feat: AI Agent Sandbox MCP Server v1を実装

Specifications、Design、ImplementationPlanの優先順位を整理し、単一Task実行モデル、typed option優先、設定可能なresource上限、local Ollamaを必須とするRelease Gateを文書化。

.NET 10/C# 14の5 production project、3 test project、E2E Clientを構築。typed YAML、en/ja locale、fixed/user prompt、stdioおよびloopback限定Streamable HTTP、agent_run/agent_status、Session、Ollama text/tool/Vision、TaskGraphとtoken accountingを実装。

Windows sandboxとしてfixed AppContainer、canonical/reparse検査、能力別ACL、path+SHA-256 executable approval、child-process restriction、Job Object、task journal、atomic file transaction、crash recoveryを実装。WFPのIPv4/IPv6 default denyとexact allow、dynamic session、temporary loopback exemption、管理者/BFE診断を追加。

Security/Recovery test、MCP/Ollama integration test、stdio/HTTP Operational E2E、Release Bundle生成・checksum・manifest・fresh extraction検査を追加。Requirement TraceabilityとPhase 0〜11の進捗、初回セットアップ可能なREADMEを整備。

Debug/Release/publish/objをrepository rootのbuild/へ集約し、旧project-local bin/objへの依存を除去。artifacts/とbuild/をGit管理外に設定し、clean checkoutでもsolution buildからE2E Clientまで生成可能にした。

1 files changed, 255 insertions, 0 deletions

diff --git a/src/Agent.Windows/Security/RestrictedProcessLauncher.cs b/src/Agent.Windows/Security/RestrictedProcessLauncher.cs
new file mode 100644
index 0000000..0786150
--- /dev/null
+++ b/src/Agent.Windows/Security/RestrictedProcessLauncher.cs
@@ -0,0 +1,255 @@
+using System.ComponentModel;
+using System.Runtime.InteropServices;
+using System.Security.Principal;
+using System.Text;
+using Microsoft.Win32.SafeHandles;
+using Windows.Win32;
+using Windows.Win32.Foundation;
+using Windows.Win32.Security;
+using Windows.Win32.System.JobObjects;
+using Windows.Win32.System.Threading;
+
+namespace Agent.Windows.Security;
+
+public sealed record RestrictedProcessResult(uint ProcessId, uint ExitCode, string StandardOutput, string StandardError);
+public sealed record SandboxJobLimits(uint MaxProcesses = 16, ulong MaxJobMemoryBytes = 4UL * 1024 * 1024 * 1024);
+
+public sealed unsafe class RestrictedProcessLauncher(ExecutablePolicy executablePolicy, ISecurityAuditSink audit, SecurityIdentifier? appContainerSid = null, SandboxJobLimits? jobLimits = null)
+{
+    private const uint ProcessCreationChildProcessRestricted = 0x1;
+    private readonly SandboxJobLimits _jobLimits = jobLimits ?? new();
+
+    public RestrictedProcessResult Run(Guid taskId, string executable, IReadOnlyList<string> arguments, string workingDirectory, TimeSpan timeout, string? standardInput = null)
+    {
+        VerifiedExecutable verified;
+        VerifiedExecutable? managedEntry = null;
+        try
+        {
+            verified = executablePolicy.Verify(executable);
+            string? managedEntryPath = ExecutablePolicy.ManagedEntryPoint(verified.CanonicalPath, arguments);
+            if (managedEntryPath is not null) managedEntry = executablePolicy.Verify(managedEntryPath);
+        }
+        catch (SandboxPolicyException ex)
+        {
+            audit.Write(new(DateTimeOffset.UtcNow, taskId, "policy.deny", "denied", new Dictionary<string, string> { ["code"] = ex.Code, ["executable"] = executable }));
+            throw;
+        }
+
+        string cwd = CanonicalPath.Resolve(workingDirectory);
+        using FileStream stdin = CaptureFile();
+        using FileStream stdout = CaptureFile();
+        using FileStream stderr = CaptureFile();
+        if (!string.IsNullOrEmpty(standardInput))
+        {
+            byte[] input = Encoding.UTF8.GetBytes(standardInput);
+            stdin.Write(input);
+            stdin.Flush(true);
+        }
+        stdin.Position = 0;
+        MakeInheritable(stdin.SafeFileHandle);
+        MakeInheritable(stdout.SafeFileHandle);
+        MakeInheritable(stderr.SafeFileHandle);
+        using SafeFileHandle job = PInvoke.CreateJobObject(null, null);
+        if (job.IsInvalid) throw LastError("CreateJobObject");
+        try
+        {
+            JOBOBJECT_EXTENDED_LIMIT_INFORMATION limits = default;
+            limits.BasicLimitInformation.LimitFlags = JOB_OBJECT_LIMIT.JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE |
+                JOB_OBJECT_LIMIT.JOB_OBJECT_LIMIT_ACTIVE_PROCESS | JOB_OBJECT_LIMIT.JOB_OBJECT_LIMIT_JOB_MEMORY;
+            limits.BasicLimitInformation.ActiveProcessLimit = _jobLimits.MaxProcesses;
+            limits.JobMemoryLimit = (nuint)_jobLimits.MaxJobMemoryBytes;
+            if (!PInvoke.SetInformationJobObject(new HANDLE(job.DangerousGetHandle()), JOBOBJECTINFOCLASS.JobObjectExtendedLimitInformation, &limits, (uint)sizeof(JOBOBJECT_EXTENDED_LIMIT_INFORMATION)))
+                throw LastError("SetInformationJobObject");
+
+            nuint attributeSize = 0;
+            uint attributeCount = appContainerSid is null ? 2u : 3u;
+            _ = PInvoke.InitializeProcThreadAttributeList(default, attributeCount, 0, &attributeSize);
+            LPPROC_THREAD_ATTRIBUTE_LIST attributes = (LPPROC_THREAD_ATTRIBUTE_LIST)NativeMemory.Alloc(attributeSize);
+            void* sidBuffer = null;
+            void* internetClientSidBuffer = null;
+            void* privateNetworkSidBuffer = null;
+            try
+            {
+                if (!PInvoke.InitializeProcThreadAttributeList(attributes, attributeCount, 0, &attributeSize)) throw LastError("InitializeProcThreadAttributeList");
+                uint childPolicy = ProcessCreationChildProcessRestricted;
+                if (!PInvoke.UpdateProcThreadAttribute(attributes, 0, PInvoke.PROC_THREAD_ATTRIBUTE_CHILD_PROCESS_POLICY, &childPolicy, sizeof(uint), null, null))
+                    throw LastError("UpdateProcThreadAttribute");
+                HANDLE[] inheritedHandles =
+                [
+                    new(stdin.SafeFileHandle.DangerousGetHandle()),
+                    new(stdout.SafeFileHandle.DangerousGetHandle()),
+                    new(stderr.SafeFileHandle.DangerousGetHandle())
+                ];
+                fixed (HANDLE* inheritedHandlePointer = inheritedHandles)
+                {
+                    if (!PInvoke.UpdateProcThreadAttribute(attributes, 0, PInvoke.PROC_THREAD_ATTRIBUTE_HANDLE_LIST,
+                        inheritedHandlePointer, (nuint)(sizeof(HANDLE) * inheritedHandles.Length), null, null))
+                        throw LastError("UpdateProcThreadAttribute(HandleList)");
+                }
+                SecurityCapabilities securityCapabilities = default;
+                if (appContainerSid is not null)
+                {
+                    byte[] sidBytes = new byte[appContainerSid.BinaryLength];
+                    appContainerSid.GetBinaryForm(sidBytes, 0);
+                    sidBuffer = NativeMemory.Alloc((nuint)sidBytes.Length);
+                    Marshal.Copy(sidBytes, 0, (nint)sidBuffer, sidBytes.Length);
+                    securityCapabilities.AppContainerSid = (nint)sidBuffer;
+                    internetClientSidBuffer = AllocateSid(new SecurityIdentifier("S-1-15-3-1"));
+                    privateNetworkSidBuffer = AllocateSid(new SecurityIdentifier("S-1-15-3-3"));
+                    SID_AND_ATTRIBUTES* capabilities = stackalloc SID_AND_ATTRIBUTES[2];
+                    capabilities[0].Sid = new PSID(internetClientSidBuffer);
+                    capabilities[0].Attributes = 0x00000004;
+                    capabilities[1].Sid = new PSID(privateNetworkSidBuffer);
+                    capabilities[1].Attributes = 0x00000004;
+                    securityCapabilities.Capabilities = (nint)capabilities;
+                    securityCapabilities.CapabilityCount = 2;
+                    if (!PInvoke.UpdateProcThreadAttribute(attributes, 0, PInvoke.PROC_THREAD_ATTRIBUTE_SECURITY_CAPABILITIES,
+                        &securityCapabilities, (nuint)sizeof(SecurityCapabilities), null, null)) throw LastError("UpdateProcThreadAttribute(SecurityCapabilities)");
+                }
+                STARTUPINFOEXW startup = default;
+                startup.StartupInfo.cb = (uint)sizeof(STARTUPINFOEXW);
+                startup.StartupInfo.dwFlags = STARTUPINFOW_FLAGS.STARTF_USESTDHANDLES;
+                startup.StartupInfo.hStdInput = inheritedHandles[0];
+                startup.StartupInfo.hStdOutput = inheritedHandles[1];
+                startup.StartupInfo.hStdError = inheritedHandles[2];
+                startup.lpAttributeList = attributes;
+                PROCESS_INFORMATION process = default;
+                string commandLine = BuildCommandLine(verified.CanonicalPath, arguments);
+                Span<char> commandBuffer = new char[commandLine.Length + 1];
+                commandLine.AsSpan().CopyTo(commandBuffer);
+                if (!PInvoke.CreateProcess(null, ref commandBuffer, null, null, true,
+                    PROCESS_CREATION_FLAGS.EXTENDED_STARTUPINFO_PRESENT | PROCESS_CREATION_FLAGS.CREATE_SUSPENDED,
+                    null, cwd, in startup.StartupInfo, out process)) throw LastError("CreateProcess");
+                try
+                {
+                    using var processView = new SafeFileHandle(process.hProcess, ownsHandle: false);
+                    if (!PInvoke.AssignProcessToJobObject(job, processView)) throw LastError("AssignProcessToJobObject");
+                    try
+                    {
+                        VerifiedExecutable postCreate = executablePolicy.Verify(executable);
+                        if (!string.Equals(postCreate.CanonicalPath, verified.CanonicalPath, StringComparison.OrdinalIgnoreCase) ||
+                            !string.Equals(postCreate.Sha256, verified.Sha256, StringComparison.Ordinal))
+                            throw new SandboxPolicyException("process.identity_changed", "Executable identity changed during process creation.");
+                        if (managedEntry is not null)
+                        {
+                            VerifiedExecutable postCreateManaged = executablePolicy.Verify(managedEntry.CanonicalPath);
+                            if (!string.Equals(postCreateManaged.Sha256, managedEntry.Sha256, StringComparison.Ordinal))
+                                throw new SandboxPolicyException("process.managed_identity_changed", "Managed entry assembly identity changed during process creation.");
+                        }
+                    }
+                    catch (SandboxPolicyException ex)
+                    {
+                        audit.Write(new(DateTimeOffset.UtcNow, taskId, "policy.deny", "denied", new Dictionary<string, string>
+                        {
+                            ["code"] = ex.Code, ["executable"] = executable, ["stage"] = "post_create_pre_resume"
+                        }));
+                        throw;
+                    }
+                    if (PInvoke.ResumeThread(process.hThread) == uint.MaxValue) throw LastError("ResumeThread");
+                    var processAudit = new Dictionary<string, string>
+                    {
+                        ["path"] = verified.CanonicalPath, ["sha256"] = verified.Sha256, ["child_process_policy"] = "restricted",
+                        ["app_container_sid"] = appContainerSid?.Value ?? "none", ["network_capabilities"] = appContainerSid is null ? "none" : "internetClient,privateNetworkClientServer",
+                        ["pid"] = process.dwProcessId.ToString()
+                    };
+                    if (managedEntry is not null)
+                    {
+                        processAudit["managed_entry_path"] = managedEntry.CanonicalPath;
+                        processAudit["managed_entry_sha256"] = managedEntry.Sha256;
+                    }
+                    audit.Write(new(DateTimeOffset.UtcNow, taskId, "process.start", "allowed", processAudit));
+                    WAIT_EVENT wait = PInvoke.WaitForSingleObject(process.hProcess, checked((uint)Math.Clamp(timeout.TotalMilliseconds, 1, uint.MaxValue - 1)));
+                    if (wait == WAIT_EVENT.WAIT_TIMEOUT)
+                    {
+                        _ = PInvoke.TerminateJobObject(job, 1460);
+                        audit.Write(new(DateTimeOffset.UtcNow, taskId, "process.timeout", "terminated", new Dictionary<string, string> { ["pid"] = process.dwProcessId.ToString() }));
+                        throw new TimeoutException("Sandbox process exceeded its timeout.");
+                    }
+                    if (!PInvoke.GetExitCodeProcess(processView, out uint exitCode)) throw LastError("GetExitCodeProcess");
+                    audit.Write(new(DateTimeOffset.UtcNow, taskId, "process.exit", "observed", new Dictionary<string, string> { ["pid"] = process.dwProcessId.ToString(), ["exit_code"] = exitCode.ToString() }));
+                    if (exitCode != 0)
+                    {
+                        audit.Write(new(DateTimeOffset.UtcNow, taskId, "policy.deny", "observed", new Dictionary<string, string>
+                        {
+                            ["code"] = "restricted_process_failure", ["pid"] = process.dwProcessId.ToString(),
+                            ["child_process_policy"] = "restricted", ["exit_code"] = exitCode.ToString()
+                        }));
+                    }
+                    return new(process.dwProcessId, exitCode, ReadCapture(stdout), ReadCapture(stderr));
+                }
+                finally
+                {
+                    PInvoke.CloseHandle(process.hThread);
+                    PInvoke.CloseHandle(process.hProcess);
+                }
+            }
+            finally
+            {
+                if (attributes.Value is not null) PInvoke.DeleteProcThreadAttributeList(attributes);
+                NativeMemory.Free(sidBuffer);
+                NativeMemory.Free(internetClientSidBuffer);
+                NativeMemory.Free(privateNetworkSidBuffer);
+                NativeMemory.Free(attributes.Value);
+            }
+        }
+        finally { }
+    }
+
+    private static Win32Exception LastError(string operation)
+    {
+        int code = Marshal.GetLastWin32Error();
+        return new(code, $"{operation} failed with Win32 error {code}.");
+    }
+    private static FileStream CaptureFile()
+    {
+        string path = Path.Combine(Path.GetTempPath(), "agent-mcp-process-" + Guid.NewGuid().ToString("N") + ".tmp");
+        return new FileStream(path, FileMode.CreateNew, FileAccess.ReadWrite, FileShare.ReadWrite | FileShare.Delete, 4096,
+            FileOptions.DeleteOnClose | FileOptions.SequentialScan);
+    }
+    private static void* AllocateSid(SecurityIdentifier sid)
+    {
+        byte[] bytes = new byte[sid.BinaryLength];
+        sid.GetBinaryForm(bytes, 0);
+        void* buffer = NativeMemory.Alloc((nuint)bytes.Length);
+        Marshal.Copy(bytes, 0, (nint)buffer, bytes.Length);
+        return buffer;
+    }
+    private static void MakeInheritable(SafeFileHandle handle)
+    {
+        if (!PInvoke.SetHandleInformation(handle, (uint)HANDLE_FLAGS.HANDLE_FLAG_INHERIT, HANDLE_FLAGS.HANDLE_FLAG_INHERIT))
+            throw LastError("SetHandleInformation");
+    }
+    private static string ReadCapture(FileStream stream)
+    {
+        const int maxCharacters = 1024 * 1024;
+        stream.Position = 0;
+        using var reader = new StreamReader(stream, Encoding.UTF8, detectEncodingFromByteOrderMarks: true, leaveOpen: true);
+        char[] buffer = new char[maxCharacters + 1];
+        int count = reader.ReadBlock(buffer, 0, buffer.Length);
+        return count > maxCharacters ? new string(buffer, 0, maxCharacters) + "\n[output truncated]" : new string(buffer, 0, count);
+    }
+    private static string BuildCommandLine(string executable, IReadOnlyList<string> arguments) => string.Join(' ', [Quote(executable), .. arguments.Select(Quote)]);
+    private static string Quote(string value)
+    {
+        if (value.Length > 0 && !value.Any(static character => char.IsWhiteSpace(character) || character == '"')) return value;
+        var result = new System.Text.StringBuilder().Append('"');
+        int slashes = 0;
+        foreach (char character in value)
+        {
+            if (character == '\\') { slashes++; continue; }
+            if (character == '"') result.Append('\\', (slashes * 2) + 1).Append('"');
+            else result.Append('\\', slashes).Append(character);
+            slashes = 0;
+        }
+        return result.Append('\\', slashes * 2).Append('"').ToString();
+    }
+
+    [StructLayout(LayoutKind.Sequential)]
+    private struct SecurityCapabilities
+    {
+        public nint AppContainerSid;
+        public nint Capabilities;
+        public uint CapabilityCount;
+        public uint Reserved;
+    }
+}