282 lines
12 KiB
Python
282 lines
12 KiB
Python
"""Local baseline policy: fake only package, network, and root privilege boundaries."""
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import hashlib
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import io
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import json
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import os
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from pathlib import Path
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import stat
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import subprocess
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import sys
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import tempfile
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from types import SimpleNamespace
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import unittest
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from unittest.mock import Mock, patch
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from engine import overlay
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from engine.lib.host import Host
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from engine.lib.sys import Sys
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base = overlay.load_module(
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str(Path(__file__).resolve().parents[1] / "actions/configure/base.py"),
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"apex_test_configure_base",
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)
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class TestBasePackages(unittest.TestCase):
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def setUp(self):
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self.system = Mock()
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self.installed = set(base.BASE_PACKAGES)
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self.system.run.side_effect = self.query
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self.system.sudo.return_value = subprocess.CompletedProcess([], 0, stdout="")
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def query(self, command, **kwargs):
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self.assertEqual(command[:3], ["dpkg-query", "-W", "-f=${Status}"])
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status = "install ok installed" if command[-1] in self.installed else "unknown ok not-installed"
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return subprocess.CompletedProcess(command, 0, stdout=status)
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def test_installed_rsyslog_and_ufw_do_not_require_executable_or_apt_update(self):
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base._install_missing(self.system, base.BASE_PACKAGES)
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self.assertEqual({call.args[0][-1] for call in self.system.run.call_args_list},
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{"curl", "wget", "git", "rsyslog", "ufw"})
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self.system.sudo.assert_not_called()
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def test_only_missing_packages_are_installed_after_safe_simulation(self):
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self.installed.remove("ufw")
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self.system.sudo.return_value = subprocess.CompletedProcess(
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[], 0, stdout="Inst ufw (0.36.2 Debian:13 [all])\nConf ufw (0.36.2 Debian:13 [all])\n",
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)
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base._install_missing(self.system, base.BASE_PACKAGES)
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commands = [call.args[0] for call in self.system.sudo.call_args_list]
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self.assertEqual(len(commands), 3)
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self.assertIn("update", commands[0])
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self.assertEqual(commands[1], [*commands[2], "--simulate"])
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install = commands[2]
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self.assertEqual(install[install.index("install"):], [
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"install", "-y", "--no-install-recommends", "--no-upgrade", "--no-remove", "ufw",
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])
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def test_privileged_apt_environment_survives_sudo_filtering(self):
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execute = subprocess.run
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operations = []
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def filtered_sudo(command, **kwargs):
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if command[0] == "dpkg-query":
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return subprocess.CompletedProcess(command, 1, stdout="")
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self.assertEqual(command[0], "sudo")
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incoming = kwargs.get("env") or os.environ
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filtered = {"PATH": os.defpath}
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if "LC_ALL" in incoming:
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filtered["LC_ALL"] = incoming["LC_ALL"]
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apt_index = command.index("apt-get")
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probe = execute([
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*command[1:apt_index], sys.executable, "-I", "-c",
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"import json, os; print(json.dumps([os.getenv('LC_ALL'), "
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"os.getenv('DEBIAN_FRONTEND')]))",
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], env=filtered, check=True, text=True, capture_output=True)
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self.assertEqual(json.loads(probe.stdout), ["C", "noninteractive"])
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operations.append(command[apt_index:])
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plan = "Inst ufw (0.36.2 Debian:13 [all])\n" if "--simulate" in command else ""
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return subprocess.CompletedProcess(command, 0, stdout=plan)
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with patch("engine.lib.sys.subprocess.run", side_effect=filtered_sudo):
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base._install_missing(Sys(Mock()), ["ufw"])
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self.assertEqual(len(operations), 3)
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self.assertIn("update", operations[0])
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self.assertIn("--simulate", operations[1])
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self.assertIn("install", operations[2])
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self.assertNotIn("--simulate", operations[2])
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def test_dependency_upgrades_and_removals_abort_before_installation(self):
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self.installed.remove("curl")
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for plan in ("Inst libcurl4 [7.0] (8.0 Debian:13 [amd64])\n",
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"Remv libcurl4 [7.0]\n"):
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with self.subTest(plan=plan):
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self.system.sudo.reset_mock()
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self.system.sudo.return_value = subprocess.CompletedProcess([], 0, stdout=plan)
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with self.assertRaisesRegex(RuntimeError, "upgrades/removals"):
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base._install_missing(self.system, base.BASE_PACKAGES)
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self.assertEqual(self.system.sudo.call_count, 2)
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def test_failed_package_query_is_not_treated_as_installed(self):
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self.system.run.return_value = subprocess.CompletedProcess([], 1, stdout="")
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self.system.run.side_effect = None
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base._install_missing(self.system, ["rsyslog"])
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self.assertEqual(self.system.sudo.call_args.args[0][-1], "rsyslog")
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class TestPinnedHelper(unittest.TestCase):
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def setUp(self):
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temporary = tempfile.TemporaryDirectory()
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self.addCleanup(temporary.cleanup)
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self.root = Path(temporary.name).resolve()
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self.path = self.root / "bin" / "ufw-docker"
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self.path.parent.mkdir()
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self.payload = b"#!/bin/sh\nprintf 'verified fixture\\n'\n"
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self.wrong_owner = None
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self.wrong_group = None
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self.system = Mock()
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self.system.sudo.side_effect = self.sudo
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self.ctx = SimpleNamespace(log=Mock(), sys=self.system)
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self.ctx.host = Host(self.ctx.log, self.system)
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real_lstat = Path.lstat
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def root_lstat(path, *args, **kwargs):
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info = list(real_lstat(path, *args, **kwargs))
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info[4] = 1001 if path == self.wrong_owner else 0
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info[5] = 1001 if path == self.wrong_group else 0
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if path not in (self.path, self.path.parent, self.root):
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info[0] &= ~0o022
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return os.stat_result(info)
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# Model root-owned ancestry without sudo/chown; content, modes and links stay real.
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self.addCleanup(patch.stopall)
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patch.object(Path, "lstat", autospec=True, side_effect=root_lstat).start()
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patch.object(base, "UFW_DOCKER_PATH", self.path).start()
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patch.object(base, "UFW_DOCKER_SHA256", hashlib.sha256(self.payload).hexdigest()).start()
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self.download = patch.object(base.urllib.request, "urlopen").start()
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self.download.return_value = io.BytesIO(self.payload)
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def sudo(self, command, **kwargs):
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if command[:3] == ["python3", "-I", "-c"]:
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return subprocess.run([sys.executable, *command[1:]], check=True, text=True, **kwargs)
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self.assertEqual(command, [str(self.path), "install"])
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self.assertEqual(self.path.read_bytes(), self.payload)
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self.assertEqual(stat.S_IMODE(self.path.stat().st_mode), 0o755)
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return subprocess.CompletedProcess(command, 0)
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def write_helper(self, payload=None, mode=0o755):
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self.path.write_bytes(self.payload if payload is None else payload)
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self.path.chmod(mode)
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def test_verified_existing_helper_executes_without_download(self):
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self.write_helper()
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base._install_helper(self.ctx)
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self.download.assert_not_called()
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self.assertEqual(self.system.sudo.call_args.args[0], [str(self.path), "install"])
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self.assertEqual(self.system.sudo.call_count, 1)
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def test_wrong_executable_content_is_replaced_only_with_verified_download(self):
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self.write_helper(b"#!/bin/sh\necho wrong\n")
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base._install_helper(self.ctx)
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self.assertEqual(self.path.read_bytes(), self.payload)
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self.assertEqual(self.system.sudo.call_count, 2)
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self.download.assert_called_once_with(base.UFW_DOCKER_URL, timeout=30)
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def test_missing_helper_is_published_with_executable_mode(self):
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base._install_helper(self.ctx)
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self.assertEqual(self.path.read_bytes(), self.payload)
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self.assertEqual(stat.S_IMODE(self.path.stat().st_mode), 0o755)
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self.assertEqual(list(self.path.parent.iterdir()), [self.path])
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def test_verified_nonexecutable_content_is_reused_and_mode_repaired(self):
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self.write_helper(mode=0o600)
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base._install_helper(self.ctx)
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self.download.assert_not_called()
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self.assertEqual(stat.S_IMODE(self.path.stat().st_mode), 0o755)
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self.assertEqual(self.system.sudo.call_count, 2)
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def test_bad_checksum_never_publishes_or_executes(self):
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self.download.return_value = io.BytesIO(b"not the pinned helper")
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with self.assertRaisesRegex(RuntimeError, "checksum mismatch"):
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base._install_helper(self.ctx)
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self.system.sudo.assert_not_called()
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self.assertFalse(self.path.exists())
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def test_bad_download_preserves_existing_wrong_helper_without_executing_it(self):
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self.write_helper(b"old unknown executable")
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self.download.return_value = io.BytesIO(b"bad download")
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with self.assertRaisesRegex(RuntimeError, "checksum mismatch"):
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base._install_helper(self.ctx)
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self.system.sudo.assert_not_called()
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self.assertEqual(self.path.read_bytes(), b"old unknown executable")
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def assert_rejected_before_network_or_sudo(self):
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with self.assertRaisesRegex(RuntimeError, "Unsafe ufw-docker"):
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base._install_helper(self.ctx)
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self.download.assert_not_called()
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self.system.sudo.assert_not_called()
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def test_symlink_target_is_rejected(self):
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target = self.root / "untrusted"
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target.write_bytes(self.payload)
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self.path.symlink_to(target)
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self.assert_rejected_before_network_or_sudo()
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def test_dangling_symlink_target_is_rejected(self):
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self.path.symlink_to(self.root / "missing")
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self.assert_rejected_before_network_or_sudo()
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def test_symlink_ancestor_is_rejected(self):
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self.path.parent.rmdir()
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target = self.root / "real-bin"
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target.mkdir()
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self.path.parent.symlink_to(target)
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self.assert_rejected_before_network_or_sudo()
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def test_writable_ancestor_is_rejected(self):
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self.path.parent.chmod(0o777)
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self.assert_rejected_before_network_or_sudo()
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def test_unsafe_helper_preflight_precedes_package_network_or_mutation(self):
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self.path.parent.chmod(0o777)
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with patch.object(base.os.path, "isfile", return_value=True):
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with self.assertRaisesRegex(RuntimeError, "Unsafe ufw-docker"):
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base.run(self.ctx, None)
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self.download.assert_not_called()
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self.system.run.assert_not_called()
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self.system.sudo.assert_not_called()
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def test_untrusted_owner_ancestor_is_rejected(self):
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self.wrong_owner = self.path.parent
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self.assert_rejected_before_network_or_sudo()
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def test_untrusted_file_owner_is_rejected(self):
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self.write_helper()
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self.wrong_owner = self.path
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self.assert_rejected_before_network_or_sudo()
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def test_untrusted_file_group_is_rejected(self):
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self.write_helper()
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self.wrong_group = self.path
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self.assert_rejected_before_network_or_sudo()
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def test_writable_helper_is_rejected(self):
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self.write_helper(mode=0o775)
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self.assert_rejected_before_network_or_sudo()
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def test_hardlinked_helper_is_rejected(self):
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self.write_helper()
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os.link(self.path, self.root / "other-link")
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self.assert_rejected_before_network_or_sudo()
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def test_nonregular_helper_is_rejected(self):
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self.path.mkdir()
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self.assert_rejected_before_network_or_sudo()
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def test_path_changed_during_download_is_rejected_before_publication(self):
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def download(*args, **kwargs):
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self.path.symlink_to(self.root / "untrusted")
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return io.BytesIO(self.payload)
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self.download.side_effect = download
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with self.assertRaisesRegex(RuntimeError, "Unsafe ufw-docker"):
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base._install_helper(self.ctx)
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self.system.sudo.assert_not_called()
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def test_changed_content_after_publication_is_not_executed(self):
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real_sudo = self.sudo
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def tamper(command, **kwargs):
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result = real_sudo(command, **kwargs)
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self.path.write_bytes(b"changed after publication")
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return result
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self.system.sudo.side_effect = tamper
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with self.assertRaisesRegex(RuntimeError, "verification failed"):
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base._install_helper(self.ctx)
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self.assertEqual(self.system.sudo.call_count, 1)
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if __name__ == "__main__":
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unittest.main()
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