Update log4j-finder.py

fixes fox-it#76

log4j-finder.py

@@ -290,6 +290,7 @@ def main():
         help="be more quiet, disables banner and summary",
     )
     parser.add_argument("-b", "--no-banner", action="store_true", help="disable banner")
+    parser.add_argument("-f", "--fail", action="store_true", help="Exit with error status when vulnerability is found")
     parser.add_argument(
         "-V", "--version", action="version", version=f"%(prog)s {__version__}"
     )
@@ -365,6 +366,10 @@ def main():
         print_summary(stats)
         print(f"\nElapsed time: {elapsed:.2f} seconds")
 
+    # If we find vulnerabilities and the args -f (or --fail), then exit with a string which cause a error status on the exit.
+    if args.fail: 
+        if stats["vulnerable"]:
+            return "Vulnerabilities found."
 
 if __name__ == "__main__":
     try: