README.md

gdylib

Module providing adding following load commands:

• LC_LOAD_DYLIB
• LC_LOAD_WEAK_DYLIB
• LC_RPATH

Adding loads can be accomplished with keeping the old signature or removal of it. Module will check whether there is enough space for the new load and return ErrNotEnoughSpace if there is not enough.

This module is heavily inspired/guided by insert_dylib, install_name_tool projects.

It supports 32bit and 64bit architectures with assumed little endian. FAT binaries are not yet supported.

Usage

package main

import (
	"github.com/lateralusd/gdylib"
	"io"
	"os"
)

func main() {
	r, err := gdylib.Run(os.Args[1], os.Args[2],
		gdylib.WithLoadType(gdylib.WEAK),
		gdylib.WithRemoveCodeSig(true))
	if err != nil {
		panic(err)
	}

	nf, err := os.Create(os.Args[3])
	if err != nil {
		panic(err)
	}
	defer nf.Close()

	io.Copy(nf, r)
}

$ go run main.go a.out @executable_path/FridaGadget.dylib new_file
$ otool -l new_file | tail
 datasize 0
Load command 16
          cmd LC_LOAD_WEAK_DYLIB
      cmdsize 64
         name @executable_path/FridaGadget.dylib (offset 24)
   time stamp 0 Thu Jan  1 01:00:00 1970
      current version 0.0.0
compatibility version 0.0.0