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| 1 | +using System.Diagnostics.CodeAnalysis; |
| 2 | +using Microsoft.AspNetCore.DataProtection; |
| 3 | +using Microsoft.AspNetCore.Http; |
| 4 | +using Microsoft.Extensions.Options; |
| 5 | +using OpenIddict.Server; |
| 6 | +using OpenIddict.Validation; |
| 7 | +using Umbraco.Cms.Core; |
| 8 | +using Umbraco.Cms.Core.Configuration.Models; |
| 9 | +using Umbraco.Cms.Core.Events; |
| 10 | +using Umbraco.Cms.Core.Notifications; |
| 11 | +using Umbraco.Cms.Web.Common.Security; |
| 12 | +using Umbraco.Extensions; |
| 13 | + |
| 14 | +namespace Umbraco.Cms.Api.Common.DependencyInjection; |
| 15 | + |
| 16 | +internal sealed class HideBackOfficeTokensHandler |
| 17 | + : IOpenIddictServerHandler<OpenIddictServerEvents.ApplyTokenResponseContext>, |
| 18 | + IOpenIddictServerHandler<OpenIddictServerEvents.ExtractTokenRequestContext>, |
| 19 | + IOpenIddictValidationHandler<OpenIddictValidationEvents.ProcessAuthenticationContext>, |
| 20 | + INotificationHandler<UserLogoutSuccessNotification> |
| 21 | +{ |
| 22 | + private const string RedactedTokenValue = "[redacted]"; |
| 23 | + private const string AccessTokenCookieKey = "__Host-umbAccessToken"; |
| 24 | + private const string RefreshTokenCookieKey = "__Host-umbRefreshToken"; |
| 25 | + |
| 26 | + private readonly IHttpContextAccessor _httpContextAccessor; |
| 27 | + private readonly IDataProtectionProvider _dataProtectionProvider; |
| 28 | + private readonly BackOfficeTokenCookieSettings _backOfficeTokenCookieSettings; |
| 29 | + private readonly GlobalSettings _globalSettings; |
| 30 | + |
| 31 | + public HideBackOfficeTokensHandler( |
| 32 | + IHttpContextAccessor httpContextAccessor, |
| 33 | + IDataProtectionProvider dataProtectionProvider, |
| 34 | + IOptions<BackOfficeTokenCookieSettings> backOfficeTokenCookieSettings, |
| 35 | + IOptions<GlobalSettings> globalSettings) |
| 36 | + { |
| 37 | + _httpContextAccessor = httpContextAccessor; |
| 38 | + _dataProtectionProvider = dataProtectionProvider; |
| 39 | + _backOfficeTokenCookieSettings = backOfficeTokenCookieSettings.Value; |
| 40 | + _globalSettings = globalSettings.Value; |
| 41 | + } |
| 42 | + |
| 43 | + /// <summary> |
| 44 | + /// This is invoked when tokens (access and refresh tokens) are issued to a client. For the back-office client, |
| 45 | + /// we will intercept the response, write the tokens from the response into HTTP-only cookies, and redact the |
| 46 | + /// tokens from the response, so they are not exposed to the client. |
| 47 | + /// </summary> |
| 48 | + public ValueTask HandleAsync(OpenIddictServerEvents.ApplyTokenResponseContext context) |
| 49 | + { |
| 50 | + if (context.Request?.ClientId is not Constants.OAuthClientIds.BackOffice) |
| 51 | + { |
| 52 | + // Only ever handle the back-office client. |
| 53 | + return ValueTask.CompletedTask; |
| 54 | + } |
| 55 | + |
| 56 | + HttpContext httpContext = GetHttpContext(); |
| 57 | + |
| 58 | + if (context.Response.AccessToken is not null) |
| 59 | + { |
| 60 | + SetCookie(httpContext, AccessTokenCookieKey, context.Response.AccessToken); |
| 61 | + context.Response.AccessToken = RedactedTokenValue; |
| 62 | + } |
| 63 | + |
| 64 | + if (context.Response.RefreshToken is not null) |
| 65 | + { |
| 66 | + SetCookie(httpContext, RefreshTokenCookieKey, context.Response.RefreshToken); |
| 67 | + context.Response.RefreshToken = RedactedTokenValue; |
| 68 | + } |
| 69 | + |
| 70 | + return ValueTask.CompletedTask; |
| 71 | + } |
| 72 | + |
| 73 | + /// <summary> |
| 74 | + /// This is invoked when requesting new tokens. |
| 75 | + /// </summary> |
| 76 | + public ValueTask HandleAsync(OpenIddictServerEvents.ExtractTokenRequestContext context) |
| 77 | + { |
| 78 | + if (context.Request?.ClientId != Constants.OAuthClientIds.BackOffice) |
| 79 | + { |
| 80 | + // Only ever handle the back-office client. |
| 81 | + return ValueTask.CompletedTask; |
| 82 | + } |
| 83 | + |
| 84 | + // For the back-office client, this only happens when a refresh token is being exchanged for a new access token. |
| 85 | + if (context.Request.RefreshToken == RedactedTokenValue |
| 86 | + && TryGetCookie(RefreshTokenCookieKey, out var refreshToken)) |
| 87 | + { |
| 88 | + context.Request.RefreshToken = refreshToken; |
| 89 | + } |
| 90 | + else |
| 91 | + { |
| 92 | + // If we got here, either the refresh token was not redacted, or nothing was found in the refresh token cookie. |
| 93 | + // If OpenIddict found a refresh token, it could be an old token that is potentially still valid. For security |
| 94 | + // reasons, we cannot accept that; at this point, we expect the refresh tokens to be explicitly redacted. |
| 95 | + context.Request.RefreshToken = null; |
| 96 | + } |
| 97 | + |
| 98 | + |
| 99 | + return ValueTask.CompletedTask; |
| 100 | + } |
| 101 | + |
| 102 | + /// <summary> |
| 103 | + /// This is invoked when extracting the auth context for a client request. |
| 104 | + /// </summary> |
| 105 | + public ValueTask HandleAsync(OpenIddictValidationEvents.ProcessAuthenticationContext context) |
| 106 | + { |
| 107 | + // For the back-office client, this only happens when an access token is sent to the API. |
| 108 | + if (context.AccessToken != RedactedTokenValue) |
| 109 | + { |
| 110 | + return ValueTask.CompletedTask; |
| 111 | + } |
| 112 | + |
| 113 | + if (TryGetCookie(AccessTokenCookieKey, out var accessToken)) |
| 114 | + { |
| 115 | + context.AccessToken = accessToken; |
| 116 | + } |
| 117 | + |
| 118 | + return ValueTask.CompletedTask; |
| 119 | + } |
| 120 | + |
| 121 | + public void Handle(UserLogoutSuccessNotification notification) |
| 122 | + { |
| 123 | + HttpContext? context = _httpContextAccessor.HttpContext; |
| 124 | + if (context is null) |
| 125 | + { |
| 126 | + // For some reason there is no ambient HTTP context, so we can't clean up the cookies. |
| 127 | + // This is OK, because the tokens in the cookies have already been revoked at user sign-out, |
| 128 | + // so the cookie clean-up is mostly cosmetic. |
| 129 | + return; |
| 130 | + } |
| 131 | + |
| 132 | + context.Response.Cookies.Delete(AccessTokenCookieKey); |
| 133 | + context.Response.Cookies.Delete(RefreshTokenCookieKey); |
| 134 | + } |
| 135 | + |
| 136 | + private HttpContext GetHttpContext() |
| 137 | + => _httpContextAccessor.GetRequiredHttpContext(); |
| 138 | + |
| 139 | + private void SetCookie(HttpContext httpContext, string key, string value) |
| 140 | + { |
| 141 | + var cookieValue = EncryptionHelper.Encrypt(value, _dataProtectionProvider); |
| 142 | + |
| 143 | + var cookieOptions = new CookieOptions |
| 144 | + { |
| 145 | + // Prevent the client-side scripts from accessing the cookie. |
| 146 | + HttpOnly = true, |
| 147 | + |
| 148 | + // Mark the cookie as essential to the application, to enforce it despite any |
| 149 | + // data collection consent options. This aligns with how ASP.NET Core Identity |
| 150 | + // does when writing cookies for cookie authentication. |
| 151 | + IsEssential = true, |
| 152 | + |
| 153 | + // Cookie path must be root for optimal security. |
| 154 | + Path = "/", |
| 155 | + |
| 156 | + // For optimal security, the cooke must be secure. However, Umbraco allows for running development |
| 157 | + // environments over HTTP, so we need to take that into account here. |
| 158 | + // Thus, we will make the cookie secure if: |
| 159 | + // - HTTPS is explicitly enabled by config (default for production environments), or |
| 160 | + // - The current request is over HTTPS (meaning the environment supports it regardless of config). |
| 161 | + Secure = _globalSettings.UseHttps || httpContext.Request.IsHttps, |
| 162 | + |
| 163 | + // SameSite is configurable (see BackOfficeTokenCookieSettings for defaults): |
| 164 | + SameSite = ParseSameSiteMode(_backOfficeTokenCookieSettings.SameSite), |
| 165 | + }; |
| 166 | + |
| 167 | + httpContext.Response.Cookies.Delete(key, cookieOptions); |
| 168 | + httpContext.Response.Cookies.Append(key, cookieValue, cookieOptions); |
| 169 | + } |
| 170 | + |
| 171 | + private bool TryGetCookie(string key, [NotNullWhen(true)] out string? value) |
| 172 | + { |
| 173 | + if (GetHttpContext().Request.Cookies.TryGetValue(key, out var cookieValue)) |
| 174 | + { |
| 175 | + value = EncryptionHelper.Decrypt(cookieValue, _dataProtectionProvider); |
| 176 | + return true; |
| 177 | + } |
| 178 | + |
| 179 | + value = null; |
| 180 | + return false; |
| 181 | + } |
| 182 | + |
| 183 | + private static SameSiteMode ParseSameSiteMode(string sameSiteMode) => |
| 184 | + Enum.TryParse(sameSiteMode, ignoreCase: true, out SameSiteMode result) |
| 185 | + ? result |
| 186 | + : throw new ArgumentException($"The provided {nameof(sameSiteMode)} value could not be parsed into as SameSiteMode value.", nameof(sameSiteMode)); |
| 187 | +} |
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