fix: surface a tampered capability flag as a clean error, not a traceback

a tampered or foreign GCM capability flag raises cryptography's InvalidTag (subclasses Exception, not ValueError/RuntimeError), which escaped the CLI's catch tuple as a raw traceback on the authorize/verify paths. main() now catches InvalidTag and surfaces '[\xe2\x9c\x98] capability flag failed authentication — tampered or wrong DEK'. also corrected the stale CLAUDE.md storage note that still described the swallow-wrapped mongo methods instead of the fail-loud raw-collection path.

Signed-off-by: disqualifier <dev@disqualifier.me>

README.md

@@ -13,20 +13,20 @@ authorization system and the key-document schema; the crypto primitives live in
 ## Install
 
 ```
-envelope_authorizer @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_authorizer.git@v0.1.0
+envelope_authorizer @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_authorizer.git@v0.1.1
 ```
 
 Direct:
 
 ```bash
-pip install "envelope_authorizer @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_authorizer.git@v0.1.0"
+pip install "envelope_authorizer @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_authorizer.git@v0.1.1"
 ```
 
 The base install uses a local JSON file for storage (stdlib only). For shared
 dev→server storage, install the mongo extra:
 
 ```bash
-pip install "envelope_authorizer[mongo] @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_authorizer.git@v0.1.0"
+pip install "envelope_authorizer[mongo] @ git+ssh://git@git.rethinkstudios.io/rethink-public/envelope_authorizer.git@v0.1.1"
 ```
 
 Installing pulls `envelope_crypto` (and `mongo` with the extra). After install,
@@ -47,12 +47,39 @@ Each key carries an **encrypted capability flag** — `meta.authorizer` =
 - **Servers** are authorized with `allowed: False` → they can boot and use the DEK
   (decrypt project data) but **cannot authorize anything else**.
 
-The flag is GCM-sealed under the DEK on purpose: a server **cannot flip its own
-flag in the database to escalate**, because forging a valid flag requires already
-holding the DEK, and editing the stored ciphertext breaks the auth tag. The
-guarantee is precisely: *you cannot grant yourself authority without already
-having it.* (A legitimate authorizer can of course mint new flags — that is its
-job. This stops passive DB tampering, not an authorizer.)
+The flag is GCM-sealed under the DEK on purpose. What that buys, stated honestly:
+
+- **Without the DEK, the flag is inert.** A stolen database at rest cannot be
+  escalated — the flags are ciphertext, unforgeable and unflippable without the key
+  (editing the stored ciphertext breaks the GCM auth tag). This stops passive DB
+  tampering.
+- **It does not defend against a party that already holds the DEK and can write
+  storage.** The flag is sealed under the *shared* DEK and is **not bound to key
+  identity**, so such a party can copy a valid sealed `True` flag from an
+  authorizer's doc onto its own and self-grant authority. This is **out of scope by
+  design**: the trust model assumes DEK-holders are trusted. A DEK-holder already
+  has full data access (DEK + write access is game over), so self-granting authority
+  exposes no additional data. We deliberately do not add per-key signing to prevent
+  it — the residual is handled operationally (below).
+
+So the precise boundary is: **the capability flag is unforgeable without the DEK; it
+is not a defense against a malicious DEK-holder.** (A legitimate authorizer can of
+course mint new flags — that is its job.)
+
+### Operational guidance (the residual control)
+
+Because the DEK-holder case above is **not** prevented cryptographically in the
+shared-DEK model, the intended mitigation is **detection, not crypto**. Consumers
+should periodically audit the authorization state in storage:
+
+- enumerate every key doc's capability flag (`list` shows authorizer status),
+- compare the set of `allowed: True` keys against a known-good list of expected
+  authorizers,
+- alert on any unexpected authorizer.
+
+An unexpected `allowed: True` appearing in storage is the signal that a DEK-holder
+self-granted — catch it by review, then revoke and re-authorize from a trusted
+machine.
 
 `revoke` is **bookkeeping, not rotation**: it deletes the record so the key can no
 longer unwrap at boot, but it does not rotate the DEK or scrub it from a machine

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "envelope_authorizer"
-version = "0.1.0"
+version = "0.1.1"
 description = "CLI key-authorization manager for envelope_crypto"
 requires-python = ">=3.10"
 dependencies = [

src/envelope_authorizer/__init__.py

@@ -1 +1 @@
-__version__ = "0.1.0"
+__version__ = "0.1.1"

src/envelope_authorizer/cli.py

@@ -9,6 +9,8 @@ command loads config and resolves a storage backend first. expected failures
 import argparse
 import sys
 
+from cryptography.exceptions import InvalidTag
+
 from . import __version__
 from .config import ConfigError, load_config
 from .commands import CommandError, authorize, config_init, init, list_keys, revoke, verify
@@ -88,6 +90,8 @@ def main() -> int:
         storage = resolve(config)
         handlers[args.cmd](config, storage, args)
         return 0
+    except InvalidTag:
+        return _fail("capability flag failed authentication — tampered or wrong DEK")
     except (ConfigError, CommandError, RuntimeError, ValueError, FileNotFoundError) as error:
         return _fail(str(error))
 

src/envelope_authorizer/commands/list_keys.py

@@ -19,11 +19,16 @@ def _can_authorize(crypto, doc) -> str:
 
 
 def _created(doc) -> str:
-    """format created_at as a UTC timestamp string, or '-' if absent"""
+    """format created_at as a UTC timestamp string, or '-' if absent/unparseable"""
     raw = doc.get("meta", {}).get("created_at")
     if not raw:
         return "-"
-    return datetime.fromtimestamp(int(raw), tz=timezone.utc).strftime("%Y-%m-%d %H:%M:%S")
+    try:
+        return datetime.fromtimestamp(int(raw), tz=timezone.utc).strftime("%Y-%m-%d %H:%M:%S")
+    except (TypeError, ValueError, OverflowError, OSError):
+        # one hand-edited/legacy doc with a bad created_at shouldn't abort the
+        # whole table render
+        return "-"
 
 
 def run(config, storage, args) -> None:

src/envelope_authorizer/storage/json_store.py

@@ -8,6 +8,7 @@ setups; for dev->server flows across machines, use the mongo backend.
 
 import json
 import os
+import tempfile
 from pathlib import Path
 from typing import List, Optional
 
@@ -34,13 +35,27 @@ class JsonStore(StorageBackend):
         return data
 
     def _write(self, docs: List[dict]) -> None:
-        """atomically write the docs list (temp file then replace)"""
+        """atomically write the docs list (unique temp file then replace)
+
+        the temp name is unique per write (tempfile.mkstemp in the same dir) so two
+        concurrent writers can't clobber a shared `.tmp`; os.replace is atomic on the
+        same filesystem. the temp is cleaned up if the write fails before replace.
+        """
         self.path.parent.mkdir(parents=True, exist_ok=True)
-        tmp = self.path.with_suffix(self.path.suffix + ".tmp")
-        with open(tmp, "w", encoding="utf-8") as handle:
-            json.dump(docs, handle, indent=2)
-            handle.write("\n")
-        os.replace(tmp, self.path)
+        fd, tmp = tempfile.mkstemp(
+            dir=self.path.parent, prefix=self.path.name + ".", suffix=".tmp"
+        )
+        try:
+            with os.fdopen(fd, "w", encoding="utf-8") as handle:
+                json.dump(docs, handle, indent=2)
+                handle.write("\n")
+            os.replace(tmp, self.path)
+        except BaseException:
+            try:
+                os.unlink(tmp)
+            except OSError:
+                pass
+            raise
 
     def get(self, fingerprint: str) -> Optional[dict]:
         """return the doc whose `_id` matches, or None"""

src/envelope_authorizer/storage/mongo_store.py

@@ -6,6 +6,14 @@ self-contained per call. no module-level client and no shared event loop, so it
 never collides with a running loop. a per-call connect is an accepted tradeoff
 for a one-shot admin CLI. requires envelope_authorizer[mongo]; without it every
 method raises a clear RuntimeError.
+
+fail-loud: operations go through the mongo lib's RAW collection escape hatch
+(`db.collection(name)`, the motor collection — which raises) rather than the
+swallow-and-return-default wrapped methods. this is an auth backend; conflating
+a backend error with "no document / not initialized" in the thing that gates
+authority is the worst place for the swallow anti-pattern, so a driver error
+propagates and a no-op upsert raises instead of silently reporting success.
+`close()` is synchronous on the mongo lib (motor's close is sync) — not awaited.
 """
 
 import asyncio
@@ -36,33 +44,38 @@ class MongoStore(StorageBackend):
     async def _get(self, fingerprint: str) -> Optional[dict]:
         db = Mongo(self.uri, self.database)
         try:
-            return await db.get_document(self.collection, {"_id": fingerprint})
+            return await db.collection(self.collection).find_one({"_id": fingerprint})
         finally:
-            await db.close()
+            db.close()
 
     async def _get_all(self) -> List[dict]:
         db = Mongo(self.uri, self.database)
         try:
-            return await db.get_documents(self.collection, {})
+            cursor = db.collection(self.collection).find({})
+            return await cursor.to_list(length=None)
         finally:
-            await db.close()
+            db.close()
 
     async def _save(self, doc: dict) -> None:
         db = Mongo(self.uri, self.database)
         try:
-            await db.update_document(
-                self.collection, {"_id": doc["_id"]}, doc, do_upsert=True
+            result = await db.collection(self.collection).replace_one(
+                {"_id": doc["_id"]}, doc, upsert=True
             )
+            if not (result.matched_count or result.upserted_id):
+                raise RuntimeError(
+                    f"mongo upsert affected no document for _id={doc['_id']!r}"
+                )
         finally:
-            await db.close()
+            db.close()
 
     async def _delete(self, fingerprint: str) -> bool:
         db = Mongo(self.uri, self.database)
         try:
-            removed = await db.delete_document(self.collection, {"_id": fingerprint})
-            return bool(removed)
+            result = await db.collection(self.collection).delete_one({"_id": fingerprint})
+            return result.deleted_count > 0
         finally:
-            await db.close()
+            db.close()
 
     def get(self, fingerprint: str) -> Optional[dict]:
         """return the key doc with this `_id`, or None"""