# S00-018: Validate bounded standalone XML ingress for the XMPP candidate

- Remediation для: S00-003; root: S00-003; depth: 1

> Generated from planning/tasks.json; status is in state/tasks.json.

- Этап: S00
- Оператор: protocol
- Reviewer: security
- Зависимости: S00-001, S00-002, S00-017
- Требования: ACC-004, NET-003, NET-004

## Один результат

One isolated runnable and independently reviewed ingress experiment enforces explicit finite XML resource limits and standalone text XML per WebSocket message before unsafe accumulation/import, through a supported library integration path.

## Разрешённые пути

- `experiments/0002-xmpp-library/parser-validation/**`
- `docs/decisions/0002-xmpp-parser-validation.md`

Не изменять другие modules, shared contracts или spec snapshots без изменения плана. Stem без расширения разрешает принятые stack-specific extensions и focused test рядом.

## Прочитать

- docs/WEB_PROFILE.md
- docs/ARCHITECTURE.md
- docs/CONTRACTS.md
- docs/TESTING.md
- roles/protocol.md
- docs/decisions/README.md
- state/blockers/S00-018.md

## Шаги

1. Read original blocker evidence, bounded probe, shipped parser/transport APIs and RFC 7395 framing; reproduce the stock failure with finite synthetic input.
2. Choose and document a supported ingress integration using vetted existing XML parsing; keep limits experiment-local, do not implement a handwritten security XML parser or patch ignored vendor sources.
3. Enforce byte/depth/element/attribute budgets and complete single-document text-message framing before unbounded tree/import work; reject invalid input terminally and clear attempt state.
4. Add valid boundary and adversarial fixtures including incomplete messages, multiple roots, oversized tokens/attributes, deep XML, malformed XML and binary messages; verify rejection causes no stanza delivery or retained cross-message state.
5. Record exact dependencies/licenses/browser API constraints if adding packages, runnable commands/results and limitations, then submit for independent security review.

## Приёмка

1. Explicit finite byte/depth/element/attribute budgets are enforced before uncontrolled accumulation/import; boundary-valid stanza still parses with actual library behavior.
2. Each WebSocket message is one complete standalone text XML document; incomplete/multiple-root/binary input is rejected and cannot be revived by a later message.
3. Original large/deep/cross-message failure categories are rejected under documented local limits without post-import-only checks, vendor patch or TLS/CORS bypass.
4. One supported integration path and cleanup/reset behavior are demonstrated by runnable actual ingress tests; no production shared contract, auth policy or product limit change.

## Focused checks

1. Positive boundary-valid framed stanza using the actual candidate registry/parser and ingress integration.
2. Original bounded probe categories exceed local budgets or fail framing and produce terminal rejection without stanza emission.
3. Malformed/unfinished/multiple-root/binary/oversized-token/attribute/depth/element cases; no cross-message retained state or late revival.
4. Fresh attempt/reset accepts valid input; dependency pin/license/API and scope inspection.

## Блокер и завершение запуска

Для всех ролей scope — только эта задача. При блокере создать issue JSON по state/ISSUE_TEMPLATE.json, вызвать escalate с текущим ID/role/agent, проверить status=blocked и resolution_task, затем немедленно завершить запуск. Не решать blocker и не выбирать следующую задачу самому. Новый агент назначается runner. Правки metadata через CLI — единственное исключение scope.

## Передача

Сохранить evidence/handoff; submit → review и завершить запуск. Reviewer также выполняет только эту задачу, включая обязательное escalate при блокере.