Re: Executing from dynamically allocated memory

From	Sébastien Fricker <sebastien.fricker@gmail.com>
Newsgroups	comp.compilers
Subject	Re: Executing from dynamically allocated memory
Date	2013-10-12 11:52 +0200
Organization	Compilers Central
Message-ID	<13-10-006@comp.compilers> (permalink)
References	<13-10-004@comp.compilers>

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On 12.10.13 02:05, news wrote:
> In the past, I've malloc'd memory, written machine instructions into it,
> and called the function I built there. ...

> Now it was a year or three ago that this worked.  Has Linux changed in
> this respect?  Is there something new I have to do to allocate executable
> writable memory for this purpose?
>
> Or might there be something even weirder going on?
>
> -- hendrik
>
> [ Sounds like the NX bit.  See http://en.wikipedia.org/wiki/NX_bit#Linux -John]

Hendrik,
this does not wonder me that it does not work anymore.
In 2003, I was working on the ARM-Linux kernel and I could see that more
and more the MMU protection bit get used principally to avoid the
possibility to misuse buffer-overflow.

But did you have a look on mmap()? (man mmap)
There is a flag PROT_EXEC. I guess this should permit to create a memory
area on which you can execute code.

SC)bastien

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Thread

Executing from dynamically allocated memory "news" <news@fx32.iad.highwinds-media.com> - 2013-10-12 00:05 +0000
  Re: Executing from dynamically allocated memory "James Harris" <james.harris.1@gmail.com> - 2013-10-12 10:10 +0100
  Re: Executing from dynamically allocated memory Sébastien Fricker <sebastien.fricker@gmail.com> - 2013-10-12 11:52 +0200
  Re: Executing from dynamically allocated memory chakaram@auth.gr - 2013-10-12 19:20 +0300
  Re: Executing from dynamically allocated memory Alex McDonald <blog@rivadpm.com> - 2013-10-12 11:12 -0700
  Re: Executing from dynamically allocated memory sandmann@cs.au.dk (Søren Sandmann) - 2013-10-12 20:58 +0200
  Re: Executing from dynamically allocated memory Jens Kallup <jkallup@web.de> - 2013-10-13 10:44 +0200

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