clawmates/crates/cm-sandbox/tests/security.rs

//! Kernel-level sandbox assertions (spec §15, acceptance-blocking): these
//! tests spawn REAL containers and probe the controls from inside —
//! asserting kernel behavior, not configuration strings.

use std::process::Command;

use cm_sandbox::{DockerDriver, SandboxDriver, SandboxSpec};

const IMAGE: &str = "clawmates/agent-base:dev";

/// Builds the agent image once if missing (subsequent runs hit the cache).
fn ensure_image() {
    let exists = Command::new("docker")
        .args(["image", "inspect", IMAGE])
        .output()
        .expect("docker available")
        .status
        .success();
    if exists {
        return;
    }
    let root = env!("CARGO_MANIFEST_DIR");
    let status = Command::new("docker")
        .args([
            "build",
            "-t",
            IMAGE,
            "-f",
            &format!("{root}/../../images/agent-base/Dockerfile"),
            &format!("{root}/../../images/agent-base"),
        ])
        .status()
        .expect("docker build runs");
    assert!(status.success(), "agent-base image build failed");
}

async fn spawn(name_suffix: &str) -> (DockerDriver, cm_sandbox::SandboxHandle) {
    ensure_image();
    let driver = DockerDriver::connect().expect("docker daemon reachable");
    let spec = SandboxSpec {
        name: format!("clawmates-test-sbx-{name_suffix}-{}", std::process::id()),
        image: IMAGE.into(),
        memory_bytes: 256 * 1024 * 1024,
        nano_cpus: 1_000_000_000,
        pids_limit: 128,
        egress: false,
        kind: cm_sandbox::SandboxKind::Agent,
        mounts: Vec::new(),
    };
    // Clean leftovers from interrupted runs, then provision fresh.
    let _ = driver.destroy_by_name(&spec.name).await;
    let handle = driver.provision(&spec).await.expect("sandbox provisions");
    (driver, handle)
}

#[tokio::test]
async fn runs_as_uid_10001_with_no_capabilities() {
    let (driver, handle) = spawn("uid").await;

    let uid = driver.exec(&handle, &["id", "-u"]).await.unwrap();
    assert_eq!(uid.stdout.trim(), "10001", "stderr: {}", uid.stderr);

    // CapEff all-zero proves cap-drop ALL took effect in the kernel.
    let caps = driver
        .exec(&handle, &["grep", "CapEff", "/proc/self/status"])
        .await
        .unwrap();
    let value = caps.stdout.split_whitespace().last().unwrap_or("");
    assert_eq!(
        u64::from_str_radix(value, 16).unwrap(),
        0,
        "effective capabilities must be empty, got {value}"
    );

    driver.destroy(&handle).await.unwrap();
}

#[tokio::test]
async fn rootfs_is_read_only_with_writable_tmp() {
    let (driver, handle) = spawn("rootfs").await;

    let write_root = driver
        .exec(&handle, &["touch", "/etc/owned"])
        .await
        .unwrap();
    assert_ne!(write_root.exit_code, 0, "rootfs must reject writes");
    assert!(
        write_root.stderr.contains("Read-only file system"),
        "got: {}",
        write_root.stderr
    );

    let write_tmp = driver
        .exec(&handle, &["touch", "/tmp/scratch"])
        .await
        .unwrap();
    assert_eq!(write_tmp.exit_code, 0, "tmpfs /tmp must be writable");

    let write_home = driver
        .exec(&handle, &["touch", "/home/agent/file"])
        .await
        .unwrap();
    assert_eq!(write_home.exit_code, 0, "workdir must be writable");

    driver.destroy(&handle).await.unwrap();
}

#[tokio::test]
async fn seccomp_denies_namespace_and_tracing_syscalls() {
    let (driver, handle) = spawn("seccomp").await;

    // unshare(2) is denied by the profile even though no capability is
    // required for a user-namespace unshare.
    let unshare = driver
        .exec(&handle, &["unshare", "--user", "true"])
        .await
        .unwrap();
    assert_ne!(unshare.exit_code, 0, "unshare must be denied");

    driver.destroy(&handle).await.unwrap();
}

#[tokio::test]
async fn sandbox_has_no_network_path_at_all() {
    let (driver, handle) = spawn("egress").await;

    // network=none: no traffic-carrying interface exists. The kernel
    // auto-creates inert DOWN tunnel devices (tunl0, gre0, sit0, ...) in
    // every namespace; what must be absent is any ethernet/veth device.
    let interfaces = driver
        .exec(&handle, &["cat", "/proc/net/dev"])
        .await
        .unwrap();
    let carriers: Vec<&str> = interfaces
        .stdout
        .lines()
        .skip(2)
        .map(str::trim_start)
        .filter(|line| {
            line.starts_with("eth") || line.starts_with("en") || line.starts_with("veth")
        })
        .collect();
    assert!(carriers.is_empty(), "unexpected interfaces: {carriers:?}");

    // And an actual connect attempt goes nowhere.
    let connect = driver
        .exec(
            &handle,
            &[
                "timeout",
                "3",
                "bash",
                "-c",
                "echo probe > /dev/tcp/1.1.1.1/443",
            ],
        )
        .await
        .unwrap();
    assert_ne!(connect.exit_code, 0, "egress connect must fail");

    driver.destroy(&handle).await.unwrap();
}

#[tokio::test]
async fn no_setuid_binaries_exist_and_privileges_cannot_grow() {
    let (driver, handle) = spawn("setuid").await;

    let setuid = driver
        .exec(
            &handle,
            &[
                "find", "/usr", "/bin", "/sbin", "-perm", "/6000", "-type", "f",
            ],
        )
        .await
        .unwrap();
    assert_eq!(setuid.stdout.trim(), "", "setuid binaries found");

    // NoNewPrivs flag is set on every process (no-new-privileges).
    let nnp = driver
        .exec(&handle, &["grep", "NoNewPrivs", "/proc/self/status"])
        .await
        .unwrap();
    assert!(nnp.stdout.trim().ends_with('1'), "got: {}", nnp.stdout);

    driver.destroy(&handle).await.unwrap();
}

#[tokio::test]
async fn destroy_removes_the_container_and_health_reflects_it() {
    let (driver, handle) = spawn("lifecycle").await;
    assert!(driver.health(&handle).await.unwrap());
    driver.destroy(&handle).await.unwrap();
    assert!(!driver.health(&handle).await.unwrap());
}