elb

ELF reader/patcher library that features

• reading and writing ELF files,
• patching RPATH, RUNPATH, SONAME and interpreter via high-level API,
• verifying correctness of ELF files,
• custom patching via low-level API.

To resolve dependencies without loading and executing files, you can use elb-dl that is based on this crate.

There is also an accompanying command-line utility.

Usage

use elb::{DynamicTag, Elf, ElfPatcher, Error};
use std::fs::{File, OpenOptions};

fn read_elf() -> Result<(), Error> {
    let mut file = File::open("/bin/ls")?;
    let page_size = 4096;
    let elf = Elf::read(&mut file, page_size)?;
    eprintln!("{:#?}", elf.header);
    Ok(())
}

fn patch_elf() -> Result<(), Error> {
    let mut file = OpenOptions::new().read(true).write(true).open("/chroot/bin/ls")?;
    let page_size = 4096;
    let elf = Elf::read(&mut file, page_size)?;
    let mut patcher = ElfPatcher::new(elf, file);
    patcher.set_interpreter(c"/chroot/lib64/ld-linux-x86-64.so.2")?;
    patcher.set_dynamic_tag(DynamicTag::Runpath, c"/chroot/lib64:/chroot/usr/lib64")?;
    patcher.finish()?;
    Ok(())
}

References

Other ELF readers/patchers:

• NixOS patchelf.
• LIEF.
• Linux binfmt_elf.

Dynamic linkers:

• Glibc.
• Musl.

Man pages:

• elf(5).

Linters:

• ELFUTILS eu-elflint.
• Binutils readelf --lint.