Fix potential SSRF attack vulnerability (#4334)

### What problem does this PR solve?

Fix potential SSRF attack vulnerability

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

Co-authored-by: liuhua <10215101452@stu.ecun.edu.cn>

agent/component/crawler.py

@@ -41,7 +41,7 @@ class Crawler(ComponentBase, ABC):
         ans = self.get_input()
         ans = " - ".join(ans["content"]) if "content" in ans else ""
         if not is_valid_url(ans):
-            return Crawler.be_output("")
+            return Crawler.be_output("URL not valid")
         try:
             result = asyncio.run(self.get_web(ans))
 

api/utils/web_utils.py

@@ -1,4 +1,7 @@
 import re
+import socket
+from urllib.parse import urlparse
+import ipaddress
 import json
 import base64
 
@@ -76,5 +79,25 @@ def __get_pdf_from_html(
         return base64.b64decode(result["data"])
 
 
+def is_private_ip(ip: str) -> bool:
+    try:
+        ip_obj = ipaddress.ip_address(ip)
+        return ip_obj.is_private
+    except ValueError:
+        return False
+
 def is_valid_url(url: str) -> bool:
-    return bool(re.match(r"(https?)://[-A-Za-z0-9+&@#/%?=~_|!:,.;]+[-A-Za-z0-9+&@#/%=~_|]", url))
+    if not re.match(r"(https?)://[-A-Za-z0-9+&@#/%?=~_|!:,.;]+[-A-Za-z0-9+&@#/%=~_|]", url):
+        return False
+    parsed_url = urlparse(url)
+    hostname = parsed_url.hostname
+
+    if not hostname:
+        return False
+    try:
+        ip = socket.gethostbyname(hostname)
+        if is_private_ip(ip):
+            return False
+    except socket.gaierror:
+        return False
+    return True