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plaidCTF2017-echo.py
from flask import render_template, flash, redirect, request, send_from_directory, url_for
import uuid
import os
import subprocess
import random
cwd = os.getcwd()
tmp_path = "/tmp/echo/"
serve_dir = "audio/"
docker_cmd = "docker run -m=100M --cpu-period=100000 --cpu-quota=40000 --network=none -v {path}:/share lumjjb/echo_container:latest python run.py"
convert_cmd = "ffmpeg -i {in_path} -codec:a libmp3lame -qscale:a 2 {out_path}"
MAX_TWEETS = 4
MAX_TWEET_LEN = 140
from flask import Flask
app = Flask(__name__)
flag = "PCTF{XXXXXXX...XXXXXXXX}"
if not os.path.exists(tmp_path):
os.makedirs(tmp_path)
def process_flag (outfile):
with open(outfile,'w') as f:
for x in flag:
c = 0
towrite = ''
for i in range(65000 - 1):
k = random.randint(0,127)
c = c ^ k
towrite += chr(k)
f.write(towrite + chr(c ^ ord(x)))
return
def process_audio (path, prefix, n):
target_path = serve_dir + prefix
if not os.path.exists(target_path):
os.makedirs(target_path)
for i in range(n):
st = os.stat(path + str(i+1) + ".wav")
if st.st_size < 5242880:
subprocess.call (convert_cmd.format(in_path=path + str(i+1) + ".wav",
out_path=target_path + str(i+1) + ".wav").split())
@app.route('/audio/<path:path>')
def static_file(path):
return send_from_directory('audio', path)
@app.route("/listen",methods=['GET', 'POST'])
def listen_tweets():
n = int(request.args['n'])
my_uuid = request.args['my_uuid']
if n > MAX_TWEETS:
return "ERR: More than MAX_TWEETS"
afiles = [my_uuid + "/" + str(i+1) + ".wav" for i in range(n)]
return render_template('listen.html', afiles = afiles)
@app.route("/",methods=['GET', 'POST'])
def read_tweets():
t1 = request.args.get('tweet_1')
if t1:
tweets = []
for i in range(MAX_TWEETS):
t = request.args.get('tweet_' + str(i+1))
if len(t) > MAX_TWEET_LEN:
return "ERR: Violation of max tween length"
if not t:
break
tweets.append(t)
my_uuid = uuid.uuid4().hex
my_path = tmp_path + my_uuid + "/"
if not os.path.exists(my_path):
os.makedirs(my_path)
with open(my_path + "input" ,"w") as f:
f.write('\n'.join(tweets))
process_flag(my_path + "flag")
out_path = my_path + "out/"
if not os.path.exists(out_path):
os.makedirs(out_path)
subprocess.call(docker_cmd.format(path=my_path).split())
process_audio(out_path, my_uuid + '/', len(tweets))
return redirect(url_for('.listen_tweets', my_uuid=my_uuid, n=len(tweets)))
else:
return render_template('form.html')
if __name__ == "__main__":
app.run(threaded=True)
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