smoketest for browser vuln, rough draft of Windows security doc (#6822)

codex-rs/windows-sandbox-rs/sandbox_smoketests.py

@@ -477,12 +477,23 @@ def main() -> int:
     rc, out, err = run_sbx("workspace-write", ["cmd", "/c", f"echo leak > {outside_after_timeout}"], WS_ROOT)
     add("WS: post-timeout outside write still denied", rc != 0 and assert_not_exists(outside_after_timeout), f"rc={rc}")
 
-    # 41. WS: additional protected path variation (.ssh)
-    ssh_var = WS_ROOT / ".SsH" / "config"
-    remove_if_exists(ssh_var.parent)
-    ssh_var.parent.mkdir(exist_ok=True)
-    rc, out, err = run_sbx("workspace-write", ["cmd", "/c", "echo key > .SsH\\config"], WS_ROOT)
-    add("WS: protected path variation (.ssh) denied", rc != 0 and assert_not_exists(ssh_var), f"rc={rc}")
+    # 41. RO: Start-Process https blocked (KNOWN FAIL until GUI escape fixed)
+    rc, out, err = run_sbx(
+        "read-only",
+        [
+            "powershell",
+            "-NoLogo",
+            "-NoProfile",
+            "-Command",
+            "Start-Process 'https://codex-invalid.local/smoke'",
+        ],
+        WS_ROOT,
+    )
+    add(
+        "RO: Start-Process https denied (KNOWN FAIL)",
+        rc != 0,
+        f"rc={rc}, stdout={out}, stderr={err}",
+    )
 
     return summarize(results)
 

docs/windows_sandbox_security.md

@@ -0,0 +1,20 @@
+# Windows Sandbox Status
+
+## Implementation Overview
+
+When commands run via `codex sandbox windows …` (or when the CLI/TUI calls into the same crate in-process for sandboxed turns), the launcher configures a restricted Windows token and an allowlist policy scoped to the declared workspace roots. Writes are blocked everywhere except inside those roots (plus `%TEMP%` when workspace-write mode is requested), and common escape vectors such as alternate data streams, UNC paths, and device handles are denied proactively. The CLI also injects stub executables (for example, wrapping `ssh`) ahead of the host PATH so we can intercept dangerous tools before they ever leave the sandbox.
+
+## Known Security Limitations
+
+Running `python windows-sandbox-rs/sandbox_smoketests.py` with full filesystem and network access currently results in **37/42** passing cases. The list below focuses on the four high-value failures numbered #32 and higher in the smoketests (earlier tests are less security-focused).
+
+| Test                                          | Purpose                                                                                                                                                                                                                                                                                                      |
+| --------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| ADS write denied (#32)                        | Ensures alternate data streams cannot be written inside the workspace, preventing tools from hiding payloads in ADS. The sandbox currently allows the write (process returns `rc=0`).                                                                                                                        |
+| protected path case-variation denied (#33)    | Confirms that protected directories such as `.git` remain blocked even when attackers use case tricks like `.GiT`. The current allowlist treats `.GiT` as distinct, so the write succeeds.                                                                                                                   |
+| PATH stub bypass denied (#35)                 | Verifies that a workspace-provided `ssh.bat` shim placed ahead of the host PATH runs instead of the real `ssh`. The sandbox exits early before emitting the shim's `stubbed` output, so we cannot prove the interception works.                                                                              |
+| Start-Process https denied (KNOWN FAIL) (#41) | Validates that read-only runs cannot launch the host's default browser via `Start-Process 'https://...'`. Today the command succeeds (exit code 0) because Explorer handles the ShellExecute request outside the sandbox. The failure is captured by `windows-sandbox-rs/sandbox_smoketests.py` (last case). |
+
+## Want to Help?
+
+If you are a security-minded Windows user, help us get these tests passing! Improved implementations that make these smoke tests pass meaningfully reduce Codex's escape surface. After iterating, rerun `python windows-sandbox-rs/sandbox_smoketests.py` to validate the fixes and help us drive the suite toward 42/42.