security improvements

backend/execution.py

@@ -25,7 +25,7 @@ import hashlib
 import json
 import uuid
 from copy import deepcopy
-from collections import defaultdict, deque
+from collections import OrderedDict, defaultdict, deque
 from math import isfinite
 from threading import RLock
 from time import perf_counter
@@ -55,9 +55,12 @@ class NodeExecutionError(Exception):
 class ExecutionEngine:
     """Synchronous (blocking) graph executor. Run inside a thread pool from async code."""
 
+    NODE_CACHE_LIMIT = 256
+
     def __init__(self) -> None:
-        self._node_cache: dict[str, dict[str, Any]] = {}
+        self._node_cache: OrderedDict[str, dict[str, Any]] = OrderedDict()
         self._cache_lock = RLock()
+        self._cache_warning_emitted = False
 
     def execute(
         self,
@@ -154,6 +157,7 @@ class ExecutionEngine:
                         input_signature=input_signature,
                         output_signatures=output_signatures,
                         outputs=self._clone_cached_outputs(result),
+                        on_warning=on_warning,
                     )
 
                 # Auto-preview: broadcast a thumbnail for any DATA_FIELD,
@@ -275,6 +279,8 @@ class ExecutionEngine:
                 return None
             if entry.get("input_signature") != input_signature:
                 return None
+            # Move to end for LRU ordering
+            self._node_cache.move_to_end(node_id)
             return entry
 
     def _store_cache_entry(
@@ -285,14 +291,27 @@ class ExecutionEngine:
         input_signature: str,
         output_signatures: tuple[str, ...],
         outputs: tuple,
+        on_warning: Callable[[str, str], None] | None = None,
     ) -> None:
         with self._cache_lock:
+            if node_id in self._node_cache:
+                self._node_cache.move_to_end(node_id)
             self._node_cache[node_id] = {
                 "class_name": class_name,
                 "input_signature": input_signature,
                 "output_signatures": output_signatures,
                 "outputs": outputs,
             }
+            if len(self._node_cache) > self.NODE_CACHE_LIMIT:
+                self._node_cache.popitem(last=False)
+                if not self._cache_warning_emitted and on_warning is not None:
+                    self._cache_warning_emitted = True
+                    on_warning(
+                        node_id,
+                        f"Node cache exceeded {self.NODE_CACHE_LIMIT} entries — "
+                        "oldest cached results are being evicted. "
+                        "Very large workflows may re-compute nodes that would otherwise be cached.",
+                    )
 
     def _build_input_signature(
         self,

backend/server.py

@@ -32,8 +32,10 @@ import asyncio
 import json
 import logging
 import math
+import re
 import secrets
 import sys
+import time
 from collections import defaultdict
 from copy import deepcopy
 from pathlib import Path
@@ -141,6 +143,9 @@ def create_app(
     session_engines: dict[str, ExecutionEngine] = {}
     session_websockets: dict[str, set[web.WebSocketResponse]] = defaultdict(set)
     pending_downloads: dict[str, Path] = {}
+    _last_download_token: dict[str, str] = {}  # session_id → token (limit one per session)
+    _prompt_last_time: dict[str, float] = {}   # session_id → monotonic timestamp
+    PROMPT_MIN_INTERVAL = 0.5  # seconds between /prompt submissions per session
 
     def _is_link(value) -> bool:
         return (
@@ -259,7 +264,12 @@ def create_app(
     def on_file_download(session_id: str, node_id: str, file_path: str) -> None:
         token = secrets.token_urlsafe(16)
         path = Path(file_path)
+        # Evict the previous pending download for this session (limit one).
+        prev_token = _last_download_token.pop(session_id, None)
+        if prev_token:
+            pending_downloads.pop(prev_token, None)
         pending_downloads[token] = path
+        _last_download_token[session_id] = token
         broadcast(session_id, {"type": "file_download", "data": {"node_id": node_id, "token": token, "filename": path.name}})
 
     async def index(request: web.Request) -> web.Response:
@@ -469,9 +479,14 @@ def create_app(
             content_type="application/json",
         )
 
+    def _sanitize_filename(name: str, fallback: str = "download") -> str:
+        """Strip path separators and control characters from a filename."""
+        clean = re.sub(r'[/\\:\x00-\x1f\x7f"*?<>|]', '_', str(name).strip())
+        return clean or fallback
+
     async def download_file(request: web.Request) -> web.Response:
         body = await request.read()
-        filename = request.query.get("filename", "workflow.png")
+        filename = _sanitize_filename(request.query.get("filename", "workflow.png"), "workflow.png")
         return web.Response(
             body=body,
             content_type="application/octet-stream",
@@ -483,9 +498,10 @@ def create_app(
         path = pending_downloads.pop(token, None)
         if path is None or not path.is_file():
             raise web.HTTPNotFound(reason="File not found")
+        filename = _sanitize_filename(path.name, "download")
         return web.FileResponse(
             path,
-            headers={"Content-Disposition": f'attachment; filename="{path.name}"'},
+            headers={"Content-Disposition": f'attachment; filename="{filename}"'},
         )
 
     async def save_workflow_png(request: web.Request) -> web.Response:
@@ -519,6 +535,15 @@ def create_app(
 
     async def submit_prompt(request: web.Request) -> web.Response:
         session_id = require_session_id(request)
+
+        now = time.monotonic()
+        last = _prompt_last_time.get(session_id, 0.0)
+        if now - last < PROMPT_MIN_INTERVAL:
+            raise web.HTTPTooManyRequests(
+                reason="Please wait before submitting another prompt",
+            )
+        _prompt_last_time[session_id] = now
+
         body = await request.json()
         prompt = body.get("prompt")
         if not isinstance(prompt, dict) or not prompt:
@@ -627,7 +652,7 @@ def create_app(
         except Exception:
             return web.json_response({"current": current, "latest": None, "update_available": False})
 
-    app = web.Application()
+    app = web.Application(client_max_size=100 * 1024 * 1024)  # 100 MB upload cap
     app["allow_local_filesystem"] = allow_local_filesystem
 
     app.router.add_get("/", index)

frontend/package-lock.json

@@ -7,6 +7,7 @@
       "name": "tono-frontend",
       "dependencies": {
         "@xyflow/react": "^12.0.0",
+        "dompurify": "^3.3.3",
         "html-to-image": "^1.11.13",
         "marked": "^17.0.5",
         "react": "^18.3.0",
@@ -15,6 +16,7 @@
       },
       "devDependencies": {
         "@eslint/js": "^9.39.4",
+        "@types/dompurify": "^3.0.5",
         "@types/react": "^19.2.14",
         "@types/react-dom": "^19.2.3",
         "@types/three": "^0.183.1",
@@ -28,7 +30,7 @@
         "vite": "^8.0.3"
       },
       "engines": {
-        "node": ">=18.0.0",
+        "node": ">=24.0.0",
         "npm": ">=9.0.0"
       }
     },
@@ -787,6 +789,16 @@
         "@types/d3-selection": "*"
       }
     },
+    "node_modules/@types/dompurify": {
+      "version": "3.0.5",
+      "resolved": "https://registry.npmjs.org/@types/dompurify/-/dompurify-3.0.5.tgz",
+      "integrity": "sha512-1Wg0g3BtQF7sSb27fJQAKck1HECM6zV1EB66j8JH9i3LCjYabJa0FSdiSgsD5K/RbrsR0SiraKacLB+T8ZVYAg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/trusted-types": "*"
+      }
+    },
     "node_modules/@types/estree": {
       "version": "1.0.8",
       "resolved": "https://registry.npmjs.org/@types/estree/-/estree-1.0.8.tgz",
@@ -851,6 +863,13 @@
         "meshoptimizer": "~1.0.1"
       }
     },
+    "node_modules/@types/trusted-types": {
+      "version": "2.0.7",
+      "resolved": "https://registry.npmjs.org/@types/trusted-types/-/trusted-types-2.0.7.tgz",
+      "integrity": "sha512-ScaPdn1dQczgbl0QFTeTOmVHFULt394XJgOQNoyVhZ6r2vLnMLJfBPd53SB52T/3G36VI1/g2MZaX0cwDuXsfw==",
+      "devOptional": true,
+      "license": "MIT"
+    },
     "node_modules/@types/webxr": {
       "version": "0.5.24",
       "resolved": "https://registry.npmjs.org/@types/webxr/-/webxr-0.5.24.tgz",
@@ -1965,6 +1984,15 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/dompurify": {
+      "version": "3.3.3",
+      "resolved": "https://registry.npmjs.org/dompurify/-/dompurify-3.3.3.tgz",
+      "integrity": "sha512-Oj6pzI2+RqBfFG+qOaOLbFXLQ90ARpcGG6UePL82bJLtdsa6CYJD7nmiU8MW9nQNOtCHV3lZ/Bzq1X0QYbBZCA==",
+      "license": "(MPL-2.0 OR Apache-2.0)",
+      "optionalDependencies": {
+        "@types/trusted-types": "^2.0.7"
+      }
+    },
     "node_modules/dunder-proto": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/dunder-proto/-/dunder-proto-1.0.1.tgz",

frontend/package.json

@@ -16,6 +16,7 @@
   },
   "dependencies": {
     "@xyflow/react": "^12.0.0",
+    "dompurify": "^3.3.3",
     "html-to-image": "^1.11.13",
     "marked": "^17.0.5",
     "react": "^18.3.0",
@@ -24,6 +25,7 @@
   },
   "devDependencies": {
     "@eslint/js": "^9.39.4",
+    "@types/dompurify": "^3.0.5",
     "@types/react": "^19.2.14",
     "@types/react-dom": "^19.2.3",
     "@types/three": "^0.183.1",

frontend/src/App.tsx

@@ -13,7 +13,7 @@ import HelpPanelManager from './HelpPanelManager';
 import ContextMenu from './ContextMenu';
 import * as api from './api';
 import { pickNativeDirectorySelection, pickNativeFileSelection } from './nativePicker';
-import { embedWorkflow, extractWorkflow } from './pngMetadata';
+import { embedWorkflow, extractWorkflow, sanitizeJson } from './pngMetadata';
 import { captureViewportBlob as captureWorkflowViewportBlob } from './workflowCapture';
 import tonoIconUrl from '../../resources/icon_1024.png';
 import { hydrateWorkflowState } from './workflowHydration';
@@ -1708,7 +1708,7 @@ function Flow() {
             return;
           }
         } else {
-          data = JSON.parse(await file.text());
+          data = sanitizeJson(JSON.parse(await file.text()));
         }
         await applyMaybePackedWorkflow(data);
         setStatus({ text: 'Workflow loaded.', level: 'info' });

frontend/src/HelpPanelManager.tsx

@@ -1,6 +1,7 @@
 import React, { useEffect, useMemo, useRef, useState } from 'react';
 import ReactDOM from 'react-dom';
 import { marked } from 'marked';
+import DOMPurify from 'dompurify';
 
 // Open external links in new tabs
 const renderer = new marked.Renderer();
@@ -172,7 +173,7 @@ function HelpContent({ content, onOpenDoc }: HelpContentProps) {
   const headings = useMemo(() => parseHeadings(md), [md]);
   const html = useMemo(() => {
     let rendered: string;
-    try { rendered = marked.parse(md) as string; } catch { rendered = md; }
+    try { rendered = DOMPurify.sanitize(marked.parse(md) as string); } catch { rendered = md; }
     return injectHeadingIds(rendered, headings);
   }, [md, headings]);
 
@@ -207,7 +208,7 @@ function JournalTab({ content, onChange, onOpenDoc }: JournalTabProps) {
   let headings: Heading[] = [];
   if (!isEditing && content?.trim()) {
     headings = parseHeadings(content);
-    try { renderedHtml = injectHeadingIds(marked.parse(content) as string, headings); } catch { renderedHtml = content; }
+    try { renderedHtml = injectHeadingIds(DOMPurify.sanitize(marked.parse(content) as string), headings); } catch { renderedHtml = content; }
   }
 
   return (

frontend/src/TextNoteNode.tsx

@@ -1,6 +1,7 @@
 import React, { useContext, useRef, useState, useEffect, useCallback, useMemo } from 'react';
 import { NodeResizeControl, useStore } from '@xyflow/react';
 import { marked } from 'marked';
+import DOMPurify from 'dompurify';
 import { NodeContext } from './CustomNode';
 import type { NodeContextValue } from './types';
 
@@ -81,7 +82,7 @@ function TextNoteNode({ id, data }: TextNoteNodeProps) {
 
   const renderedHtml = useMemo(() => {
     if (!text.trim()) return '';
-    return marked.parse(text);
+    return DOMPurify.sanitize(marked.parse(text) as string);
   }, [text]);
 
   return (

frontend/src/pngMetadata.ts

@@ -90,7 +90,24 @@ function parseTextChunk(type: string, chunkData: Uint8Array) {
   const translatedEnd = chunkData.indexOf(0, offset);
   if (translatedEnd === -1) return null;
 
-  return JSON.parse(decoder.decode(chunkData.subarray(translatedEnd + 1)));
+  return sanitizeJson(JSON.parse(decoder.decode(chunkData.subarray(translatedEnd + 1))));
+}
+
+// ── JSON sanitisation ────────────────────────────────────────────────
+
+const DANGEROUS_KEYS = new Set(['__proto__', 'constructor', 'prototype']);
+
+/**
+ * Recursively strip keys that could cause prototype pollution.
+ */
+export function sanitizeJson(value: unknown): unknown {
+  if (value === null || typeof value !== 'object') return value;
+  if (Array.isArray(value)) return value.map(sanitizeJson);
+  const result: Record<string, unknown> = {};
+  for (const [k, v] of Object.entries(value as Record<string, unknown>)) {
+    if (!DANGEROUS_KEYS.has(k)) result[k] = sanitizeJson(v);
+  }
+  return result;
 }
 
 // ── Public API ───────────────────────────────────────────────────────