Split 2/4 of the companion bridge (#863 was 1/4). A paired bearer-token caller
runs as the sandboxed 'api' pseudo-user, so its sessions were stranded in a
separate 'api'-owned silo, invisible to the owner's desktop UI.
Add effective_user(): for a bearer token it resolves to the token's real owner
(request.state.api_token_owner); for cookie sessions it is identical to
get_current_user, so the swap is a no-op for browser users. Route session
ownership/attribution in routes/session_routes.py through it.
Tests (tests/test_session_owner_attribution.py):
- cookie/browser users are unchanged
- a bearer token attributes to its owner; with no owner it does NOT escalate
- _verify_session_owner: a bearer token for owner A cannot verify owner B's
session (404); owner verifies their own; missing -> 404; unauth -> 403
Hardens issues found in a security review of the current tree (separate from
the cookbook SSH PR):
- Email thread rendering (static/js/emailLibrary.js): the flat read path runs
inbound HTML through the allowlist sanitizer, but the two threaded paths
(_renderTurnsAsBubbles / _renderTurnsFromServer — the default view) injected
server-parsed `body_html` raw into the DOM. A crafted inbound email could
inject arbitrary markup (phishing/form/credential-capture/tracking; full XSS
if a deployment relaxes the script CSP). Now sanitized on all paths.
- Attachment extraction (routes/email_routes.py, routes/email_helpers.py): the
on-disk extraction dir was `ATTACHMENTS_DIR / f"{folder}_{uid}"` with
user-controlled folder/uid and no containment, so a folder like `../../tmp`
could escape ATTACHMENTS_DIR. New attachment_extract_dir() flattens both to a
single safe segment and asserts containment.
- Diagnostics routes (routes/diagnostics_routes.py): /api/db/stats,
/api/rag/stats, /api/test/youtube, /api/test-research relied only on the
global session check (any logged-in user). Now require_admin-gated.
- Defense-in-depth HTML escaping: session HTML export escapes the session name
(routes/session_routes.py); the MCP OAuth page escapes the reflected Host
header / server_id (routes/mcp_routes.py).
- Internal-tool token now compared with secrets.compare_digest (constant time)
in core/middleware.py and app.py.
Adds regression tests in tests/test_security_regressions.py.
Mahdi Salmanzade