feat: patched up regex issues

backend/src/ee/services/ssh-certificate-template/ssh-certificate-template-validators.ts

@@ -1,14 +1,34 @@
+import { isIP } from "net";
+
+import { isFQDN } from "@app/lib/validator/validate-url";
+
 // Validates usernames or wildcard (*)
 export const isValidUserPattern = (value: string): boolean => {
-  // Matches valid Linux usernames or a wildcard (*)
-  const userRegex = /^(?:\*|[a-z_][a-z0-9_-]{0,31})$/;
+  // Length check before regex to prevent ReDoS
+  if (typeof value !== "string") return false;
+  if (value.length > 32) return false; // Maximum Linux username length
+  if (value === "*") return true; // Handle wildcard separately
+
+  // Simpler, more specific pattern for usernames
+  const userRegex = /^[a-z_][a-z0-9_-]$/;
   return userRegex.test(value);
 };
 
 // Validates hostnames, wildcard domains, or IP addresses
 export const isValidHostPattern = (value: string): boolean => {
-  // Matches FQDNs, wildcard domains (*.example.com), IPv4, and IPv6 addresses
-  const hostRegex =
-    /^(?:\*|\*\.[a-z0-9-]+(?:\.[a-z0-9-]+)*|[a-z0-9-]+(?:\.[a-z0-9-]+)*|\d{1,3}(\.\d{1,3}){3}|([a-fA-F0-9:]+:+)+[a-fA-F0-9]+(?:%[a-zA-Z0-9]+)?)$/;
-  return hostRegex.test(value);
+  // Input validation
+  if (typeof value !== "string") return false;
+
+  // Length check
+  if (value.length > 255) return false;
+
+  // Handle the wildcard case separately
+  if (value === "*") return true;
+
+  // Check for IP addresses using Node.js built-in functions
+  if (isIP(value)) return true;
+
+  return isFQDN(value, {
+    allow_wildcard: true
+  });
 };