Creating ELF executable from scratch

Prerequisites

Go (Golang): Installation instructions: https://golang.org/doc/install
NASM (Netwide Assembler): sudo apt-get install nasm

File Descriptions

min.asm

This creates our reference executable so we can explore a binary file that is properly structured.

To compile and run:

nasm -f elf64 -o min.o min.asm
ld -o min_asm min.o
./min_asm

minimal_elf.go

This Go program creates a minimal ELF file. It will only create the parts were absolutely necessary to run a executable:

ELF header
Program header
Instructions/Data

To run:

go run min.go
chmod +x minimal_elf
./minimal_elf

valid_elf.go

This is creates an (almost) valid elf file by copying the structure from the min.asm nasm output. Therefore it will work with most utilities like objdump or readelf.

To run:

go run valid_elf.go

This will overwrite minimal_elf.

Utility programs

objdump
readelf
vbindiff

Video

Video explanation

Note

This project is for educational purposes only. The created ELF files are minimal examples and should not be used as templates for production executables.

Kn0rk/elf_video