Kernel version
cyrus@ubuntu:/$ uname -a Linux ubuntu 2.6.38-8-generic #42-Ubuntu SMP Mon Apr 11 03:31:24 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux cyrus@ubuntu:/$ randomize_va_space default value cyrus@ubuntu:/$ cat /proc/sys/kernel/randomize_va_space 2 cyrus@ubuntu:/$ randomize_va_space values 0: No randomization of address space. 1: Conservative address space randomization. Code start register will be randomized. 2: Full address space randomization. Contains the feature of value 1 in addition brk area is randomized. Virtual memory Each program will have exactly the same memory structure, making hardcoding of instruction and push the instruction to the fixed memory space easier. With address space randomization, each execution of a program will be residing in different starting addresses. This makes hardcoding and pushing of hardcoded instruction to the predicted memory space harder. Reference: http://www.kernel.org/pub/linux/kernel/people/jikos/randomization/brk-fix-2.patch
cyruslab 
good 1 🙂