dsh-sandbox-console-fix

Windows only. A DeepSeek Harness bundle that makes the confined sandbox usable on the desktop app: workspace-write shell calls start again, and read-only keeps working — without relaxing any confinement. Both of this bundle's patch rows are platform-guarded, so on Linux/macOS the composition is untouched and the package is inert.

Targets DeepSeek Harness desktop 0.2.0-rc.2 — Electron 44.0.0 / Node 24.18.1, verified on Windows 11 22H2 x64. Reported upstream as a Discussion: https://github.com/deepseek-ai/deepseek-harness/discussions/9280.

⚠️ NOT REVIEWED BY ANY HUMAN

AI-generated code. Found, designed, written and tested end-to-end by DeepSeek V4.1-flash, an AI agent running in DeepSeek Harness. A human directed the work and approved the steps, but no human has read, reviewed, audited or approved this code or its evidence. Treat it exactly like unreviewed third-party code from an unknown author: read index.js, console-shim.mjs and cordis.patch.yml yourself before installing, and do not run it anywhere you would not run an unreviewed script.

The same warning accompanies every comment this project posts upstream.

Prior art and corroboration

@argszero/cordis-plugin-sandbox-grant-advisor (0.17.0) already names this failure shape as its native-init family and explains it: a confined child that never reaches its first instruction, split into the packaged GUI-subsystem host and a console-subsystem node.exe whose runner was started with DETACHED_PROCESS. It is an advisor — it names and diagnoses; this bundle is the repair. Its measured remedies (Harness discussions #8193 / #8208) are followed here, including restoring the runner's three standard handles around AllocConsole(). The longer mechanism write-up is discussion #9238, and the report is #9280.

The problem

On the packaged Windows desktop app, any shell call under workspace-write fails immediately:

[exit code: 3221225794]        # 0xC0000142 STATUS_DLL_INIT_FAILED

pwsh, cmd and powershell all fail the same way, both MSI and Store-packaged PowerShell builds, while danger-full-access and read-only work — so the shell tool is fine and the workspace-write confinement path is the problem.

The failure needs two conditions together — a console-less runner host (the Electron binary) and workspace-write. The complete matrix is in docs/VERIFICATION.md. Why the child's own console creation succeeds in the one mode and fails in the other is not isolated — see sections 5 and 9 of that record; the fix works in both modes either way.

Root cause, in the shipped code (dsh-sandbox-local, windowsAclRunnerInvocation()):

if (existsSync(builtEntry)) return [process.execPath, builtEntry];

In the desktop app process.execPath is DeepSeek Harness.exe — an Electron binary, i.e. a GUI-subsystem image, which never has a console. Measured on one machine, same parent process:

The ACL runner then spawns the confined child without CREATE_NO_WINDOW / CREATE_NEW_CONSOLE — on purpose, because per DSH's own documentation such children die during DLL initialization under the restricted token — and relies on the child inheriting the runner's console. With nothing to inherit, the console-subsystem child must create a console itself; that creation fails under the Low-integrity write-restricted token, and the process exits STATUS_DLL_INIT_FAILED (0xC0000142).

The fix

One extra argv entry, in the position DSH's own development path already uses for the same runner ([process.execPath, "--import", <url>, entry]):

shipped:  [execPath, runner.js, …profile, --, target]
this:     [execPath, --import <console-shim.mjs>, runner.js, …profile, --, target]

console-shim.mjs calls AllocConsole() when the process has no console, and nothing else, so the confined child inherits a console and starts normally.

What does not change

Verified with an escape-write test run inside the confined child: four out-of-workspace targets are denied and absent on disk, while an in-workspace write succeeds — see docs/VERIFICATION.md.

Install

Install it the way dsh expects — through the Plugin Manager, which performs package installation and bundle selection itself:

1. Open the Plugin Manager page and install a bundle from https://github.com/TJZF-4j97/dsh-sandbox-console-fix, or from an absolute path to a checkout of this directory.
2. Restart the Harness.
3. Set the session to workspace-write and run any shell command.

Nothing is downloaded and no build script is requested, because the package deliberately declares no dependencies: index.js loads LocalSandboxProvider from the running Harness bundle, and console-shim.mjs resolves koffi there too. The Harness's own installer recorded exactly that — Packages: +1, zero downloads, no pending build scripts.

cordis.patch.yml mounts this provider by disabling the shipped sandbox row and inserting its own, both rows platform-guarded with !!js — the idiom the shipped dsh-base patch uses for its own bash-sandbox row. That shape is required by the Loader dialect: a non-insert patch that targets an existing row replaces its fields, and a truthy name only asserts the existing plugin name, so a provider row cannot be swapped by overriding its id. On Windows the composition keeps exactly one ctx.sandbox provider and the shipped package still resolves from the dsh installation; on other platforms the shipped row stays enabled and this bundle's row stays disabled.

Copy-Item -Recurse -Force .\dsh-sandbox-console-fix "$env:USERPROFILE\.dsh\profiles\desktop\node_modules\dsh-sandbox-console-fix"

{ "dsh": { "profile": { "bundles": ["@deepseek-ai/dsh-base", "@deepseek-ai/dsh-web-app", "dsh-sandbox-console-fix"] } } }

Verify

With the session set to workspace-write:

$PSVersionTable.PSVersion                      # expect 7.6.6 — not 0xC0000142
Set-Content 'C:\Users\<you>\nope.txt' 'x'      # expect [sandbox: file access denied under workspace-write mode]
Set-Content '.\ok.txt' 'x'                     # expect success
Remove-Item '.\ok.txt'

Not caused by this bundle: inside the confined shell the sandbox blocks piped stdio between programs, so $x = & some.exe … and some.exe | Out-Null fail (EPERM; PowerShell surfaces it as StandardOutputEncoding is only supported when standard output is redirected), while a bare & some.exe …, PowerShell's own cmdlet pipelines and file redirection work. That is the sandbox's documented confinement. Reproduce the underlying mechanism without installing anything:

node scripts/console-probe.cjs                        # host-console probe
node scripts/console-probe.cjs --host electron        # same parent, Electron host
node scripts/full-chain-repro.js --help               # drive the shipped runner under both hosts
powershell -File scripts/escape-test.ps1 -Workspace <dir>   # confinement check

See scripts/README.md for the extracted-runner paths those scripts need.

Uninstall

Remove the bundle name from the profile's bundles list (and the dependency), then restart. No system-level change is left behind — the workspace ACEs and integrity label that the Harness itself owns are not touched by this bundle.

Compatibility

Because it subclasses a Harness-internal class, re-check after a Harness upgrade — the upstream fix (see the issue report) makes this package unnecessary.

Discovery

DeepSeek Harness's CONTRIBUTING.md asks ecosystem plugins to associate their GitHub project with the dsh-plugin topic. This repository carries it — together with dsh, deepseek-harness, sandbox, windows and pwsh — so the plugin is discoverable from that topic listing.

Security

The bundle does not widen file authority. It only lets the runner allocate a console; the write boundary still comes from the restricted token, the write-restricted SIDs, the Low integrity label and the Harness's ACL grants and denies, all inherited unchanged. The shim performs no file access, no process creation and no environment change, and swallows every error.

License

MIT