tegwick
4ddb2f896c
lab/app.py (users, tenants, auth, resources, sharing, read/write, revoke, audit), lab/http_api.py (JSON API + browser UI, stdlib only), 20 labelled composable version-stamped mutations, ground-truth matrix. 48 tests pass. Detection against the reference scenario: MECHANICAL 0/10 flagged (correct), DEFECT 6/6, SEMANTIC 2/4 with both inert cases declared. - F-0002: M16 and M18 initially escaped detection entirely. A use case protects exactly what it asserts. Resolved by adding two claims already stated as intent in INTENT.md; the six-mutation catalogue would never have surfaced this. - test-id axis added: stable selectors survive most UI mutations, which would make H-001 trivially false. Mutations now vary on preserves_test_ids so the hypothesis is analysed split by that axis rather than rigged. - M12 (semantic deferred revoke) and M19 (defect race) are behaviourally identical and asserted as such - the discrimination problem as a test. lab/minimal.py removed; superseded by lab/app.py. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Assistant: claude-code Assistant-Model: opus Assistant-Process: 1629012@bnt-lap001 Assistant-Session: 78d4fb13-8a1e-474b-87a3-9b9261c49a39
309 lines
12 KiB
Python
309 lines
12 KiB
Python
"""The test-driver lab — the system under test.
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Grown from the T04 seed (`lab/minimal.py`, now removed). Users belong to
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tenants, own resources, share them with READ or WRITE permission, and revoke
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that sharing. Every state change is audited.
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Two access paths exist, and the distinction is the whole point:
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* the **enforcement path** (`request`) is what an actor uses. It checks
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authorization and can therefore be *wrong* — that is where a seeded
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authorization defect lives.
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* the **observation channel** (`ObservationChannel`) reads stored state directly
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and probes enforcement out-of-band. It is the independent channel required by
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decision D-07.
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An oracle consulting only stored state would verify test-driver's own
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reimplementation of the rules rather than the system's enforcement of them. An
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oracle consulting only enforcement could not notice that record and enforcement
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disagree. test-driver observes both and treats disagreement as meaningful in
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itself — that disagreement is the precise signature of an authorization defect
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which leaves the audit trail looking correct.
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Mutations are applied by `lab.mutations.build_lab`, never by editing this file.
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"""
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from __future__ import annotations
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import time
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from dataclasses import dataclass, field
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from typing import Any, Callable, Literal
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Permission = Literal["READ", "WRITE"]
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BASE_VERSION = "lab-0.2.0"
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class Denied(Exception):
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"""The enforcement path refused the request."""
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def __init__(self, reason: str, status: int = 403) -> None:
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super().__init__(reason)
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self.status = status
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@dataclass(slots=True)
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class AuditRecord:
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sequence: int
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event: str
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actor_id: str
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resource_id: str | None = None
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subject_id: str | None = None
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permission: str | None = None
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@dataclass(slots=True)
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class User:
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id: str
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tenant_id: str
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token: str
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@dataclass(slots=True)
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class LabApp:
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"""In-process resource-sharing service.
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Mutation hooks are plain attributes holding callables or flags. A mutation
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replaces one, so that every mutated build differs from baseline in exactly
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one named way and the difference is inspectable at runtime.
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"""
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version: str = f"{BASE_VERSION}-baseline"
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applied_mutations: tuple[str, ...] = ()
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users: dict[str, User] = field(default_factory=dict)
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_tokens: dict[str, str] = field(default_factory=dict)
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resources: dict[str, dict[str, Any]] = field(default_factory=dict)
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grants: dict[tuple[str, str], Permission] = field(default_factory=dict)
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audit: list[AuditRecord] = field(default_factory=list)
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_seq: int = 0
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# --- mutation hooks (baseline behaviour) ----------------------------
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may_read: Callable[["LabApp", str, str], bool] | None = None
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grant_permission_for: Callable[[str | None], Permission] | None = None
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audit_revoke: bool = True
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revoke_delay_seconds: float = 0.0
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denied_status: int = 403
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require_share_acceptance: bool = False
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enforce_tenant_isolation: bool = True
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response_id_field: str = "resource_id"
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latency_seconds: float = 0.0
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# --- presentation hooks (surface only; never affect domain semantics) ---
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ui_share_control: str = "inline"
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ui_dom_style: str = "flat"
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ui_labels: str = "plain"
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ui_field_order: str = "natural"
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ui_button_element: str = "button"
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ui_test_ids: str = "stable"
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ui_confirm_revoke: bool = False
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api_path_style: str = "long"
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tenant_sharing_announced: bool = False
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# -- setup -----------------------------------------------------------
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def add_user(self, user_id: str, tenant_id: str = "t-acme") -> str:
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token = f"tok-{user_id}"
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self.users[user_id] = User(user_id, tenant_id, token)
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self._tokens[token] = user_id
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return token
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def _audit(self, event: str, actor_id: str, **kw: Any) -> None:
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self._seq += 1
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self.audit.append(AuditRecord(self._seq, event, actor_id, **kw))
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def _whoami(self, token: str) -> str:
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if token not in self._tokens:
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raise Denied("unknown token", status=401)
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return self._tokens[token]
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def tenant_of(self, user_id: str) -> str | None:
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user = self.users.get(user_id)
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return user.tenant_id if user else None
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# -- enforcement path (what actors use) ------------------------------
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def request(self, token: str, op: str, **args: Any) -> Any:
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"""The single entry point actors go through. Authorization is enforced here."""
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if self.latency_seconds:
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time.sleep(self.latency_seconds)
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user_id = self._whoami(token)
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handler = getattr(self, f"_op_{op}", None)
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if handler is None:
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raise Denied(f"unknown operation {op!r}", status=404)
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return handler(user_id, **args)
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def _op_create_resource(self, user_id: str, resource_id: str, content: str) -> dict:
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self.resources[resource_id] = {"owner": user_id, "content": content}
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self._audit("create", user_id, resource_id=resource_id)
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return {self.response_id_field: resource_id}
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def _op_read_resource(self, user_id: str, resource_id: str) -> dict:
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resource = self.resources.get(resource_id)
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if resource is None:
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raise Denied("no such resource", status=404)
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if not self._may_read(user_id, resource_id):
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raise Denied("not authorized to read", status=self.denied_status)
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return {self.response_id_field: resource_id, "content": resource["content"]}
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def _op_write_resource(self, user_id: str, resource_id: str, content: str) -> dict:
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resource = self.resources.get(resource_id)
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if resource is None:
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raise Denied("no such resource", status=404)
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if not self._may_write(user_id, resource_id):
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raise Denied("not authorized to write", status=self.denied_status)
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resource["content"] = content
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self._audit("write", user_id, resource_id=resource_id)
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return {"written": True}
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def _op_grant(
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self,
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user_id: str,
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resource_id: str,
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subject_id: str,
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permission: Permission | None = None,
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) -> dict:
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resource = self.resources.get(resource_id)
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if resource is None or resource["owner"] != user_id:
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raise Denied("only the owner may grant")
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if self.enforce_tenant_isolation:
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if self.tenant_of(subject_id) != self.tenant_of(user_id):
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raise Denied("cross-tenant sharing is not permitted")
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effective = (
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self.grant_permission_for(permission)
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if self.grant_permission_for
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else (permission or "READ")
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)
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self.grants[(resource_id, subject_id)] = effective
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if self.require_share_acceptance:
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self.resources[resource_id].setdefault("pending", set()).add(subject_id)
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self._audit(
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"grant", user_id, resource_id=resource_id,
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subject_id=subject_id, permission=effective,
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)
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return {"granted": effective}
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def _op_accept_share(self, user_id: str, resource_id: str) -> dict:
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pending = self.resources.get(resource_id, {}).get("pending")
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if pending:
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pending.discard(user_id)
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self._audit("accept", user_id, resource_id=resource_id, subject_id=user_id)
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return {"accepted": True}
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def _op_revoke(self, user_id: str, resource_id: str, subject_id: str) -> dict:
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resource = self.resources.get(resource_id)
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if resource is None or resource["owner"] != user_id:
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raise Denied("only the owner may revoke")
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if self.revoke_delay_seconds:
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self.resources[resource_id].setdefault("revoke_after", {})[subject_id] = (
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time.monotonic() + self.revoke_delay_seconds
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)
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else:
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self.grants.pop((resource_id, subject_id), None)
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if self.audit_revoke:
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self._audit("revoke", user_id, resource_id=resource_id, subject_id=subject_id)
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return {"revoked": True}
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def _may_read(self, user_id: str, resource_id: str) -> bool:
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"""Authorization as the system actually enforces it."""
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if self.may_read is not None:
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return self.may_read(self, user_id, resource_id)
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return self.baseline_may_read(user_id, resource_id)
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def _may_write(self, user_id: str, resource_id: str) -> bool:
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resource = self.resources.get(resource_id)
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if resource is None:
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return False
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if resource["owner"] == user_id:
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return True
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return self.grants.get((resource_id, user_id)) == "WRITE"
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def baseline_may_read(self, user_id: str, resource_id: str) -> bool:
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resource = self.resources.get(resource_id)
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if resource is None:
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return False
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if resource["owner"] == user_id:
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return True
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deadline = resource.get("revoke_after", {}).get(user_id)
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if deadline is not None and time.monotonic() < deadline:
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return True # revocation is scheduled but not yet effective
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if user_id in resource.get("pending", set()):
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return False
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return (resource_id, user_id) in self.grants
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class ObservationChannel:
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"""Independent read access to lab state — decision D-07.
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Bypasses authorization deliberately. This is the channel test-driver requires
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of any system under test, and the main integration burden the framework
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imposes on an adopter.
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"""
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def __init__(self, app: LabApp) -> None:
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self._app = app
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@property
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def version(self) -> str:
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return self._app.version
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def state_permission(self, user_id: str, resource_id: str) -> str | None:
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"""What the stored record says, independent of any enforcement decision."""
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resource = self._app.resources.get(resource_id)
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if resource is None:
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return None
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if resource["owner"] == user_id:
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return "OWNER"
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return self._app.grants.get((resource_id, user_id))
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def probe_read(self, user_id: str, resource_id: str) -> bool:
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"""Exercise the enforcement path out-of-band and report what it did.
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This uses the subject's own credentials, which can look like a violation
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of actor isolation but is not: independence means the *actor's report* is
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never the evidence. The observer issues its own request and records the
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raw outcome. No actor is ever asked whether it succeeded.
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"""
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user = self._app.users.get(user_id)
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if user is None:
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return False
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try:
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self._app.request(user.token, "read_resource", resource_id=resource_id)
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except Denied:
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return False
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return True
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def probe_write(self, user_id: str, resource_id: str) -> bool:
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"""Out-of-band probe of the write path, non-destructive on refusal."""
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user = self._app.users.get(user_id)
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if user is None:
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return False
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original = self._app.resources.get(resource_id, {}).get("content")
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try:
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self._app.request(
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user.token, "write_resource", resource_id=resource_id, content=original
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)
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except Denied:
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return False
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return True
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def audit_events(self, resource_id: str) -> list[dict[str, Any]]:
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return [
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{
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"sequence": r.sequence,
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"event": r.event,
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"actor_id": r.actor_id,
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"subject_id": r.subject_id,
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"permission": r.permission,
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}
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for r in self._app.audit
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if r.resource_id == resource_id
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]
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def build_baseline() -> tuple[LabApp, dict[str, str]]:
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"""Known initial state, so that runs replay from the same starting point."""
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app = LabApp()
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tokens = {u: app.add_user(u) for u in ("alice", "bob", "carol")}
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tokens["mallory"] = app.add_user("mallory", tenant_id="t-other")
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return app, tokens
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