I am in Linux, and I have seen this question a few times but never, nobody answered how to really make this work.

I need to add a section to an already compiled binary. Lets say for a moment is an ELF file. I'm using objcopy so this should be generic for any format because objcopy uses libbfd that handles many formats.

My process is as follows.

I create the bytecode for a section I want to append to an already compiled ELF file. Let's name this file bytecode.bin

Then I do:

objcopy --add-section .mysection=bytecode.bin \
--set-section-flags .mysection=code,contents,alloc,load,readonly \
myprogram myprogram_edited

Then I adjust the VMA of the secition:

objcopy --adjust-section-vma .mysection=$((16#XXXXX)) myprogram_edited myprogram_edited

Where XXXXXX is the new VMA address for the section.

I get the warning:

objcopy: stIbZt3t: warning: allocated section `.mysection' not in segment

When I do:

objdump -d myprogram_edited

I see:

Disassembly of section .mysection:

0000000000201011 <.mysection>:

So I see the section is created OK and the VMA adjusted. But the section is not mapped to segments, so it can't be loaded at runtime.

How can I solve this?


I opted for using Intel's PIN tool. Very useful and powerful for RI and binary injection.

3 Answers 3


libbfd is not a magic wand, it is in fact pretty limited (it's one of the reasons why GDB cannot debug files without a section table). In particular, objcopy won't add PHT entries for you, so you will have to extend or adjust the PHT manually. You can either do it manually with a hex editor or try using a library such as libelf (it gives you necessary primitives but you'll need to implement the logic yourself).

  • 1
    "it's one of the reasons why GDB cannot debug files without a section table" - thats something I've been wondering about for a while. Thanks for mentioning this
    – julian
    Mar 1, 2017 at 9:57
  • The problem is, I need some generic tool that handles more executable file formats, not only ELF. But I think it is already a nice problem with ELF only.
    – 0xfede7c8
    Mar 1, 2017 at 18:44
  • Well, I'm not aware of any such tool so I guess you'll have to write your own.
    – Igor Skochinsky
    Mar 1, 2017 at 19:31

Maybe you can look at LIEF:

GitHub page: https://github.com/lief-project/LIEF

Site: https://lief.quarkslab.com

  • 5
    Your answer would be much more valuable if you can provide a basic example on how to code what is asked in LIEF.
    – perror
    Apr 5, 2017 at 10:31

I ended up using Intel PIN

Edit: I know this isn't actually an answer to the question. I was trying to change the behavior of a native executable and thought that I needed to change the binary on disk, when actually a binary instrumentation tool was enough for my purpuse.

  • 3
    well, PIN doesn't "add a section to an already compiled binary", so this is not an answer to the question as it was stated.
    – Igor Skochinsky
    Aug 12, 2019 at 18:54
  • Well, I was so ignorant back then I event didn't know what I needed.
    – 0xfede7c8
    Feb 17, 2022 at 21:08
  • 1
    Congratulations on discovering XY questions
    – Igor Skochinsky
    Feb 17, 2022 at 21:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.