2022DASCTF X SU 三月春季挑战赛 Calc

#coding=utf-8
from flask import Flask,render_template,url_for,render_template_string,redirect,request,current_app,session,abort,send_from_directory
import random
from urllib import parse
import os
from werkzeug.utils import secure_filename
import time


app=Flask(__name__)

def waf(s):
    blacklist = [\'import\',\'(\',\')\',\' \',\'_\',\'|\',\';\',\'\"\',\'{\',\'}\',\'&\',\'getattr\',\'os\',\'system\',\'class\',\'subclasses\',\'mro\',\'request\',\'args\',\'eval\',\'if\',\'subprocess\',\'file\',\'open\',\'popen\',\'builtins\',\'compile\',\'execfile\',\'from_pyfile\',\'config\',\'local\',\'self\',\'item\',\'getitem\',\'getattribute\',\'func_globals\',\'__init__\',\'join\',\'__dict__\']
    flag = True
    for no in blacklist:
        if no.lower() in s.lower():
            flag= False
            print(no)
            break
    return flag
    num=1#`ls`

@app.route(\"/\")
def index():
    \"欢迎来到SUctf2022\"
    return render_template(\"index.html\")

@app.route(\"/calc\",methods=[\'GET\'])
def calc():
    ip = request.remote_addr
    num = request.values.get(\"num\")
    log = \"echo {0} {1} {2}> ./tmp/log.txt\".format(time.strftime(\"%Y%m%d-%H%M%S\",time.localtime()),ip,num)
    
    if waf(num):
        try:
            data = eval(num)
            os.system(log)
        except:
            pass
        return str(data)
    else:
        return \"waf!!\"



    

if __name__ == \"__main__\":
    app.run(host=\'0.0.0.0\',port=5000)