From 3711555f704d3a99d037081b7b3e8d7486b68f51 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Damian=20B=C3=BCchel?= <damian.buechel@let.ethz.ch>
Date: Tue, 5 Sep 2023 17:47:05 +0200
Subject: [PATCH] SEBWIN-727: Implemented support for configuration data URIs.

---
 .../Handlers/RequestHandlerTests.cs           | 44 ++++++++++++++++---
 .../Handlers/RequestHandler.cs                | 26 ++++++++---
 SafeExamBrowser.Client/ClientController.cs    |  4 +-
 .../Operations/ServerOperation.cs             |  5 +++
 .../Windows/ServerFailureDialog.xaml          |  2 +-
 5 files changed, 68 insertions(+), 13 deletions(-)

diff --git a/SafeExamBrowser.Browser.UnitTests/Handlers/RequestHandlerTests.cs b/SafeExamBrowser.Browser.UnitTests/Handlers/RequestHandlerTests.cs
index 34b24d44..7d15ace7 100644
--- a/SafeExamBrowser.Browser.UnitTests/Handlers/RequestHandlerTests.cs
+++ b/SafeExamBrowser.Browser.UnitTests/Handlers/RequestHandlerTests.cs
@@ -69,6 +69,7 @@ namespace SafeExamBrowser.Browser.UnitTests.Handlers
 			var quitUrl = "http://www.byebye.com";
 			var request = new Mock<IRequest>();
 
+			appConfig.ConfigurationFileMimeType = "application/seb";
 			request.SetupGet(r => r.Url).Returns(quitUrl);
 			settings.QuitUrl = quitUrl;
 			sut.QuitUrlVisited += (url) => eventFired = true;
@@ -122,6 +123,7 @@ namespace SafeExamBrowser.Browser.UnitTests.Handlers
 			var request = new Mock<IRequest>();
 			var url = "https://www.test.org";
 
+			appConfig.ConfigurationFileMimeType = "application/seb";
 			filter.Setup(f => f.Process(It.Is<Request>(r => r.Url.Equals(url)))).Returns(FilterResult.Block);
 			request.SetupGet(r => r.ResourceType).Returns(ResourceType.MainFrame);
 			request.SetupGet(r => r.Url).Returns(url);
@@ -155,6 +157,7 @@ namespace SafeExamBrowser.Browser.UnitTests.Handlers
 			var request = new Mock<IRequest>();
 			var url = "https://www.test.org";
 
+			appConfig.ConfigurationFileMimeType = "application/seb";
 			filter.Setup(f => f.Process(It.Is<Request>(r => r.Url.Equals(url)))).Returns(FilterResult.Block);
 			request.SetupGet(r => r.ResourceType).Returns(ResourceType.SubFrame);
 			request.SetupGet(r => r.Url).Returns(url);
@@ -182,13 +185,34 @@ namespace SafeExamBrowser.Browser.UnitTests.Handlers
 		}
 
 		[TestMethod]
-		public void MustInitiateConfigurationFileDownload()
+		public void MustInitiateDataUriConfigurationFileDownload()
 		{
 			var browser = new Mock<IBrowser>();
 			var host = new Mock<IBrowserHost>();
 			var request = new Mock<IRequest>();
 
 			appConfig.ConfigurationFileExtension = ".xyz";
+			appConfig.ConfigurationFileMimeType = "application/seb";
+			appConfig.SebUriScheme = "abc";
+			appConfig.SebUriSchemeSecure = "abcd";
+			browser.Setup(b => b.GetHost()).Returns(host.Object);
+			request.SetupGet(r => r.Url).Returns($"{appConfig.SebUriSchemeSecure}://{appConfig.ConfigurationFileMimeType};base64,H4sIAAAAAAAAE41WbXPaRhD...");
+
+			var handled = sut.OnBeforeBrowse(Mock.Of<IWebBrowser>(), browser.Object, Mock.Of<IFrame>(), request.Object, false, false);
+
+			host.Verify(h => h.StartDownload(It.Is<string>(u => u == $"data:{appConfig.ConfigurationFileMimeType};base64,H4sIAAAAAAAAE41WbXPaRhD...")));
+			Assert.IsTrue(handled);
+		}
+
+		[TestMethod]
+		public void MustInitiateHttpConfigurationFileDownload()
+		{
+			var browser = new Mock<IBrowser>();
+			var host = new Mock<IBrowserHost>();
+			var request = new Mock<IRequest>();
+
+			appConfig.ConfigurationFileExtension = ".xyz";
+			appConfig.ConfigurationFileMimeType = "application/seb";
 			appConfig.SebUriScheme = "abc";
 			appConfig.SebUriSchemeSecure = "abcd";
 			browser.Setup(b => b.GetHost()).Returns(host.Object);
@@ -198,13 +222,23 @@ namespace SafeExamBrowser.Browser.UnitTests.Handlers
 
 			host.Verify(h => h.StartDownload(It.Is<string>(u => u == $"{Uri.UriSchemeHttp}://host.com/path/file{appConfig.ConfigurationFileExtension}")));
 			Assert.IsTrue(handled);
+		}
 
-			handled = false;
-			host.Reset();
-			request.Reset();
+		[TestMethod]
+		public void MustInitiateHttpsConfigurationFileDownload()
+		{
+			var browser = new Mock<IBrowser>();
+			var host = new Mock<IBrowserHost>();
+			var request = new Mock<IRequest>();
+
+			appConfig.ConfigurationFileExtension = ".xyz";
+			appConfig.ConfigurationFileMimeType = "application/seb";
+			appConfig.SebUriScheme = "abc";
+			appConfig.SebUriSchemeSecure = "abcd";
+			browser.Setup(b => b.GetHost()).Returns(host.Object);
 			request.SetupGet(r => r.Url).Returns($"{appConfig.SebUriSchemeSecure}://host.com/path/file{appConfig.ConfigurationFileExtension}");
 
-			handled = sut.OnBeforeBrowse(Mock.Of<IWebBrowser>(), browser.Object, Mock.Of<IFrame>(), request.Object, false, false);
+			var handled = sut.OnBeforeBrowse(Mock.Of<IWebBrowser>(), browser.Object, Mock.Of<IFrame>(), request.Object, false, false);
 
 			host.Verify(h => h.StartDownload(It.Is<string>(u => u == $"{Uri.UriSchemeHttps}://host.com/path/file{appConfig.ConfigurationFileExtension}")));
 			Assert.IsTrue(handled);
diff --git a/SafeExamBrowser.Browser/Handlers/RequestHandler.cs b/SafeExamBrowser.Browser/Handlers/RequestHandler.cs
index 3e34af3c..c7a6f32e 100644
--- a/SafeExamBrowser.Browser/Handlers/RequestHandler.cs
+++ b/SafeExamBrowser.Browser/Handlers/RequestHandler.cs
@@ -121,19 +121,35 @@ namespace SafeExamBrowser.Browser.Handlers
 		private bool IsConfigurationFile(IRequest request, out string downloadUrl)
 		{
 			var isValidUri = Uri.TryCreate(request.Url, UriKind.RelativeOrAbsolute, out var uri);
-			var isConfigurationFile = isValidUri && string.Equals(appConfig.ConfigurationFileExtension, Path.GetExtension(uri.AbsolutePath), StringComparison.OrdinalIgnoreCase);
+			var hasFileExtension = string.Equals(appConfig.ConfigurationFileExtension, Path.GetExtension(uri.AbsolutePath), StringComparison.OrdinalIgnoreCase);
+			var isDataUri = request.Url.Contains(appConfig.ConfigurationFileMimeType);
+			var isConfigurationFile = isValidUri && (hasFileExtension || isDataUri);
 
 			downloadUrl = request.Url;
 
 			if (isConfigurationFile)
 			{
-				if (uri.Scheme == appConfig.SebUriScheme)
+				if (isDataUri)
 				{
-					downloadUrl = new UriBuilder(uri) { Scheme = Uri.UriSchemeHttp }.Uri.AbsoluteUri;
+					if (uri.Scheme == appConfig.SebUriScheme)
+					{
+						downloadUrl = request.Url.Replace($"{appConfig.SebUriScheme}{Uri.SchemeDelimiter}", "data:");
+					}
+					else if (uri.Scheme == appConfig.SebUriSchemeSecure)
+					{
+						downloadUrl = request.Url.Replace($"{appConfig.SebUriSchemeSecure}{Uri.SchemeDelimiter}", "data:");
+					}
 				}
-				else if (uri.Scheme == appConfig.SebUriSchemeSecure)
+				else
 				{
-					downloadUrl = new UriBuilder(uri) { Scheme = Uri.UriSchemeHttps }.Uri.AbsoluteUri;
+					if (uri.Scheme == appConfig.SebUriScheme)
+					{
+						downloadUrl = new UriBuilder(uri) { Scheme = Uri.UriSchemeHttp }.Uri.AbsoluteUri;
+					}
+					else if (uri.Scheme == appConfig.SebUriSchemeSecure)
+					{
+						downloadUrl = new UriBuilder(uri) { Scheme = Uri.UriSchemeHttps }.Uri.AbsoluteUri;
+					}
 				}
 
 				logger.Debug($"Detected configuration file {(windowSettings.UrlPolicy.CanLog() ? $"'{uri}'" : "")}.");
diff --git a/SafeExamBrowser.Client/ClientController.cs b/SafeExamBrowser.Client/ClientController.cs
index 0fe3af8f..ad497c28 100644
--- a/SafeExamBrowser.Client/ClientController.cs
+++ b/SafeExamBrowser.Client/ClientController.cs
@@ -624,10 +624,10 @@ namespace SafeExamBrowser.Client
 			logger.Info($"Received server failure action request with id '{args.RequestId}'.");
 
 			var dialog = uiFactory.CreateServerFailureDialog(args.Message, args.ShowFallback);
-			var result = dialog.Show(splashScreen);
+			var result = dialog.Show();
 
 			runtime.SubmitServerFailureActionResult(args.RequestId, result.Abort, result.Fallback, result.Retry);
-			logger.Info($"Server failure action request with id '{args.RequestId}' is complete.");
+			logger.Info($"Server failure action request with id '{args.RequestId}' is complete, the user chose to {(result.Abort ? "abort" : (result.Fallback ? "fallback" : "retry"))}.");
 		}
 
 		private void ClientHost_Shutdown()
diff --git a/SafeExamBrowser.Runtime/Operations/ServerOperation.cs b/SafeExamBrowser.Runtime/Operations/ServerOperation.cs
index 5a07a129..5553a35d 100644
--- a/SafeExamBrowser.Runtime/Operations/ServerOperation.cs
+++ b/SafeExamBrowser.Runtime/Operations/ServerOperation.cs
@@ -241,6 +241,11 @@ namespace SafeExamBrowser.Runtime.Operations
 			abort = args.Abort;
 			fallback = args.Fallback;
 
+			if (args.Retry)
+			{
+				logger.Debug("The user chose to retry the current server request.");
+			}
+
 			return args.Retry;
 		}
 
diff --git a/SafeExamBrowser.UserInterface.Desktop/Windows/ServerFailureDialog.xaml b/SafeExamBrowser.UserInterface.Desktop/Windows/ServerFailureDialog.xaml
index f5b13700..0e2c463b 100644
--- a/SafeExamBrowser.UserInterface.Desktop/Windows/ServerFailureDialog.xaml
+++ b/SafeExamBrowser.UserInterface.Desktop/Windows/ServerFailureDialog.xaml
@@ -5,7 +5,7 @@
         xmlns:fa="http://schemas.fontawesome.io/icons/"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:local="clr-namespace:SafeExamBrowser.UserInterface.Desktop.Windows"
-        mc:Ignorable="d" Height="250" Width="450" ResizeMode="NoResize" Topmost="True">
+        mc:Ignorable="d" Height="250" Width="450" ResizeMode="NoResize" Topmost="True" WindowStartupLocation="CenterScreen">
     <Window.Resources>
         <ResourceDictionary>
             <ResourceDictionary.MergedDictionaries>