Arbitrary stack overflow.

I use `_dl_make_stack_executable` then open-read-write flag1

[exploit here](https://github.com/bash-c/pwn_repo/blob/master/Bamboofox2019_app/solve-1.py)

Original writeup (https://github.com/bash-c/pwn_repo/blob/master/Bamboofox2019_app/solve-1.py).