Enable TLS validation with parsec.

Introduce new IAuthenticationPlugin3 interface and deprecate IAuthenticationPlugin2. Authentication plugins will now compute the password hash and the authentication response in one call, and the session will cache the password hash for later use.

Signed-off-by: Bradley Grainger <[email protected]>

Author: bgrainger

src/MySqlConnector.Authentication.Ed25519/Chaos.NaCl/Ed25519.cs

@@ -34,19 +34,6 @@ public static byte[] Sign(byte[] message, byte[] expandedPrivateKey)
             return signature;
         }
 
-        public static byte[] ExpandedPrivateKeyFromSeed(byte[] privateKeySeed)
-        {
-            byte[] privateKey;
-            byte[] publicKey;
-            KeyPairFromSeed(out publicKey, out privateKey, privateKeySeed);
-#if NETSTANDARD2_1_OR_GREATER || NETCOREAPP2_1_OR_GREATER
-            CryptographicOperations.ZeroMemory(publicKey);
-#else
-            CryptoBytes.Wipe(publicKey);
-#endif
-            return privateKey;
-        }
-
         public static void KeyPairFromSeed(out byte[] publicKey, out byte[] expandedPrivateKey, byte[] privateKeySeed)
         {
             if (privateKeySeed == null)

src/MySqlConnector.Authentication.Ed25519/Ed25519AuthenticationPlugin.cs

@@ -10,7 +10,9 @@ namespace MySqlConnector.Authentication.Ed25519;
 /// Provides an implementation of the <c>client_ed25519</c> authentication plugin for MariaDB.
 /// </summary>
 /// <remarks>See <a href="https://mariadb.com/kb/en/library/authentication-plugin-ed25519/">Authentication Plugin - ed25519</a>.</remarks>
-public sealed class Ed25519AuthenticationPlugin : IAuthenticationPlugin2
+#pragma warning disable CS0618 // Type or member is obsolete
+public sealed class Ed25519AuthenticationPlugin : IAuthenticationPlugin3, IAuthenticationPlugin2
+#pragma warning restore CS0618 // Type or member is obsolete
 {
 	/// <summary>
 	/// Registers the Ed25519 authentication plugin with MySqlConnector. You must call this method once before
@@ -32,7 +34,7 @@ public static void Install()
 	/// </summary>
 	public byte[] CreateResponse(string password, ReadOnlySpan<byte> authenticationData)
 	{
-		CreateResponseAndHash(password, authenticationData, out _, out var authenticationResponse);
+		CreateResponseAndPasswordHash(password, authenticationData, out var authenticationResponse, out _);
 		return authenticationResponse;
 	}
 
@@ -41,11 +43,20 @@ public byte[] CreateResponse(string password, ReadOnlySpan<byte> authenticationD
 	/// </summary>
 	public byte[] CreatePasswordHash(string password, ReadOnlySpan<byte> authenticationData)
 	{
-		CreateResponseAndHash(password, authenticationData, out var passwordHash, out _);
+		CreateResponseAndPasswordHash(password, authenticationData, out _, out var passwordHash);
 		return passwordHash;
 	}
 
-	private static void CreateResponseAndHash(string password, ReadOnlySpan<byte> authenticationData, out byte[] passwordHash, out byte[] authenticationResponse)
+	/// <summary>
+	/// Creates the authentication response and hashes the client's password (e.g., for TLS certificate fingerprint verification).
+	/// </summary>
+	/// <param name="password">The client's password.</param>
+	/// <param name="authenticationData">The authentication data supplied by the server; this is the <code>auth method data</code>
+	/// from the <a href="https://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::AuthSwitchRequest">Authentication
+	/// Method Switch Request Packet</a>.</param>
+	/// <param name="authenticationResponse">The authentication response.</param>
+	/// <param name="passwordHash">The authentication-method-specific hash of the client's password.</param>
+	public void CreateResponseAndPasswordHash(string password, ReadOnlySpan<byte> authenticationData, out byte[] authenticationResponse, out byte[] passwordHash)
 	{
 		// Java reference: https://github.com/MariaDB/mariadb-connector-j/blob/master/src/main/java/org/mariadb/jdbc/internal/com/send/authentication/Ed25519PasswordPlugin.java
 		// C reference:  https://github.com/MariaDB/server/blob/592fe954ef82be1bc08b29a8e54f7729eb1e1343/plugin/auth_ed25519/ref10/sign.c#L7

src/MySqlConnector.Authentication.Ed25519/ParsecAuthenticationPlugin.cs

@@ -8,7 +8,7 @@ namespace MySqlConnector.Authentication.Ed25519;
 /// <summary>
 /// Provides an implementation of the Parsec authentication plugin for MariaDB.
 /// </summary>
-public sealed class ParsecAuthenticationPlugin : IAuthenticationPlugin
+public sealed class ParsecAuthenticationPlugin : IAuthenticationPlugin3
 {
 	/// <summary>
 	/// Registers the Parsec authentication plugin with MySqlConnector. You must call this method once before
@@ -29,6 +29,15 @@ public static void Install()
 	/// Creates the authentication response.
 	/// </summary>
 	public byte[] CreateResponse(string password, ReadOnlySpan<byte> authenticationData)
+	{
+		CreateResponseAndPasswordHash(password, authenticationData, out var response, out _);
+		return response;
+	}
+
+	/// <summary>
+	/// Creates the authentication response.
+	/// </summary>
+	public void CreateResponseAndPasswordHash(string password, ReadOnlySpan<byte> authenticationData, out byte[] authenticationResponse, out byte[] passwordHash)
 	{
 		// first 32 bytes are server scramble
 		var serverScramble = authenticationData.Slice(0, 32);
@@ -54,32 +63,37 @@ public byte[] CreateResponse(string password, ReadOnlySpan<byte> authenticationD
 		var salt = extendedSalt.Slice(2);
 
 		// derive private key using PBKDF2-SHA512
-		byte[] privateKey;
+		byte[] privateKeySeed;
 #if NET6_0_OR_GREATER
-		privateKey = Rfc2898DeriveBytes.Pbkdf2(Encoding.UTF8.GetBytes(password), salt, iterationCount, HashAlgorithmName.SHA512, 32);
+		privateKeySeed = Rfc2898DeriveBytes.Pbkdf2(Encoding.UTF8.GetBytes(password), salt, iterationCount, HashAlgorithmName.SHA512, 32);
 #elif NET472_OR_GREATER || NETSTANDARD2_1_OR_GREATER
 		using (var pbkdf2 = new Rfc2898DeriveBytes(Encoding.UTF8.GetBytes(password), salt.ToArray(), iterationCount, HashAlgorithmName.SHA512))
-			privateKey = pbkdf2.GetBytes(32);
+			privateKeySeed = pbkdf2.GetBytes(32);
 #else
-		privateKey = Microsoft.AspNetCore.Cryptography.KeyDerivation.KeyDerivation.Pbkdf2(
+		privateKeySeed = Microsoft.AspNetCore.Cryptography.KeyDerivation.KeyDerivation.Pbkdf2(
 			password, salt.ToArray(), Microsoft.AspNetCore.Cryptography.KeyDerivation.KeyDerivationPrf.HMACSHA512,
 			iterationCount, numBytesRequested: 32);
 #endif
-		var expandedPrivateKey = Chaos.NaCl.Ed25519.ExpandedPrivateKeyFromSeed(privateKey);
+		Chaos.NaCl.Ed25519.KeyPairFromSeed(out var publicKey, out var privateKey, privateKeySeed);
 
 		// generate Ed25519 keypair and sign concatenated scrambles
 		var message = new byte[serverScramble.Length + clientScramble.Length];
 		serverScramble.CopyTo(message);
 		clientScramble.CopyTo(message.AsSpan(serverScramble.Length));
 
-		var signature = Chaos.NaCl.Ed25519.Sign(message, expandedPrivateKey);
+		var signature = Chaos.NaCl.Ed25519.Sign(message, privateKey);
+
+#if NETSTANDARD2_1_OR_GREATER || NETCOREAPP2_1_OR_GREATER
+		CryptographicOperations.ZeroMemory(privateKey);
+#endif
 
 		// return client scramble followed by signature
-		var response = new byte[clientScramble.Length + signature.Length];
-		clientScramble.CopyTo(response.AsSpan());
-		signature.CopyTo(response.AsSpan(clientScramble.Length));
-		
-		return response;
+		authenticationResponse = new byte[clientScramble.Length + signature.Length];
+		clientScramble.CopyTo(authenticationResponse.AsSpan());
+		signature.CopyTo(authenticationResponse.AsSpan(clientScramble.Length));
+
+		// "password hash" for parsec is the extended salt followed by the public key
+		passwordHash = [(byte) 'P', (byte) iterationCount, .. salt, .. publicKey];
 	}
 
 	private ParsecAuthenticationPlugin()

src/MySqlConnector/Authentication/IAuthenticationPlugin.cs

@@ -24,6 +24,7 @@ public interface IAuthenticationPlugin
 /// <summary>
 /// <see cref="IAuthenticationPlugin2"/> is an extension to <see cref="IAuthenticationPlugin"/> that returns a hash of the client's password.
 /// </summary>
+[Obsolete("Use IAuthenticationPlugin3 instead.")]
 public interface IAuthenticationPlugin2 : IAuthenticationPlugin
 {
 	/// <summary>
@@ -36,3 +37,21 @@ public interface IAuthenticationPlugin2 : IAuthenticationPlugin
 	/// <returns>The authentication-method-specific hash of the client's password.</returns>
 	byte[] CreatePasswordHash(string password, ReadOnlySpan<byte> authenticationData);
 }
+
+/// <summary>
+/// <see cref="IAuthenticationPlugin3"/> is an extension to <see cref="IAuthenticationPlugin"/> that also returns a hash of the client's password.
+/// </summary>
+/// <remarks>If an authentication plugin supports this interface, the base <see cref="IAuthenticationPlugin.CreateResponse(string, ReadOnlySpan{byte})"/> method will not be called.</remarks>
+public interface IAuthenticationPlugin3 : IAuthenticationPlugin
+{
+	/// <summary>
+	/// Creates the authentication response and hashes the client's password (e.g., for TLS certificate fingerprint verification).
+	/// </summary>
+	/// <param name="password">The client's password.</param>
+	/// <param name="authenticationData">The authentication data supplied by the server; this is the <code>auth method data</code>
+	/// from the <a href="https://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::AuthSwitchRequest">Authentication
+	/// Method Switch Request Packet</a>.</param>
+	/// <param name="authenticationResponse">The authentication response.</param>
+	/// <param name="passwordHash">The authentication-method-specific hash of the client's password.</param>
+	void CreateResponseAndPasswordHash(string password, ReadOnlySpan<byte> authenticationData, out byte[] authenticationResponse, out byte[] passwordHash);
+}

src/MySqlConnector/Core/ServerSession.cs

@@ -448,13 +448,13 @@ public async Task DisposeAsync(IOBehavior ioBehavior, CancellationToken cancella
 			var initialHandshake = InitialHandshakePayload.Create(payload.Span);
 
 			// if PluginAuth is supported, then use the specified auth plugin; else, fall back to protocol capabilities to determine the auth type to use
-			m_currentAuthenticationMethod = (initialHandshake.ProtocolCapabilities & ProtocolCapabilities.PluginAuth) != 0 ? initialHandshake.AuthPluginName! :
+			var currentAuthenticationMethod = (initialHandshake.ProtocolCapabilities & ProtocolCapabilities.PluginAuth) != 0 ? initialHandshake.AuthPluginName! :
 				(initialHandshake.ProtocolCapabilities & ProtocolCapabilities.SecureConnection) == 0 ? "mysql_old_password" :
 				"mysql_native_password";
-			Log.ServerSentAuthPluginName(m_logger, Id, m_currentAuthenticationMethod);
-			if (m_currentAuthenticationMethod is not "mysql_native_password" and not "sha256_password" and not "caching_sha2_password")
+			Log.ServerSentAuthPluginName(m_logger, Id, currentAuthenticationMethod);
+			if (currentAuthenticationMethod is not "mysql_native_password" and not "sha256_password" and not "caching_sha2_password")
 			{
-				Log.UnsupportedAuthenticationMethod(m_logger, Id, m_currentAuthenticationMethod);
+				Log.UnsupportedAuthenticationMethod(m_logger, Id, currentAuthenticationMethod);
 				throw new NotSupportedException($"Authentication method '{initialHandshake.AuthPluginName}' is not supported.");
 			}
 
@@ -532,7 +532,13 @@ public async Task DisposeAsync(IOBehavior ioBehavior, CancellationToken cancella
 			var useCachingSha2 = initialHandshake.AuthPluginName == "caching_sha2_password";
 
 			var password = GetPassword(cs, connection);
-			using (var handshakeResponsePayload = HandshakeResponse41Payload.Create(initialHandshake, cs, password, useCachingSha2, m_compressionMethod, connection.ZstandardPlugin?.CompressionLevel, m_characterSet, m_supportsConnectionAttributes ? cs.ConnectionAttributes : null))
+			byte[] authenticationResponse;
+			if (useCachingSha2)
+				authenticationResponse = AuthenticationUtility.CreateScrambleResponse(Utility.TrimZeroByte(initialHandshake.AuthPluginData.AsSpan()), password);
+			else
+				AuthenticationUtility.CreateResponseAndPasswordHash(password, initialHandshake.AuthPluginData, out authenticationResponse, out m_passwordHash);
+
+			using (var handshakeResponsePayload = HandshakeResponse41Payload.Create(initialHandshake, cs, authenticationResponse, m_compressionMethod, connection.ZstandardPlugin?.CompressionLevel, m_characterSet, m_supportsConnectionAttributes ? cs.ConnectionAttributes : null))
 				await SendReplyAsync(handshakeResponsePayload, ioBehavior, cancellationToken).ConfigureAwait(false);
 			payload = await ReceiveReplyAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
 
@@ -553,7 +559,7 @@ public async Task DisposeAsync(IOBehavior ioBehavior, CancellationToken cancella
 				}
 				else if (!m_isSecureConnection && password.Length != 0)
 				{
-					var publicKey = await GetRsaPublicKeyAsync(m_currentAuthenticationMethod, cs, ioBehavior, cancellationToken).ConfigureAwait(false);
+					var publicKey = await GetRsaPublicKeyAsync(currentAuthenticationMethod, cs, ioBehavior, cancellationToken).ConfigureAwait(false);
 					payload = await SendEncryptedPasswordAsync(AuthPluginData, publicKey, password, ioBehavior, cancellationToken).ConfigureAwait(false);
 				}
 				else
@@ -583,7 +589,7 @@ public async Task DisposeAsync(IOBehavior ioBehavior, CancellationToken cancella
 					// there is no shared secret that can be used to validate the certificate
 					Log.CertificateErrorNoPassword(m_logger, Id, m_sslPolicyErrors);
 				}
-				else if (ValidateFingerprint(ok.StatusInfo, initialHandshake.AuthPluginData.AsSpan(0, 20), password))
+				else if (ValidateFingerprint(ok.StatusInfo, initialHandshake.AuthPluginData.AsSpan(0, 20)))
 				{
 					Log.CertificateErrorValidThumbprint(m_logger, Id, m_sslPolicyErrors);
 					ignoreCertificateError = true;
@@ -649,36 +655,20 @@ public async Task DisposeAsync(IOBehavior ioBehavior, CancellationToken cancella
 	/// </summary>
 	/// <param name="validationHash">The validation hash received from the server.</param>
 	/// <param name="challenge">The auth plugin data from the initial handshake.</param>
-	/// <param name="password">The user's password.</param>
 	/// <returns><c>true</c> if the validation hash matches the locally-computed value; otherwise, <c>false</c>.</returns>
-	private bool ValidateFingerprint(byte[]? validationHash, ReadOnlySpan<byte> challenge, string password)
+	private bool ValidateFingerprint(byte[]? validationHash, ReadOnlySpan<byte> challenge)
 	{
 		// expect 0x01 followed by 64 hex characters giving a SHA2 hash
 		if (validationHash?.Length != 65 || validationHash[0] != 1)
 			return false;
 
-		byte[]? passwordHashResult = null;
-		switch (m_currentAuthenticationMethod)
-		{
-			case "mysql_native_password":
-				passwordHashResult = AuthenticationUtility.HashPassword([], password, onlyHashPassword: true);
-				break;
-
-			case "client_ed25519":
-				AuthenticationPlugins.TryGetPlugin(m_currentAuthenticationMethod, out var ed25519Plugin);
-				if (ed25519Plugin is IAuthenticationPlugin2 plugin2)
-					passwordHashResult = plugin2.CreatePasswordHash(password, challenge);
-				break;
-		}
-		if (passwordHashResult is null)
+		// the authentication plugin must have provided a password hash (via IAuthenticationPlugin3) that we saved for future use
+		if (m_passwordHash is null)
 			return false;
 
-		Span<byte> combined = stackalloc byte[32 + challenge.Length + passwordHashResult.Length];
-		passwordHashResult.CopyTo(combined);
-		challenge.CopyTo(combined[passwordHashResult.Length..]);
-		m_remoteCertificateSha2Thumbprint!.CopyTo(combined[(passwordHashResult.Length + challenge.Length)..]);
-
+		// hash password hash || scramble || certificate thumbprint
 		Span<byte> hashBytes = stackalloc byte[32];
+		Span<byte> combined = [.. m_passwordHash, .. challenge, .. m_remoteCertificateSha2Thumbprint!];
 #if NET5_0_OR_GREATER
 		SHA256.TryHashData(combined, hashBytes, out _);
 #else
@@ -827,8 +817,8 @@ public async Task<bool> TryResetConnectionAsync(ConnectionSettings cs, MySqlConn
 					DatabaseOverride = null;
 				}
 				var password = GetPassword(cs, connection);
-				var hashedPassword = AuthenticationUtility.CreateAuthenticationResponse(AuthPluginData!, password);
-				using (var changeUserPayload = ChangeUserPayload.Create(cs.UserID, hashedPassword, cs.Database, m_characterSet, m_supportsConnectionAttributes ? cs.ConnectionAttributes : null))
+				AuthenticationUtility.CreateResponseAndPasswordHash(password, AuthPluginData, out var nativeResponse, out m_passwordHash);
+				using (var changeUserPayload = ChangeUserPayload.Create(cs.UserID, nativeResponse, cs.Database, m_characterSet, m_supportsConnectionAttributes ? cs.ConnectionAttributes : null))
 					await SendAsync(changeUserPayload, ioBehavior, cancellationToken).ConfigureAwait(false);
 				payload = await ReceiveReplyAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
 				if (payload.HeaderByte == AuthenticationMethodSwitchRequestPayload.Signature)
@@ -872,13 +862,12 @@ private async Task<PayloadData> SwitchAuthenticationAsync(ConnectionSettings cs,
 		// if the server didn't support the hashed password; rehash with the new challenge
 		var switchRequest = AuthenticationMethodSwitchRequestPayload.Create(payload.Span);
 		Log.SwitchingToAuthenticationMethod(m_logger, Id, switchRequest.Name);
-		m_currentAuthenticationMethod = switchRequest.Name;
 		switch (switchRequest.Name)
 		{
 			case "mysql_native_password":
 				AuthPluginData = switchRequest.Data;
-				var hashedPassword = AuthenticationUtility.CreateAuthenticationResponse(AuthPluginData, password);
-				payload = new(hashedPassword);
+				AuthenticationUtility.CreateResponseAndPasswordHash(password, AuthPluginData, out var nativeResponse, out m_passwordHash);
+				payload = new(nativeResponse);
 				await SendReplyAsync(payload, ioBehavior, cancellationToken).ConfigureAwait(false);
 				return await ReceiveReplyAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
 
@@ -931,14 +920,15 @@ private async Task<PayloadData> SwitchAuthenticationAsync(ConnectionSettings cs,
 				throw new NotSupportedException("'MySQL Server is requesting the insecure pre-4.1 auth mechanism (mysql_old_password). The user password must be upgraded; see https://dev.mysql.com/doc/refman/5.7/en/account-upgrades.html.");
 
 			case "client_ed25519":
-				if (!AuthenticationPlugins.TryGetPlugin(switchRequest.Name, out var ed25519Plugin))
+				if (!AuthenticationPlugins.TryGetPlugin(switchRequest.Name, out var ed25519Plugin) || ed25519Plugin is not IAuthenticationPlugin3 ed25519Plugin3)
 					throw new NotSupportedException("You must install the MySqlConnector.Authentication.Ed25519 package and call Ed25519AuthenticationPlugin.Install to use client_ed25519 authentication.");
-				payload = new(ed25519Plugin.CreateResponse(password, switchRequest.Data));
+				ed25519Plugin3.CreateResponseAndPasswordHash(password, switchRequest.Data, out var ed25519Response, out m_passwordHash);
+				payload = new(ed25519Response);
 				await SendReplyAsync(payload, ioBehavior, cancellationToken).ConfigureAwait(false);
 				return await ReceiveReplyAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
 
 			case "parsec":
-				if (!AuthenticationPlugins.TryGetPlugin(switchRequest.Name, out var parsecPlugin))
+				if (!AuthenticationPlugins.TryGetPlugin(switchRequest.Name, out var parsecPlugin) || parsecPlugin is not IAuthenticationPlugin3 parsecPlugin3)
 					throw new NotSupportedException("You must install the MySqlConnector.Authentication.Ed25519 package and call ParsecAuthenticationPlugin.Install to use parsec authentication.");
 				payload = new([]);
 				await SendReplyAsync(payload, ioBehavior, cancellationToken).ConfigureAwait(false);
@@ -948,7 +938,8 @@ private async Task<PayloadData> SwitchAuthenticationAsync(ConnectionSettings cs,
 				switchRequest.Data.CopyTo(combinedData);
 				payload.Span.CopyTo(combinedData.Slice(switchRequest.Data.Length));
 
-				payload = new(parsecPlugin.CreateResponse(password, combinedData));
+				parsecPlugin3.CreateResponseAndPasswordHash(password, combinedData, out var parsecResponse, out m_passwordHash);
+				payload = new(parsecResponse);
 				await SendReplyAsync(payload, ioBehavior, cancellationToken).ConfigureAwait(false);
 				return await ReceiveReplyAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
 
@@ -2216,7 +2207,7 @@ protected override void OnStatementBegin(int index)
 	private PayloadData m_setNamesPayload;
 	private byte[]? m_pipelinedResetConnectionBytes;
 	private Dictionary<string, PreparedStatements>? m_preparedStatements;
-	private string? m_currentAuthenticationMethod;
+	private byte[]? m_passwordHash;
 	private byte[]? m_remoteCertificateSha2Thumbprint;
 	private SslPolicyErrors m_sslPolicyErrors;
 }