hermes-agent/tests/tools/test_docker_environment.py
Ubuntu a3014a4481 fix(docker): add SETUID/SETGID caps so gosu drop in entrypoint succeeds
The Docker terminal backend runs containers with `--cap-drop ALL`
and re-adds only DAC_OVERRIDE, CHOWN, FOWNER. Since commit fee0e0d3
("run as non-root user, use virtualenv") the image entrypoint drops
from root to the `hermes` user via `gosu`, which requires CAP_SETUID
and CAP_SETGID. Without them every sandbox container exits
immediately with:

    Dropping root privileges
    error: failed switching to 'hermes': operation not permitted

Breaking every terminal/file tool invocation in `terminal.backend: docker`
mode.

Fix: add SETUID and SETGID to the cap-add list. The `no-new-privileges`
security-opt is kept, so gosu still cannot escalate back to root after
the one-way drop — the hardening posture is preserved.

Reproduction
------------
With any image whose ENTRYPOINT calls `gosu <user>`, the container
exits immediately under the pre-fix cap set. Post-fix, the drop
succeeds and the container proceeds normally.

    docker run --rm \
        --cap-drop ALL \
        --cap-add DAC_OVERRIDE --cap-add CHOWN --cap-add FOWNER \
        --security-opt no-new-privileges \
        --entrypoint /usr/local/bin/gosu \
        hermes-claude:latest hermes id
    # -> error: failed switching to 'hermes': operation not permitted

    # Same command with SETUID+SETGID added:
    # -> uid=10000(hermes) gid=10000(hermes) groups=10000(hermes)

Tests
-----
Added `test_security_args_include_setuid_setgid_for_gosu_drop` that
asserts both caps are present and the overall hardening posture
(cap-drop ALL + no-new-privileges) is preserved.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-22 18:13:14 -07:00

412 lines
15 KiB
Python

import logging
from io import StringIO
import subprocess
import sys
import types
import pytest
from tools.environments import docker as docker_env
def _mock_subprocess_run(monkeypatch):
"""Mock subprocess.run to intercept docker run -d and docker version calls.
Returns a list of captured (cmd, kwargs) tuples for inspection.
"""
calls = []
def _run(cmd, **kwargs):
calls.append((list(cmd) if isinstance(cmd, list) else cmd, kwargs))
if isinstance(cmd, list) and len(cmd) >= 2:
if cmd[1] == "version":
return subprocess.CompletedProcess(cmd, 0, stdout="Docker version", stderr="")
if cmd[1] == "run":
return subprocess.CompletedProcess(cmd, 0, stdout="fake-container-id\n", stderr="")
return subprocess.CompletedProcess(cmd, 0, stdout="", stderr="")
monkeypatch.setattr(docker_env.subprocess, "run", _run)
return calls
def _make_dummy_env(**kwargs):
"""Helper to construct DockerEnvironment with minimal required args."""
return docker_env.DockerEnvironment(
image=kwargs.get("image", "python:3.11"),
cwd=kwargs.get("cwd", "/root"),
timeout=kwargs.get("timeout", 60),
cpu=kwargs.get("cpu", 0),
memory=kwargs.get("memory", 0),
disk=kwargs.get("disk", 0),
persistent_filesystem=kwargs.get("persistent_filesystem", False),
task_id=kwargs.get("task_id", "test-task"),
volumes=kwargs.get("volumes", []),
network=kwargs.get("network", True),
host_cwd=kwargs.get("host_cwd"),
auto_mount_cwd=kwargs.get("auto_mount_cwd", False),
env=kwargs.get("env"),
)
def test_ensure_docker_available_logs_and_raises_when_not_found(monkeypatch, caplog):
"""When docker cannot be found, raise a clear error before container setup."""
monkeypatch.setattr(docker_env, "find_docker", lambda: None)
monkeypatch.setattr(
docker_env.subprocess,
"run",
lambda *args, **kwargs: pytest.fail("subprocess.run should not be called when docker is missing"),
)
with caplog.at_level(logging.ERROR):
with pytest.raises(RuntimeError) as excinfo:
_make_dummy_env()
assert "Docker executable not found in PATH or known install locations" in str(excinfo.value)
assert any(
"no docker executable was found in PATH or known install locations"
in record.getMessage()
for record in caplog.records
)
def test_ensure_docker_available_logs_and_raises_on_timeout(monkeypatch, caplog):
"""When docker version times out, surface a helpful error instead of hanging."""
def _raise_timeout(*args, **kwargs):
raise subprocess.TimeoutExpired(cmd=["/custom/docker", "version"], timeout=5)
monkeypatch.setattr(docker_env, "find_docker", lambda: "/custom/docker")
monkeypatch.setattr(docker_env.subprocess, "run", _raise_timeout)
with caplog.at_level(logging.ERROR):
with pytest.raises(RuntimeError) as excinfo:
_make_dummy_env()
assert "Docker daemon is not responding" in str(excinfo.value)
assert any(
"/custom/docker version' timed out" in record.getMessage()
for record in caplog.records
)
def test_ensure_docker_available_uses_resolved_executable(monkeypatch):
"""When docker is found outside PATH, preflight should use that resolved path."""
calls = []
def _run(cmd, **kwargs):
calls.append((cmd, kwargs))
return subprocess.CompletedProcess(cmd, 0, stdout="Docker version", stderr="")
monkeypatch.setattr(docker_env, "find_docker", lambda: "/opt/homebrew/bin/docker")
monkeypatch.setattr(docker_env.subprocess, "run", _run)
docker_env._ensure_docker_available()
assert calls == [
(["/opt/homebrew/bin/docker", "version"], {
"capture_output": True,
"text": True,
"timeout": 5,
})
]
def test_auto_mount_host_cwd_adds_volume(monkeypatch, tmp_path):
"""Opt-in docker cwd mounting should bind the host cwd to /workspace."""
project_dir = tmp_path / "my-project"
project_dir.mkdir()
monkeypatch.setattr(docker_env, "find_docker", lambda: "/usr/bin/docker")
calls = _mock_subprocess_run(monkeypatch)
_make_dummy_env(
cwd="/workspace",
host_cwd=str(project_dir),
auto_mount_cwd=True,
)
# Find the docker run call and check its args
run_calls = [c for c in calls if isinstance(c[0], list) and len(c[0]) >= 2 and c[0][1] == "run"]
assert run_calls, "docker run should have been called"
run_args_str = " ".join(run_calls[0][0])
assert f"{project_dir}:/workspace" in run_args_str
def test_auto_mount_disabled_by_default(monkeypatch, tmp_path):
"""Host cwd should not be mounted unless the caller explicitly opts in."""
project_dir = tmp_path / "my-project"
project_dir.mkdir()
monkeypatch.setattr(docker_env, "find_docker", lambda: "/usr/bin/docker")
calls = _mock_subprocess_run(monkeypatch)
_make_dummy_env(
cwd="/root",
host_cwd=str(project_dir),
auto_mount_cwd=False,
)
run_calls = [c for c in calls if isinstance(c[0], list) and len(c[0]) >= 2 and c[0][1] == "run"]
assert run_calls, "docker run should have been called"
run_args_str = " ".join(run_calls[0][0])
assert f"{project_dir}:/workspace" not in run_args_str
def test_auto_mount_skipped_when_workspace_already_mounted(monkeypatch, tmp_path):
"""Explicit user volumes for /workspace should take precedence over cwd mount."""
project_dir = tmp_path / "my-project"
project_dir.mkdir()
other_dir = tmp_path / "other"
other_dir.mkdir()
monkeypatch.setattr(docker_env, "find_docker", lambda: "/usr/bin/docker")
calls = _mock_subprocess_run(monkeypatch)
_make_dummy_env(
cwd="/workspace",
host_cwd=str(project_dir),
auto_mount_cwd=True,
volumes=[f"{other_dir}:/workspace"],
)
run_calls = [c for c in calls if isinstance(c[0], list) and len(c[0]) >= 2 and c[0][1] == "run"]
assert run_calls, "docker run should have been called"
run_args_str = " ".join(run_calls[0][0])
assert f"{other_dir}:/workspace" in run_args_str
assert run_args_str.count(":/workspace") == 1
def test_auto_mount_replaces_persistent_workspace_bind(monkeypatch, tmp_path):
"""Persistent mode should still prefer the configured host cwd at /workspace."""
project_dir = tmp_path / "my-project"
project_dir.mkdir()
monkeypatch.setattr(docker_env, "find_docker", lambda: "/usr/bin/docker")
calls = _mock_subprocess_run(monkeypatch)
_make_dummy_env(
cwd="/workspace",
persistent_filesystem=True,
host_cwd=str(project_dir),
auto_mount_cwd=True,
task_id="test-persistent-auto-mount",
)
run_calls = [c for c in calls if isinstance(c[0], list) and len(c[0]) >= 2 and c[0][1] == "run"]
assert run_calls, "docker run should have been called"
run_args_str = " ".join(run_calls[0][0])
assert f"{project_dir}:/workspace" in run_args_str
assert "/sandboxes/docker/test-persistent-auto-mount/workspace:/workspace" not in run_args_str
def test_non_persistent_cleanup_removes_container(monkeypatch):
"""When persistent=false, cleanup() must schedule docker stop + rm."""
monkeypatch.setattr(docker_env, "find_docker", lambda: "/usr/bin/docker")
calls = _mock_subprocess_run(monkeypatch)
popen_cmds = []
monkeypatch.setattr(
docker_env.subprocess, "Popen",
lambda cmd, **kw: (popen_cmds.append(cmd), type("P", (), {"poll": lambda s: 0, "wait": lambda s, **k: None, "returncode": 0, "stdout": iter([]), "stdin": None})())[1],
)
env = _make_dummy_env(persistent_filesystem=False, task_id="ephemeral-task")
assert env._container_id
container_id = env._container_id
env.cleanup()
# Should have stop and rm calls via Popen
stop_cmds = [c for c in popen_cmds if container_id in str(c) and "stop" in str(c)]
assert len(stop_cmds) >= 1, f"cleanup() should schedule docker stop for {container_id}"
class _FakePopen:
def __init__(self, cmd, **kwargs):
self.cmd = cmd
self.kwargs = kwargs
self.stdout = StringIO("")
self.stdin = None
self.returncode = 0
def poll(self):
return self.returncode
def _make_execute_only_env(forward_env=None):
env = docker_env.DockerEnvironment.__new__(docker_env.DockerEnvironment)
env.cwd = "/root"
env.timeout = 60
env._forward_env = forward_env or []
env._env = {}
env._prepare_command = lambda command: (command, None)
env._timeout_result = lambda timeout: {"output": f"timed out after {timeout}", "returncode": 124}
env._container_id = "test-container"
env._docker_exe = "/usr/bin/docker"
# Base class attributes needed by unified execute()
env._session_id = "test123"
env._snapshot_path = "/tmp/hermes-snap-test123.sh"
env._cwd_file = "/tmp/hermes-cwd-test123.txt"
env._cwd_marker = "__HERMES_CWD_test123__"
env._snapshot_ready = True
env._last_sync_time = None
env._init_env_args = []
return env
def test_init_env_args_uses_hermes_dotenv_for_allowlisted_env(monkeypatch):
"""_build_init_env_args picks up forwarded env vars from .env file at init time."""
# Use a var that is NOT in _HERMES_PROVIDER_ENV_BLOCKLIST (GITHUB_TOKEN
# is in the copilot provider's api_key_env_vars and gets stripped).
env = _make_execute_only_env(["DATABASE_URL"])
monkeypatch.delenv("DATABASE_URL", raising=False)
monkeypatch.setattr(docker_env, "_load_hermes_env_vars", lambda: {"DATABASE_URL": "value_from_dotenv"})
args = env._build_init_env_args()
args_str = " ".join(args)
assert "DATABASE_URL=value_from_dotenv" in args_str
def test_init_env_args_prefers_shell_env_over_hermes_dotenv(monkeypatch):
"""Shell env vars take priority over .env file values in init env args."""
env = _make_execute_only_env(["DATABASE_URL"])
monkeypatch.setenv("DATABASE_URL", "value_from_shell")
monkeypatch.setattr(docker_env, "_load_hermes_env_vars", lambda: {"DATABASE_URL": "value_from_dotenv"})
args = env._build_init_env_args()
args_str = " ".join(args)
assert "DATABASE_URL=value_from_shell" in args_str
assert "value_from_dotenv" not in args_str
# ── docker_env tests ──────────────────────────────────────────────
def test_docker_env_appears_in_run_command(monkeypatch):
"""Explicit docker_env values should be passed via -e at docker run time."""
monkeypatch.setattr(docker_env, "find_docker", lambda: "/usr/bin/docker")
calls = _mock_subprocess_run(monkeypatch)
_make_dummy_env(env={"SSH_AUTH_SOCK": "/run/user/1000/ssh-agent.sock", "GNUPGHOME": "/root/.gnupg"})
run_calls = [c for c in calls if isinstance(c[0], list) and len(c[0]) >= 2 and c[0][1] == "run"]
assert run_calls, "docker run should have been called"
run_args = run_calls[0][0]
run_args_str = " ".join(run_args)
assert "SSH_AUTH_SOCK=/run/user/1000/ssh-agent.sock" in run_args_str
assert "GNUPGHOME=/root/.gnupg" in run_args_str
def test_docker_env_appears_in_init_env_args(monkeypatch):
"""Explicit docker_env values should appear in _build_init_env_args."""
env = _make_execute_only_env()
env._env = {"MY_VAR": "my_value"}
args = env._build_init_env_args()
args_str = " ".join(args)
assert "MY_VAR=my_value" in args_str
def test_forward_env_overrides_docker_env_in_init_args(monkeypatch):
"""docker_forward_env should override docker_env for the same key."""
env = _make_execute_only_env(forward_env=["MY_KEY"])
env._env = {"MY_KEY": "static_value"}
monkeypatch.setenv("MY_KEY", "dynamic_value")
monkeypatch.setattr(docker_env, "_load_hermes_env_vars", lambda: {})
args = env._build_init_env_args()
args_str = " ".join(args)
assert "MY_KEY=dynamic_value" in args_str
assert "MY_KEY=static_value" not in args_str
def test_docker_env_and_forward_env_merge_in_init_args(monkeypatch):
"""docker_env and docker_forward_env with different keys should both appear."""
env = _make_execute_only_env(forward_env=["TOKEN"])
env._env = {"SSH_AUTH_SOCK": "/run/user/1000/agent.sock"}
monkeypatch.setenv("TOKEN", "secret123")
monkeypatch.setattr(docker_env, "_load_hermes_env_vars", lambda: {})
args = env._build_init_env_args()
args_str = " ".join(args)
assert "SSH_AUTH_SOCK=/run/user/1000/agent.sock" in args_str
assert "TOKEN=secret123" in args_str
def test_normalize_env_dict_filters_invalid_keys():
"""_normalize_env_dict should reject invalid variable names."""
result = docker_env._normalize_env_dict({
"VALID_KEY": "ok",
"123bad": "rejected",
"": "rejected",
"also valid": "rejected", # spaces invalid
"GOOD": "ok",
})
assert result == {"VALID_KEY": "ok", "GOOD": "ok"}
def test_normalize_env_dict_coerces_scalars():
"""_normalize_env_dict should coerce int/float/bool to str."""
result = docker_env._normalize_env_dict({
"PORT": 8080,
"DEBUG": True,
"RATIO": 0.5,
})
assert result == {"PORT": "8080", "DEBUG": "True", "RATIO": "0.5"}
def test_normalize_env_dict_rejects_non_dict():
"""_normalize_env_dict should return empty dict for non-dict input."""
assert docker_env._normalize_env_dict("not a dict") == {}
assert docker_env._normalize_env_dict(None) == {}
assert docker_env._normalize_env_dict([]) == {}
def test_normalize_env_dict_rejects_complex_values():
"""_normalize_env_dict should reject list/dict values."""
result = docker_env._normalize_env_dict({
"GOOD": "string",
"BAD_LIST": [1, 2, 3],
"BAD_DICT": {"nested": True},
})
assert result == {"GOOD": "string"}
def test_security_args_include_setuid_setgid_for_gosu_drop():
"""_SECURITY_ARGS must include SETUID and SETGID so the image entrypoint
can drop from root to the non-root `hermes` user via gosu.
Without these caps gosu exits with
``error: failed switching to 'hermes': operation not permitted``
and the container exits immediately (exit 1) before running any work.
`no-new-privileges` is kept, so gosu still cannot escalate back to root
after the drop — the drop is a one-way transition performed before the
`no_new_privs` bit is enforced on the exec boundary.
"""
args = docker_env._SECURITY_ARGS
# Flatten to set of added caps for clarity.
added = {
args[i + 1]
for i, flag in enumerate(args[:-1])
if flag == "--cap-add"
}
assert "SETUID" in added, "SETUID cap missing — gosu drop in entrypoint will fail"
assert "SETGID" in added, "SETGID cap missing — gosu drop in entrypoint will fail"
# Sanity: the hardening posture is still in place.
assert "--cap-drop" in args and "ALL" in args
assert "--security-opt" in args and "no-new-privileges" in args