Follow-up on top of #16243. Two small tweaks:
- Compile the regex once as `_SAFE_IDENTIFIER_RE` and pin it to
`[A-Za-z0-9@.+\-]`. The previous `\w` accepts Unicode word chars
(full-width digits, accented letters) which aren't valid WhatsApp
identifiers and shouldn't reach the mapping-file lookup.
- Add a comment clarifying this is defense-in-depth, not a live
traversal. The hardcoded `lid-mapping-{current}{suffix}.json`
prefix already prevents escape via pathlib's component split —
with `current='../secrets'`, the first path component under
`session/` is the literal directory name `lid-mapping-..`,
which the attacker cannot create.
E2E verified: legit mapping chains still resolve, all probed attack
shapes (`../`, absolute paths, shell metacharacters, Unicode digit
tricks) are rejected before any file access.
expand_whatsapp_aliases() interpolated untrusted identifiers directly
into filenames (lid-mapping-{current}.json) without validation.
An identifier containing ../ or / could escape the session directory.
Also replaced bare except Exception: continue with targeted
(OSError, json.JSONDecodeError) and a debug log so mapping
corruption is diagnosable instead of silently skipped.
Fixes:
- Reject identifiers with unsafe characters via re.match guard
- Replace broad exception swallow with specific catch + debug log
Follow-up to the canonical-identity session-key fix: pull the
JID/LID normalize/expand/canonical helpers into gateway/whatsapp_identity.py
instead of living in two places. gateway/session.py (session-key build) and
gateway/run.py (authorisation allowlist) now both import from the shared
module, so the two resolution paths can't drift apart.
Also switches the auth path from module-level _hermes_home (cached at
import time) to dynamic get_hermes_home() lookup, which matches the
session-key path and correctly reflects HERMES_HOME env overrides. The
lone test that monkeypatched gateway.run._hermes_home for the WhatsApp
auth path is updated to set HERMES_HOME env var instead; all other
tests that monkeypatch _hermes_home for unrelated paths (update,
restart drain, shutdown marker, etc.) still work — the module-level
_hermes_home is untouched.
