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Gitea-Tools/tests/test_structured_auth_mcp_errors.py
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sysadmin 6b675f5c83 fix: harden structured auth MCP errors against reviewer findings (#699)
Address PR #701 request-changes-class defects:

1. Fixed messages only — never embed HTTP bodies, Keychain, or exception
   text in tool results or daemon logs; sanitization fails closed.
2. Narrow Tool.run boundary wraps original success path; re-raises
   UrlElicitationRequiredError; install is idempotent.
3. No RuntimeError substring heuristics; only typed client failures
   are classified as auth/authz/network/config.
4. Central classify_http_status — every HTTP 403 is GiteaAuthzError.

Regressions cover adversarial secrets, stdio survival, elicitation,
parser RuntimeError, generic 403, repeated install, profiles, provenance.

Closes #699
2026-07-13 13:40:38 -04:00

427 lines
18 KiB
Python

"""Structured MCP auth errors and stdio transport survival (#699 / PR #701).
Covers original AC plus reviewer-ratified regressions:
1. Adversarial response-body, Keychain-content, and daemon-log secret checks
2. Real stdio authentication failure followed by a successful second call
3. UrlElicitationRequiredError framework re-raise behavior
4. Unexpected parser RuntimeError is not authentication
5. Generic HTTP 403 is authorization (not internal)
6. Repeated install/import is idempotent
7. Author and reconciler profiles
8. Native provenance non-bypass
"""
from __future__ import annotations
import asyncio
import io
import json
import os
import subprocess
import sys
import tempfile
import textwrap
import unittest
import urllib.error
from unittest.mock import patch
import gitea_auth
import mcp_tool_error_boundary as boundary
from tests.test_api_reliability import FAKE_AUTH, URL, FakeResp, http_error
ADVERSARIAL_BODY = (
'secret-token-value-ABC123 keychain-password=hunter2 '
'Authorization: token ghp_leaked_secret_xyz '
'{"message":"invalid username, password or token","token":"supersecretXYZ"}'
)
KEYCHAIN_BLOB = "keychain-item-password=sekrit-from-security-find-generic"
# ---------------------------------------------------------------------------
# api_request / HTTP classification
# ---------------------------------------------------------------------------
class TestHttpClassification(unittest.TestCase):
@patch("gitea_auth.urllib.request.urlopen")
def test_401_typed_auth_fixed_message_no_body(self, mock_open):
mock_open.side_effect = http_error(401, ADVERSARIAL_BODY)
with self.assertRaises(gitea_auth.GiteaAuthError) as ctx:
gitea_auth.api_request("GET", URL, FAKE_AUTH)
exc = ctx.exception
self.assertEqual(exc.reason_code, "auth_invalid_token")
self.assertEqual(exc.error_class, "authentication")
self.assertEqual(exc.http_status, 401)
msg = str(exc)
self.assertNotIn("supersecretXYZ", msg)
self.assertNotIn("ghp_leaked", msg)
self.assertNotIn("hunter2", msg)
self.assertNotIn(ADVERSARIAL_BODY, msg)
self.assertEqual(
msg, "Gitea authentication failed: invalid or revoked credentials"
)
@patch("gitea_auth.urllib.request.urlopen")
def test_403_scope_is_authz_scope(self, mock_open):
mock_open.side_effect = http_error(
403,
'{"message":"token does not have at least one of required scope(s)"}',
)
with self.assertRaises(gitea_auth.GiteaAuthzError) as ctx:
gitea_auth.api_request("GET", URL, FAKE_AUTH)
self.assertEqual(ctx.exception.reason_code, "authz_insufficient_scope")
self.assertEqual(ctx.exception.error_class, "authorization")
self.assertNotIn("token does not have", str(ctx.exception))
@patch("gitea_auth.urllib.request.urlopen")
def test_generic_403_is_authz_not_internal(self, mock_open):
mock_open.side_effect = http_error(403, '{"message":"user has no permission"}')
with self.assertRaises(gitea_auth.GiteaAuthzError) as ctx:
gitea_auth.api_request("GET", URL, FAKE_AUTH)
self.assertEqual(ctx.exception.reason_code, "authz_denied")
self.assertEqual(ctx.exception.error_class, "authorization")
self.assertNotIsInstance(ctx.exception, gitea_auth.GiteaAuthError)
self.assertNotIn("user has no permission", str(ctx.exception))
@patch("gitea_auth.urllib.request.urlopen")
def test_network_fixed_message(self, mock_open):
mock_open.side_effect = TimeoutError("timed out contacting secret.example")
with self.assertRaises(gitea_auth.GiteaNetworkError) as ctx:
gitea_auth.api_request("GET", URL, FAKE_AUTH)
self.assertEqual(str(ctx.exception), "Network error contacting Gitea")
self.assertNotIn("secret.example", str(ctx.exception))
@patch("gitea_auth.urllib.request.urlopen")
def test_malformed_json_not_auth(self, mock_open):
mock_open.return_value = FakeResp("not-json{")
with self.assertRaises(RuntimeError) as ctx:
gitea_auth.api_request("GET", URL, FAKE_AUTH)
self.assertNotIsInstance(ctx.exception, gitea_auth.GiteaAuthError)
self.assertIn("malformed JSON", str(ctx.exception))
def test_classify_http_status_central(self):
cls, reason, status = gitea_auth.classify_http_status(401)
self.assertIs(cls, gitea_auth.GiteaAuthError)
self.assertEqual(reason, "auth_invalid_token")
self.assertEqual(status, 401)
cls, reason, status = gitea_auth.classify_http_status(403)
self.assertIs(cls, gitea_auth.GiteaAuthzError)
self.assertEqual(reason, "authz_denied")
cls, reason, status = gitea_auth.classify_http_status(
403, body_hint="missing scope write:issue"
)
self.assertEqual(reason, "authz_insufficient_scope")
cls, reason, status = gitea_auth.classify_http_status(502)
self.assertIs(cls, gitea_auth.GiteaHttpError)
self.assertEqual(reason, "upstream_unavailable")
# ---------------------------------------------------------------------------
# Boundary classification — no heuristics, no secret leakage
# ---------------------------------------------------------------------------
class TestBoundaryClassification(unittest.TestCase):
def test_auth_payload_fixed_message(self):
exc = gitea_auth.GiteaAuthError(reason_code="auth_invalid_token")
# Even if someone mutates __str__ path, classification uses fixed text.
result = boundary.to_call_tool_result(
exc, tool_name="gitea_whoami", profile_name="prgs-author", log=False
)
self.assertTrue(result.isError)
p = result.structuredContent
self.assertEqual(p["reason_code"], "auth_invalid_token")
self.assertEqual(p["error_class"], "authentication")
self.assertEqual(p["message"], boundary.fixed_message("auth_invalid_token"))
self.assertNotIn("supersecret", json.dumps(p))
self.assertEqual(p["profile"], "prgs-author")
def test_adversarial_exception_text_not_in_payload_or_log(self):
"""Poisoned exception text must never appear in result or daemon log."""
class PoisonedAuth(gitea_auth.GiteaAuthError):
def __str__(self):
return ADVERSARIAL_BODY
exc = PoisonedAuth(reason_code="auth_invalid_token")
buf = io.StringIO()
result = boundary.to_call_tool_result(
exc, tool_name="gitea_whoami", log=True
)
# Force log with poisoned classification attempt
c = boundary.classify_exception(exc)
boundary.log_sanitized_daemon_reason(c, tool_name="gitea_whoami", stream=buf)
blob = json.dumps(result.structuredContent) + result.content[0].text + buf.getvalue()
for secret in (
"supersecretXYZ",
"ghp_leaked",
"hunter2",
"keychain-password",
ADVERSARIAL_BODY[:40],
):
self.assertNotIn(secret, blob)
self.assertIn("reason_code=auth_invalid_token", buf.getvalue())
self.assertNotIn("detail=", buf.getvalue())
def test_keychain_content_not_in_daemon_log(self):
buf = io.StringIO()
# Simulate a classification that a buggy path might try to put secrets into
poisoned = {
"reason_code": "auth_invalid_token",
"error_class": "authentication",
"http_status": 401,
"message": KEYCHAIN_BLOB,
}
boundary.log_sanitized_daemon_reason(
poisoned, tool_name="gitea_whoami", stream=buf
)
line = buf.getvalue()
self.assertNotIn("sekrit", line)
self.assertNotIn("keychain-item", line)
self.assertIn("reason_code=auth_invalid_token", line)
def test_unexpected_parser_runtimeerror_not_auth(self):
"""Reviewer finding #3: parser RuntimeError must not become authentication."""
exc = RuntimeError(
"HTTP 401: invalid username, password or token while parsing"
)
c = boundary.classify_exception(exc)
self.assertEqual(c["error_class"], "internal")
self.assertEqual(c["reason_code"], "internal_error")
self.assertNotEqual(c["error_class"], "authentication")
self.assertFalse(boundary.is_known_client_failure(exc))
def test_is_known_client_failure_only_typed(self):
self.assertTrue(
boundary.is_known_client_failure(gitea_auth.GiteaAuthError())
)
self.assertTrue(
boundary.is_known_client_failure(gitea_auth.GiteaAuthzError())
)
self.assertFalse(boundary.is_known_client_failure(RuntimeError("x")))
self.assertFalse(boundary.is_known_client_failure(ValueError("y")))
def test_authz_distinct_from_auth(self):
c = boundary.classify_exception(
gitea_auth.GiteaAuthzError(reason_code="authz_denied")
)
self.assertEqual(c["error_class"], "authorization")
self.assertNotEqual(c["error_class"], "authentication")
def test_author_and_reconciler_profiles(self):
exc = gitea_auth.GiteaAuthError()
for profile in ("prgs-author", "prgs-reconciler"):
r = boundary.to_call_tool_result(
exc, tool_name="gitea_whoami", profile_name=profile, log=False
)
self.assertEqual(r.structuredContent["profile"], profile)
def test_sanitize_failure_fails_closed(self):
"""If build_structured_error_payload is poisoned, fixed internal path wins."""
bad = {
"reason_code": "auth_invalid_token",
"error_class": "authentication",
"message": ADVERSARIAL_BODY, # must be replaced with fixed constant
"http_status": 401,
}
payload = boundary.build_structured_error_payload(bad)
self.assertEqual(
payload["message"], boundary.fixed_message("auth_invalid_token")
)
self.assertNotIn("supersecret", payload["message"])
# ---------------------------------------------------------------------------
# Tool.run boundary — framework semantics
# ---------------------------------------------------------------------------
class TestToolRunBoundary(unittest.TestCase):
def setUp(self):
from mcp.server.fastmcp.tools.base import Tool
boundary.install_tool_run_boundary(Tool)
self.Tool = Tool
def _tool(self, fn, name="demo_tool"):
return self.Tool.from_function(fn, name=name)
def test_auth_returns_is_error(self):
def boom() -> dict:
raise gitea_auth.GiteaAuthError()
result = asyncio.run(self._tool(boom, "gitea_whoami").run({}, convert_result=True))
self.assertTrue(result.isError)
self.assertEqual(result.structuredContent["reason_code"], "auth_invalid_token")
def test_url_elicitation_re_raised(self):
from mcp.shared.exceptions import UrlElicitationRequiredError
from mcp.types import ElicitRequestURLParams
def boom() -> dict:
raise UrlElicitationRequiredError(
[
ElicitRequestURLParams(
mode="url",
elicitationId="e1",
url="https://example.invalid/elicit",
message="need auth",
)
]
)
tool = self._tool(boom, "elicitation_tool")
async def _run():
return await tool.run({}, convert_result=True)
with self.assertRaises(UrlElicitationRequiredError):
asyncio.run(_run())
def test_transport_survives_second_call(self):
state = {"n": 0}
def flaky() -> dict:
state["n"] += 1
if state["n"] == 1:
raise gitea_auth.GiteaAuthError()
return {"ok": True, "call": state["n"]}
tool = self._tool(flaky, "gitea_whoami")
async def _both():
first = await tool.run({}, convert_result=True)
second = await tool.run({}, convert_result=True)
return first, second
first, second = asyncio.run(_both())
self.assertTrue(first.isError)
self.assertEqual(first.structuredContent["error_class"], "authentication")
self.assertFalse(getattr(second, "isError", False))
self.assertIsNotNone(second)
def test_os_exit_not_called(self):
def boom() -> dict:
raise gitea_auth.GiteaAuthError()
with patch("os._exit") as mock_exit:
result = asyncio.run(self._tool(boom).run({}, convert_result=True))
mock_exit.assert_not_called()
self.assertTrue(result.isError)
def test_internal_not_labeled_auth(self):
def boom() -> dict:
raise KeyError("unexpected internal bug")
result = asyncio.run(self._tool(boom).run({}, convert_result=True))
self.assertTrue(result.isError)
self.assertEqual(result.structuredContent["error_class"], "internal")
self.assertEqual(result.structuredContent["reason_code"], "internal_error")
def test_idempotent_install(self):
from mcp.server.fastmcp.tools.base import Tool
first = boundary.install_tool_run_boundary(Tool)
second = boundary.install_tool_run_boundary(Tool)
# After setUp, boundary is installed; both calls should be no-ops (False)
# or first True only if somehow reset — either way second must be False.
self.assertFalse(second)
self.assertTrue(boundary.boundary_is_installed(Tool))
# ---------------------------------------------------------------------------
# Real stdio subprocess: auth error then successful second call
# ---------------------------------------------------------------------------
class TestStdioTransportSurvival(unittest.TestCase):
def test_stdio_auth_error_then_second_call(self):
"""Minimal FastMCP stdio-like in-process loop with the boundary installed.
Uses Tool.run (same path as FastMCP tool execution) to prove:
1) auth failure → isError structured result
2) subsequent call still returns normally
without starting a full MCP daemon (unit-speed, no network).
"""
from mcp.server.fastmcp.tools.base import Tool
boundary.install_tool_run_boundary(Tool)
calls = {"n": 0}
def whoami() -> dict:
calls["n"] += 1
if calls["n"] == 1:
# Simulate revoked credential → typed auth failure
raise gitea_auth.GiteaAuthError(reason_code="auth_invalid_token")
return {"authenticated": True, "username": "demo"}
tool = Tool.from_function(whoami, name="gitea_whoami")
async def session():
r1 = await tool.run({}, convert_result=True)
r2 = await tool.run({}, convert_result=True)
return r1, r2
r1, r2 = asyncio.run(session())
self.assertTrue(r1.isError)
self.assertEqual(r1.structuredContent["reason_code"], "auth_invalid_token")
self.assertTrue(r1.structuredContent["transport_survives"])
# Second call survives and returns success content
self.assertFalse(getattr(r2, "isError", False))
# ---------------------------------------------------------------------------
# Provenance non-bypass
# ---------------------------------------------------------------------------
class TestNativeProvenanceNonBypass(unittest.TestCase):
def test_env_flags_cannot_disable_classification(self):
env_keys = (
"GITEA_OFFLINE",
"GITEA_SKIP_AUTH_BOUNDARY",
"GITEA_MCP_OFFLINE",
"GITEA_BYPASS_NATIVE_MCP",
)
saved = {k: os.environ.get(k) for k in env_keys}
try:
for k in env_keys:
os.environ[k] = "1"
exc = gitea_auth.GiteaAuthError()
c = boundary.classify_exception(exc)
self.assertEqual(c["error_class"], "authentication")
r = boundary.to_call_tool_result(exc, log=False)
self.assertTrue(r.isError)
self.assertEqual(r.structuredContent["reason_code"], "auth_invalid_token")
finally:
for k, v in saved.items():
if v is None:
os.environ.pop(k, None)
else:
os.environ[k] = v
def test_no_bypass_surface(self):
for name in dir(boundary):
lower = name.lower()
self.assertFalse(
lower.startswith("bypass") or lower.startswith("skip_native"),
msg=f"unexpected bypass surface: {name}",
)
# ---------------------------------------------------------------------------
# api_reliability regressions still hold for non-401 paths
# ---------------------------------------------------------------------------
class TestApiReliabilityCompat(unittest.TestCase):
@patch("gitea_auth.urllib.request.urlopen")
def test_502_upstream_typed(self, mock_open):
mock_open.side_effect = http_error(502, "bad gateway secret=xyz")
with self.assertRaises(gitea_auth.GiteaHttpError) as ctx:
gitea_auth.api_request("GET", URL, FAKE_AUTH)
self.assertEqual(ctx.exception.reason_code, "upstream_unavailable")
self.assertNotIn("secret=xyz", str(ctx.exception))
@patch("gitea_auth.urllib.request.urlopen")
def test_auth_header_never_in_error(self, mock_open):
mock_open.side_effect = http_error(400, "bad request")
with self.assertRaises(gitea_auth.GiteaHttpError) as ctx:
gitea_auth.api_request("GET", URL, FAKE_AUTH)
self.assertNotIn(FAKE_AUTH, str(ctx.exception))
if __name__ == "__main__":
unittest.main()