first buffer overflow - overwrite nbytes

second buffer overflow - overwrite return address

[read more](http://taqini.space/2020/04/29/hackpackctf2020-pwn-wp/#HackPack-CTF-2020)

Original writeup (http://taqini.space/2020/04/29/hackpackctf2020-pwn-wp/#HackPack-CTF-2020).