Elevated Sandbox 3 (#7809)

dedicated sandbox command runner exe.

Author: iceweasel-oai

codex-rs/windows-sandbox-rs/Cargo.toml

@@ -13,6 +13,10 @@ path = "src/lib.rs"
 name = "codex-windows-sandbox-setup"
 path = "src/bin/setup_main.rs"
 
+[[bin]]
+name = "codex-command-runner"
+path = "src/bin/command_runner.rs"
+
 [dependencies]
 anyhow = "1.0"
 base64 = { workspace = true }

codex-rs/windows-sandbox-rs/src/bin/command_runner.rs

@@ -0,0 +1,12 @@
+#[path = "../command_runner_win.rs"]
+mod win;
+
+#[cfg(target_os = "windows")]
+fn main() -> anyhow::Result<()> {
+    win::main()
+}
+
+#[cfg(not(target_os = "windows"))]
+fn main() {
+    panic!("codex-command-runner is Windows-only");
+}

codex-rs/windows-sandbox-rs/src/command_runner_win.rs

@@ -0,0 +1,225 @@
+#![cfg(target_os = "windows")]
+
+use anyhow::Context;
+use anyhow::Result;
+use codex_windows_sandbox::allow_null_device;
+use codex_windows_sandbox::convert_string_sid_to_sid;
+use codex_windows_sandbox::create_process_as_user;
+use codex_windows_sandbox::create_readonly_token_with_cap_from;
+use codex_windows_sandbox::create_workspace_write_token_with_cap_from;
+use codex_windows_sandbox::get_current_token_for_restriction;
+use codex_windows_sandbox::log_note;
+use codex_windows_sandbox::parse_policy;
+use codex_windows_sandbox::to_wide;
+use codex_windows_sandbox::SandboxPolicy;
+use serde::Deserialize;
+use std::collections::HashMap;
+use std::ffi::c_void;
+use std::path::PathBuf;
+use windows_sys::Win32::Foundation::CloseHandle;
+use windows_sys::Win32::Foundation::GetLastError;
+use windows_sys::Win32::Foundation::HANDLE;
+use windows_sys::Win32::Storage::FileSystem::CreateFileW;
+use windows_sys::Win32::Storage::FileSystem::FILE_GENERIC_READ;
+use windows_sys::Win32::Storage::FileSystem::FILE_GENERIC_WRITE;
+use windows_sys::Win32::Storage::FileSystem::OPEN_EXISTING;
+use windows_sys::Win32::System::JobObjects::AssignProcessToJobObject;
+use windows_sys::Win32::System::JobObjects::CreateJobObjectW;
+use windows_sys::Win32::System::JobObjects::JobObjectExtendedLimitInformation;
+use windows_sys::Win32::System::JobObjects::SetInformationJobObject;
+use windows_sys::Win32::System::JobObjects::JOBOBJECT_EXTENDED_LIMIT_INFORMATION;
+use windows_sys::Win32::System::JobObjects::JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE;
+use windows_sys::Win32::System::Threading::TerminateProcess;
+use windows_sys::Win32::System::Threading::WaitForSingleObject;
+use windows_sys::Win32::System::Threading::INFINITE;
+
+#[derive(Debug, Deserialize)]
+struct RunnerRequest {
+    policy_json_or_preset: String,
+    // Writable location for logs (sandbox user's .codex).
+    codex_home: PathBuf,
+    // Real user's CODEX_HOME for shared data (caps, config).
+    real_codex_home: PathBuf,
+    cap_sid: String,
+    command: Vec<String>,
+    cwd: PathBuf,
+    env_map: HashMap<String, String>,
+    timeout_ms: Option<u64>,
+    stdin_pipe: String,
+    stdout_pipe: String,
+    stderr_pipe: String,
+}
+
+const WAIT_TIMEOUT: u32 = 0x0000_0102;
+
+unsafe fn create_job_kill_on_close() -> Result<HANDLE> {
+    let h = CreateJobObjectW(std::ptr::null_mut(), std::ptr::null());
+    if h == 0 {
+        return Err(anyhow::anyhow!("CreateJobObjectW failed"));
+    }
+    let mut limits: JOBOBJECT_EXTENDED_LIMIT_INFORMATION = std::mem::zeroed();
+    limits.BasicLimitInformation.LimitFlags = JOB_OBJECT_LIMIT_KILL_ON_JOB_CLOSE;
+    let ok = SetInformationJobObject(
+        h,
+        JobObjectExtendedLimitInformation,
+        &mut limits as *mut _ as *mut _,
+        std::mem::size_of::<JOBOBJECT_EXTENDED_LIMIT_INFORMATION>() as u32,
+    );
+    if ok == 0 {
+        return Err(anyhow::anyhow!("SetInformationJobObject failed"));
+    }
+    Ok(h)
+}
+
+pub fn main() -> Result<()> {
+    let mut input = String::new();
+    let mut args = std::env::args().skip(1);
+    if let Some(first) = args.next() {
+        if let Some(rest) = first.strip_prefix("--request-file=") {
+            let req_path = PathBuf::from(rest);
+            input = std::fs::read_to_string(&req_path).context("read request file")?;
+        }
+    }
+    if input.is_empty() {
+        anyhow::bail!("runner: no request-file provided");
+    }
+    let req: RunnerRequest = serde_json::from_str(&input).context("parse runner request json")?;
+    let log_dir = Some(req.codex_home.as_path());
+    log_note(
+        &format!(
+            "runner start cwd={} cmd={:?} real_codex_home={}",
+            req.cwd.display(),
+            req.command,
+            req.real_codex_home.display()
+        ),
+        Some(&req.codex_home),
+    );
+
+    let policy = parse_policy(&req.policy_json_or_preset).context("parse policy_json_or_preset")?;
+    let psid_cap: *mut c_void = unsafe { convert_string_sid_to_sid(&req.cap_sid).unwrap() };
+
+    // Create restricted token from current process token.
+    let base = unsafe { get_current_token_for_restriction()? };
+    let token_res: Result<(HANDLE, *mut c_void)> = unsafe {
+        match &policy {
+            SandboxPolicy::ReadOnly => create_readonly_token_with_cap_from(base, psid_cap),
+            SandboxPolicy::WorkspaceWrite { .. } => {
+                create_workspace_write_token_with_cap_from(base, psid_cap)
+            }
+            SandboxPolicy::DangerFullAccess => unreachable!(),
+        }
+    };
+    let (h_token, psid_to_use) = token_res?;
+    unsafe {
+        CloseHandle(base);
+    }
+    unsafe {
+        allow_null_device(psid_to_use);
+    }
+
+    // Open named pipes for stdio.
+    let open_pipe = |name: &str, access: u32| -> Result<HANDLE> {
+        let path = to_wide(name);
+        let handle = unsafe {
+            CreateFileW(
+                path.as_ptr(),
+                access,
+                0,
+                std::ptr::null_mut(),
+                OPEN_EXISTING,
+                0,
+                0,
+            )
+        };
+        if handle == windows_sys::Win32::Foundation::INVALID_HANDLE_VALUE {
+            let err = unsafe { GetLastError() };
+            log_note(
+                &format!("CreateFileW failed for pipe {name}: {err}"),
+                Some(&req.codex_home),
+            );
+            return Err(anyhow::anyhow!("CreateFileW failed for pipe {name}: {err}"));
+        }
+        Ok(handle)
+    };
+    let h_stdin = open_pipe(&req.stdin_pipe, FILE_GENERIC_READ)?;
+    let h_stdout = open_pipe(&req.stdout_pipe, FILE_GENERIC_WRITE)?;
+    let h_stderr = open_pipe(&req.stderr_pipe, FILE_GENERIC_WRITE)?;
+
+    // Build command and env, spawn with CreateProcessAsUserW.
+    let spawn_result = unsafe {
+        create_process_as_user(
+            h_token,
+            &req.command,
+            &req.cwd,
+            &req.env_map,
+            Some(&req.codex_home),
+            Some((h_stdin, h_stdout, h_stderr)),
+        )
+    };
+    let (proc_info, _si) = match spawn_result {
+        Ok(v) => v,
+        Err(e) => {
+            log_note(&format!("runner: spawn failed: {e:?}"), log_dir);
+            unsafe {
+                CloseHandle(h_stdin);
+                CloseHandle(h_stdout);
+                CloseHandle(h_stderr);
+                CloseHandle(h_token);
+            }
+            return Err(e);
+        }
+    };
+
+    // Optional job kill on close.
+    let h_job = unsafe { create_job_kill_on_close().ok() };
+    if let Some(job) = h_job {
+        unsafe {
+            let _ = AssignProcessToJobObject(job, proc_info.hProcess);
+        }
+    }
+
+    // Wait for process.
+    let wait_res = unsafe {
+        WaitForSingleObject(
+            proc_info.hProcess,
+            req.timeout_ms.map(|ms| ms as u32).unwrap_or(INFINITE),
+        )
+    };
+    let timed_out = wait_res == WAIT_TIMEOUT;
+
+    let exit_code: i32;
+    unsafe {
+        if timed_out {
+            let _ = TerminateProcess(proc_info.hProcess, 1);
+            exit_code = 128 + 64;
+        } else {
+            let mut raw_exit: u32 = 1;
+            windows_sys::Win32::System::Threading::GetExitCodeProcess(
+                proc_info.hProcess,
+                &mut raw_exit,
+            );
+            exit_code = raw_exit as i32;
+        }
+        if proc_info.hThread != 0 {
+            CloseHandle(proc_info.hThread);
+        }
+        if proc_info.hProcess != 0 {
+            CloseHandle(proc_info.hProcess);
+        }
+        CloseHandle(h_stdin);
+        CloseHandle(h_stdout);
+        CloseHandle(h_stderr);
+        CloseHandle(h_token);
+        if let Some(job) = h_job {
+            CloseHandle(job);
+        }
+    }
+    if exit_code != 0 {
+        eprintln!("runner child exited with code {}", exit_code);
+    }
+    log_note(
+        &format!("runner exit pid={} code={}", proc_info.hProcess, exit_code),
+        log_dir,
+    );
+    std::process::exit(exit_code);
+}

codex-rs/windows-sandbox-rs/src/lib.rs

@@ -12,6 +12,8 @@ windows_modules!(
 #[path = "setup_orchestrator.rs"]
 mod setup;
 
+#[cfg(target_os = "windows")]
+pub use acl::allow_null_device;
 #[cfg(target_os = "windows")]
 pub use acl::ensure_allow_write_aces;
 #[cfg(target_os = "windows")]
@@ -33,6 +35,12 @@ pub use logging::log_note;
 #[cfg(target_os = "windows")]
 pub use logging::LOG_FILE_NAME;
 #[cfg(target_os = "windows")]
+pub use policy::parse_policy;
+#[cfg(target_os = "windows")]
+pub use policy::SandboxPolicy;
+#[cfg(target_os = "windows")]
+pub use process::create_process_as_user;
+#[cfg(target_os = "windows")]
 pub use setup::run_elevated_setup;
 #[cfg(target_os = "windows")]
 pub use setup::run_setup_refresh;
@@ -43,11 +51,19 @@ pub use setup::SETUP_VERSION;
 #[cfg(target_os = "windows")]
 pub use token::convert_string_sid_to_sid;
 #[cfg(target_os = "windows")]
+pub use token::create_readonly_token_with_cap_from;
+#[cfg(target_os = "windows")]
+pub use token::create_workspace_write_token_with_cap_from;
+#[cfg(target_os = "windows")]
+pub use token::get_current_token_for_restriction;
+#[cfg(target_os = "windows")]
 pub use windows_impl::run_windows_sandbox_capture;
 #[cfg(target_os = "windows")]
 pub use windows_impl::CaptureResult;
 #[cfg(target_os = "windows")]
 pub use winutil::string_from_sid_bytes;
+#[cfg(target_os = "windows")]
+pub use winutil::to_wide;
 
 #[cfg(not(target_os = "windows"))]
 pub use stub::apply_world_writable_scan_and_denies;