.IsNullOrEmpty(token))
{
string authorization = Request.Headers[HeaderNames.Authorization];
// If no authorization header found, nothing to process further
if (string.IsNullOrEmpty(authorization))
{
return AuthenticateResult.NoResult();
}
if (authorization.StartsWith("Bearer ", StringComparison.OrdinalIgnoreCase))
{
token = authorization.Substring("Bearer ".Length).Trim();
}
// If no token found, no further work possible
if (string.IsNullOrEmpty(token))
{
return AuthenticateResult.NoResult();
}
}
if (_configuration == null && Options.ConfigurationManager != null)
{
_configuration = await Options.ConfigurationManager.GetConfigurationAsync(Context.RequestAborted);
}
var validationParameters = Options.TokenValidationParameters.Clone();
if (_configuration != null)
{
var issuers = new[] { _configuration.Issuer };
validationParameters.ValidIssuers = validationParameters.ValidIssuers?.Concat(issuers) ?? issuers;
validationParameters.IssuerSigningKeys = validationParameters.IssuerSigningKeys?.Concat(_configuration.SigningKeys)
?? _configuration.SigningKeys;
}
List<Exception> validationFailures = null;
SecurityToken validatedToken;
foreach (var validator in Options.SecurityTokenValidators)
{
if (validator.CanReadToken(token))
{
ClaimsPrincipal principal;
try
{
principal = validator.ValidateToken(token, validationParameters, out validatedToken);
}
catch (Exception ex)
{
Logger.TokenValidationFailed(ex);
// Refresh the configuration for exceptions that may be caused by key rollovers. The user can also request a refresh in the event.
if (Options.RefreshOnIssuerKeyNotFound && Options.ConfigurationManager != null
&& ex is SecurityTokenSignatureKeyNotFoundException)
{
Options.ConfigurationManager.RequestRefresh();
}
if (validationFailures == null)
{
validationFailures = new List<Exception>(1);
}
validationFailures.Add(ex);
continue;
}
Logger.TokenValidationSucceeded();
var tokenValidatedContext = new TokenValidatedContext(Context, Scheme, Options)
{
Principal = principal,
SecurityToken = validatedToken
};
await Events.TokenValidated(tokenValidatedContext);
if (tokenValidatedContext.Result != null)
{
return tokenValidatedContext.Result;
}
if (Options.SaveToken)
{
tokenValidatedContext.Properties.StoreTokens(new[]
{
new AuthenticationToken { Name = "access_token", Value = token }
});
}
tokenValidatedContext.Success();
return tokenValidatedContext.Result;
}
}
if (validationFailures != null)
{
var authenticationFailedContext = new AuthenticationFailedContext(Context, Scheme, Options)
{
Exception = (validationFailures.Count == 1) ? validationFailures[0] : new AggregateException(validationFailures)
};
await Events.AuthenticationFailed(authenticationFailedContext);
if (authenticationFailedContext.Result != null)
{
return authenticationFailedContext.Result;
}
return AuthenticateResult.Fail(authenticationFailedContext.Exception);
}
return AuthenticateResult.Fail("No SecurityTokenValidator available for token: " + token ?? "[null]");
}
catch (Exception ex)
{
Logger.ErrorProcessingMessage(ex);
var authenticationFailedContext = new AuthenticationFailedContext(Context, Scheme, Options)
{
Exception = ex
};
await Events.AuthenticationFailed(authenticationFailedContext);
if (authenticationFailedContext.Result != null)
{
return authenticationFailedContext.Result;
}
throw;
}
}
protected override async Task HandleChallengeAsync(AuthenticationProperties properties)
{
var authResult = await HandleAuthenticateOnceSafeAsync();
var eventContext = new JwtBearerChallengeContext(Context, Scheme, Options, properties)
{
AuthenticateFailure = authResult?.Failure
};
// Avoid returning error=invalid_token if the error is not caused by an authentication failure (e.g missing token).
if (Options.IncludeErrorDetails && eventContext.AuthenticateFailure != null)
{
eventContext.Error = "invalid_token";
eventContext.ErrorDescription = CreateErrorDescription(eventContext.AuthenticateFailure);
}
await Events.Challenge(eventContext);
if (eventContext.Handled)
{
return;
}
Response.StatusCode = 401;
if (string.IsNullOrEmpty(eventContext.Error) &&
string.IsNullOrEmpty(eventContext.ErrorDescription) &&
string.IsNullOrEmpty(eventContext.ErrorUri))
{
Response.Headers.Append(HeaderNames.WWWAuthenticate, Options.Challenge);
}
else
{
// https://tools.ietf.org/html/rfc6750#section-3.1
// WWW-Authenticate: Bearer realm="example", error="invalid_token", error_description="The access token expired"
var builder = new StringBuilder(Options.Challenge);
if (Options.Challenge.IndexOf(' ') > 0)
{
// Only add a comma after the first param, if any
builder.Append(',');
}
if (!string.IsNullOrEmpty(eventContext.Error))
{
builder.Append(" error=\"");
builder.Append(eventContext.Error);
builder.Append("\"");
}
if (!string.IsNullOrEmpty(eventContext.ErrorDescription))
{
if (!string.IsNullOrEmpty(eventContext.Error))
{
builder.Append(",");
}
builder.Append(" error_description=\"");
builder.Append(eventContext.ErrorDescription);
builder.Append('\"');
}
if (!string.IsNullOrEmpty(eventContext.ErrorUri))
{
if (!string.IsNullOrEmpty(eventContext.Error) ||
!string.IsNullOrEmpty(eventContext.ErrorDescription))
{
builder.Append(",");
}
builder.Append(" error_uri=\"");
builder.Append(eventContext.ErrorUri);
builder.Append('\"');
}
Response.Headers.Append(HeaderNames.WWWAuthenticate, builder.ToString());
}
}
protected override Task HandleForbiddenAsync(AuthenticationProperties properties)
{
var forbiddenContext = new ForbiddenContext(Context, Scheme, Options);
Response.StatusCode = 403;
return Events.Forbidden(forbiddenContext);
}
private static string CreateErrorDescription(Exception authFailure)
{
IEnumerable<Exception> exceptions;
if (authFailure is AggregateException agEx)
{
exceptions = agEx.InnerExceptions;
}
else
{
exceptions = new[] { authFailure };
}
var messages = new List<string>();
foreach (var ex in exceptions)
{
// Order sensitive, some of these exceptions derive from others
// and we want to display the most specific message possible.
switch (ex)
{
case SecurityTokenInvalidAudienceException stia:
messages.Add($"The audience '{stia.InvalidAudience ?? "(null)"}' is invalid");
break;
case SecurityTokenInvalidIssuerException stii:
messages.Add($"The issuer '{stii.InvalidIssuer ?? "(null)"}' is invalid");
break;
case SecurityTokenNoExpirationException _:
messages.Add("The token has no expiration");
break;
case SecurityTokenInvalidLifetimeException stil:
messages.Add("The token lifetime is invalid; NotBefore: "
+ $"'{stil.NotBefore?.ToString(CultureInfo.InvariantCulture) ?? "(null)"}'"
+ $", Expires: '{stil.Expires?.ToString(CultureInfo.InvariantCulture) ?? "(null)"}'");
break;
case SecurityTokenNotYetValidException stnyv:
messages.Add($"The token is not valid before '{stnyv.NotBefore.ToString(CultureInfo.InvariantCulture)}'");
break;
case SecurityTokenExpiredException ste:
messages.Add($"The token expired at '{ste.Expires.ToString(CultureInfo.InvariantCulture)}'");
break;
case SecurityTokenSignatureKeyNotFoundException _:
messages.Add("The signature key was not found");
break;
case SecurityTokenInvalidSignatureException _:
messages.Add("The signature is invalid");
break;
}
}
return string.Join("; ", messages);
}
}
}
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