I am using Ubuntu 12.04 32-bits, for some experiment I need to disable ASLR; how do I accomplish that? What should I do after that to enable ASLR again?
According to an article How Effective is ASLR on Linux Systems?, you can configure ASLR in Linux using the /proc/sys/kernel/randomize_va_space interface.
The following values are supported:
- 0 – No randomization. Everything is static.
- 1 – Conservative
randomization. Shared libraries, stack,mmap(), VDSO and heap are
randomized.
- 2 – Full randomization. In addition to elements listed in
the previous point, memory managed throughbrk()is also randomized.
So, to disable it, run
echo 0 | sudo tee /proc/sys/kernel/randomize_va_space
and to enable it again, run
echo 2 | sudo tee /proc/sys/kernel/randomize_va_space
This won't survive a reboot, so you'll have to configure this in sysctl. Add a file /etc/sysctl.d/01-disable-aslr.conf containing:
kernel.randomize_va_space = 0
should permanently disable this.
