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fn_registry/dev/issues/0165-matrix-media-store-luks.md
T
egutierrez 1cbbad9ff9 feat(matrix): 4 synapse quick wins applied + 6 follow-up issues
Server-side homeserver.yaml on organic-machine VPS:
- encryption_enabled_by_default_for_room_type: invite -> all
- presence.enabled: false (block EDU metadata leak)
- url_preview_enabled: false (block SSRF + IP leak)
- msc4108 rendezvous endpoint uncommented (QR login)

Synapse restarted, /versions shows e2ee_forced.* + msc4108 unstable
features active. Backup at synapse_data/homeserver.yaml.bak.1779659423.

Issues opened for remaining gaps:
- 0165 LUKS for media_store (at-rest encryption)
- 0166 LiveKit TURN deploy (NAT traversal gap)
- 0167 STUN leak to Google (hardcode external_ip)
- 0168 UDP range expand 200 -> 500
- 0169 LIVEKIT_SECRET rotation (audit exposure)
- 0170 livekit.example.yaml rename hygiene

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-24 23:53:37 +02:00

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2.5 KiB
Markdown

---
id: "0165"
title: "Cifrar media_store/ Synapse con LUKS at-rest"
status: pendiente
type: infra
domain:
- matrix
scope: app:element_matrix_chat
priority: media
depends: []
blocks: []
related: ["0162"]
created: 2026-05-24
updated: 2026-05-24
tags: [matrix, synapse, encryption, security, luks]
---
# 0165 — Cifrar media_store/ Synapse con LUKS at-rest
**Status:** pendiente
**Created:** 2026-05-24
**Type:** infra
**Priority:** media
**Domain:** matrix
**Scope:** app:element_matrix_chat
**Depends:**
**Blocks:**
## Problema
`synapse_data/media_store/` contiene archivos subidos (fotos, voice messages, attachments) + thumbnails. Rooms NO-E2EE: media cleartext en disco. Tabla `media_repository` Postgres: filename/mime/uploader/room_id siempre cleartext. Riesgo: VPS provider snapshot disk, backups desencriptados, disco fisico.
## Objetivo
`media_store/` cifrado at-rest. Synapse arranca y sirve media normal. Decrypt automatico via keyfile en TPM o passphrase al boot.
## Plan
1. Decidir estrategia: LUKS container file-based (loop device) vs LUKS sobre volumen Docker dedicado.
2. Crear LUKS container 50GB (ajustar segun crecimiento previsto).
3. Montar como `/home/ubuntu/CodeProyects/element_matrix_chat/synapse_data/media_store_encrypted/`.
4. Stop Synapse → rsync `media_store/``media_store_encrypted/` → swap mountpoint.
5. Verificar Synapse sirve thumbnails + uploads OK.
6. Configurar auto-unlock via keyfile en `/root/.luks-media.key` con permisos 0400.
7. Documentar recovery passphrase en `pass` (entry `matrix/luks-media-passphrase`).
## Acceptance
- [ ] `media_store/` montado sobre LUKS, `lsblk -f` muestra crypto_LUKS.
- [ ] Synapse arranca tras reboot completo del VPS sin intervencion manual.
- [ ] Test: subir imagen via Element, verificar thumb generado.
- [ ] Test: leer media_store via `dd if=/dev/sdX` directo retorna basura cifrada.
- [ ] Passphrase backed up en `pass`.
## Definition of Done
- [ ] Repetibilidad: reboot VPS, media accesible sin intervencion.
- [ ] Observabilidad: log entry en `journalctl -u systemd-cryptsetup@*`.
- [ ] User-facing: clientes Element no notan diferencia.
- [ ] Recovery probado: detach LUKS y reattach con passphrase.
## Notas
LUKS solo protege at-rest. VPS provider con acceso a RAM viva ve plaintext via memory dump. Sin TPM atestado, utilidad real = anti-snapshot/anti-backup-leak/anti-physical-theft.
Caveat: si keyfile vive en mismo disco que LUKS device, no protege contra disk theft. Mover keyfile a USB removible o TPM2 (`systemd-cryptenroll`).