SEBWIN-221: Simplified configuration API for loading and client configuration.

SafeExamBrowser.Configuration/ConfigurationRepository.cs

@@ -55,21 +55,20 @@ namespace SafeExamBrowser.Configuration
 			this.programVersion = programVersion ?? string.Empty;
 		}
 
-		public void ConfigureClientWith(Uri resource, EncryptionParameters encryption = null)
+		public SaveStatus ConfigureClientWith(Uri resource, PasswordParameters password = null)
 		{
 			logger.Info($"Attempting to configure local client settings from '{resource}'...");
 
 			try
 			{
-				TryLoadData(resource, out Stream stream);
+				TryLoadData(resource, out var stream);
 
 				using (stream)
 				{
-					// TODO:
+					TryParseData(stream, out var encryption, out var format, out var data, password);
-					//TryParseData(stream, encryption, out _, out _, out var data);
+					HandleIdentityCertificates(data);
-					//HandleIdentityCertificates(data);
 
-					// Save configuration data as local client config under %APPDATA%!
+					// TODO: Encrypt and save configuration data as local client config under %APPDATA%!
 					// -> New key will determine whether to use default password or current settings password!
 					//     -> "clientConfigEncryptUsingSettingsPassword"
 					//     -> Default settings password for local client configuration appears to be string.Empty -> passwords.SettingsPassword
@@ -77,10 +76,14 @@ namespace SafeExamBrowser.Configuration
 				}
 
 				logger.Info($"Successfully configured local client settings with '{resource}'.");
+
+				return SaveStatus.Success;
 			}
 			catch (Exception e)
 			{
 				logger.Error($"Unexpected error while trying to configure local client settings '{resource}'!", e);
+
+				return SaveStatus.UnexpectedError;
 			}
 		}
 
@@ -166,17 +169,15 @@ namespace SafeExamBrowser.Configuration
 			dataResources.Add(dataResource);
 		}
 
-		public LoadStatus TryLoadSettings(Uri resource, PasswordParameters password, out EncryptionParameters encryption, out Format format, out Settings settings)
+		public LoadStatus TryLoadSettings(Uri resource, out Settings settings, PasswordParameters password = null)
 		{
 			logger.Info($"Attempting to load '{resource}'...");
 
-			encryption = default(EncryptionParameters);
-			format = default(Format);
 			settings = LoadDefaultSettings();
 
 			try
 			{
-				var status = TryLoadData(resource, out Stream stream);
+				var status = TryLoadData(resource, out var stream);
 
 				using (stream)
 				{
@@ -185,7 +186,7 @@ namespace SafeExamBrowser.Configuration
 						return status;
 					}
 
-					status = TryParseData(stream, password, out encryption, out format, out var data);
+					status = TryParseData(stream, out _, out _, out var data, password);
 
 					if (status == LoadStatus.Success)
 					{
@@ -219,7 +220,7 @@ namespace SafeExamBrowser.Configuration
 
 				foreach (var certificate in certificates)
 				{
-					var isIdentity = certificate.TryGetValue("type", out object t) && t is int type && type == IDENTITY_CERTIFICATE;
+					var isIdentity = certificate.TryGetValue("type", out var o) && o is int type && type == IDENTITY_CERTIFICATE;
 					var hasData = certificate.TryGetValue("certificateData", out value);
 
 					if (isIdentity && hasData && value is byte[] certificateData)
@@ -278,7 +279,7 @@ namespace SafeExamBrowser.Configuration
 			return status;
 		}
 
-		private LoadStatus TryParseData(Stream data, PasswordParameters password, out EncryptionParameters encryption, out Format format, out IDictionary<string, object> rawData)
+		private LoadStatus TryParseData(Stream data, out EncryptionParameters encryption, out Format format, out IDictionary<string, object> rawData, PasswordParameters password = null)
 		{
 			var dataFormat = dataFormats.FirstOrDefault(f => f.CanParse(data));
 			var status = LoadStatus.NotSupported;

SafeExamBrowser.Configuration/DataFormats/BinaryFormat.cs

@@ -60,7 +60,7 @@ namespace SafeExamBrowser.Configuration.DataFormats
 			return false;
 		}
 
-		public ParseResult TryParse(Stream data, PasswordParameters password)
+		public ParseResult TryParse(Stream data, PasswordParameters password = null)
 		{
 			var prefix = ParsePrefix(data);
 			var success = TryDetermineFormat(prefix, out FormatType format);
@@ -94,29 +94,36 @@ namespace SafeExamBrowser.Configuration.DataFormats
 			return new ParseResult { Status = LoadStatus.InvalidData };
 		}
 
-		private ParseResult ParsePasswordBlock(Stream data, FormatType format, PasswordParameters password)
+		private ParseResult ParsePasswordBlock(Stream data, FormatType format, PasswordParameters password = null)
 		{
 			var encryption = new PasswordEncryption(logger.CloneFor(nameof(PasswordEncryption)));
 			var encryptionParams = new PasswordParameters();
 			var result = new ParseResult();
 
-			if (format == FormatType.PasswordConfigureClient)
+			if (password != null)
 			{
-				encryptionParams.Password = password.IsHash ? password.Password : hashAlgorithm.GenerateHashFor(password.Password);
+				if (format == FormatType.PasswordConfigureClient)
-				encryptionParams.IsHash = true;
+				{
+					encryptionParams.Password = password.IsHash ? password.Password : hashAlgorithm.GenerateHashFor(password.Password);
+					encryptionParams.IsHash = true;
+				}
+				else
+				{
+					encryptionParams.Password = password.Password;
+					encryptionParams.IsHash = password.IsHash;
+				}
+
+				result.Status = encryption.Decrypt(data, encryptionParams.Password, out var decrypted);
+
+				if (result.Status == LoadStatus.Success)
+				{
+					result = ParsePlainDataBlock(decrypted);
+					result.Encryption = encryptionParams;
+				}
 			}
 			else
 			{
-				encryptionParams.Password = password.Password;
+				result.Status = LoadStatus.PasswordNeeded;
-				encryptionParams.IsHash = password.IsHash;
-			}
-
-			result.Status = encryption.Decrypt(data, encryptionParams.Password, out var decrypted);
-
-			if (result.Status == LoadStatus.Success)
-			{
-				result = ParsePlainDataBlock(decrypted);
-				result.Encryption = encryptionParams;
 			}
 
 			return result;
@@ -134,7 +141,7 @@ namespace SafeExamBrowser.Configuration.DataFormats
 			return xmlFormat.TryParse(data);
 		}
 
-		private ParseResult ParsePublicKeyHashBlock(Stream data, PasswordParameters password)
+		private ParseResult ParsePublicKeyHashBlock(Stream data, PasswordParameters password = null)
 		{
 			var encryption = new PublicKeyHashEncryption(logger.CloneFor(nameof(PublicKeyHashEncryption)));
 			var result = new ParseResult();
@@ -155,7 +162,7 @@ namespace SafeExamBrowser.Configuration.DataFormats
 			return result;
 		}
 
-		private ParseResult ParsePublicKeyHashWithSymmetricKeyBlock(Stream data, PasswordParameters password)
+		private ParseResult ParsePublicKeyHashWithSymmetricKeyBlock(Stream data, PasswordParameters password = null)
 		{
 			var passwordEncryption = new PasswordEncryption(logger.CloneFor(nameof(PasswordEncryption)));
 			var encryption = new PublicKeyHashWithSymmetricKeyEncryption(logger.CloneFor(nameof(PublicKeyHashWithSymmetricKeyEncryption)), passwordEncryption);

SafeExamBrowser.Contracts/Configuration/IConfigurationRepository.cs

@@ -19,9 +19,9 @@ namespace SafeExamBrowser.Contracts.Configuration
 	public interface IConfigurationRepository
 	{
 		/// <summary>
-		/// Saves the given resource as local client configuration.
+		/// Attempts to save the given resource as local client configuration.
 		/// </summary>
-		void ConfigureClientWith(Uri resource, EncryptionParameters encryption = null);
+		SaveStatus ConfigureClientWith(Uri resource, PasswordParameters password = null);
 
 		/// <summary>
 		/// Initializes the global configuration information for the currently running application instance.
@@ -51,7 +51,7 @@ namespace SafeExamBrowser.Contracts.Configuration
 		/// <summary>
 		/// Attempts to load settings from the specified resource.
 		/// </summary>
-		LoadStatus TryLoadSettings(Uri resource, PasswordParameters password, out EncryptionParameters encryption, out Format format, out Settings.Settings settings);
+		LoadStatus TryLoadSettings(Uri resource, out Settings.Settings settings, PasswordParameters password = null);
 
 		/// <summary>
 		/// Attempts to save settings according to the specified parameters.

SafeExamBrowser.Contracts/Configuration/LoadStatus.cs

@@ -29,17 +29,17 @@ namespace SafeExamBrowser.Contracts.Configuration
 		NotSupported,
 
 		/// <summary>
-		/// Indicates that a password is needed in order to decrypt the settings.
+		/// Indicates that a password is needed in order to decrypt the configuration.
 		/// </summary>
 		PasswordNeeded,
 
 		/// <summary>
-		/// The settings were loaded successfully.
+		/// The configuration was loaded successfully.
 		/// </summary>
 		Success,
 
 		/// <summary>
-		/// An unexpected error occurred while trying to load the settings.
+		/// An unexpected error occurred while trying to load the configuration.
 		/// </summary>
 		UnexpectedError
 	}

SafeExamBrowser.Contracts/Configuration/SaveStatus.cs

@@ -13,6 +13,14 @@ namespace SafeExamBrowser.Contracts.Configuration
 	/// </summary>
 	public enum SaveStatus
 	{
+		/// <summary>
+		/// The configuration was saved successfully.
+		/// </summary>
+		Success,
 
+		/// <summary>
+		/// An unexpected error occurred while trying to save the configuration.
+		/// </summary>
+		UnexpectedError
 	}
 }

SafeExamBrowser.Contracts/I18n/TextKey.cs

@@ -18,6 +18,8 @@ namespace SafeExamBrowser.Contracts.I18n
 		LogWindow_Title,
 		MessageBox_ApplicationError,
 		MessageBox_ApplicationErrorTitle,
+		MessageBox_ClientConfigurationError,
+		MessageBox_ClientConfigurationErrorTitle,
 		MessageBox_ClientConfigurationQuestion,
 		MessageBox_ClientConfigurationQuestionTitle,
 		MessageBox_ConfigurationDownloadError,

SafeExamBrowser.I18n/Text.xml

@@ -12,6 +12,12 @@
   <Entry key="MessageBox_ApplicationErrorTitle">
     Application Error
   </Entry>
+  <Entry key="MessageBox_ClientConfigurationError">
+    The local client configuration has failed! Please consult the application log for more information. The application will now shut down...
+  </Entry>
+  <Entry key="MessageBox_ClientConfigurationErrorTitle">
+    Client Configuration Error
+  </Entry>
   <Entry key="MessageBox_ClientConfigurationQuestion">
     The client configuration has been saved and will be used when you start the application the next time. Do you want to quit for now?
   </Entry>

SafeExamBrowser.Runtime/Operations/ConfigurationOperation.cs

@@ -11,7 +11,6 @@ using System.IO;
 using SafeExamBrowser.Contracts.Communication.Data;
 using SafeExamBrowser.Contracts.Configuration;
 using SafeExamBrowser.Contracts.Configuration.Cryptography;
-using SafeExamBrowser.Contracts.Configuration.DataFormats;
 using SafeExamBrowser.Contracts.Configuration.Settings;
 using SafeExamBrowser.Contracts.Core.OperationModel;
 using SafeExamBrowser.Contracts.Core.OperationModel.Events;
@@ -114,14 +113,14 @@ namespace SafeExamBrowser.Runtime.Operations
 		private OperationResult LoadSettings(Uri uri)
 		{
 			var passwordParams = new PasswordParameters { Password = string.Empty, IsHash = true };
-			var status = configuration.TryLoadSettings(uri, passwordParams, out var encryption, out var format, out var settings);
+			var status = configuration.TryLoadSettings(uri, out var settings, passwordParams);
 
 			if (status == LoadStatus.PasswordNeeded && Context.Current?.Settings.AdminPasswordHash != null)
 			{
 				passwordParams.Password = Context.Current.Settings.AdminPasswordHash;
 				passwordParams.IsHash = true;
 
-				status = configuration.TryLoadSettings(uri, passwordParams, out encryption, out format, out settings);
+				status = configuration.TryLoadSettings(uri, out settings, passwordParams);
 			}
 
 			for (int attempts = 0; attempts < 5 && status == LoadStatus.PasswordNeeded; attempts++)
@@ -138,15 +137,15 @@ namespace SafeExamBrowser.Runtime.Operations
 					return OperationResult.Aborted;
 				}
 
-				status = configuration.TryLoadSettings(uri, passwordParams, out encryption, out format, out settings);
+				status = configuration.TryLoadSettings(uri, out settings, passwordParams);
 			}
 
 			Context.Next.Settings = settings;
 
-			return HandleLoadResult(uri, settings, status, passwordParams, encryption, format);
+			return HandleLoadResult(uri, settings, status, passwordParams);
 		}
 
-		private OperationResult HandleLoadResult(Uri uri, Settings settings, LoadStatus status, PasswordParameters password, EncryptionParameters encryption, Format format)
+		private OperationResult HandleLoadResult(Uri uri, Settings settings, LoadStatus status, PasswordParameters password)
 		{
 			if (status == LoadStatus.LoadWithBrowser)
 			{
@@ -155,7 +154,7 @@ namespace SafeExamBrowser.Runtime.Operations
 
 			if (status == LoadStatus.Success && settings.ConfigurationMode == ConfigurationMode.ConfigureClient)
 			{
-				return HandleClientConfiguration(uri, password, encryption, format);
+				return HandleClientConfiguration(uri, password);
 			}
 
 			if (status == LoadStatus.Success)
@@ -176,7 +175,7 @@ namespace SafeExamBrowser.Runtime.Operations
 			return OperationResult.Success;
 		}
 
-		private OperationResult HandleClientConfiguration(Uri resource, PasswordParameters password, EncryptionParameters encryption, Format format)
+		private OperationResult HandleClientConfiguration(Uri resource, PasswordParameters password)
 		{
 			var isAppDataFile = Path.GetFullPath(resource.AbsolutePath).Equals(AppDataFile, StringComparison.OrdinalIgnoreCase);
 			var isProgramDataFile = Path.GetFullPath(resource.AbsolutePath).Equals(ProgramDataFile, StringComparison.OrdinalIgnoreCase);
@@ -202,11 +201,19 @@ namespace SafeExamBrowser.Runtime.Operations
 					logger.Info("Authentication is not required.");
 				}
 
-				configuration.ConfigureClientWith(resource, encryption);
+				var status = configuration.ConfigureClientWith(resource, password);
+
+				if (status != SaveStatus.Success)
+				{
+					logger.Error($"Client configuration failed with status '{status}'!");
+					ActionRequired?.Invoke(new ClientConfigurationErrorMessageArgs());
+
+					return OperationResult.Failed;
+				}
 
 				if (isFirstSession)
 				{
-					var result = HandleClientConfigurationSuccess();
+					var result = HandleClientConfigurationOnStartup();
 
 					if (result != OperationResult.Success)
 					{
@@ -270,21 +277,19 @@ namespace SafeExamBrowser.Runtime.Operations
 
 				return OperationResult.Success;
 			}
-			else
-			{
-				logger.Info("Authentication has failed!");
-				ActionRequired?.Invoke(new InvalidPasswordMessageArgs());
 
-				return OperationResult.Failed;
+			logger.Info("Authentication has failed!");
-			}
+			ActionRequired?.Invoke(new InvalidPasswordMessageArgs());
+
+			return OperationResult.Failed;
 		}
 
-		private OperationResult HandleClientConfigurationSuccess()
+		private OperationResult HandleClientConfigurationOnStartup()
 		{
 			var args = new ConfigurationCompletedEventArgs();
 
 			ActionRequired?.Invoke(args);
-			logger.Info($"The user chose to {(args.AbortStartup ? "abort" : "continue")} after successful client configuration.");
+			logger.Info($"The user chose to {(args.AbortStartup ? "abort" : "continue")} startup after successful client configuration.");
 
 			if (args.AbortStartup)
 			{

SafeExamBrowser.Runtime/Operations/Events/ClientConfigurationErrorMessageArgs.cs

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2018 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using SafeExamBrowser.Contracts.I18n;
+using SafeExamBrowser.Contracts.UserInterface.MessageBox;
+
+namespace SafeExamBrowser.Runtime.Operations.Events
+{
+	internal class ClientConfigurationErrorMessageArgs : MessageEventArgs
+	{
+		internal ClientConfigurationErrorMessageArgs()
+		{
+			Icon = MessageBoxIcon.Error;
+			Message = TextKey.MessageBox_ClientConfigurationError;
+			Title = TextKey.MessageBox_ClientConfigurationErrorTitle;
+		}
+	}
+}

SafeExamBrowser.Runtime/SafeExamBrowser.Runtime.csproj

@@ -89,6 +89,7 @@
     <Compile Include="Operations\ClientOperation.cs" />
     <Compile Include="Operations\ClientTerminationOperation.cs" />
     <Compile Include="Operations\ConfigurationOperation.cs" />
+    <Compile Include="Operations\Events\ClientConfigurationErrorMessageArgs.cs" />
     <Compile Include="Operations\Events\ConfigurationCompletedEventArgs.cs" />
     <Compile Include="Operations\Events\InvalidDataMessageArgs.cs" />
     <Compile Include="Operations\Events\InvalidPasswordMessageArgs.cs" />