ELF object files: executable stack and security risk?

[Marco Leise]

Am 27.07.2011, 03:51 Uhr, schrieb Walter Bright  
<newshound2 at digitalmars.com>:

> On 7/26/2011 6:45 PM, Marco Leise wrote:
>> I'm not into the details of ELF and object file stacks, but Gentoo  
>> Linux gives
>> me some QA warnings about executable writable sections. A Gentoo hacker  
>> helped
>> me by writing a patch to dmd and the security warnings are now gone.
>>
>> See http://d.puremagic.com/issues/show_bug.cgi?id=6387 for details.
>>
>> I posted here to shed some light on the issue. GNU C closures need an  
>> executable
>> stack, but D doesn't. Would there be any other feature that require  
>> executable
>> stacks?
>
> Not at the moment.

Thank you for the info. That means when compiling the source this is a  
valid patch.

>> If yes, then an option to disable these features and make the stacks
>> non-executable would help. And why is it anyway that each object file  
>> has a
>> stack of it's own? I thought stacks were a per-thread thing?
>
> Object files don't have their own stacks. I don't know what you're  
> referring to.

I was wondering why scanelf was printing out lines for every object file  
in the libraries and read sentences like "Sure enough, these objects lack  
the .note.GNU-stack ELF section and they are linked into the final  
libsmpeg.so library." That made me assume that each object file can have  
this section and thus must have an own stack.
Anyway me and Andrei wanted to at least notify you about this and that's  
done now. It seemed somewhat me, like when an old lady sees a fake website  
pop-up a virus warning.