fix: do not echo setting values in configuration errors; test: stdio and config redaction

src/aegis_gitea_mcp/config.py

@@ -336,10 +336,11 @@ class Settings(BaseSettings):
         """Accept only granular Gitea scopes (unknown scopes make Gitea grant full access)."""
         unknown = sorted({scope for scope in value if scope not in GITEA_SCOPES})
         if unknown:
+            # The offending values are not echoed: a misplaced secret must not reach stderr.
             raise ValueError(
-                f"OAUTH_SCOPES contains unknown scope(s): {', '.join(unknown)}. "
-                "Gitea grants full access for unknown scopes, so only granular "
-                "read:/write: scopes are accepted"
+                f"OAUTH_SCOPES contains {len(unknown)} unknown scope(s). Gitea grants full "
+                "access for unknown scopes, so only granular read:/write: scopes are accepted "
+                f"({', '.join(sorted(GITEA_SCOPES))})"
             )
         if not value:
             raise ValueError("OAUTH_SCOPES must not be empty")
@@ -365,9 +366,7 @@ class Settings(BaseSettings):
         unknown = sorted({item for item in lowered if item != "all" and item not in TOOL_DOMAINS})
         if unknown:
             allowed = ", ".join(sorted(TOOL_DOMAINS | {"all"}))
-            raise ValueError(
-                f"TOOLSETS contains unknown domain(s): {', '.join(unknown)}; use {allowed}"
-            )
+            raise ValueError(f"TOOLSETS contains {len(unknown)} unknown domain(s); use {allowed}")
         if not lowered:
             raise ValueError("TOOLSETS must not be empty (use 'all')")
         return list(dict.fromkeys(lowered))

tests/security/test_redaction.py

@@ -304,3 +304,85 @@ def test_secrets_in_object_keys_are_masked_like_values() -> None:
     assert token not in json.dumps(masked) and token not in json.dumps(blocked)
     assert masked["outer"][0]["plain"] != token
     assert blocked != nested
+
+
+# Configuration errors and a real stdio process
+
+
+@pytest.mark.parametrize(
+    ("variable", "value"),
+    [
+        ("GITEA_URL", "https://user:" + GITEA_TOKEN + "@gitea.example.com"),
+        ("GITEA_URL", "https://gitea.example.com?token=" + GITEA_TOKEN),
+        ("MCP_BEARER_TOKEN", "short-" + "x" * 5),
+        ("PUBLIC_BASE_URL", "http://mcp.example.com/" + GITEA_TOKEN),
+        ("OAUTH_SCOPES", GITEA_TOKEN),
+        ("TOKEN_ENCRYPTION_KEY", "tooshort-" + ENCRYPTION_KEY[:5]),
+        ("MCP_PORT", GITEA_TOKEN),
+        ("MCP_PATH", GITEA_TOKEN),
+        ("FORWARDED_ALLOW_IPS", GITEA_TOKEN),
+        ("LOG_LEVEL", GITEA_TOKEN),
+    ],
+)
+def test_configuration_errors_name_the_setting_but_never_echo_its_value(
+    variable: str,
+    value: str,
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    from aegis_gitea_mcp import cli
+    from aegis_gitea_mcp.cli import main
+
+    monkeypatch.setenv("GITEA_URL", "https://gitea.example.com")
+    monkeypatch.setenv("GITEA_TOKEN", GITEA_TOKEN)
+    monkeypatch.setenv(variable, value)
+    monkeypatch.setattr(cli, "configure_logging", lambda level: None)
+
+    assert main(["serve", "--transport", "http"]) == 2
+
+    err = capsys.readouterr().err
+    assert variable in err
+    assert value not in err and GITEA_TOKEN not in err
+    assert "Traceback" not in err
+
+
+async def test_a_real_stdio_process_keeps_every_secret_out_of_stdout_stderr_and_the_audit_file(
+    tmp_path: Any,
+) -> None:
+    import sys
+
+    from mcp import Client
+    from mcp.client.stdio import StdioServerParameters, stdio_client
+
+    secrets = [GITEA_TOKEN, BEARER_TOKEN, APP_CLIENT_SECRET, ENCRYPTION_KEY]
+    env = {
+        "GITEA_URL": "http://127.0.0.1:9",  # nothing listens: every call fails
+        "GITEA_TOKEN": GITEA_TOKEN,
+        "MCP_BEARER_TOKEN": BEARER_TOKEN,
+        "GITEA_OAUTH_CLIENT_SECRET": APP_CLIENT_SECRET,
+        "TOKEN_ENCRYPTION_KEY": ENCRYPTION_KEY,
+        "DATA_DIR": str(tmp_path / "state"),
+        "AUDIT_LOG_PATH": str(tmp_path / "state" / "audit.log"),
+        "REQUEST_TIMEOUT_SECONDS": "2",
+        "LOG_LEVEL": "DEBUG",
+    }
+    params = StdioServerParameters(
+        command=sys.executable,
+        args=["-m", "aegis_gitea_mcp.cli", "serve", "--transport", "stdio"],
+        env=env,
+        cwd=str(tmp_path),
+    )
+    stderr_path = tmp_path / "stderr.log"
+    with stderr_path.open("w", encoding="utf-8") as errlog:
+        async with Client(stdio_client(params, errlog=errlog)) as client:
+            results = [
+                await client.call_tool("gitea_repo_get", {"owner": "o", "repo": "r"}),
+                await client.call_tool("gitea_repo_get", {"owner": 5}),
+                await client.call_tool("gitea_api_request", {"method": "GET", "path": "/user"}),
+            ]
+
+    for result in results:
+        assert result.is_error
+        assert_clean(result.content[0].text, secrets)  # type: ignore[union-attr]
+    assert_clean(stderr_path.read_text(encoding="utf-8"), secrets)
+    assert_clean((tmp_path / "state" / "audit.log").read_text(encoding="utf-8"), secrets)