Blog

hexcess!

Introduction

EDIT: Hex editing is now implemented!

Let me introduce my new baby to you, hexcess! It's a TUI hex viewer, and soon editor as I'm still working on it! The edit feature will (probably) be available next week! It was initially a project idea I had when I was participating in some CTF and I needed to modify some file signatures to be able to open the file.

Why C and Ncurses

I initially wanted to write it in Rust with the Ratatui library, however I ended up using C and Ncurses instead. Why ?

1. Because I still haven't read the Rust book, so I don't feel comfortable making a project using a language I'm not familiar enough with. Learning how to correctly use the language and being familiar with the good practices before coding is something very important to me.

2. Although it got a little bit rusty, I used to program a lot in C when I was at School 19. Even though I had trouble remembering how to write a correct Makefile, Includes files, and how to use GCC correctly to compile with the library and use the flags to detect potential errors, I found my way through the depths of my memory and how to write code in C.

3. As an aspiring Reverse Engineer myself, I want to get used again to C to be able to understand the decompiled code generated by Ghidra or IDA.

4. I'm trying to apply for an internship at a nice company where C is heavily used (I hope they take me in)! This project is a nice way to highlight my skills in this language I guess ?

My experience using C again

It's been a while since I programmed in C, and one thing I had a hard time to get used to again is to make sure that I write secure code. I can't count how many times my program went out of bounds from the memory I allocated. This is probably a skill issue from my part, and a more experienced C programmer would probably make sure that the program never reads a single byte of memory past what it's supposed to have access to, but I think it's very easy to be distracted and not handle this correctly. I would have preferred to use a memory-safe and blazingly fast™ language like Rust. Maybe I will rewrite the this program in Rust sometimes!

Discovering Ncurses

Ncurses is quite simple and straightforward in my opinion, I still had a hard time starting to use this library correctly. There are some nice tutorials around, like this one from https://tldp.org/HOWTO/NCURSES-Programming-HOWTO/, but I wasn't sure if I should use it since it hasn't been updated since 2005, I used it anyway since it was really well written and in-depth, along with the Ncurses man, because RTFM. In comparison, when I tried using Ratatui, I had a better experience learning the library thanks to the tutorial included in their website. I really recommend checking it out!

Conclusion

I still liked making this project, although I didn't plan on taking such a long time to write the code for it. Now that I have commited myself to writing this project in C and Ncurses, I will stick to it and try to push this project as far as I can! Here is the link to the repository, feel free to contribute!