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    SubjectRe: caps in elf, next itteration (the hack get's bigger)
    Ulrich Drepper writes:

    > I've not seen this patch but I've seen a bit of the old patches. I've
    > a big problem with changing the signalture (the first four bytes).
    > This should not be done and definitely is completely unnecessary.

    The need: No existing kernel can run the executable.

    > What should be done instead is registering an OS ABI and an ABI
    > version. The draft for the ELF standard revision defines bytes 7 and
    > 8 of the ELF header for this purpose. This information is as easy to
    > read the the signature in the first four bytes.

    Great, but only if existing kernels check the version.
    If not, there would be a huge security hole.

    I expect that the header must be mangled, unless you have some other
    way to stop old (unpatched) kernels from running the executable.

    > So, any solution should there be implemented as follows:
    > - register ELFOSABI_LINUX
    > I could probably do this if it's wanted

    As you may have guessed (by the tack-it-on-the-end hack), ELF format
    knowledge is surprisingly hard to find. Help is welcome. I and several
    other people will be abusing the format this weekend.

    Q: What is the easiest way to modify an ELF section, adding it if it
    does not already exist? Are there naming or ordering rules?

    > For more information see the ELF draft or elf.h in glibc 2.1.

    I hope that is on the web somewhere.

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      Last update: 2005-03-22 13:51    [W:0.021 / U:13.540 seconds]
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