# XShop – Security

## 1. Principles

- Sanitize in, validate, escape out.
- Nonce + capability for every state-changing request.
- Use WP/WC APIs; no hand-rolled auth/crypto.

## 2. Input

- `sanitize_text_field`, `sanitize_textarea_field`, `sanitize_email`, `wc_clean`, `absint`, `esc_url_raw` per type.
- Validate: enums via allow-list, URLs via `wp_http_validate_url` where remote, dates via `DateTimeImmutable`.
- No `$_GET`/`$_POST` without sanitization. No `extract()`.

## 3. Output

- `esc_html`, `esc_attr`, `esc_url`, `esc_html__`, `wp_kses_post` (only for intentionally HTML fields with allow-list), `wp_kses` for narrow HTML.
- No `echo $raw`.

## 4. CSRF

- Every POST/AJAX/REST mutation: `check_ajax_referer` / `wp_verify_nonce` / `X-WP-Nonce` header for REST.
- REST: `permission_callback` checks nonce and capability.

## 5. AuthZ

- Admin screens: `current_user_can('manage_options')` or `manage_woocommerce` where appropriate (documented per screen).
- Q&A: `edit_posts` for moderation; user can delete own question via `delete_post` cap check.
- Banners: `manage_options`.

## 6. XSS

- No inline `onclick` with untrusted data. No `innerHTML` with unsanitized server data – DOM via `textContent` or sanitized fragment.
- Stored XSS: banner CTA/link, Q&A body – sanitized on save, escaped on render.

## 7. SQLi

- No raw SQL unless via `$wpdb->prepare`. Prefer `WP_Query`/`WC` CRUD. No string-concatenated queries.

## 8. Special Cases

- **File uploads**: use `wp_handle_upload` + `wp_check_filetype`, no arbitrary file execution, no path traversal (`sanitize_file_name`, `realpath` check).
- **Redirects**: `wp_safe_redirect` + `wp_validate_redirect` allow-list.
- **Unserialize**: never `unserialize` user data; use JSON.
- **Secrets**: no inline secrets; no committed `.env`.
- **Remote import**: validate MIME, size cap, timeout, no SSRF (allow-list demo asset host if any).

## 9. Headers (theme-level)

- Theme does not override server headers; document recommended headers for host (CSP, etc.) in `docs/security.md`.

## 10. Checklist per Feature

- [ ] Inputs sanitized + validated
- [ ] Nonce verified
- [ ] Capability checked
- [ ] Outputs escaped
- [ ] No raw SQL
- [ ] No unsafe redirect/unserialize/upload

## 11. Review Process

- PHPCS `WordPress.Security` + manual review before each release.
- Security note in CHANGELOG.md.