Fix(auth) Fix bug #1515 PLAIN and LOGIN always returning failure if "…

…allow any" turned off. (#1551)

smtpserver/Rnwood.SmtpServer.Tests/Extensions/Auth/LoginMechanismProcessorTests.cs

@@ -111,6 +111,24 @@ await Assert.ThrowsAsync<BadBase64Exception>(async () =>
             await processor.ProcessResponse("rob blah");
         });
 
+    [Fact]
+    public void ValidateCredentials_Correct()
+    {
+        var creds = new LoginAuthenticationCredentials("a", "b");
+        bool result = creds.ValidateResponse("b");
+
+        Assert.True(result);
+    }
+
+    [Fact]
+    public void ValidateCredentials_Incorrect()
+    {
+        var creds = new LoginAuthenticationCredentials("a", "b");
+        bool result = creds.ValidateResponse("c");
+
+        Assert.False(result);
+    }
+
     /// <summary>
     /// </summary>
     /// <param name="mocks">The mocks<see cref="TestMocks" /></param>

smtpserver/Rnwood.SmtpServer.Tests/Extensions/Auth/PlainMechanismProcessorTests.cs

@@ -0,0 +1,35 @@
+// Licensed to the.NET Foundation under one or more agreements.
+// The.NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Rnwood.SmtpServer.Extensions.Auth;
+using Xunit;
+
+namespace Rnwood.SmtpServer.Tests.Extensions.Auth
+{
+    public class PlainMechanismProcessorTests
+    {
+
+        [Fact]
+        public void ValidateCredentials_Correct()
+        {
+            var creds = new PlainAuthenticationCredentials("a", "b");
+            bool result = creds.ValidateResponse("b");
+
+            Assert.True(result);
+        }
+
+        [Fact]
+        public void ValidateCredentials_Incorrect()
+        {
+            var creds = new PlainAuthenticationCredentials("a", "b");
+            bool result = creds.ValidateResponse("c");
+
+            Assert.False(result);
+        }
+    }
+}

smtpserver/Rnwood.SmtpServer/Extensions/Auth/UsernameAndPasswordAuthenticationCredentials.cs

@@ -8,7 +8,7 @@ namespace Rnwood.SmtpServer.Extensions.Auth;
 /// <summary>
 ///     Defines the <see cref="UsernameAndPasswordAuthenticationCredentials" />.
 /// </summary>
-public abstract class UsernameAndPasswordAuthenticationCredentials : IAuthenticationCredentials
+public abstract class UsernameAndPasswordAuthenticationCredentials : IAuthenticationCredentials, IAuthenticationCredentialsCanValidateWithPassword
 {
     /// <summary>
     ///     Initializes a new instance of the <see cref="UsernameAndPasswordAuthenticationCredentials" /> class.
@@ -33,4 +33,9 @@ protected UsernameAndPasswordAuthenticationCredentials(string username, string p
 
     /// <inheritdoc />
     public string Type { get => "USERNAME_PASSWORD"; }
+
+    /// <inheritdoc/>
+    public bool ValidateResponse(string password) {
+        return string.Equals(Password, password);
+    }
 }