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Re: code and data

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"Melzzzzz" <mel@zzzzz.com> wrote in message 
news:20141021001137.6b93d8c5@maxa-pc...
> On Mon, 20 Oct 2014 17:34:56 -0400
> "Bill Cunningham" <nospam@nspam.invalid> wrote:
>
>>
>> "Melzzzzz" <mel@zzzzz.com> wrote in message
>> news:20141020222517.4d3ceaf8@maxa-pc...
>> > On Mon, 20 Oct 2014 15:55:15 -0400
>> > "Bill Cunningham" <nospam@nspam.invalid> wrote:
>> >
>> >>     Now is a flat binary only data or does it contain any code? I
>> >> know the sections are stripped away.
>> >>
>> >> Bill
>> >>
>> >>
>> >
>> > What you mean by that? You can load binary into RAM and execute
>> > it no problem on Linux and Windows.
>>
>>     Only if there is relaocatable data mapped by the linker or loader
>> for execution.
>
> Well, you can write relocatable code in assembler or compile with PIC...
> I did it. Loaded file in memory, mprotect it and just casted to
> pointer to function and ...;)
>
> And the binary happens to have executable code. If you
>> remove section (or segment) headers which would be meaningful code,
>> You'll have something that linux's file command would call data
>> because it's unidentifiable. Not all binaries are executable on their
>> own. JPEGs have a header and are binaries but not executable.
>
> You can execute anything in memory. Question is if you would get
> meaningful result ;)
>
>>
>>     What exactly is left when something has been reduced to a "flat
>> binary"? That is what I'm meaning. Linux certainly can't identify it
>> I know that.
>
> Flat binary can be loaded into memory and run no problem. It just need
> to have position independent code.

    Sounds like gcc -fPIC libraries.

Hummm

Bill

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code and data "Bill Cunningham" <nospam@nspam.invalid> - 2014-10-20 15:55 -0400
  Re: code and data Melzzzzz <mel@zzzzz.com> - 2014-10-20 22:25 +0200
    Re: code and data "Bill Cunningham" <nospam@nspam.invalid> - 2014-10-20 17:34 -0400
      Re: code and data Melzzzzz <mel@zzzzz.com> - 2014-10-21 00:11 +0200
        Re: code and data "Bill Cunningham" <nospam@nspam.invalid> - 2014-10-20 20:01 -0400
  Re: code and data Richard Heathfield <invalid@see.sig.invalid> - 2014-10-20 21:29 +0100
    Re: code and data "Bill Cunningham" <nospam@nspam.invalid> - 2014-10-20 17:38 -0400
      Re: code and data Richard Heathfield <invalid@see.sig.invalid> - 2014-10-20 23:09 +0100

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