Hacker News new | ask | show | jobs
by dkopi 3687 days ago
Usually. Just make sure the new machine code is the same size as the old.

That said, if the code is signed and there's a signature check - the check will fail if you modify the code.

If the signature is a simple crc/checksum, you could also update the checksum. If it's a cryptographic signature, it might be a lot more difficult.

1 comments

Or, you also have to modify the check code.
Huh? Isn't that what he said - or did I miss something? How is your check code related comment different from his checksum related statement?
The code that checks the signature. If you can identify all the places that checks the signature and disable that code, then it no longer matters if you are unable to correctly update the signature itself.
I was talking about changing the signature/checksum to match the new code. Corecoder pointed out that sometimes you just need to patch the checksum checking code, and not the checksum itself.