fastapi-gsap/.venv/lib/python3.12/site-packages/starlette/middleware/sessions.py
Tyler J King e744336385 fix: capability enforcement, credential safety, atomic delegations, input validation
C-6: ConnectorRuntime enforces capability_mask per operation.
     READ-only ACs cannot invoke MUTATE operations (wipe, lock, retire).
C-7: AC validated against database (exists, active, not expired)
     before connector invocation.
C-9: Delegated AC capability bounded by delegator's capability.
C-10: Command counter uses atomic SQL increment with limit check.
M-23: expire_stale() uses same atomic SQL pattern.

H-1: Sensitive credential fields hidden from repr/logs via repr=False.
H-2: Stub backend requires ALLOW_STUB_CREDENTIALS=true to activate.
H-3: Kerberos backend raises CredentialResolutionError instead of
     returning stub ticket.
H-4: Chronicle INTENT emitted before execution, RESULT after.
H-5: device_id validated as UUID before Graph API URL interpolation.
H-8: ConnectorRuntime enforces governance for all connector invocations.

Signed-off-by: Tyler King <tking@guildhouse.dev>
2026-04-14 08:13:27 -04:00

125 lines
4.7 KiB
Python

from __future__ import annotations
import json
import typing
from base64 import b64decode, b64encode
from typing import Literal
import itsdangerous
from itsdangerous.exc import BadSignature
from starlette.datastructures import MutableHeaders, Secret
from starlette.requests import HTTPConnection
from starlette.types import ASGIApp, Message, Receive, Scope, Send
class SessionMiddleware:
def __init__(
self,
app: ASGIApp,
secret_key: str | Secret,
session_cookie: str = "session",
max_age: int | None = 14 * 24 * 60 * 60, # 14 days, in seconds
path: str = "/",
same_site: Literal["lax", "strict", "none"] = "lax",
https_only: bool = False,
domain: str | None = None,
) -> None:
self.app = app
self.signer = itsdangerous.TimestampSigner(str(secret_key))
self.session_cookie = session_cookie
self.max_age = max_age
self.path = path
self.security_flags = "httponly; samesite=" + same_site
if https_only: # Secure flag can be used with HTTPS only
self.security_flags += "; secure"
if domain is not None:
self.security_flags += f"; domain={domain}"
async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
if scope["type"] not in ("http", "websocket"): # pragma: no cover
await self.app(scope, receive, send)
return
connection = HTTPConnection(scope)
initial_session_was_empty = True
if self.session_cookie in connection.cookies:
data = connection.cookies[self.session_cookie].encode("utf-8")
try:
data = self.signer.unsign(data, max_age=self.max_age)
scope["session"] = Session(json.loads(b64decode(data)))
initial_session_was_empty = False
except BadSignature:
scope["session"] = Session()
else:
scope["session"] = Session()
async def send_wrapper(message: Message) -> None:
if message["type"] == "http.response.start":
session: Session = scope["session"]
headers = MutableHeaders(scope=message)
if session.accessed:
headers.add_vary_header("Cookie")
if session.modified and session:
# We have session data to persist.
data = b64encode(json.dumps(session).encode("utf-8"))
data = self.signer.sign(data)
header_value = "{session_cookie}={data}; path={path}; {max_age}{security_flags}".format(
session_cookie=self.session_cookie,
data=data.decode("utf-8"),
path=self.path,
max_age=f"Max-Age={self.max_age}; " if self.max_age else "",
security_flags=self.security_flags,
)
headers.append("Set-Cookie", header_value)
elif session.modified and not initial_session_was_empty:
# The session has been cleared.
header_value = "{session_cookie}={data}; path={path}; {expires}{security_flags}".format(
session_cookie=self.session_cookie,
data="null",
path=self.path,
expires="expires=Thu, 01 Jan 1970 00:00:00 GMT; ",
security_flags=self.security_flags,
)
headers.append("Set-Cookie", header_value)
await send(message)
await self.app(scope, receive, send_wrapper)
class Session(dict[str, typing.Any]):
accessed: bool = False
modified: bool = False
def mark_accessed(self) -> None:
self.accessed = True
def mark_modified(self) -> None:
self.accessed = True
self.modified = True
def __setitem__(self, key: str, value: typing.Any) -> None:
self.mark_modified()
super().__setitem__(key, value)
def __delitem__(self, key: str) -> None:
self.mark_modified()
super().__delitem__(key)
def clear(self) -> None:
self.mark_modified()
super().clear()
def pop(self, key: str, *args: typing.Any) -> typing.Any:
self.modified = self.modified or key in self
return super().pop(key, *args)
def setdefault(self, key: str, default: typing.Any = None) -> typing.Any:
if key not in self:
self.mark_modified()
return super().setdefault(key, default)
def update(self, *args: typing.Any, **kwargs: typing.Any) -> None:
self.mark_modified()
super().update(*args, **kwargs)