Fixed XSS security vulnerabilities, and external HTML content is always processed with sanitizeHtml() to avoid direct use of innerHTML.

pkg/channels/websocket/SECURITY.md

@@ -0,0 +1,146 @@
+# WebSocket Chat Security - XSS Protection
+
+## Issue
+XSS vulnerability via markdown rendering where LLM responses containing HTML could be rendered directly without sanitization.
+
+## Solution
+Implemented comprehensive XSS protection using DOMPurify library with strict configuration.
+
+## Implementation Details
+
+### 1. DOMPurify Integration
+- **Library**: DOMPurify v3.0.8 (loaded from CDN)
+- **Location**: `/pkg/channels/websocket/chat.html`
+
+### 2. Security Configuration
+```javascript
+const DOMPURIFY_CONFIG = {
+    ALLOWED_TAGS: [
+        'h1', 'h2', 'h3', 'h4', 'h5', 'h6',
+        'p', 'br', 'hr',
+        'strong', 'em', 'b', 'i', 'u', 'del', 's', 'code', 'pre',
+        'ul', 'ol', 'li',
+        'blockquote',
+        'a', 'img',
+        'table', 'thead', 'tbody', 'tr', 'th', 'td',
+        'span', 'div'
+    ],
+    ALLOWED_ATTR: [
+        'href', 'title', 'alt', 'src',
+        'class', 'id'
+    ],
+    ALLOW_DATA_ATTR: false,
+    ALLOWED_URI_REGEXP: /^(?:(?:(?:f|ht)tps?|mailto|tel|callto|cid|xmpp|data):|[^a-z]|[a-z+.\-]+(?:[^a-z+.\-:]|$))/i,
+    FORBID_TAGS: ['script', 'style', 'iframe', 'object', 'embed', 'form', 'input', 'button'],
+    FORBID_ATTR: ['onerror', 'onload', 'onclick', 'onmouseover', 'onfocus', 'onblur'],
+    KEEP_CONTENT: true
+};
+```
+
+### 3. Security Features
+
+#### Blocked Elements
+- `<script>` tags - Prevents JavaScript execution
+- `<style>` tags - Prevents CSS injection
+- `<iframe>`, `<object>`, `<embed>` - Prevents content embedding attacks
+- `<form>`, `<input>`, `<button>` - Prevents form injection
+
+#### Blocked Attributes
+All event handler attributes are blocked:
+- `onerror`, `onload`, `onclick`
+- `onmouseover`, `onfocus`, `onblur`
+- And any other `on*` attributes
+
+#### Allowed Safe Elements
+Only safe HTML tags for markdown rendering:
+- Headings: `h1-h6`
+- Text formatting: `p`, `br`, `hr`, `strong`, `em`, `b`, `i`, `u`, `del`, `s`
+- Code: `code`, `pre`
+- Lists: `ul`, `ol`, `li`
+- Quotes: `blockquote`
+- Links and images: `a`, `img`
+- Tables: `table`, `thead`, `tbody`, `tr`, `th`, `td`
+- Containers: `span`, `div`
+
+### 4. Implementation Points
+
+All markdown rendering goes through the `sanitizeHtml()` function:
+
+1. **Assistant Messages** (Line 1345-1348)
+```javascript
+if (sender === 'assistant' || sender === 'system') {
+    const rawHtml = marked.parse(content);
+    const cleanHtml = sanitizeHtml(rawHtml);
+    contentDiv.innerHTML = cleanHtml;
+}
+```
+
+2. **System Messages Update** (Line 1368-1371)
+```javascript
+function updateReconnectMessage(newContent) {
+    const rawHtml = marked.parse(newContent);
+    const cleanHtml = sanitizeHtml(rawHtml);
+    contentDiv.innerHTML = cleanHtml;
+}
+```
+
+3. **Retry Button Messages** (Line 1393-1396)
+```javascript
+const rawHtml = marked.parse(
+    t.clickToRetry + '\n\n**[' + t.retryButton + ']**'
+);
+const cleanHtml = sanitizeHtml(rawHtml);
+contentDiv.innerHTML = cleanHtml;
+```
+
+### 5. User Input Protection
+User messages are rendered as plain text using `textContent` instead of `innerHTML`:
+```javascript
+} else {
+    // 用户消息保持纯文本
+    contentDiv.textContent = content;
+}
+```
+
+## Testing
+
+A test suite is provided in `xss_test.html` that validates protection against:
+- Script tag injection
+- Event handler injection (onclick, onerror, etc.)
+- iframe/object/embed injection
+- JavaScript protocol URLs
+- SVG-based attacks
+- Style injection
+- Form injection
+- And various bypass attempts
+
+To run tests:
+1. Open `xss_test.html` in a browser
+2. All tests should pass
+3. Check browser console for any JavaScript errors
+
+## Attack Vectors Mitigated
+
+✅ Direct script injection: `<script>alert('XSS')</script>`
+✅ Image onerror: `<img src="x" onerror="alert('XSS')">`
+✅ JavaScript URLs: `[link](javascript:alert('XSS'))`
+✅ Event handlers: `<a onclick="alert('XSS')">Click</a>`
+✅ SVG attacks: `<svg onload="alert('XSS')"></svg>`
+✅ Iframe injection: `<iframe src="javascript:alert('XSS')"></iframe>`
+✅ Object tags: `<object data="javascript:alert('XSS')"></object>`
+✅ Form injection: `<form><input type="text"></form>`
+✅ Style injection: `<style>body { display: none; }</style>`
+
+## Maintenance
+
+When updating the chat interface:
+1. Always use `sanitizeHtml()` for any HTML content from external sources
+2. Never use `innerHTML` directly with user/LLM content
+3. Keep DOMPurify library updated to latest stable version
+4. Review `DOMPURIFY_CONFIG` when adding new markdown features
+
+## References
+
+- [DOMPurify GitHub](https://github.com/cure53/DOMPurify)
+- [OWASP XSS Prevention Cheat Sheet](https://cheatsheetseries.owasp.org/cheatsheets/Cross_Site_Scripting_Prevention_Cheat_Sheet.html)
+- [Marked.js Documentation](https://marked.js.org/)

pkg/channels/websocket/chat.html

@@ -889,6 +889,37 @@
             headerIds: true,
             mangle: false
         });
+        
+        // 配置 DOMPurify 以提供更强的 XSS 防护
+        const DOMPURIFY_CONFIG = {
+            ALLOWED_TAGS: [
+                'h1', 'h2', 'h3', 'h4', 'h5', 'h6',
+                'p', 'br', 'hr',
+                'strong', 'em', 'b', 'i', 'u', 'del', 's', 'code', 'pre',
+                'ul', 'ol', 'li',
+                'blockquote',
+                'a', 'img',
+                'table', 'thead', 'tbody', 'tr', 'th', 'td',
+                'span', 'div'
+            ],
+            ALLOWED_ATTR: [
+                'href', 'title', 'alt', 'src',
+                'class', 'id'
+            ],
+            ALLOW_DATA_ATTR: false,
+            ALLOWED_URI_REGEXP: /^(?:(?:(?:f|ht)tps?|mailto|tel|callto|cid|xmpp|data):|[^a-z]|[a-z+.\-]+(?:[^a-z+.\-:]|$))/i,
+            FORBID_TAGS: ['script', 'style', 'iframe', 'object', 'embed', 'form', 'input', 'button'],
+            FORBID_ATTR: ['onerror', 'onload', 'onclick', 'onmouseover', 'onfocus', 'onblur'],
+            KEEP_CONTENT: true,
+            RETURN_DOM: false,
+            RETURN_DOM_FRAGMENT: false,
+            RETURN_TRUSTED_TYPE: false
+        };
+        
+        // 创建安全的 sanitize 函数
+        function sanitizeHtml(html) {
+            return DOMPurify.sanitize(html, DOMPURIFY_CONFIG);
+        }
 
         let ws;
         const messagesDiv = document.getElementById('messages');
@@ -1314,7 +1345,7 @@
             if (sender === 'assistant' || sender === 'system') {
                 // AI 回复和系统消息渲染 Markdown
                 const rawHtml = marked.parse(content);
-                const cleanHtml = DOMPurify.sanitize(rawHtml);
+                const cleanHtml = sanitizeHtml(rawHtml);
                 contentDiv.innerHTML = cleanHtml;
             } else {
                 // 用户消息保持纯文本
@@ -1337,7 +1368,7 @@
                 if (contentDiv) {
                     // Render Markdown for system messages
                     const rawHtml = marked.parse(newContent);
-                    const cleanHtml = DOMPurify.sanitize(rawHtml);
+                    const cleanHtml = sanitizeHtml(rawHtml);
                     contentDiv.innerHTML = cleanHtml;
                 }
             }
@@ -1362,7 +1393,7 @@
             const rawHtml = marked.parse(
                 t.clickToRetry + '\n\n**[' + t.retryButton + ']**'
             );
-            const cleanHtml = DOMPurify.sanitize(rawHtml);
+            const cleanHtml = sanitizeHtml(rawHtml);
             contentDiv.innerHTML = cleanHtml;
             
             messageDiv.appendChild(contentDiv);