johndough on A minimal, complete, and correct ELF file

Comment on A minimal, complete, and correct ELF file

When trying to run this binary on a 64 bit Debian system, I get an error:

    echo 'f0VMRgIBAQAAAAAAAAAAAAIAPgABAAAA+ABAAAAAAAAAAQAAAAAAAEAAAAAAAAAAAAAAAEAAOAABAEAAAgABAAEAAAABAAAABgAAAAAAAAD4AEAAAAAAAPgAAAAAAAAADgAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAHAAAAAwAAAAAAAAAAAAAAAAAAAAAAAAAGAQAAAAAAABEAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAQAAAAUAAAD4AAAAAAAAAPgAQAAAAAAA+ABAAAAAAAAOAAAAAAAAAA4AAAAAAAAAABAAAAAAAABIx8A8AAAAvyoAAAAPBQAudGV4dAAuc2hzdHJ0YWIA' | base64 -d > main
    chmod +x main
    ./main

    # bash: ./main: cannot execute binary file: Exec format error

Am I doing it incorrectly? I hope I copied the bytes correctly since copy & pasting from the website is a bit challenging.

johndough 2y

Found the mistake. The offset for the program header table should be c0 00 instead of 00 01 (third row on the website, starting at byte 0020). Here is the correct code.

    echo 'f0VMRgIBAQAAAAAAAAAAAAIAPgABAAAA+ABAAAAAAADAAAAAAAAAAEAAAAAAAAAAAAAAAEAAOAABAEAAAgABAAEAAAABAAAABgAAAAAAAAD4AEAAAAAAAPgAAAAAAAAADgAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAHAAAAAwAAAAAAAAAAAAAAAAAAAAAAAAAGAQAAAAAAABEAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAQAAAAUAAAD4AAAAAAAAAPgAQAAAAAAA+ABAAAAAAAAOAAAAAAAAAA4AAAAAAAAAABAAAAAAAABIx8A8AAAAvyoAAAAPBQAudGV4dAAuc2hzdHJ0YWIA' | base64 -d > main
    ./main
    echo $? # should print 42

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