manage aslr

aslr

#!/bin/bash

# Default Mode: 2
# MODES:
#	0 - disable
#       1 - stack and code segment
#       2 - stack, code and data segment (default)

# Options:
# aslr on # 2
# aslr stack # 1
# aslr off # 0

function usage() {
	echo "Usage: aslr <mode> [off|stack|on]"
	echo -e "Available modes:\n\toff   => 0\n\tstack => 1\n\ton    => 2"
}

function get_mode(){
	if [[ -z $1 ]]; then return 0; fi
	if [[ $1 -eq 0 ]]; then echo -n "Off"
	elif [[ $1 -eq 1 ]]; then echo -n "On [Limited]"
	elif [[ $1 -eq 2 ]]; then echo -n "On"
	else echo -n "Unknown"; fi
}

current=$(sysctl -a --pattern "randomize" | rev | cut -d ' ' -f 1)

# echo 0 | sudo tee /proc/sys/kernel/randomize_va_space

if [[ -z $1 ]]; then echo "[*] Current aslr mode: $current [$(get_mode $current)]"; exit 0; fi

_mode="$1"
if [[ "$_mode" == "off" ]]; then
	mode=0
elif [[ "$_mode" == "stack" ]]; then
	mode=1
elif [[ "$_mode" == "on" ]]; then
	mode=2
else
	echo "Invalid mode \"$mode\""
	usage
	exit 1
fi

if [[ $mode -eq current ]]; then
	echo "[x] Aslr mode is already set to $(get_mode $current) [$current]"
else
	echo "[*] Changing mode from $(get_mode $current) to $(get_mode $mode)"
	_o=$(echo $mode | sudo tee /proc/sys/kernel/randomize_va_space)
	if [[ $_o -eq $mode ]]; then
		echo '[+] Done!'
	else
		echo "[*] An error occrured: $_o"
		exit 1
	fi
fi