## Made Sense- Tags: Misc, Makekjail, Jail- Description: i couldn't log in to my server so my friend kindly spun up a server to let me test makefiles. at least, they thought i couldn't log in :P
## Solution- When we visit that website, we can see there a link to source code of it.
```import osfrom pathlib import Pathimport reimport subprocessimport tempfile
from flask import Flask, request, send_file
app = Flask(__name__)flag = open('flag.txt').read()
def write_flag(path):    with open(path / 'flag.txt', 'w') as f:        f.write(flag)
def generate_makefile(name, content, path):    with open(path / 'Makefile', 'w') as f:        f.write(f"""SHELL := /bin/bash.PHONY: {name}{name}: flag.txt\t{content}""")
@app.route('/', methods=['GET'])def index():    return send_file('index.html')
@app.route('/src/', methods=['GET'])def src():    return send_file(__file__)
# made sense@app.route('/make', methods=['POST'])def make():    target_name = request.form.get('name')    code = request.form.get('code')
    print(code)    if not re.fullmatch(r'[A-Za-z0-9]+', target_name):        return 'no'    if '\n' in code:        return 'no'    if re.search(r'flag', code):        return 'no'
    with tempfile.TemporaryDirectory() as dir:        run_dir = Path(dir)        write_flag(run_dir)        generate_makefile(target_name, code, run_dir)        sp = subprocess.run(['make'], capture_output=True, cwd=run_dir)        return f"""<h1>stdout:</h1>{sp.stdout}<h1>stderr:</h1>{sp.stderr}    """
app.run('localhost', 8000)```
- This code below is used to check what we are entering to create a Makefile.
```if not re.fullmatch(r'[A-Za-z0-9]+', target_name):    return 'no'if '\n' in code:    return 'no'if re.search(r'flag', code):    return 'no'```
- We can't enter "flag" and we have to bypass this system to get the flag. First, what's comes to mind: enter some random letters into the "Target name" field. Then, we can bypass the check, by entering this command.
```cat *.txt```
- This will open all the files within the directory. We don't explicitly enter "flag.txt", so the website is not yelling at us. There you will find a flag.
```wctf{m4k1ng_vuln3r4b1l1t135}```