offsetter

README

offsetter

Small package to convert between file offsets and virtual addresses (partialy inspired by some code of pwnlib). For the moment, only ELF files are supported.

Install

Install with go get -u github.com/guitmz/offsetter

Example

$ cat example.go

package main

import (
   "debug/elf"
   "fmt"

   "github.com/guitmz/offsetter"
)

func check(err error) {
   if err != nil {
   	panic(err)
   }
}

func main() {
   targetFile, err := elf.Open("/bin/ls")
   check(err)
   defer targetFile.Close()

   loadAddress, err := offsetter.GetLoadAddress(targetFile)
   check(err)

   hexOffset, uintOffset, err := offsetter.VaddrToOffset(targetFile, loadAddress, targetFile.Entry)
   check(err)
   fmt.Printf("Offset: %s (%d)\n", hexOffset, uintOffset)

   hexVaddr, uintVaddr, err := offsetter.OffsetToVaddr(targetFile, uintOffset)
   check(err)
   fmt.Printf("Vaddr: %s (%d)\n", hexVaddr, uintVaddr)
}

$ go run example.go
Offset: 0x42d4 (17108)
Vaddr: 0x4042d4 (4211412)

Documentation

Index

• func GetLoadAddress(f *elf.File) (uint64, error)
• func OffsetToVaddr(f *elf.File, offset uint64) (string, uint64, error)
• func VaddrToOffset(f *elf.File, load, addr uint64) (string, uint64, error)

Functions

func GetLoadAddress

func GetLoadAddress(f *elf.File) (uint64, error)

GetLoadAddress returns input ELF file Load Address (in memory)

func OffsetToVaddr

func OffsetToVaddr(f *elf.File, offset uint64) (string, uint64, error)

OffsetToVaddr converts a file offset to a virtual address (returns string and uint64 representations of the resulting virtual address)

func VaddrToOffset

func VaddrToOffset(f *elf.File, load, addr uint64) (string, uint64, error)

VaddrToOffset converts a virtual address to a file offset (returns string and uint64 representations of the resulting file offset)