risky_file_permissions.py

# Copyright (c) 2020 Sorin Sbarnea <sorin.sbarnea@gmail.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
"""MissingFilePermissionsRule used with ansible-lint."""
from __future__ import annotations

import sys
from typing import TYPE_CHECKING, Any

from ansiblelint.rules import AnsibleLintRule

if TYPE_CHECKING:
    from ansiblelint.file_utils import Lintable


# Despite documentation mentioning 'preserve' only these modules support it:
_modules_with_preserve = (
    "copy",
    "template",
)

_MODULES: set[str] = {
    "archive",
    "community.general.archive",
    "assemble",
    "ansible.builtin.assemble",
    "copy",  # supports preserve
    "ansible.builtin.copy",
    "file",
    "ansible.builtin.file",
    "get_url",
    "ansible.builtin.get_url",
    "replace",  # implicit preserve behavior but mode: preserve is invalid
    "ansible.builtin.replace",
    "template",  # supports preserve
    "ansible.builtin.template",
    # 'unarchive',  # disabled because .tar.gz files can have permissions inside
}

_MODULES_WITH_CREATE: dict[str, bool] = {
    "blockinfile": False,
    "ansible.builtin.blockinfile": False,
    "htpasswd": True,
    "community.general.htpasswd": True,
    "ini_file": True,
    "community.general.ini_file": True,
    "lineinfile": False,
    "ansible.builtin.lineinfile": False,
}


class MissingFilePermissionsRule(AnsibleLintRule):
    """File permissions unset or incorrect."""

    id = "risky-file-permissions"
    description = (
        "Missing or unsupported mode parameter can cause unexpected file "
        "permissions based "
        "on version of Ansible being used. Be explicit, like `mode: 0644` to "
        "avoid hitting this rule. Special `preserve` value is accepted "
        f"only by {', '.join([f'`{x}`' for x in _modules_with_preserve])} modules."
    )
    link = "https://github.com/ansible/ansible/issues/71200"
    severity = "VERY_HIGH"
    tags = ["unpredictability", "experimental"]
    version_added = "v4.3.0"

    _modules = _MODULES
    _modules_with_create = _MODULES_WITH_CREATE

    # pylint: disable=too-many-return-statements
    def matchtask(
        self, task: dict[str, Any], file: Lintable | None = None
    ) -> bool | str:
        module = task["action"]["__ansible_module__"]
        mode = task["action"].get("mode", None)

        if module not in self._modules and module not in self._modules_with_create:
            return False

        if mode == "preserve" and module not in _modules_with_preserve:
            return True

        if module in self._modules_with_create:
            create = task["action"].get("create", self._modules_with_create[module])
            return create and mode is None

        # A file that doesn't exist cannot have a mode
        if task["action"].get("state", None) == "absent":
            return False

        # A symlink always has mode 0777
        if task["action"].get("state", None) == "link":
            return False

        # Recurse on a directory does not allow for an uniform mode
        if task["action"].get("recurse", None):
            return False

        # The file module does not create anything when state==file (default)
        if module == "file" and task["action"].get("state", "file") == "file":
            return False

        # replace module is the only one that has a valid default preserve
        # behavior, but we want to trigger rule if user used incorrect
        # documentation and put 'preserve', which is not supported.
        if module == "replace" and mode is None:
            return False

        return mode is None


if "pytest" in sys.modules:  # noqa: C901
    import pytest

    from ansiblelint.testing import RunFromText  # pylint: disable=ungrouped-imports

    SUCCESS_PERMISSIONS_PRESENT = """
- hosts: all
  tasks:
    - name: Permissions not missing and numeric
      file:
        path: foo
        mode: 0600
"""

    SUCCESS_PERMISSIONS_PRESENT_GET_URL = """
- hosts: all
  tasks:
    - name: Permissions not missing and numeric
      get_url:
        url: http://foo
        dest: foo
        mode: 0600
"""

    SUCCESS_ABSENT_STATE = """
- hosts: all
  tasks:
    - name: Permissions missing while state is absent is fine
      file:
        path: foo
        state: absent
"""

    SUCCESS_DEFAULT_STATE = """
- hosts: all
  tasks:
    - name: Permissions missing while state is file (default) is fine
      file:
        path: foo
"""

    SUCCESS_LINK_STATE = """
- hosts: all
  tasks:
    - name: Permissions missing while state is link is fine
      file:
        path: foo2
        src: foo
        state: link
"""

    SUCCESS_CREATE_FALSE = """
- hosts: all
  tasks:
    - name: File edit when create is false
      lineinfile:
        path: foo
        create: false
        line: some content here
"""

    SUCCESS_REPLACE = """
- hosts: all
  tasks:
    - name: Replace should not require mode
      replace:
        path: foo
"""

    SUCCESS_RECURSE = """
- hosts: all
  tasks:
    - name: File with recursive does not require mode
      file:
        state: directory
        recurse: yes
    - name: Permissions not missing and numeric (fqcn)
      ansible.builtin.file:
        path: bar
        mode: 755
    - name: File edit when create is false (fqcn)
      ansible.builtin.lineinfile:
        path: foo
        create: false
        line: some content here
"""

    FAIL_PRESERVE_MODE = """
- hosts: all
  tasks:
    - name: File does not allow preserve value for mode
      file:
        path: foo
        mode: preserve
"""

    FAIL_MISSING_PERMISSIONS_TOUCH = """
- hosts: all
  tasks:
    - name: Permissions missing and might create file
      file:
        path: foo
        state: touch
    - name: Permissions missing and might create file (fqcn)
      ansible.builtin.file:
        path: foo
        state: touch
"""

    FAIL_MISSING_PERMISSIONS_DIRECTORY = """
- hosts: all
  tasks:
    - name: Permissions missing and might create directory
      file:
        path: foo
        state: directory
    - name: Lineinfile when create is true (fqcn)
      ansible.builtin.lineinfile:
        path: foo
        create: true
        line: some content here
"""

    FAIL_MISSING_PERMISSIONS_GET_URL = """
---
- hosts: all
  tasks:
    - name: Permissions missing
      # noqa: fqcn-builtins
      get_url:
        url: http://foo
        dest: foo
"""

    FAIL_LINEINFILE_CREATE = """
- hosts: all
  tasks:
    - name: Lineinfile when create is true
      ansible.builtin.lineinfile:
        path: foo
        create: true
        line: some content here
"""

    FAIL_REPLACE_PRESERVE = """
- hosts: all
  tasks:
    - name: Replace does not allow preserve mode
      replace:
        path: foo
        mode: preserve
"""

    FAIL_PERMISSION_COMMENT = """
- hosts: all
  tasks:
    - name: Permissions is only a comment
      file:
        path: foo
        owner: root
        group: root
        state: directory
        # mode: 0755
"""

    FAIL_INI_PERMISSION = """
- hosts: all
  tasks:
    - name: Permissions needed if create is used
      ini_file:
        path: foo
        create: true
"""

    FAIL_INI_PRESERVE = """
- hosts: all
  tasks:
    - name: Ini_file does not accept preserve mode
      ini_file:
        path: foo
        create: true
        mode: preserve
"""

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_success_permissions_present(rule_runner: RunFromText) -> None:
        """Permissions present and numeric."""
        results = rule_runner.run_playbook(SUCCESS_PERMISSIONS_PRESENT)
        assert len(results) == 0

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_success_permissions_present_get_url(rule_runner: RunFromText) -> None:
        """Permissions present and numeric for get_url."""
        results = rule_runner.run_playbook(SUCCESS_PERMISSIONS_PRESENT_GET_URL)
        assert len(results) == 0

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_success_absent_state(rule_runner: RunFromText) -> None:
        """No permissions required if file is absent."""
        results = rule_runner.run_playbook(SUCCESS_ABSENT_STATE)
        assert len(results) == 0

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_success_default_state(rule_runner: RunFromText) -> None:
        """No permissions required if default state."""
        results = rule_runner.run_playbook(SUCCESS_DEFAULT_STATE)
        assert len(results) == 0

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_success_link_state(rule_runner: RunFromText) -> None:
        """No permissions required if it is a link."""
        results = rule_runner.run_playbook(SUCCESS_LINK_STATE)
        assert len(results) == 0

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_success_create_false(rule_runner: RunFromText) -> None:
        """No permissions required if file is not created."""
        results = rule_runner.run_playbook(SUCCESS_CREATE_FALSE)
        assert len(results) == 0

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_success_replace(rule_runner: RunFromText) -> None:
        """Replacing a file do not require mode."""
        results = rule_runner.run_playbook(SUCCESS_REPLACE)
        assert len(results) == 0

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_success_recurse(rule_runner: RunFromText) -> None:
        """Do not require mode when recursing."""
        results = rule_runner.run_playbook(SUCCESS_RECURSE)
        assert len(results) == 0

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_fail_preserve_mode(rule_runner: RunFromText) -> None:
        """File does not allow preserve value for mode."""
        results = rule_runner.run_playbook(FAIL_PRESERVE_MODE)
        assert len(results) == 1

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_fail_missing_permissions_touch(rule_runner: RunFromText) -> None:
        """Missing permissions when possibly creating file."""
        results = rule_runner.run_playbook(FAIL_MISSING_PERMISSIONS_TOUCH)
        assert len(results) == 2

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_fail_missing_permissions_directory(rule_runner: RunFromText) -> None:
        """Missing permissions when possibly creating a directory."""
        results = rule_runner.run_playbook(FAIL_MISSING_PERMISSIONS_DIRECTORY)
        assert len(results) == 2

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_fail_missing_permissions_get_url(rule_runner: RunFromText) -> None:
        """Missing permissions with get_url module."""
        results = rule_runner.run_playbook(FAIL_MISSING_PERMISSIONS_GET_URL)
        assert len(results) == 1

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_fail_lineinfile_create(rule_runner: RunFromText) -> None:
        """Lineinfile might create a file."""
        results = rule_runner.run_playbook(FAIL_LINEINFILE_CREATE)
        assert len(results) == 1

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_fail_replace_preserve(rule_runner: RunFromText) -> None:
        """Replace does not allow preserve mode."""
        results = rule_runner.run_playbook(FAIL_REPLACE_PRESERVE)
        assert len(results) == 1

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_fail_permission_comment(rule_runner: RunFromText) -> None:
        """Permissions is only a comment."""
        results = rule_runner.run_playbook(FAIL_PERMISSION_COMMENT)
        assert len(results) == 1

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_fail_ini_permission(rule_runner: RunFromText) -> None:
        """Permissions needed if create is used."""
        results = rule_runner.run_playbook(FAIL_INI_PERMISSION)
        assert len(results) == 1

    @pytest.mark.parametrize(
        "rule_runner", (MissingFilePermissionsRule,), indirect=["rule_runner"]
    )
    def test_fail_ini_preserve(rule_runner: RunFromText) -> None:
        """The ini_file module does not accept preserve mode."""
        results = rule_runner.run_playbook(FAIL_INI_PRESERVE)
        assert len(results) == 1