# Summary
This PR introduces the Windows sandbox runner IPC foundation that later
unified_exec work will build on.
The key point is that this is intentionally infrastructure-only. The new
IPC transport, runner plumbing, and ConPTY helpers are added here, but
the active elevated Windows sandbox path still uses the existing
request-file bootstrap. In other words, this change prepares the
transport and module layout we need for unified_exec without switching
production behavior over yet.
Part of this PR is also a source-layout cleanup: some Windows sandbox
files are moved into more explicit `elevated/`, `conpty/`, and shared
locations so it is clearer which code is for the elevated sandbox flow,
which code is legacy/direct-spawn behavior, and which helpers are shared
between them. That reorganization is intentional in this first PR so
later behavioral changes do not also have to carry a large amount of
file-move churn.
# Why This Is Needed For unified_exec
Windows elevated sandboxed unified_exec needs a long-lived,
bidirectional control channel between the CLI and a helper process
running under the sandbox user. That channel has to support:
- starting a process and reporting structured spawn success/failure
- streaming stdout/stderr back incrementally
- forwarding stdin over time
- terminating or polling a long-lived process
- supporting both pipe-backed and PTY-backed sessions
The existing elevated one-shot path is built around a request-file
bootstrap and does not provide those primitives cleanly. Before we can
turn on Windows sandbox unified_exec, we need the underlying runner
protocol and transport layer that can carry those lifecycle events and
streams.
# Why Windows Needs More Machinery Than Linux Or macOS
Linux and macOS can generally build unified_exec on top of the existing
sandbox/process model: the parent can spawn the child directly, retain
normal ownership of stdio or PTY handles, and manage the lifetime of the
sandboxed process without introducing a second control process.
Windows elevated sandboxing is different. To run inside the sandbox
boundary, we cross into a different user/security context and then need
to manage a long-lived process from outside that boundary. That means we
need an explicit helper process plus an IPC transport to carry spawn,
stdin, output, and exit events back and forth. The extra code here is
mostly that missing Windows sandbox infrastructure, not a conceptual
difference in unified_exec itself.
# What This PR Adds
- the framed IPC message types and transport helpers for parent <->
runner communication
- the renamed Windows command runner with both the existing request-file
bootstrap and the dormant IPC bootstrap
- named-pipe helpers for the elevated runner path
- ConPTY helpers and process-thread attribute plumbing needed for
PTY-backed sessions
- shared sandbox/process helpers that later PRs will reuse when
switching live execution paths over
- early file/module moves so later PRs can focus on behavior rather than
layout churn
# What This PR Does Not Yet Do
- it does not switch the active elevated one-shot path over to IPC yet
- it does not enable Windows sandbox unified_exec yet
- it does not remove the existing request-file bootstrap yet
So while this code compiles and the new path has basic validation, it is
not yet the exercised production path. That is intentional for this
first PR: the goal here is to land the transport and runner foundation
cleanly before later PRs start routing real command execution through
it.
# Follow-Ups
Planned follow-up PRs will:
1. switch elevated one-shot Windows sandbox execution to the new runner
IPC path
2. layer Windows sandbox unified_exec sessions on top of the same
transport
3. remove the legacy request-file path once the IPC-based path is live
# Validation
- `cargo build -p codex-windows-sandbox`
The elevated setup synchronously applies read/write ACLs to any
workspace roots.
However, until we apply *read* permission to the full path, powershell
cannot use some roots as a cwd as it needs access to all parts of the
path in order to apply it as the working directory for a command.
The solution is, while the async read-ACL part of setup is running, use
a "junction" that lives in C:\Users\CodexSandbox{Offline|Online} that
points to the cwd.
Once the read ACLs are applied, we stop using the junction.
-----
this PR also removes some dead code and overly-verbose logging, and has
some light refactoring to the ACL-related functions
- updating helpers, refactoring some functions that will be used in the
elevated sandbox
- better logging
- better and faster handling of ACL checks/writes
- No functional change—legacy restricted-token sandbox
remains the only path.
- Added the new codex-windows-sandbox crate that builds both a library
entry point (run_windows_sandbox_capture) and a CLI executable to launch
commands inside a Windows restricted-token sandbox, including ACL
management, capability SID provisioning, network lockdown, and output
capture
(windows-sandbox-rs/src/lib.rs:167, windows-sandbox-rs/src/main.rs:54).
- Introduced the experimental WindowsSandbox feature flag and wiring so
Windows builds can opt into the sandbox:
SandboxType::WindowsRestrictedToken, the in-process execution path, and
platform sandbox selection now honor the flag (core/src/features.rs:47,
core/src/config.rs:1224, core/src/safety.rs:19,
core/src/sandboxing/mod.rs:69, core/src/exec.rs:79,
core/src/exec.rs:172).
- Updated workspace metadata to include the new crate and its
Windows-specific dependencies so the core crate can link against it
(codex-rs/
Cargo.toml:91, core/Cargo.toml:86).
- Added a PowerShell bootstrap script that installs the Windows
toolchain, required CLI utilities, and builds the workspace to ease
development
on the platform (scripts/setup-windows.ps1:1).
- Landed a Python smoke-test suite that exercises
read-only/workspace-write policies, ACL behavior, and network denial for
the Windows sandbox
binary (windows-sandbox-rs/sandbox_smoketests.py:1).
