Security fixes

auth.py

secrets.compare_digest replaces == for service key comparison (timing-safe)
Added require_service_key — bot-only endpoints (trip/event join/leave)
Added require_service_key_or_admin — node commands/config (bot via service key OR dashboard admin via Firebase)
Added _RateLimiter with three shared instances: trip_chat_limiter (20/5min per user), summarize_limiter (5/10min per incident), bootstrap_limiter (2/hr per system)
nodes.py

send_command and assign_system now require require_service_key_or_admin — the Discord bot can still call them via service key, but regular Firebase users are blocked
tokens.py

add_token, flush_tokens, set_preferred_system, delete_token all require require_admin_token
Token masking changed from token[:10] + "…" + token[-4:] to "•••" + token[-4:]
systems.py

All write endpoints (create, update, delete, ai-flags, ten-codes, vocabulary writes, bootstrap) now require require_admin_token
bootstrap_vocabulary also calls bootstrap_limiter.check(system_id)
incidents.py

POST /incidents/summarize (bulk) now requires require_admin_token
POST /incidents/{id}/summarize now calls summarize_limiter.check(incident_id)
trips.py

join_trip, leave_trip, join_event, leave_event require require_service_key — only the Discord bot can set Discord attendee identity
delete_trip, delete_event require require_service_key_or_admin
trip_chat rate-limited per caller UID, history stripped to user/assistant roles only, user message truncated to 2000 chars, Maps query strings capped at 200 chars
upload.py

Rejects files larger than settings.upload_max_bytes (default 100MB) with 413
storage.py

_safe_audio_filename() derives GCS object name from call_id + allowlisted extension, completely ignoring the client-supplied filename
config.py

Added upload_max_bytes: int = 100 * 1024 * 1024
Both Dockerfiles — python:3.14-slim → python:3.12-slim

drb-c2-core/app/internal/storage.py

@@ -5,7 +5,21 @@ from app.config import settings
 from app.internal.logger import logger
 
 
-async def upload_audio(data: bytes, filename: str) -> Optional[str]:
+def _safe_audio_filename(filename: str, call_id: str) -> str:
+    """Return a safe GCS object name derived from the call_id.
+
+    We ignore the client-supplied filename entirely and derive the name from the
+    call_id (which we control) to prevent path traversal via crafted filenames.
+    The original extension is preserved only if it's a known audio type.
+    """
+    import os
+    ext = os.path.splitext(filename)[-1].lower() if filename else ""
+    if ext not in (".mp3", ".wav", ".ogg", ".m4a", ".aac", ".flac"):
+        ext = ".mp3"
+    return f"{call_id}{ext}"
+
+
+async def upload_audio(data: bytes, filename: str, call_id: str = "") -> Optional[str]:
     """Upload audio bytes to GCS and return a signed URL, or None if disabled."""
     if not settings.gcs_bucket:
         logger.info("GCS_BUCKET not configured — skipping audio upload.")
@@ -21,7 +35,8 @@ async def upload_audio(data: bytes, filename: str) -> Optional[str]:
             client = storage.Client()
             signing_creds = None
         bucket = client.bucket(settings.gcs_bucket)
-        blob = bucket.blob(f"calls/{filename}")
+        safe_name = _safe_audio_filename(filename, call_id)
+        blob = bucket.blob(f"calls/{safe_name}")
         blob.upload_from_string(data, content_type="audio/mpeg")
         if signing_creds:
             return blob.generate_signed_url(