"""Docker execution environment for sandboxed command execution. Security hardened (cap-drop ALL, no-new-privileges, PID limits), configurable resource limits (CPU, memory, disk), and optional filesystem persistence via bind mounts. """ import logging import os import re import shutil import subprocess import sys import threading import time import uuid from typing import Optional from tools.environments.base import BaseEnvironment from tools.interrupt import is_interrupted logger = logging.getLogger(__name__) # Common Docker Desktop install paths checked when 'docker' is not in PATH. # macOS Intel: /usr/local/bin, macOS Apple Silicon (Homebrew): /opt/homebrew/bin, # Docker Desktop app bundle: /Applications/Docker.app/Contents/Resources/bin _DOCKER_SEARCH_PATHS = [ "/usr/local/bin/docker", "/opt/homebrew/bin/docker", "/Applications/Docker.app/Contents/Resources/bin/docker", ] _docker_executable: Optional[str] = None # resolved once, cached _ENV_VAR_NAME_RE = re.compile(r"^[A-Za-z_][A-Za-z0-9_]*$") def _normalize_forward_env_names(forward_env: list[str] | None) -> list[str]: """Return a deduplicated list of valid environment variable names.""" normalized: list[str] = [] seen: set[str] = set() for item in forward_env or []: if not isinstance(item, str): logger.warning("Ignoring non-string docker_forward_env entry: %r", item) continue key = item.strip() if not key: continue if not _ENV_VAR_NAME_RE.match(key): logger.warning("Ignoring invalid docker_forward_env entry: %r", item) continue if key in seen: continue seen.add(key) normalized.append(key) return normalized def _load_hermes_env_vars() -> dict[str, str]: """Load ~/.hermes/.env values without failing Docker command execution.""" try: from hermes_cli.config import load_env return load_env() or {} except Exception: return {} def find_docker() -> Optional[str]: """Locate the docker CLI binary. Checks ``shutil.which`` first (respects PATH), then probes well-known install locations on macOS where Docker Desktop may not be in PATH (e.g. when running as a gateway service via launchd). Returns the absolute path, or ``None`` if docker cannot be found. """ global _docker_executable if _docker_executable is not None: return _docker_executable found = shutil.which("docker") if found: _docker_executable = found return found for path in _DOCKER_SEARCH_PATHS: if os.path.isfile(path) and os.access(path, os.X_OK): _docker_executable = path logger.info("Found docker at non-PATH location: %s", path) return path return None # Security flags applied to every container. # The container itself is the security boundary (isolated from host). # We drop all capabilities then add back the minimum needed: # DAC_OVERRIDE - root can write to bind-mounted dirs owned by host user # CHOWN/FOWNER - package managers (pip, npm, apt) need to set file ownership # Block privilege escalation and limit PIDs. # /tmp is size-limited and nosuid but allows exec (needed by pip/npm builds). _SECURITY_ARGS = [ "--cap-drop", "ALL", "--cap-add", "DAC_OVERRIDE", "--cap-add", "CHOWN", "--cap-add", "FOWNER", "--security-opt", "no-new-privileges", "--pids-limit", "256", "--tmpfs", "/tmp:rw,nosuid,size=512m", "--tmpfs", "/var/tmp:rw,noexec,nosuid,size=256m", "--tmpfs", "/run:rw,noexec,nosuid,size=64m", ] _storage_opt_ok: Optional[bool] = None # cached result across instances def _ensure_docker_available() -> None: """Best-effort check that the docker CLI is available before use. Reuses ``find_docker()`` so this preflight stays consistent with the rest of the Docker backend, including known non-PATH Docker Desktop locations. """ docker_exe = find_docker() if not docker_exe: logger.error( "Docker backend selected but no docker executable was found in PATH " "or known install locations. Install Docker Desktop and ensure the " "CLI is available." ) raise RuntimeError( "Docker executable not found in PATH or known install locations. " "Install Docker and ensure the 'docker' command is available." ) try: result = subprocess.run( [docker_exe, "version"], capture_output=True, text=True, timeout=5, ) except FileNotFoundError: logger.error( "Docker backend selected but the resolved docker executable '%s' could " "not be executed.", docker_exe, exc_info=True, ) raise RuntimeError( "Docker executable could not be executed. Check your Docker installation." ) except subprocess.TimeoutExpired: logger.error( "Docker backend selected but '%s version' timed out. " "The Docker daemon may not be running.", docker_exe, exc_info=True, ) raise RuntimeError( "Docker daemon is not responding. Ensure Docker is running and try again." ) except Exception: logger.error( "Unexpected error while checking Docker availability.", exc_info=True, ) raise else: if result.returncode != 0: logger.error( "Docker backend selected but '%s version' failed " "(exit code %d, stderr=%s)", docker_exe, result.returncode, result.stderr.strip(), ) raise RuntimeError( "Docker command is available but 'docker version' failed. " "Check your Docker installation." ) class DockerEnvironment(BaseEnvironment): """Hardened Docker container execution with resource limits and persistence. Security: all capabilities dropped, no privilege escalation, PID limits, size-limited tmpfs for scratch dirs. The container itself is the security boundary — the filesystem inside is writable so agents can install packages (pip, npm, apt) as needed. Writable workspace via tmpfs or bind mounts. Persistence: when enabled, bind mounts preserve /workspace and /root across container restarts. """ def __init__( self, image: str, cwd: str = "/root", timeout: int = 60, cpu: float = 0, memory: int = 0, disk: int = 0, persistent_filesystem: bool = False, task_id: str = "default", volumes: list = None, forward_env: list[str] | None = None, network: bool = True, host_cwd: str = None, auto_mount_cwd: bool = False, ): if cwd == "~": cwd = "/root" super().__init__(cwd=cwd, timeout=timeout) self._base_image = image self._persistent = persistent_filesystem self._task_id = task_id self._forward_env = _normalize_forward_env_names(forward_env) self._container_id: Optional[str] = None logger.info(f"DockerEnvironment volumes: {volumes}") # Ensure volumes is a list (config.yaml could be malformed) if volumes is not None and not isinstance(volumes, list): logger.warning(f"docker_volumes config is not a list: {volumes!r}") volumes = [] # Fail fast if Docker is not available. _ensure_docker_available() # Build resource limit args resource_args = [] if cpu > 0: resource_args.extend(["--cpus", str(cpu)]) if memory > 0: resource_args.extend(["--memory", f"{memory}m"]) if disk > 0 and sys.platform != "darwin": if self._storage_opt_supported(): resource_args.extend(["--storage-opt", f"size={disk}m"]) else: logger.warning( "Docker storage driver does not support per-container disk limits " "(requires overlay2 on XFS with pquota). Container will run without disk quota." ) if not network: resource_args.append("--network=none") # Persistent workspace via bind mounts from a configurable host directory # (TERMINAL_SANDBOX_DIR, default ~/.hermes/sandboxes/). Non-persistent # mode uses tmpfs (ephemeral, fast, gone on cleanup). from tools.environments.base import get_sandbox_dir # User-configured volume mounts (from config.yaml docker_volumes) volume_args = [] workspace_explicitly_mounted = False for vol in (volumes or []): if not isinstance(vol, str): logger.warning(f"Docker volume entry is not a string: {vol!r}") continue vol = vol.strip() if not vol: continue if ":" in vol: volume_args.extend(["-v", vol]) if ":/workspace" in vol: workspace_explicitly_mounted = True else: logger.warning(f"Docker volume '{vol}' missing colon, skipping") host_cwd_abs = os.path.abspath(os.path.expanduser(host_cwd)) if host_cwd else "" bind_host_cwd = ( auto_mount_cwd and bool(host_cwd_abs) and os.path.isdir(host_cwd_abs) and not workspace_explicitly_mounted ) if auto_mount_cwd and host_cwd and not os.path.isdir(host_cwd_abs): logger.debug(f"Skipping docker cwd mount: host_cwd is not a valid directory: {host_cwd}") self._workspace_dir: Optional[str] = None self._home_dir: Optional[str] = None writable_args = [] if self._persistent: sandbox = get_sandbox_dir() / "docker" / task_id self._home_dir = str(sandbox / "home") os.makedirs(self._home_dir, exist_ok=True) writable_args.extend([ "-v", f"{self._home_dir}:/root", ]) if not bind_host_cwd and not workspace_explicitly_mounted: self._workspace_dir = str(sandbox / "workspace") os.makedirs(self._workspace_dir, exist_ok=True) writable_args.extend([ "-v", f"{self._workspace_dir}:/workspace", ]) else: if not bind_host_cwd and not workspace_explicitly_mounted: writable_args.extend([ "--tmpfs", "/workspace:rw,exec,size=10g", ]) writable_args.extend([ "--tmpfs", "/home:rw,exec,size=1g", "--tmpfs", "/root:rw,exec,size=1g", ]) if bind_host_cwd: logger.info(f"Mounting configured host cwd to /workspace: {host_cwd_abs}") volume_args = ["-v", f"{host_cwd_abs}:/workspace", *volume_args] elif workspace_explicitly_mounted: logger.debug("Skipping docker cwd mount: /workspace already mounted by user config") logger.info(f"Docker volume_args: {volume_args}") all_run_args = list(_SECURITY_ARGS) + writable_args + resource_args + volume_args logger.info(f"Docker run_args: {all_run_args}") # Resolve the docker executable once so it works even when # /usr/local/bin is not in PATH (common on macOS gateway/service). self._docker_exe = find_docker() or "docker" # Start the container directly via `docker run -d`. container_name = f"hermes-{uuid.uuid4().hex[:8]}" run_cmd = [ self._docker_exe, "run", "-d", "--name", container_name, "-w", cwd, *all_run_args, image, "sleep", "2h", ] logger.debug(f"Starting container: {' '.join(run_cmd)}") result = subprocess.run( run_cmd, capture_output=True, text=True, timeout=120, # image pull may take a while check=True, ) self._container_id = result.stdout.strip() logger.info(f"Started container {container_name} ({self._container_id[:12]})") @staticmethod def _storage_opt_supported() -> bool: """Check if Docker's storage driver supports --storage-opt size=. Only overlay2 on XFS with pquota supports per-container disk quotas. Ubuntu (and most distros) default to ext4, where this flag errors out. """ global _storage_opt_ok if _storage_opt_ok is not None: return _storage_opt_ok try: docker = find_docker() or "docker" result = subprocess.run( [docker, "info", "--format", "{{.Driver}}"], capture_output=True, text=True, timeout=10, ) driver = result.stdout.strip().lower() if driver != "overlay2": _storage_opt_ok = False return False # overlay2 only supports storage-opt on XFS with pquota. # Probe by attempting a dry-ish run — the fastest reliable check. probe = subprocess.run( [docker, "create", "--storage-opt", "size=1m", "hello-world"], capture_output=True, text=True, timeout=15, ) if probe.returncode == 0: # Clean up the created container container_id = probe.stdout.strip() if container_id: subprocess.run([docker, "rm", container_id], capture_output=True, timeout=5) _storage_opt_ok = True else: _storage_opt_ok = False except Exception: _storage_opt_ok = False logger.debug("Docker --storage-opt support: %s", _storage_opt_ok) return _storage_opt_ok def execute(self, command: str, cwd: str = "", *, timeout: int | None = None, stdin_data: str | None = None) -> dict: exec_command, sudo_stdin = self._prepare_command(command) work_dir = cwd or self.cwd effective_timeout = timeout or self.timeout # Merge sudo password (if any) with caller-supplied stdin_data. if sudo_stdin is not None and stdin_data is not None: effective_stdin = sudo_stdin + stdin_data elif sudo_stdin is not None: effective_stdin = sudo_stdin else: effective_stdin = stdin_data # docker exec -w doesn't expand ~, so prepend a cd into the command if work_dir == "~" or work_dir.startswith("~/"): exec_command = f"cd {work_dir} && {exec_command}" work_dir = "/" assert self._container_id, "Container not started" cmd = [self._docker_exe, "exec"] if effective_stdin is not None: cmd.append("-i") cmd.extend(["-w", work_dir]) hermes_env = _load_hermes_env_vars() if self._forward_env else {} for key in self._forward_env: value = os.getenv(key) if value is None: value = hermes_env.get(key) if value is not None: cmd.extend(["-e", f"{key}={value}"]) cmd.extend([self._container_id, "bash", "-lc", exec_command]) try: _output_chunks = [] proc = subprocess.Popen( cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, stdin=subprocess.PIPE if effective_stdin else subprocess.DEVNULL, text=True, ) if effective_stdin: try: proc.stdin.write(effective_stdin) proc.stdin.close() except Exception: pass def _drain(): try: for line in proc.stdout: _output_chunks.append(line) except Exception: pass reader = threading.Thread(target=_drain, daemon=True) reader.start() deadline = time.monotonic() + effective_timeout while proc.poll() is None: if is_interrupted(): proc.terminate() try: proc.wait(timeout=1) except subprocess.TimeoutExpired: proc.kill() reader.join(timeout=2) return { "output": "".join(_output_chunks) + "\n[Command interrupted]", "returncode": 130, } if time.monotonic() > deadline: proc.kill() reader.join(timeout=2) return self._timeout_result(effective_timeout) time.sleep(0.2) reader.join(timeout=5) return {"output": "".join(_output_chunks), "returncode": proc.returncode} except Exception as e: return {"output": f"Docker execution error: {e}", "returncode": 1} def cleanup(self): """Stop and remove the container. Bind-mount dirs persist if persistent=True.""" if self._container_id: try: # Stop in background so cleanup doesn't block stop_cmd = ( f"(timeout 60 {self._docker_exe} stop {self._container_id} || " f"{self._docker_exe} rm -f {self._container_id}) >/dev/null 2>&1 &" ) subprocess.Popen(stop_cmd, shell=True) except Exception as e: logger.warning("Failed to stop container %s: %s", self._container_id, e) if not self._persistent: # Also schedule removal (stop only leaves it as stopped) try: subprocess.Popen( f"sleep 3 && {self._docker_exe} rm -f {self._container_id} >/dev/null 2>&1 &", shell=True, ) except Exception: pass self._container_id = None if not self._persistent: for d in (self._workspace_dir, self._home_dir): if d: shutil.rmtree(d, ignore_errors=True)