codex/codex-rs/linux-sandbox/tests/suite/managed_proxy.rs

#![cfg(target_os = "linux")]
#![allow(clippy::unwrap_used)]

use codex_core::exec_env::create_env;
use codex_protocol::config_types::ShellEnvironmentPolicy;
use codex_protocol::models::PermissionProfile;
use codex_protocol::permissions::FileSystemAccessMode;
use codex_protocol::permissions::FileSystemPath;
use codex_protocol::permissions::FileSystemSandboxEntry;
use codex_protocol::permissions::FileSystemSandboxPolicy;
use codex_protocol::permissions::FileSystemSpecialPath;
use codex_protocol::permissions::NetworkSandboxPolicy;
use codex_utils_absolute_path::AbsolutePathBuf;
use pretty_assertions::assert_eq;
use std::collections::HashMap;
use std::io::Read;
use std::io::Write;
use std::net::Ipv4Addr;
use std::net::TcpListener;
use std::os::unix::fs::MetadataExt;
use std::process::Output;
use std::process::Stdio;
use std::time::Duration;
use tempfile::NamedTempFile;
use tokio::process::Command;

const BWRAP_UNAVAILABLE_ERR: &str = "bubblewrap is unavailable: no system bwrap was found";
const NETWORK_TIMEOUT_MS: u64 = 4_000;
const MANAGED_PROXY_PERMISSION_ERR_SNIPPETS: &[&str] = &[
    "loopback: Failed RTM_NEWADDR",
    "loopback: Failed RTM_NEWLINK",
    "setting up uid map: Permission denied",
    "No permissions to create a new namespace",
    "error isolating Linux network namespace for proxy mode",
];

const PROXY_ENV_KEYS: &[&str] = &[
    "HTTP_PROXY",
    "HTTPS_PROXY",
    "WS_PROXY",
    "WSS_PROXY",
    "ALL_PROXY",
    "FTP_PROXY",
    "YARN_HTTP_PROXY",
    "YARN_HTTPS_PROXY",
    "NPM_CONFIG_HTTP_PROXY",
    "NPM_CONFIG_HTTPS_PROXY",
    "NPM_CONFIG_PROXY",
    "BUNDLE_HTTP_PROXY",
    "BUNDLE_HTTPS_PROXY",
    "PIP_PROXY",
    "DOCKER_HTTP_PROXY",
    "DOCKER_HTTPS_PROXY",
];

fn create_env_from_core_vars() -> HashMap<String, String> {
    let policy = ShellEnvironmentPolicy::default();
    create_env(&policy, /*thread_id*/ None)
}

fn strip_proxy_env(env: &mut HashMap<String, String>) {
    for key in PROXY_ENV_KEYS {
        env.remove(*key);
        let lower = key.to_ascii_lowercase();
        env.remove(lower.as_str());
    }
}

fn is_bwrap_unavailable_output(output: &Output) -> bool {
    String::from_utf8_lossy(&output.stderr).contains(BWRAP_UNAVAILABLE_ERR)
}

async fn should_skip_bwrap_tests() -> bool {
    let mut env = create_env_from_core_vars();
    strip_proxy_env(&mut env);

    let output = run_linux_sandbox_direct(
        &["bash", "-c", "true"],
        &PermissionProfile::read_only(),
        /*allow_network_for_proxy*/ false,
        env,
        NETWORK_TIMEOUT_MS,
    )
    .await;
    is_bwrap_unavailable_output(&output)
}

fn is_managed_proxy_permission_error(stderr: &str) -> bool {
    MANAGED_PROXY_PERMISSION_ERR_SNIPPETS
        .iter()
        .any(|snippet| stderr.contains(snippet))
}

async fn managed_proxy_skip_reason() -> Option<String> {
    if should_skip_bwrap_tests().await {
        return Some("bubblewrap is unavailable in this environment".to_string());
    }

    let mut env = create_env_from_core_vars();
    strip_proxy_env(&mut env);
    env.insert("HTTP_PROXY".to_string(), "http://127.0.0.1:9".to_string());

    let output = run_linux_sandbox_direct(
        &["bash", "-c", "true"],
        &PermissionProfile::Disabled,
        /*allow_network_for_proxy*/ true,
        env,
        NETWORK_TIMEOUT_MS,
    )
    .await;
    if output.status.success() {
        return None;
    }

    let stderr = String::from_utf8_lossy(&output.stderr);
    if is_managed_proxy_permission_error(stderr.as_ref()) {
        return Some(format!(
            "managed proxy requires kernel namespace privileges unavailable here: {}",
            stderr.trim()
        ));
    }

    None
}

async fn run_linux_sandbox_direct(
    command: &[&str],
    permission_profile: &PermissionProfile,
    allow_network_for_proxy: bool,
    env: HashMap<String, String>,
    timeout_ms: u64,
) -> Output {
    let mut command =
        linux_sandbox_command(command, permission_profile, allow_network_for_proxy, env);
    tokio::time::timeout(Duration::from_millis(timeout_ms), command.output())
        .await
        .expect("sandbox command should not time out")
        .expect("sandbox command should execute")
}

fn linux_sandbox_command(
    command: &[&str],
    permission_profile: &PermissionProfile,
    allow_network_for_proxy: bool,
    env: HashMap<String, String>,
) -> Command {
    let cwd = std::env::current_dir().expect("current directory should exist");
    let permission_profile_json =
        serde_json::to_string(permission_profile).expect("permission profile should serialize");

    let mut args = vec![
        "--sandbox-policy-cwd".to_string(),
        cwd.to_string_lossy().to_string(),
        "--permission-profile".to_string(),
        permission_profile_json,
    ];
    if allow_network_for_proxy {
        args.push("--allow-network-for-proxy".to_string());
    }
    args.push("--".to_string());
    args.extend(command.iter().map(|entry| (*entry).to_string()));

    let mut cmd = Command::new(env!("CARGO_BIN_EXE_codex-linux-sandbox"));
    cmd.args(args)
        .current_dir(cwd)
        .env_clear()
        .envs(env)
        .stdin(Stdio::null())
        .stdout(Stdio::piped())
        .stderr(Stdio::piped());
    cmd
}

#[tokio::test]
async fn managed_proxy_full_filesystem_uses_minimal_dev_nodes() {
    if let Some(skip_reason) = managed_proxy_skip_reason().await {
        eprintln!("skipping managed proxy test: {skip_reason}");
        return;
    }

    let host_dev = std::fs::metadata("/dev").expect("host /dev should exist");
    let host_dev_id = format!("{}:{}", host_dev.dev(), host_dev.ino());
    let shared_memory_file = match NamedTempFile::new_in("/dev/shm") {
        Ok(file) => {
            std::fs::write(file.path(), "host-before").expect("seed /dev/shm file");
            Some(file)
        }
        Err(err) => {
            eprintln!("skipping /dev/shm interoperability check: {err}");
            None
        }
    };

    let mut env = create_env_from_core_vars();
    strip_proxy_env(&mut env);
    env.insert("HTTP_PROXY".to_string(), "http://127.0.0.1:9".to_string());
    if let Some(file) = &shared_memory_file {
        env.insert(
            "CODEX_TEST_SHM_PATH".to_string(),
            file.path().to_string_lossy().into_owned(),
        );
    }

    let output = run_linux_sandbox_direct(
        &[
            "bash",
            "-c",
            concat!(
                "set -e; ",
                "for node in null zero urandom; do test -c \"/dev/$node\"; done; ",
                "printf test >/dev/null; ",
                "head -c 1 /dev/zero >/dev/null; ",
                "head -c 1 /dev/urandom >/dev/null; ",
                "if command -v python3 >/dev/null 2>&1; then ",
                "python3 -c 'import os; assert len(os.urandom(16)) == 16'; ",
                "fi; ",
                "if [ -n \"${CODEX_TEST_SHM_PATH:-}\" ]; then ",
                "test \"$(cat \"$CODEX_TEST_SHM_PATH\")\" = host-before; ",
                "printf sandbox-after >\"$CODEX_TEST_SHM_PATH\"; ",
                "fi; ",
                "stat -c '%d:%i' /dev",
            ),
        ],
        &PermissionProfile::Disabled,
        /*allow_network_for_proxy*/ true,
        env,
        NETWORK_TIMEOUT_MS,
    )
    .await;

    assert_eq!(
        output.status.success(),
        true,
        "standard devices should be usable; stderr={}",
        String::from_utf8_lossy(&output.stderr)
    );
    assert_ne!(
        String::from_utf8_lossy(&output.stdout).trim(),
        host_dev_id,
        "/dev should be synthetic rather than inherited from the host"
    );
    if let Some(file) = shared_memory_file {
        assert_eq!(
            std::fs::read_to_string(file.path()).expect("read /dev/shm file"),
            "sandbox-after"
        );
    }
}

#[tokio::test]
async fn managed_proxy_bridges_release_command_output_after_exit() {
    if let Some(skip_reason) = managed_proxy_skip_reason().await {
        eprintln!("skipping managed proxy test: {skip_reason}");
        return;
    }

    let mut env = create_env_from_core_vars();
    strip_proxy_env(&mut env);
    env.insert("HTTP_PROXY".to_string(), "http://127.0.0.1:9".to_string());

    let output = run_linux_sandbox_direct(
        &["bash", "-c", "printf 'bridge output closed\\n'"],
        &PermissionProfile::Disabled,
        /*allow_network_for_proxy*/ true,
        env,
        NETWORK_TIMEOUT_MS,
    )
    .await;

    assert_eq!(output.status.success(), true);
    assert_eq!(output.stdout, b"bridge output closed\n");
}

#[tokio::test]
async fn managed_proxy_readiness_survives_closed_standard_descriptors() {
    if let Some(skip_reason) = managed_proxy_skip_reason().await {
        eprintln!("skipping managed proxy test: {skip_reason}");
        return;
    }

    let mut env = create_env_from_core_vars();
    strip_proxy_env(&mut env);
    env.insert("HTTP_PROXY".to_string(), "http://127.0.0.1:9".to_string());

    let mut command = linux_sandbox_command(
        &["bash", "-c", "true"],
        &PermissionProfile::Disabled,
        /*allow_network_for_proxy*/ true,
        env,
    );
    unsafe {
        command.pre_exec(|| {
            libc::close(libc::STDIN_FILENO);
            libc::close(libc::STDOUT_FILENO);
            Ok(())
        });
    }

    let output = tokio::time::timeout(Duration::from_millis(NETWORK_TIMEOUT_MS), command.output())
        .await
        .expect("sandbox command should not time out")
        .expect("sandbox command should execute");

    assert_eq!(
        output.status.success(),
        true,
        "managed proxy readiness should survive closed standard descriptors; stderr={}",
        String::from_utf8_lossy(&output.stderr)
    );
}

#[tokio::test]
async fn managed_proxy_mode_fails_closed_without_proxy_env() {
    if let Some(skip_reason) = managed_proxy_skip_reason().await {
        eprintln!("skipping managed proxy test: {skip_reason}");
        return;
    }

    let mut env = create_env_from_core_vars();
    strip_proxy_env(&mut env);

    let output = run_linux_sandbox_direct(
        &["bash", "-c", "true"],
        &PermissionProfile::Disabled,
        /*allow_network_for_proxy*/ true,
        env,
        NETWORK_TIMEOUT_MS,
    )
    .await;

    assert_eq!(output.status.success(), false);
    let stderr = String::from_utf8_lossy(&output.stderr);
    assert!(
        stderr.contains("managed proxy mode requires proxy environment variables"),
        "expected fail-closed managed-proxy message, got stderr: {stderr}"
    );
}

#[tokio::test]
async fn managed_proxy_mode_routes_through_bridge_and_blocks_direct_egress() {
    if let Some(skip_reason) = managed_proxy_skip_reason().await {
        eprintln!("skipping managed proxy test: {skip_reason}");
        return;
    }

    let listener = TcpListener::bind((Ipv4Addr::LOCALHOST, 0)).expect("bind proxy listener");
    let proxy_port = listener
        .local_addr()
        .expect("proxy listener local addr")
        .port();
    let (request_tx, request_rx) = std::sync::mpsc::channel();
    std::thread::spawn(move || {
        let (mut stream, _) = listener.accept().expect("accept proxy connection");
        stream
            .set_read_timeout(Some(Duration::from_secs(3)))
            .expect("set read timeout");
        let mut buf = [0_u8; 4096];
        let read = stream.read(&mut buf).expect("read proxy request");
        let request = String::from_utf8_lossy(&buf[..read]).to_string();
        request_tx.send(request).expect("send proxy request");
        stream
            .write_all(b"HTTP/1.1 200 OK\r\nContent-Length: 2\r\n\r\nOK")
            .expect("write proxy response");
    });

    let mut env = create_env_from_core_vars();
    strip_proxy_env(&mut env);
    env.insert(
        "HTTP_PROXY".to_string(),
        format!("http://127.0.0.1:{proxy_port}"),
    );
    env.insert(
        "WSS_PROXY".to_string(),
        format!("http://127.0.0.1:{proxy_port}"),
    );

    let sandbox_helper_dir = std::path::Path::new(env!("CARGO_BIN_EXE_codex-linux-sandbox"))
        .parent()
        .expect("sandbox helper should have a parent");
    let file_system_sandbox_policy =
        FileSystemSandboxPolicy::restricted(vec![FileSystemSandboxEntry {
            path: FileSystemPath::Special {
                value: FileSystemSpecialPath::Minimal,
            },
            access: FileSystemAccessMode::Read,
            missing_path_behavior: None,
        }])
        .with_additional_readable_roots(
            std::env::current_dir()
                .expect("current directory should exist")
                .as_path(),
            &[AbsolutePathBuf::try_from(sandbox_helper_dir).expect("absolute helper dir")],
        );
    let permission_profile = PermissionProfile::from_runtime_permissions(
        &file_system_sandbox_policy,
        NetworkSandboxPolicy::Restricted,
    );

    let routed_output = run_linux_sandbox_direct(
        &[
            "bash",
            "-c",
            "proxy=\"${WSS_PROXY#*://}\"; host=\"${proxy%%:*}\"; port=\"${proxy##*:}\"; exec 3<>/dev/tcp/${host}/${port}; printf 'GET http://example.com/ HTTP/1.1\\r\\nHost: example.com\\r\\n\\r\\n' >&3; IFS= read -r line <&3; printf '%s\\n' \"$line\"",
        ],
        &permission_profile,
        /*allow_network_for_proxy*/ true,
        env.clone(),
        NETWORK_TIMEOUT_MS,
    )
    .await;

    assert_eq!(
        routed_output.status.success(),
        true,
        "expected routed command to execute successfully; status={:?}; stdout={}; stderr={}",
        routed_output.status.code(),
        String::from_utf8_lossy(&routed_output.stdout),
        String::from_utf8_lossy(&routed_output.stderr)
    );
    let stdout = String::from_utf8_lossy(&routed_output.stdout);
    assert!(
        stdout.contains("HTTP/1.1 200 OK"),
        "expected bridge-routed proxy response, got stdout: {stdout}"
    );

    let request = request_rx
        .recv_timeout(Duration::from_secs(3))
        .expect("expected proxy request");
    assert!(
        request.contains("GET http://example.com/ HTTP/1.1"),
        "expected HTTP proxy absolute-form request, got request: {request}"
    );

    let direct_egress_output = run_linux_sandbox_direct(
        &["bash", "-c", "echo hi > /dev/tcp/192.0.2.1/80"],
        &PermissionProfile::Disabled,
        /*allow_network_for_proxy*/ true,
        env,
        NETWORK_TIMEOUT_MS,
    )
    .await;
    assert_eq!(direct_egress_output.status.success(), false);
}

#[tokio::test]
async fn managed_proxy_mode_denies_af_unix_socket_but_allows_socketpair() {
    if let Some(skip_reason) = managed_proxy_skip_reason().await {
        eprintln!("skipping managed proxy test: {skip_reason}");
        return;
    }

    let python_available = Command::new("bash")
        .arg("-c")
        .arg("command -v python3 >/dev/null")
        .status()
        .await
        .expect("python3 probe should execute")
        .success();
    if !python_available {
        eprintln!("skipping managed proxy AF_UNIX test: python3 is unavailable");
        return;
    }

    let mut env = create_env_from_core_vars();
    strip_proxy_env(&mut env);
    env.insert("HTTP_PROXY".to_string(), "http://127.0.0.1:9".to_string());

    let output = run_linux_sandbox_direct(
        &[
            "python3",
            "-c",
            "import socket,sys\ntry:\n    socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)\nexcept PermissionError:\n    pass\nexcept OSError:\n    sys.exit(2)\nelse:\n    sys.exit(1)\nleft,right = socket.socketpair(socket.AF_UNIX, socket.SOCK_STREAM)\nleft.sendall(b'ok')\nif right.recv(2) != b'ok':\n    sys.exit(3)\n",
        ],
        &PermissionProfile::Disabled,
        /*allow_network_for_proxy*/ true,
        env,
        NETWORK_TIMEOUT_MS,
    )
    .await;

    assert_eq!(
        output.status.code(),
        Some(0),
        "expected AF_UNIX socket creation to be denied and socketpair to work; status={:?}; stdout={}; stderr={}",
        output.status.code(),
        String::from_utf8_lossy(&output.stdout),
        String::from_utf8_lossy(&output.stderr)
    );
}