Security Basics mailing list archives

Re: Library address randomization


From: "kalgecin () gmail com" <kalgecin () gmail com>
Date: Fri, 23 Jan 2009 06:27:34 +0300

duno but "cat /proc/sys/kernel/randomize_va_space" should yield 1 for
on and 0 for off. I may be wrong but never heard of 2 in there. try

"echo 1 > /proc/sys/kernel/randomize_va_space"

On 1/23/09, Ricardo Rolim <ricardorolim () hotmail com> wrote:

Hi there,

Currently I'm using Fedora 10 and apparently I'm not getting any library
address randomization for programs compiled as PIE. Whereas the binary
itself, stack and heap are randomly getting their addresses changed from one
execution to the next, the library stands still at a predictable location.
Strangely enough I've got the expected result out of Ubuntu 8.10. This is
how I'm checking:

      #include

int main() {
        printf("printf: %p\n", printf);
        printf("main  : %p\n", main);
}

[ricardo@localhost ~]$ cat /proc/sys/kernel/randomize_va_space
2
[ricardo@localhost ~]$ cat /proc/sys/kernel/exec-shield
1
[ricardo@localhost ~]$ gcc -fpie -pie -o dummy dummy.c
[ricardo@localhost ~]$ ./dummy
printf: 0x17c900
main  : 0xb7f8851c
[ricardo@localhost ~]$ ./dummy
printf: 0x17c900
main  : 0xb7f5051c

Am I missing something? Thanks a lot :)               
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