Use LDAP support from DirectoryServices.Protocols for RBAC claim resolution on Linux for Negotiate (#25075)

Author: John Luo

eng/Dependencies.props

@@ -64,6 +64,7 @@ and are generated based on the last package release.
     <LatestPackageReference Include="System.ComponentModel.Annotations" />
     <LatestPackageReference Include="System.Diagnostics.DiagnosticSource" />
     <LatestPackageReference Include="System.Diagnostics.EventLog" />
+    <LatestPackageReference Include="System.DirectoryServices.Protocols" />
     <LatestPackageReference Include="System.Drawing.Common" />
     <LatestPackageReference Include="System.IO.Pipelines" />
     <LatestPackageReference Include="System.Net.Http" />

eng/Version.Details.xml

@@ -205,6 +205,10 @@
       <Uri>https://github.com/dotnet/runtime</Uri>
       <Sha>f4e99f4afa445b519abcd7c5c87cbf54771614db</Sha>
     </Dependency>
+    <Dependency Name="System.DirectoryServices.Protocols" Version="5.0.0-rc.1.20425.1">
+      <Uri>https://github.com/dotnet/runtime</Uri>
+      <Sha>f4e99f4afa445b519abcd7c5c87cbf54771614db</Sha>
+    </Dependency>
     <Dependency Name="System.Drawing.Common" Version="5.0.0-rc.1.20425.1">
       <Uri>https://github.com/dotnet/runtime</Uri>
       <Sha>f4e99f4afa445b519abcd7c5c87cbf54771614db</Sha>

eng/Versions.props

@@ -108,6 +108,7 @@
     <SystemComponentModelAnnotationsPackageVersion>5.0.0-rc.1.20425.1</SystemComponentModelAnnotationsPackageVersion>
     <SystemDiagnosticsDiagnosticSourcePackageVersion>5.0.0-rc.1.20425.1</SystemDiagnosticsDiagnosticSourcePackageVersion>
     <SystemDiagnosticsEventLogPackageVersion>5.0.0-rc.1.20425.1</SystemDiagnosticsEventLogPackageVersion>
+    <SystemDirectoryServicesProtocolsPackageVersion>5.0.0-rc.1.20425.1</SystemDirectoryServicesProtocolsPackageVersion>
     <SystemDrawingCommonPackageVersion>5.0.0-rc.1.20425.1</SystemDrawingCommonPackageVersion>
     <SystemIOPipelinesPackageVersion>5.0.0-rc.1.20425.1</SystemIOPipelinesPackageVersion>
     <SystemNetHttpJsonPackageVersion>5.0.0-rc.1.20425.1</SystemNetHttpJsonPackageVersion>

src/Security/Authentication/Negotiate/samples/NegotiateAuthSample/Startup.cs

@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Authentication.Negotiate;
 using Microsoft.AspNetCore.Builder;
@@ -22,6 +23,23 @@ public void ConfigureServices(IServiceCollection services)
             services.AddAuthentication(NegotiateDefaults.AuthenticationScheme)
                 .AddNegotiate(options =>
                 {
+                    if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+                    {
+                        /*
+                        options.EnableLdap("DOMAIN.net");
+
+                        options.EnableLdap(settings =>
+                        {
+                            // Mandatory settings
+                            settings.Domain = "DOMAIN.com";
+                            // Optional settings
+                            settings.MachineAccountName = "machineName";
+                            settings.MachineAccountPassword = "PassW0rd";
+                            settings.IgnoreNestedGroups = true;
+                        });
+                        */
+                    }
+
                     options.Events = new NegotiateEvents()
                     {
                         OnAuthenticationFailed = context =>

src/Security/Authentication/Negotiate/src/Events/LdapContext.cs

@@ -0,0 +1,35 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Authentication.Negotiate
+{
+    /// <summary>
+    /// State for the RetrieveLdapClaims event.
+    /// </summary>
+    public class LdapContext : ResultContext<NegotiateOptions>
+    {
+        /// <summary>
+        /// Creates a new <see cref="LdapContext"/>.
+        /// </summary>
+        /// <param name="context"></param>
+        /// <param name="scheme"></param>
+        /// <param name="options"></param>
+        /// <param name="settings"></param>
+        public LdapContext(
+            HttpContext context,
+            AuthenticationScheme scheme,
+            NegotiateOptions options,
+            LdapSettings settings)
+            : base(context, scheme, options)
+        {
+            LdapSettings = settings;
+        }
+
+        /// <summary>
+        /// The LDAP settings to use for the RetrieveLdapClaims event.
+        /// </summary>
+        public LdapSettings LdapSettings { get; }
+    }
+}

src/Security/Authentication/Negotiate/src/Events/NegotiateEvents.cs

@@ -16,6 +16,12 @@ public class NegotiateEvents
         /// </summary>
         public Func<AuthenticationFailedContext, Task> OnAuthenticationFailed { get; set; } = context => Task.CompletedTask;
 
+        /// <summary>
+        /// Invoked after the authentication before ClaimsIdentity is populated with claims retrieved through the LDAP connection.
+        /// This event is invoked when <see cref="LdapSettings.EnableLdapClaimResolution"/> is set to true on <see cref="LdapSettings"/>.
+        /// </summary>
+        public Func<LdapContext, Task> OnRetrieveLdapClaims { get; set; } = context => Task.CompletedTask;
+
         /// <summary>
         /// Invoked after the authentication is complete and a ClaimsIdentity has been generated.
         /// </summary>
@@ -31,6 +37,11 @@ public class NegotiateEvents
         /// </summary>
         public virtual Task AuthenticationFailed(AuthenticationFailedContext context) => OnAuthenticationFailed(context);
 
+        /// <summary>
+        /// Invoked after the authentication before ClaimsIdentity is populated with claims retrieved through the LDAP connection.
+        /// </summary>
+        public virtual Task RetrieveLdapClaims(LdapContext context) => OnRetrieveLdapClaims(context);
+
         /// <summary>
         /// Invoked after the authentication is complete and a ClaimsIdentity has been generated.
         /// </summary>

src/Security/Authentication/Negotiate/src/Internal/LdapAdapter.cs

@@ -0,0 +1,97 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.DirectoryServices.Protocols;
+using System.Linq;
+using System.Security.Claims;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
+
+namespace Microsoft.AspNetCore.Authentication.Negotiate
+{
+    internal static class LdapAdapter
+    {
+        public static async Task RetrieveClaimsAsync(LdapSettings settings, ClaimsIdentity identity, ILogger logger)
+        {
+            var user = identity.Name;
+            var userAccountName = user.Substring(0, user.IndexOf('@'));
+            var distinguishedName = settings.Domain.Split('.').Select(name => $"dc={name}").Aggregate((a, b) => $"{a},{b}");
+
+            var filter = $"(&(objectClass=user)(sAMAccountName={userAccountName}))"; // This is using ldap search query language, it is looking on the server for someUser
+            var searchRequest = new SearchRequest(distinguishedName, filter, SearchScope.Subtree, null);
+            var searchResponse = (SearchResponse) await Task<DirectoryResponse>.Factory.FromAsync(
+                settings.LdapConnection.BeginSendRequest,
+                settings.LdapConnection.EndSendRequest,
+                searchRequest,
+                PartialResultProcessing.NoPartialResultSupport,
+                null);
+
+            if (searchResponse.Entries.Count > 0)
+            {
+                if (searchResponse.Entries.Count > 1)
+                {
+                    logger.LogWarning($"More than one response received for query: {filter} with distinguished name: {distinguishedName}");
+                }
+
+                var userFound = searchResponse.Entries[0]; //Get the object that was found on ldap
+                var memberof = userFound.Attributes["memberof"]; // You can access ldap Attributes with Attributes property
+
+                foreach (var group in memberof)
+                {
+                    // Example distinguished name: CN=TestGroup,DC=KERB,DC=local
+                    var groupDN = $"{Encoding.UTF8.GetString((byte[])group)}";
+                    var groupCN = groupDN.Split(',')[0].Substring("CN=".Length);
+
+                    if (!settings.IgnoreNestedGroups)
+                    {
+                        GetNestedGroups(settings.LdapConnection, identity, distinguishedName, groupCN, logger);
+                    }
+                    else
+                    {
+                        AddRole(identity, groupCN);
+                    }
+                }
+            }
+            else
+            {
+                logger.LogWarning($"No response received for query: {filter} with distinguished name: {distinguishedName}");
+            }
+        }
+
+        private static void GetNestedGroups(LdapConnection connection, ClaimsIdentity principal, string distinguishedName, string groupCN, ILogger logger)
+        {
+            var filter = $"(&(objectClass=group)(sAMAccountName={groupCN}))"; // This is using ldap search query language, it is looking on the server for someUser
+            var searchRequest = new SearchRequest(distinguishedName, filter, System.DirectoryServices.Protocols.SearchScope.Subtree, null);
+            var searchResponse = (SearchResponse)connection.SendRequest(searchRequest);
+
+            if (searchResponse.Entries.Count > 0)
+            {
+                if (searchResponse.Entries.Count > 1)
+                {
+                    logger.LogWarning($"More than one response received for query: {filter} with distinguished name: {distinguishedName}");
+                }
+
+                var group = searchResponse.Entries[0]; //Get the object that was found on ldap
+                string name = group.DistinguishedName;
+                AddRole(principal, name);
+
+                var memberof = group.Attributes["memberof"]; // You can access ldap Attributes with Attributes property
+                if (memberof != null)
+                {
+                    foreach (var member in memberof)
+                    {
+                        var groupDN = $"{Encoding.UTF8.GetString((byte[])member)}";
+                        var nestedGroupCN = groupDN.Split(',')[0].Substring("CN=".Length);
+                        GetNestedGroups(connection, principal, distinguishedName, nestedGroupCN, logger);
+                    }
+                }
+            }
+        }
+
+        private static void AddRole(ClaimsIdentity identity, string role)
+        {
+            identity.AddClaim(new Claim(identity.RoleClaimType, role));
+        }
+    }
+}

src/Security/Authentication/Negotiate/src/Internal/NegotiateOptionsValidationStartupFilter.cs

@@ -0,0 +1,31 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+
+namespace Microsoft.AspNetCore.Authentication.Negotiate.Internal
+{
+    internal class NegotiateOptionsValidationStartupFilter : IStartupFilter
+    {
+        private readonly string _authenticationScheme;
+
+        public NegotiateOptionsValidationStartupFilter(string authenticationScheme)
+        {
+            _authenticationScheme = authenticationScheme;
+        }
+
+        public Action<IApplicationBuilder> Configure(Action<IApplicationBuilder> next)
+        {
+            return builder =>
+            {
+                // Resolve NegotiateOptions on startup to trigger post configuration and bind LdapConnection if needed
+                var options = builder.ApplicationServices.GetRequiredService<IOptionsMonitor<NegotiateOptions>>().Get(_authenticationScheme);
+                next(builder);
+            };
+        }
+    }
+}

src/Security/Authentication/Negotiate/src/LdapSettings.cs

@@ -0,0 +1,75 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.DirectoryServices.Protocols;
+
+namespace Microsoft.AspNetCore.Authentication.Negotiate
+{
+    /// <summary>
+    /// Options class for configuring LDAP connections on Linux
+    /// </summary>
+    public class LdapSettings
+    {
+        /// <summary>
+        /// Configure whether LDAP connection should be used to resolve claims.
+        /// This is mainly used on Linux.
+        /// </summary>
+        public bool EnableLdapClaimResolution { get; set; }
+
+        /// <summary>
+        /// The domain to use for the LDAP connection. This is a mandatory setting.
+        /// </summary>
+        /// <example>
+        /// DOMAIN.com
+        /// </example>
+        public string Domain { get; set; }
+
+        /// <summary>
+        /// The machine account name to use when opening the LDAP connection.
+        /// If this is not provided, the machine wide credentials of the
+        /// domain joined machine will be used.
+        /// </summary>
+        public string MachineAccountName { get; set; }
+
+        /// <summary>
+        /// The machine account password to use when opening the LDAP connection.
+        /// This must be provided if a <see cref="MachineAccountName"/> is provided.
+        /// </summary>
+        public string MachineAccountPassword { get; set; }
+
+        /// <summary>
+        /// This option indicates whether nested groups should be ignored when
+        /// resolving Roles. The default is false.
+        /// </summary>
+        public bool IgnoreNestedGroups { get; set; }
+
+        /// <summary>
+        /// The <see cref="LdapConnection"/> to be used to retrieve role claims.
+        /// If no explicit connection is provided, an LDAP connection will be
+        /// automatically created based on the <see cref="Domain"/>,
+        /// <see cref="MachineAccountName"/> and <see cref="MachineAccountPassword"/>
+        /// options. If provided, this connection will be used and the
+        /// <see cref="Domain"/>, <see cref="MachineAccountName"/> and
+        /// <see cref="MachineAccountPassword"/>  options will not be used to create
+        /// the <see cref="LdapConnection"/>.
+        /// </summary>
+        public LdapConnection LdapConnection { get; set; }
+
+        public void Validate()
+        {
+            if (EnableLdapClaimResolution)
+            {
+                if (string.IsNullOrEmpty(Domain))
+                {
+                    throw new ArgumentException($"{nameof(EnableLdapClaimResolution)} is set to true but {nameof(Domain)} is not set.");
+                }
+
+                if (string.IsNullOrEmpty(MachineAccountName) && !string.IsNullOrEmpty(MachineAccountPassword))
+                {
+                    throw new ArgumentException($"{nameof(MachineAccountPassword)} should only be specified when {nameof(MachineAccountName)} is configured.");
+                }
+            }
+        }
+    }
+}

src/Security/Authentication/Negotiate/src/Microsoft.AspNetCore.Authentication.Negotiate.csproj

@@ -10,7 +10,9 @@
   <ItemGroup>
     <Reference Include="Microsoft.AspNetCore.Authentication" />
     <Reference Include="Microsoft.AspNetCore.Connections.Abstractions" />
+    <Reference Include="Microsoft.AspNetCore.Hosting.Abstractions" />
     <Reference Include="Microsoft.AspNetCore.Hosting.Server.Abstractions" />
+    <Reference Include="System.DirectoryServices.Protocols" />
   </ItemGroup>
 
 </Project>