RTQ

Architecture • Platform Isolation

Platform Sandboxing Support

RTQ delegates execution containment to platform security mechanisms rather than relying on soft in-process JavaScript checks. Below is the exact evidence, test runner, and known limitations for each supported operating system.

macOS

Apple Seatbelt (sandbox-exec driver)

LEVEL 3 — REAL OS ENFORCEMENT

Compiles Scheme profiles (.sb) dynamically. The kernel driver enforces filesystem subpath allowlists, blocks network sockets, and restricts process execution.

CI Runnermacos-15
Implementationindex.ts
Platform Limitations (What This Test Does NOT Prove):

Seatbelt is marked deprecated by Apple in modern macOS versions. Live tests demonstrate file-write and network egress denial, but do not guarantee resistance against kernel-level exploits.

Linux

bubblewrap (bwrap) namespaces

LEVEL 1 — UNIT TESTED

Generates argument vectors for bwrap to isolate PID, mount, IPC, UTS, and network namespaces. Binds host root as read-only and allocates private tmpfs.

CI Runnerubuntu-latest
Implementationindex.ts
Test Filelinux.test.ts
Platform Limitations (What This Test Does NOT Prove):

Requires the bubblewrap binary installed on the host system. The current Linux test suite asserts argument construction and probe detection; it does not execute live adversarial rootkit binaries in CI.

Windows

AppContainer & Windows Job Object

LEVEL 1 — UNIT TESTED

Executes via PowerShell runner script configuring low-privilege AppContainer SIDs and Job Objects to restrict process capabilities and memory.

CI Runnerwindows-latest
Implementationwindows-runner.ps1
Platform Limitations (What This Test Does NOT Prove):

Requires Windows 10/11 or Windows Server with PowerShell. Test suite verifies runner script fail-closed behavior and output parsing; does not test native Win32 token isolation against kernel driver bugs.

Fail-Closed Sandbox Invariants

The sandbox execution path rejects execution when the required sandbox backend cannot be initialized. RTQ does not silently fall back to unsandboxed execution:

  • •macOS: If /usr/bin/sandbox-exec is missing or returns a configuration error, execution fails with E_SANDBOX_INIT_FAILED.
  • •Linux: If bwrap is absent from PATH, execution is blocked before spawning child processes.
  • •Windows: If AppContainer profile creation or job assignment fails, the runner script exits with code 1 and reports sandboxed: false.
View Sandbox Evidence Chains →Threat Model & Kernel Boundaries →