Re: [gentoo-amd64] Questions about No Execute and security

[Marco Matthies]

Hemmann, Volker Armin wrote:
> and I get:
>
> strace gzip > /dev/null
> execve("/bin/gzip", ["gzip"], [/* 63 vars */]) = 0
> <snip>
> open("/lib/tls/libc.so.6", O_RDONLY)    = 3
> <snip>
> mmap(NULL, 2261000, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) =
> 0x2aaaaabc3000
> <snip>

Thanks for the reply. So it seems you were right about Gentoo's 
versatility also showing in different addresses used for loading glibc. 
 From your output i'm guessing you are using the linuxthreads-tls USE 
flag for glibc and this does seem to cause a different address for 
glibc. Is this the case or do you know what causes these differences?

So if there are more of these things that can cause different addresses, 
that in itself would mean some sort of randomization. It would be 
interesting to see though how many variations can actually occur, i.e. 
if every different configuration does indeed cause different addresses. 
So if anyone else wants to post their findings we could see just how 
many variations exist, although maybe that would be helping the wrong 
sort of people, if you know what i mean...
Alternatively, if someone knows the answer without checking on lots of 
different installs, i'd be glad to know.

BTW, i also found out that "ldd /bin/gzip" will show you the addresses 
of the libs, no need to wade through the strace output.

Thanks,
Marco
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