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.