Validate policy yaml with unittest and pydantic

This commit is contained in:
2026-09-27 17:55:44 +10:00
parent 733d1211b4
commit b944c61e7e
6 changed files with 142 additions and 125 deletions
+6 -5
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@@ -24,9 +24,10 @@ repos:
]
- repo: local
hooks:
- id: policy-path-scope
name: policy rule paths stay within their own directory
entry: python3 scripts/check_policy_paths.py
- id: vault-yaml-tests
name: vault yaml definitions pass their unit tests
entry: python3 -m unittest discover -s tests -t .
language: python
additional_dependencies: [pyyaml]
files: ^policies/.*\.yaml$
additional_dependencies: [pyyaml, pydantic]
pass_filenames: false
always_run: true
+3 -3
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@@ -1,4 +1,4 @@
.PHONY: init plan apply format check-policies
.PHONY: init plan apply format test
VAULT_AUTH_METHOD ?= approle
VAULT_K8S_ROLE ?= woodpecker_terraform_vault
@@ -28,8 +28,8 @@ apply: init
@$(call vault_env) && \
terragrunt run --all --parallelism 2 --non-interactive apply
check-policies:
@python3 scripts/check_policy_paths.py
test:
@uv run --with pyyaml --with pydantic python -m unittest discover -s tests -t .
format:
@echo "Formatting OpenTofu files..."
-61
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@@ -1,61 +0,0 @@
#!/usr/bin/env python3
"""Fail when a rule path in policies/**/*.yaml grants outside the policy's own directory."""
import glob
import sys
from pathlib import PurePosixPath
import yaml
# kv-v2 inserts one of these directly after the mount; it is not part of the scope.
KV_API_SEGMENTS = {"data", "metadata", "delete", "undelete", "destroy"}
ALLOWED = {
("policies/global-root.yaml", "*"), # root policy
("policies/gpg/admin.yaml", "sys/plugins/catalog/secret/vault-plugin-secrets-gpg"), # plugin catalog registration
("policies/kv/service/terraform/authentik.yaml", "kv/data/kubernetes/namespace/+/default/oauth-credentials"), # terraform writes k8s namespace secrets
("policies/kv/service/terraform/authentik.yaml", "kv/data/kubernetes/namespace/logging/default/vlogs-oauth-credentials"), # terraform writes k8s namespace secrets
("policies/kv/service/terraform/enc-encapi-environment.yaml", "kv/data/kubernetes/namespace/encapi/default/environment"), # terraform writes k8s namespace secrets
("policies/kv/service/terraform/rancher.yaml", "kv/data/kubernetes/namespace/cattle-system/default/oauth-credentials"), # terraform writes k8s namespace secrets
("policies/identity/group/admin.yaml", "identity/group-alias"), # group-alias endpoint for the same groups
("policies/identity/group/admin.yaml", "identity/group-alias/*"), # group-alias endpoint for the same groups
("policies/identity/group/admin.yaml", "identity/lookup/group"), # group lookup endpoint
("policies/sys/policy/admin.yaml", "sys/policies/acl"), # dir is policy, API path is policies
("policies/sys/policy/admin.yaml", "sys/policies/acl/*"), # dir is policy, API path is policies
("policies/sys/mounts/admin.yaml", "sys/mounts-tune/*"), # sibling API path of the mounts endpoint
}
def policy_scope(path):
parts = PurePosixPath(path).parts
rel = PurePosixPath(*parts[parts.index("policies") + 1:])
# a policy at the policies/ root has no directory, so its own name is the scope
return "policies" / rel, rel.parent if rel.parent.parts else PurePosixPath(rel.stem)
def rule_scope(rule_path):
path = PurePosixPath(rule_path)
if len(path.parts) > 1 and path.parts[1] in KV_API_SEGMENTS:
return PurePosixPath(path.parts[0], *path.parts[2:])
return path
def violations(files):
for f in files:
key, scope = policy_scope(f)
rules = (yaml.safe_load(open(f)) or {}).get("rules")
if not rules:
yield f"{f}: no rules"
continue
for rule in rules:
path = rule.get("path")
if not path:
yield f"{f}: rule without a path"
elif (str(key), path) not in ALLOWED and not rule_scope(path).is_relative_to(scope):
yield f'{f}: rule path "{path}" escapes policy scope "{scope}"'
if __name__ == "__main__":
found = list(violations(sys.argv[1:] or sorted(glob.glob("policies/**/*.yaml", recursive=True))))
for v in found:
print(v)
sys.exit(1 if found else 0)
-56
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@@ -1,56 +0,0 @@
#!/usr/bin/env python3
"""Run with: python3 scripts/test_check_policy_paths.py"""
import sys
import tempfile
from pathlib import Path
sys.path.insert(0, str(Path(__file__).parent))
from check_policy_paths import violations
TMP = Path(tempfile.mkdtemp())
def check(rel, *rule_paths):
f = TMP / rel
f.parent.mkdir(parents=True, exist_ok=True)
f.write_text("rules:\n" + "".join(f' - path: "{p}"\n' for p in rule_paths))
return [v.replace(f"{TMP}/", "") for v in violations([str(f)])]
# in scope, including kv-v2 data/metadata segments and any kv-v2 mount
assert check("policies/sys/mounts/admin.yaml", "sys/mounts", "sys/mounts/*") == []
assert check("policies/rundeck/rundeck.yaml", "rundeck/data/*", "rundeck/metadata/*") == []
assert check("policies/kv/service/authentik/oidc-vault/read.yaml", "kv/data/service/authentik/oidc-vault") == []
# + and * below the directory are fine
assert check("policies/kv/service/vault/read.yaml", "kv/data/service/vault/+/+/auth_backend/*") == []
assert check("policies/kubernetes/au/admin.yaml", "kubernetes/au/+/config") == []
# + standing in for a literal directory segment is not
assert check("policies/kv/service/vault/au/syd1/ghp/write.yaml", "kv/data/service/vault/+/+/ghp/config") == [
'policies/kv/service/vault/au/syd1/ghp/write.yaml: rule path '
'"kv/data/service/vault/+/+/ghp/config" escapes policy scope "kv/service/vault/au/syd1/ghp"'
]
# a sibling API path is not a prefix match
assert check("policies/sys/thing/admin.yaml", "sys/thing-tune/*") == [
'policies/sys/thing/admin.yaml: rule path "sys/thing-tune/*" escapes policy scope "sys/thing"'
]
# out of tree entirely
assert check("policies/kv/foo/bar/baz.yaml", "kv/data/foo/baz/bar") == [
'policies/kv/foo/bar/baz.yaml: rule path "kv/data/foo/baz/bar" escapes policy scope "kv/foo/bar"'
]
# allowlisted outliers pass
assert check("policies/global-root.yaml", "*") == []
assert check("policies/sys/policy/admin.yaml", "sys/policies/acl", "sys/policies/acl/*") == []
assert check("policies/sys/mounts/admin.yaml", "sys/mounts-tune/*") == []
# malformed policies fail
(TMP / "policies/empty.yaml").write_text("auth:\n approle:\n - x\n")
assert list(violations([str(TMP / "policies/empty.yaml")]))[0].endswith(": no rules")
(TMP / "policies/nopath.yaml").write_text("rules:\n - capabilities:\n - read\n")
assert list(violations([str(TMP / "policies/nopath.yaml")]))[0].endswith(": rule without a path")
print("ok")
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+133
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@@ -0,0 +1,133 @@
"""Validate the Vault policy definitions under policies/."""
import unittest
from pathlib import Path, PurePosixPath
from typing import Literal
import yaml
from pydantic import BaseModel, ConfigDict, Field, ValidationError
REPO_ROOT = Path(__file__).resolve().parent.parent
# kv-v2 inserts one of these directly after the mount; it is not part of the scope.
KV_API_SEGMENTS = {"data", "metadata", "delete", "undelete", "destroy"}
ALLOWED = {
("policies/global-root.yaml", "*"), # root policy
("policies/gpg/admin.yaml", "sys/plugins/catalog/secret/vault-plugin-secrets-gpg"), # plugin catalog registration
("policies/kv/service/terraform/authentik.yaml", "kv/data/kubernetes/namespace/+/default/oauth-credentials"), # terraform writes k8s namespace secrets
("policies/kv/service/terraform/authentik.yaml", "kv/data/kubernetes/namespace/logging/default/vlogs-oauth-credentials"), # terraform writes k8s namespace secrets
("policies/kv/service/terraform/enc-encapi-environment.yaml", "kv/data/kubernetes/namespace/encapi/default/environment"), # terraform writes k8s namespace secrets
("policies/kv/service/terraform/rancher.yaml", "kv/data/kubernetes/namespace/cattle-system/default/oauth-credentials"), # terraform writes k8s namespace secrets
("policies/identity/group/admin.yaml", "identity/group-alias"), # group-alias endpoint for the same groups
("policies/identity/group/admin.yaml", "identity/group-alias/*"), # group-alias endpoint for the same groups
("policies/identity/group/admin.yaml", "identity/lookup/group"), # group lookup endpoint
("policies/sys/policy/admin.yaml", "sys/policies/acl"), # dir is policy, API path is policies
("policies/sys/policy/admin.yaml", "sys/policies/acl/*"), # dir is policy, API path is policies
("policies/sys/mounts/admin.yaml", "sys/mounts-tune/*"), # sibling API path of the mounts endpoint
}
class Rule(BaseModel):
model_config = ConfigDict(extra="forbid")
path: str = Field(min_length=1)
capabilities: list[
Literal["create", "read", "update", "patch", "delete", "list", "sudo", "deny"]
] = Field(min_length=1)
class Policy(BaseModel):
model_config = ConfigDict(extra="forbid")
rules: list[Rule] = Field(min_length=1)
auth: dict[str, list[str]]
def policy_files():
return sorted(REPO_ROOT.glob("policies/**/*.yaml"))
def escaping_scope(policy_file, rule_path):
"""The policy directory a rule path reaches outside of, or None when in scope."""
if (policy_file, rule_path) in ALLOWED:
return None
parts = PurePosixPath(policy_file).parts
below_policies = PurePosixPath(*parts[parts.index("policies") + 1:])
# a policy at the policies/ root has no directory, so its own name is the scope
scope = below_policies.parent if below_policies.parent.parts else PurePosixPath(below_policies.stem)
path = PurePosixPath(rule_path)
if len(path.parts) > 1 and path.parts[1] in KV_API_SEGMENTS:
path = PurePosixPath(path.parts[0], *path.parts[2:])
return None if path.is_relative_to(scope) else str(scope)
class PolicyFileTests(unittest.TestCase):
def setUp(self):
self.files = policy_files()
self.assertTrue(self.files, f"no policy files discovered under {REPO_ROOT}/policies")
def test_schema(self):
for f in self.files:
with self.subTest(path=f.relative_to(REPO_ROOT).as_posix()):
Policy.model_validate(yaml.safe_load(f.read_text()))
def test_paths(self):
for f in self.files:
rel = f.relative_to(REPO_ROOT).as_posix()
for rule in yaml.safe_load(f.read_text()).get("rules") or []:
rule_path = rule.get("path")
with self.subTest(path=rel, rule=rule_path):
self.assertIsNotNone(rule_path, "rule has no path")
scope = escaping_scope(rel, rule_path)
self.assertIsNone(scope, f'rule path "{rule_path}" escapes policy scope "{scope}"')
class RuleScopeTests(unittest.TestCase):
"""The scope rule against fixtures, so a clean tree cannot hide a broken check."""
def test_in_scope(self):
for policy_file, rule_path in [
("policies/sys/mounts/admin.yaml", "sys/mounts"),
("policies/sys/mounts/admin.yaml", "sys/mounts/*"),
("policies/rundeck/rundeck.yaml", "rundeck/data/*"),
("policies/rundeck/rundeck.yaml", "rundeck/metadata/*"),
("policies/kv/service/authentik/oidc-vault/read.yaml", "kv/data/service/authentik/oidc-vault"),
("policies/kv/service/vault/read.yaml", "kv/data/service/vault/+/+/auth_backend/*"),
("policies/kubernetes/au/admin.yaml", "kubernetes/au/+/config"),
]:
with self.subTest(policy=policy_file, rule=rule_path):
self.assertIsNone(escaping_scope(policy_file, rule_path))
def test_escapes(self):
for policy_file, rule_path, scope in [
("policies/sys/thing/admin.yaml", "sys/thing-tune/*", "sys/thing"),
("policies/kv/foo/bar/baz.yaml", "kv/data/foo/baz/bar", "kv/foo/bar"),
("policies/kv/service/vault/au/syd1/ghp/w.yaml", "kv/data/service/vault/+/+/ghp/config", "kv/service/vault/au/syd1/ghp"),
]:
with self.subTest(policy=policy_file, rule=rule_path):
self.assertEqual(escaping_scope(policy_file, rule_path), scope)
def test_allowlisted(self):
for policy_file, rule_path in [
("policies/global-root.yaml", "*"),
("policies/sys/policy/admin.yaml", "sys/policies/acl"),
("policies/sys/policy/admin.yaml", "sys/policies/acl/*"),
("policies/sys/mounts/admin.yaml", "sys/mounts-tune/*"),
]:
with self.subTest(policy=policy_file, rule=rule_path):
self.assertIsNone(escaping_scope(policy_file, rule_path))
def test_schema_rejects_malformed(self):
auth = {"approle": ["tf_vault"]}
rule = {"path": "kv/data/x", "capabilities": ["read"]}
for doc in [
{"auth": auth}, # no rules
{"rules": [], "auth": auth}, # empty rules
{"rules": [{"capabilities": ["read"]}], "auth": auth}, # rule without a path
{"rules": [{"path": "kv/data/x", "capabilities": []}], "auth": auth}, # rule without capabilities
{"rules": [{"path": "kv/data/x", "capabilities": ["write"]}], "auth": auth}, # not a Vault capability
{"rules": [rule]}, # no auth
{"rules": [rule], "auth": auth, "rulez": []}, # typo'd top-level key
]:
with self.subTest(doc=doc), self.assertRaises(ValidationError):
Policy.model_validate(doc)