Full writeup : [here](https://alexandre.fresnais.fr/posts/UTCTF_2021/)

Exploit code : [here](https://github.com/alexandrefresnais/CTFs/blob/master/UTCTF_2021/functionalprogramming/exploit.py)

Summary : You can jump wherever you want and you have a libc leak.

Solution : find corresponding libc to get system address.