The address displayed by ldd

The address displayed by ldd

[gan_xiao_jun]

Hi,

I have a small question, 
I am not sure if it belongs to kernel.
I often use ldd to find librarys needed.
In some systems,the address display by ldd not
changes,
But in other systems, it changes.

What is the reason of the difference?
Is it cause by some setting in kernel?

Thanks in advance.
gan



		
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Re: The address displayed by ldd

[Kevin Puetz]

It's the load address of the library, and it's basically not meant to be a
stable value. It will at least depend on the load order and size of the
libraries, and it may in fact be intentionally randomized each run as a
security measure against ret2libc type attacks (PaX, execshield, etc all do
this, as does prelink everytime it re-prelinks libraries). It's entirely
plausible for it to change from run to run, much less machine to machine.

gan_xiao_jun@yahoo.com wrote:

> Hi,
> 
> I have a small question,
> I am not sure if it belongs to kernel.
> I often use ldd to find librarys needed.
> In some systems,the address display by ldd not
> changes,
> But in other systems, it changes.
> 
> What is the reason of the difference?
> Is it cause by some setting in kernel?
> 
> Thanks in advance.
> gan
> 
> 
> 
> 
> __________________________________
> Do you Yahoo!?
> Yahoo! Mail - Find what you need with new enhanced search.
> http://info.mail.yahoo.com/mail_250