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assemblyreverse-engineeringelf

Replace code / text segment of ELF executable

I am looking for a way to replace the code / text segment of an ELF executable before executing it. Is this possible? If yes, are there any utilities or libraries that I can use to replace it?

Solution

  • Its possible, but not trivial (I am warning you :) ). ELF contains lots of information about its content in the header files. text is just single section in a ELF file. I am also trying do it but not being successful so far.

    I haven't tried objcopy to replace text segment but try this. I had few problem with this so i didn't continue this. 

    objcopy srcELF--dump-section .text=text.dump

objcopy dstELF --add-section .text=text.dump

    My prefered way is to use libelf.

    With libelf you can modify an ELF binary (add section, modify data in a section, etc). This tutorial provides a good start.

    libelf-by-example