Security hardening: fix RCE, auth and SSRF issues

Critical:
- backup: prevent Zip Slip path traversal and zip bombs in restore/convert
  via safe_extract(); serialize get_backup() with backup_lock and always
  restore CWD so concurrent requests can't corrupt the os.chdir state
- app: only enable the Werkzeug debugger/reloader when ENVIRONMENT=dev;
  always init rate limits (also under WSGI), not just under __main__
- apikey: fix create_key never committing (session.commit -> commit()),
  validate roles against an allowlist, and fix revoke_key/update_last_used
  operating on detached instances so revocation actually persists
- env_provider: redact DB_PASSWORD and SESSION_SECRET_KEY in summerize()

High:
- markdown: filter private/protected docs for non-admins in the listing,
  get_home, get_index and search endpoints (was an anonymous data leak);
  escape LIKE metacharacters and cap search results
- webhooks: validate target URL to block SSRF (loopback/private/link-local/
  metadata IPs), disable redirects, safely parse additional_header
- auth: validate JWT issuer and require exp/iat; add timeout to JWKS fetch;
  harden Authorization header parsing against malformed values
- log: require admin for GET /api/log and auth for POST; bound entry size

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

api/markdown.py

@@ -15,6 +15,40 @@ logger = logging.getLogger(__name__)
 
 markdown_bp = Blueprint('markdown', __name__, url_prefix='/api/markdown')
 
+
+def _permission_of(session, markdown):
+    """Return the effective permission string ('private'/'protected'/None)."""
+    if markdown.setting_id is None:
+        return None
+    setting = session.query(MarkdownSetting).get(markdown.setting_id)
+    if not setting or not setting.permission_setting_id:
+        return None
+    ps = session.query(MarkdownPermissionSetting).get(setting.permission_setting_id)
+    return ps.permission if ps else None
+
+
+def _filter_visible(session, markdowns, is_admin):
+    """
+    Apply markdown permission settings to a list for non-admin callers:
+    private documents are dropped entirely, protected documents have their
+    content masked. Admins see everything. Mirrors get_markdown()'s checks
+    so listing/search endpoints can no longer leak restricted content.
+    """
+    if is_admin:
+        return [md.to_dict() for md in markdowns]
+
+    visible = []
+    for md in markdowns:
+        permission = _permission_of(session, md)
+        if permission == 'private':
+            continue
+        data = md.to_dict()
+        if permission == 'protected':
+            data['content'] = None
+            data['protected'] = True
+        visible.append(data)
+    return visible
+
 @markdown_bp.route('/', methods=['GET'])
 @limiter.limit(api.get_rate_limit)
 @etag_response
@@ -30,9 +64,10 @@ def get_markdowns():
     Response Codes:
         - 200: Success
     """
+    is_admin = is_user_admin()
     with get_db() as session:
         mds = session.query(Markdown).all()
-    return jsonify([md.to_dict() for md in mds]), 200
+        return jsonify(_filter_visible(session, mds, is_admin)), 200
 
 @markdown_bp.route('/get_home', methods=['GET'])
 @limiter.limit(api.get_rate_limit)
@@ -51,11 +86,15 @@ def get_home():
         - 200: Success
         - 204: No content (home markdown not found)
     """
+    is_admin = is_user_admin()
     with get_db() as session:
         markdown = session.query(Markdown).filter(Markdown.path_id == 1, Markdown.title == "index").first()
         if markdown is None:
             return jsonify({}), 204
-        return jsonify(markdown.to_dict()), 200
+        visible = _filter_visible(session, [markdown], is_admin)
+        if not visible:
+            return jsonify({}), 204
+        return jsonify(visible[0]), 200
 
 @markdown_bp.route('/by_path/<int:path_id>', methods=['GET'])
 @limiter.limit(api.get_rate_limit)
@@ -75,9 +114,10 @@ def get_markdowns_by_path(path_id):
     Response Codes:
         - 200: Success
     """
+    is_admin = is_user_admin()
     with get_db() as session:
         markdowns = session.query(Markdown).filter(Markdown.path_id == path_id).all()
-        return jsonify([md.to_dict() for md in markdowns]), 200
+        return jsonify(_filter_visible(session, markdowns, is_admin)), 200
 
 @markdown_bp.route('/get_index/<int:path_id>', methods=['GET'])
 @limiter.limit(api.get_rate_limit)
@@ -99,11 +139,15 @@ def get_index(path_id):
         - 200: Success
         - 204: No content (index markdown not found)
     """
+    is_admin = is_user_admin()
     with get_db() as session:
         markdown = session.query(Markdown).filter(Markdown.path_id == path_id).filter(Markdown.title == "index").first()
         if markdown is None:
             return jsonify({}), 204
-        return jsonify(markdown.to_dict()), 200
+        visible = _filter_visible(session, [markdown], is_admin)
+        if not visible:
+            return jsonify({}), 204
+        return jsonify(visible[0]), 200
 
 
 
@@ -429,11 +473,19 @@ def search_markdowns(keyword):
     Response Codes:
         - 200: Success
     """
+    is_admin = is_user_admin()
+    # Escape LIKE metacharacters so user input can't inject wildcards
+    # (full-table-scan DoS) and so search actually matches substrings.
+    escaped = keyword.replace('\\', '\\\\').replace('%', '\\%').replace('_', '\\_')
+    pattern = f"%{escaped}%"
     with get_db() as session:
         res = session.query(Markdown).filter(
-            or_(Markdown.title.like(keyword), Markdown.content.like(keyword))
-        ).all()
-        return jsonify([md.to_dict() for md in res]), 200
+            or_(
+                Markdown.title.like(pattern, escape='\\'),
+                Markdown.content.like(pattern, escape='\\'),
+            )
+        ).limit(200).all()
+        return jsonify(_filter_visible(session, res, is_admin)), 200
 
 @markdown_bp.route('/links', methods=['GET'])
 @limiter.limit(api.get_rate_limit)