randomize_va_space values

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

randomize_va_space default value
cyrus@ubuntu:/$ cat /proc/sys/kernel/randomize_va_space

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

One thought on “randomize_va_space values

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s