SEBWIN-309: Implemented draft of browser exam key.

SafeExamBrowser.Browser/Handlers/ResourceHandler.cs

@@ -106,12 +106,16 @@ namespace SafeExamBrowser.Browser.Handlers
 		{
 			var headers = new NameValueCollection(request.Headers);
 			var urlWithoutFragment = request.Url.Split('#')[0];
-			var hash = algorithm.ComputeHash(Encoding.UTF8.GetBytes(urlWithoutFragment + settings.HashValue));
+			var configurationBytes = algorithm.ComputeHash(Encoding.UTF8.GetBytes(urlWithoutFragment + settings.HashValue));
-			var configurationKey = BitConverter.ToString(hash).ToLower().Replace("-", string.Empty);
+			var configurationKey = BitConverter.ToString(configurationBytes).ToLower().Replace("-", string.Empty);
+			var browserExamBytes = algorithm.ComputeHash(Encoding.UTF8.GetBytes(appConfig.CodeSignatureHash + appConfig.ProgramBuildVersion + configurationKey));
+			var browserExamKey = BitConverter.ToString(browserExamBytes).ToLower().Replace("-", string.Empty);
+			var requestHashBytes = algorithm.ComputeHash(Encoding.UTF8.GetBytes(urlWithoutFragment + browserExamKey));
+			var requestHashKey = BitConverter.ToString(requestHashBytes).ToLower().Replace("-", string.Empty);
 
-			// TODO: Implement Browser Exam Key calculation.
-			// headers["X-SafeExamBrowser-RequestHash"] = ...;
 			headers["X-SafeExamBrowser-ConfigKeyHash"] = configurationKey;
+			headers["X-SafeExamBrowser-RequestHash"] = requestHashKey;
+
 			request.Headers = headers;
 		}
 

SafeExamBrowser.Configuration.Contracts/AppConfig.cs

@@ -86,6 +86,11 @@ namespace SafeExamBrowser.Configuration.Contracts
 		/// </summary>
 		public string ClientLogFilePath { get; set; }
 
+		/// <summary>
+		/// The hash value of the certificate used to sign the application binaries, or <c>null</c> if the binaries are unsigned.
+		/// </summary>
+		public string CodeSignatureHash { get; set; }
+
 		/// <summary>
 		/// The file extension of configuration files for the application (including the period).
 		/// </summary>

SafeExamBrowser.Configuration.UnitTests/ConfigurationRepositoryTests.cs

@@ -39,8 +39,6 @@ namespace SafeExamBrowser.Configuration.UnitTests
 		[TestInitialize]
 		public void Initialize()
 		{
-			var executablePath = Assembly.GetExecutingAssembly().Location;
-
 			binaryParser = new Mock<IDataParser>();
 			binarySerializer = new Mock<IDataSerializer>();
 			certificateStore = new Mock<ICertificateStore>();
@@ -56,7 +54,7 @@ namespace SafeExamBrowser.Configuration.UnitTests
 			fileSaver.Setup(f => f.CanSave(It.IsAny<Uri>())).Returns<Uri>(u => u.IsFile);
 			networkLoader.Setup(n => n.CanLoad(It.IsAny<Uri>())).Returns<Uri>(u => u.Scheme.Equals("http") || u.Scheme.Equals("seb"));
 
-			sut = new ConfigurationRepository(certificateStore.Object, hashAlgorithm.Object, logger.Object, executablePath, string.Empty, string.Empty, string.Empty, string.Empty);
+			sut = new ConfigurationRepository(certificateStore.Object, hashAlgorithm.Object, logger.Object);
 			sut.InitializeAppConfig();
 		}
 

SafeExamBrowser.Configuration/ConfigurationData/DataValues.cs

@@ -7,7 +7,10 @@
  */
 
 using System;
+using System.Diagnostics;
 using System.IO;
+using System.Linq;
+using System.Reflection;
 using SafeExamBrowser.Configuration.Contracts;
 using SafeExamBrowser.Settings;
 using SafeExamBrowser.Settings.Browser;
@@ -22,27 +25,7 @@ namespace SafeExamBrowser.Configuration.ConfigurationData
 	internal class DataValues
 	{
 		private const string DEFAULT_CONFIGURATION_NAME = "SebClientSettings.seb";
-
 		private AppConfig appConfig;
-		private string executablePath;
-		private string programBuild;
-		private string programCopyright;
-		private string programTitle;
-		private string programVersion;
-
-		internal DataValues(
-			string executablePath,
-			string programBuild,
-			string programCopyright,
-			string programTitle,
-			string programVersion)
-		{
-			this.executablePath = executablePath ?? string.Empty;
-			this.programBuild = programBuild ?? string.Empty;
-			this.programCopyright = programCopyright ?? string.Empty;
-			this.programTitle = programTitle ?? string.Empty;
-			this.programVersion = programVersion ?? string.Empty;
-		}
 
 		internal string GetAppDataFilePath()
 		{
@@ -51,6 +34,12 @@ namespace SafeExamBrowser.Configuration.ConfigurationData
 
 		internal AppConfig InitializeAppConfig()
 		{
+			var executable = Assembly.GetExecutingAssembly();
+			var certificate = executable.Modules.First().GetSignerCertificate();
+			var programBuild = FileVersionInfo.GetVersionInfo(executable.Location).FileVersion;
+			var programCopyright = executable.GetCustomAttribute<AssemblyCopyrightAttribute>().Copyright;
+			var programTitle = executable.GetCustomAttribute<AssemblyTitleAttribute>().Title;
+			var programVersion = executable.GetCustomAttribute<AssemblyInformationalVersionAttribute>().InformationalVersion;
 			var appDataLocalFolder = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), nameof(SafeExamBrowser));
 			var appDataRoamingFolder = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), nameof(SafeExamBrowser));
 			var programDataFolder = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData), nameof(SafeExamBrowser));
@@ -65,8 +54,9 @@ namespace SafeExamBrowser.Configuration.ConfigurationData
 			appConfig.BrowserLogFilePath = Path.Combine(logFolder, $"{logFilePrefix}_Browser.log");
 			appConfig.ClientId = Guid.NewGuid();
 			appConfig.ClientAddress = $"{AppConfig.BASE_ADDRESS}/client/{Guid.NewGuid()}";
-			appConfig.ClientExecutablePath = Path.Combine(Path.GetDirectoryName(executablePath), $"{nameof(SafeExamBrowser)}.Client.exe");
+			appConfig.ClientExecutablePath = Path.Combine(Path.GetDirectoryName(executable.Location), $"{nameof(SafeExamBrowser)}.Client.exe");
 			appConfig.ClientLogFilePath = Path.Combine(logFolder, $"{logFilePrefix}_Client.log");
+			appConfig.CodeSignatureHash = certificate?.GetCertHashString();
 			appConfig.ConfigurationFileExtension = ".seb";
 			appConfig.ConfigurationFileMimeType = "application/seb";
 			appConfig.ProgramBuildVersion = programBuild;

SafeExamBrowser.Configuration/ConfigurationRepository.cs

@@ -33,15 +33,7 @@ namespace SafeExamBrowser.Configuration
 		private IList<IResourceLoader> resourceLoaders;
 		private IList<IResourceSaver> resourceSavers;
 
-		public ConfigurationRepository(
+		public ConfigurationRepository(ICertificateStore certificateStore, IHashAlgorithm hashAlgorithm, IModuleLogger logger)
-			ICertificateStore certificateStore,
-			IHashAlgorithm hashAlgorithm,
-			IModuleLogger logger,
-			string executablePath,
-			string programBuild,
-			string programCopyright,
-			string programTitle,
-			string programVersion)
 		{
 			this.certificateStore = certificateStore;
 			this.hashAlgorithm = hashAlgorithm;
@@ -51,7 +43,7 @@ namespace SafeExamBrowser.Configuration
 			dataSerializers = new List<IDataSerializer>();
 			dataMapper = new DataMapper();
 			dataProcessor = new DataProcessor();
-			dataValues = new DataValues(executablePath, programBuild, programCopyright, programTitle, programVersion);
+			dataValues = new DataValues();
 			resourceLoaders = new List<IResourceLoader>();
 			resourceSavers = new List<IResourceSaver>();
 		}

SafeExamBrowser.Runtime/CompositionRoot.cs

@@ -8,7 +8,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Diagnostics;
 using System.IO;
 using System.Reflection;
 using SafeExamBrowser.Communication.Contracts;
@@ -129,12 +128,6 @@ namespace SafeExamBrowser.Runtime
 
 		private void InitializeConfiguration()
 		{
-			var executable = Assembly.GetExecutingAssembly();
-			var programBuild = FileVersionInfo.GetVersionInfo(executable.Location).FileVersion;
-			var programCopyright = executable.GetCustomAttribute<AssemblyCopyrightAttribute>().Copyright;
-			var programTitle = executable.GetCustomAttribute<AssemblyTitleAttribute>().Title;
-			var programVersion = executable.GetCustomAttribute<AssemblyInformationalVersionAttribute>().InformationalVersion;
-
 			var certificateStore = new CertificateStore(ModuleLogger(nameof(CertificateStore)));
 			var compressor = new GZipCompressor(ModuleLogger(nameof(GZipCompressor)));
 			var passwordEncryption = new PasswordEncryption(ModuleLogger(nameof(PasswordEncryption)));
@@ -144,15 +137,7 @@ namespace SafeExamBrowser.Runtime
 			var xmlParser = new XmlParser(compressor, ModuleLogger(nameof(XmlParser)));
 			var xmlSerializer = new XmlSerializer(ModuleLogger(nameof(XmlSerializer)));
 
-			configuration = new ConfigurationRepository(
+			configuration = new ConfigurationRepository(certificateStore, new HashAlgorithm(), repositoryLogger);
-				certificateStore,
-				new HashAlgorithm(),
-				repositoryLogger,
-				executable.Location,
-				programBuild,
-				programCopyright,
-				programTitle,
-				programVersion);
 			appConfig = configuration.InitializeAppConfig();
 
 			configuration.Register(new BinaryParser(