From 73a88245b17605c9d9cb49d6592e417876f30f2b Mon Sep 17 00:00:00 2001
From: Jordan Brown <Cyberboss@users.noreply.github.com>
Date: Mon, 7 Dec 2020 14:14:11 -0500
Subject: [PATCH] Adds Keycloak OAuth support

---
 README.md                                     |  3 +-
 docs/API.dox                                  |  1 +
 .../Security/OAuth/KeycloakOAuthValidator.cs  | 54 +++++++++++++++++++
 .../Security/OAuth/OAuthProviders.cs          |  8 +++
 src/Tgstation.Server.Host/appsettings.json    |  3 +-
 5 files changed, 67 insertions(+), 2 deletions(-)
 create mode 100644 src/Tgstation.Server.Host/Security/OAuth/KeycloakOAuthValidator.cs

diff --git a/README.md b/README.md
index 26a84e81dd..841fdb4e12 100644
--- a/README.md
+++ b/README.md
@@ -143,10 +143,11 @@ The following providers use the `RedirectUrl` setting:
 
 - GitHub
 - TGForums
+- Keycloak
 
 The following providers use the `ServerUrl` setting:
 
-- None so far
+- Keycloak
 
 ### Database Configuration
 
diff --git a/docs/API.dox b/docs/API.dox
index 5507fa7f83..927d3cd0c5 100644
--- a/docs/API.dox
+++ b/docs/API.dox
@@ -147,6 +147,7 @@ You will be granted a bearer token as in basic auth. This will have an extended
 - GitHub: https://developer.github.com/apps/building-oauth-apps/authorizing-oauth-apps/
 - Discord: https://discord.com/developers/docs/topics/oauth2
 - TGForums: https://tgstation13.org/phpBB/viewtopic.php?f=45&t=9922
+- Keycloak: https://plugins.miniorange.com/keycloak-single-sign-on-wordpress-sso-oauth-openid-connect
 
 @section api_perms Permissions
 
diff --git a/src/Tgstation.Server.Host/Security/OAuth/KeycloakOAuthValidator.cs b/src/Tgstation.Server.Host/Security/OAuth/KeycloakOAuthValidator.cs
new file mode 100644
index 0000000000..61e08a56ab
--- /dev/null
+++ b/src/Tgstation.Server.Host/Security/OAuth/KeycloakOAuthValidator.cs
@@ -0,0 +1,54 @@
+using Microsoft.Extensions.Logging;
+using System;
+using System.Net.Http;
+using Tgstation.Server.Api.Models;
+using Tgstation.Server.Host.Configuration;
+using Tgstation.Server.Host.System;
+
+namespace Tgstation.Server.Host.Security.OAuth
+{
+	/// <summary>
+	/// OAuth validator for Keycloak.
+	/// </summary>
+	sealed class KeycloakOAuthValidator : GenericOAuthValidator
+	{
+		/// <inheritdoc />
+		public override OAuthProvider Provider => OAuthProvider.Keycloak;
+
+		/// <inheritdoc />
+		protected override Uri TokenUrl => new Uri($"{BaseProtocolPath}/token");
+
+		/// <inheritdoc />
+		protected override Uri UserInformationUrl => new Uri($"{BaseProtocolPath}/userinfo");
+
+		/// <summary>
+		/// Base path to the server's OAuth endpoint.
+		/// </summary>
+		string BaseProtocolPath => $"{OAuthConfiguration.ServerUrl}/protocol/openid-connect";
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="KeycloakOAuthValidator"/> <see langword="class"/>.
+		/// </summary>
+		/// <param name="httpClientFactory">The <see cref="IHttpClientFactory"/> for the <see cref="GenericOAuthValidator"/>.</param>
+		/// <param name="assemblyInformationProvider">The <see cref="IAssemblyInformationProvider"/> for the <see cref="GenericOAuthValidator"/>.</param>
+		/// <param name="logger">The <see cref="ILogger"/> for the <see cref="GenericOAuthValidator"/>.</param>
+		/// <param name="oAuthConfiguration">The <see cref="OAuthConfiguration"/> for the <see cref="GenericOAuthValidator"/>.</param>
+		public KeycloakOAuthValidator(
+			IHttpClientFactory httpClientFactory,
+			IAssemblyInformationProvider assemblyInformationProvider,
+			ILogger<KeycloakOAuthValidator> logger,
+			OAuthConfiguration oAuthConfiguration)
+			: base(httpClientFactory, assemblyInformationProvider, logger, oAuthConfiguration)
+		{
+		}
+
+		/// <inheritdoc />
+		protected override OAuthTokenRequest CreateTokenRequest(string code) => new OAuthTokenRequest(OAuthConfiguration, code, "openid");
+
+		/// <inheritdoc />
+		protected override string DecodeTokenPayload(dynamic responseJson) => responseJson.access_token;
+
+		/// <inheritdoc />
+		protected override string DecodeUserInformationPayload(dynamic responseJson) => responseJson.sub;
+	}
+}
diff --git a/src/Tgstation.Server.Host/Security/OAuth/OAuthProviders.cs b/src/Tgstation.Server.Host/Security/OAuth/OAuthProviders.cs
index 9087aad25b..e8133706b2 100644
--- a/src/Tgstation.Server.Host/Security/OAuth/OAuthProviders.cs
+++ b/src/Tgstation.Server.Host/Security/OAuth/OAuthProviders.cs
@@ -66,6 +66,14 @@ namespace Tgstation.Server.Host.Security.OAuth
 						loggerFactory.CreateLogger<TGForumsOAuthValidator>(),
 						tgConfig));
 
+			if (securityConfiguration.OAuth.TryGetValue(OAuthProvider.Keycloak, out var keyCloakConfig))
+				validatorsBuilder.Add(
+					new KeycloakOAuthValidator(
+						httpClientFactory,
+						assemblyInformationProvider,
+						loggerFactory.CreateLogger<KeycloakOAuthValidator>(),
+						keyCloakConfig));
+
 			validators = validatorsBuilder;
 		}
 
diff --git a/src/Tgstation.Server.Host/appsettings.json b/src/Tgstation.Server.Host/appsettings.json
index 00506b5762..b0df570838 100644
--- a/src/Tgstation.Server.Host/appsettings.json
+++ b/src/Tgstation.Server.Host/appsettings.json
@@ -58,7 +58,8 @@
     "OAuth": {
       "GitHub": null,
       "Discord": null,
-      "TGForums": null
+      "TGForums": null,
+      "Keycloak": null
     }
   }
 }