metasploit-gs/lib/msf/core/post/linux/kernel.rb

# -*- coding: binary -*-
require 'msf/core/post/common'

module Msf
class Post
module Linux
module Kernel
  include ::Msf::Post::Common

  #
  # Returns uname output
  #
  # @return [String]
  #
  def uname(opts='-a')
    cmd_exec("uname #{opts}").to_s.strip
  rescue
    raise "Failed to run uname #{opts}"
  end

  #
  # Returns the kernel release
  #
  # @return [String]
  #
  def kernel_release
    uname('-r')
  end

  #
  # Returns the kernel version
  #
  # @return [String]
  #
  def kernel_version
    uname('-v')
  end

  #
  # Returns the kernel name
  #
  # @return [String]
  #
  def kernel_name
    uname('-s')
  end

  #
  # Returns the kernel hardware
  #
  # @return [String]
  #
  def kernel_hardware
    uname('-m')
  end

  #
  # Returns the kernel modules
  #
  # @return [Array]
  #
  def kernel_modules
    cmd_exec('cat /proc/modules').to_s.scan(/^[^ ]+/)
  rescue
    raise 'Could not determine kernel modules'
  end

  #
  # Returns true if kernel and hardware supports Supervisor Mode Access Prevention (SMAP), false if not.
  #
  # @return [Boolean]
  #
  def smap_enabled?
    cmd_exec('cat /proc/cpuinfo').to_s.include? 'smap'
  rescue
    raise 'Could not determine SMAP status'
  end

  #
  # Returns true if kernel and hardware supports Supervisor Mode Execution Protection (SMEP), false if not.
  #
  # @return [Boolean]
  #
  def smep_enabled?
    cmd_exec('cat /proc/cpuinfo').to_s.include? 'smep'
  rescue
    raise 'Could not determine SMEP status'
  end

  #
  # Returns true if Kernel Address Isolation (KAISER) is enabled
  #
  # @return [Boolean]
  #
  def kaiser_enabled?
    cmd_exec('cat /proc/cpuinfo').to_s.include? 'kaiser'
  rescue
    raise 'Could not determine KAISER status'
  end

  #
  # Returns true if user namespaces are enabled, false if not.
  #
  # @return [Boolean]
  #
  def userns_enabled?
    return false if cmd_exec('cat /proc/sys/user/max_user_namespaces').to_s.strip.eql? '0'
    cmd_exec('cat /proc/sys/kernel/unprivileged_userns_clone').to_s.strip.eql? '1'
  rescue
    raise 'Could not determine userns status'
  end

  #
  # Returns true if Address Space Layout Randomization (ASLR) is enabled
  #
  # @return [Boolean]
  #
  def aslr_enabled?
    aslr = cmd_exec('cat /proc/sys/kernel/randomize_va_space').to_s.strip
    (aslr.eql?('1') || aslr.eql?('2'))
  rescue
    raise 'Could not determine ASLR status'
  end

  #
  # Returns true if unprivileged bpf is disabled
  #
  # @return [Boolean]
  #
  def unprivileged_bpf_disabled?
    cmd_exec('cat /proc/sys/kernel/unprivileged_bpf_disabled').to_s.strip.eql? '1' 
  rescue
    raise 'Could not determine kernel.unprivileged_bpf_disabled status'
  end

  #
  # Returns true if kernel pointer restriction is enabled
  #
  # @return [Boolean]
  #
  def kptr_restrict?
    cmd_exec('cat /proc/sys/kernel/kptr_restrict').to_s.strip.eql? '1' 
  rescue
    raise 'Could not determine kernel.kptr_restrict status'
  end

  #
  # Returns true if dmesg restriction is enabled
  #
  # @return [Boolean]
  #
  def dmesg_restrict?
    cmd_exec('cat /proc/sys/kernel/dmesg_restrict').to_s.strip.eql? '1' 
  rescue
    raise 'Could not determine kernel.dmesg_restrict status'
  end

  #
  # Returns mmap minimum address
  #
  # @return [Integer]
  #
  def mmap_min_addr
    mmap_min_addr = cmd_exec('cat /proc/sys/vm/mmap_min_addr').to_s.strip
    return 0 unless mmap_min_addr =~ /\A\d+\z/
    mmap_min_addr
  rescue
    raise 'Could not determine system mmap_min_addr'
  end

  #
  # Returns true if SELinux is installed
  #
  # @return [Boolean]
  #
  def selinux_installed?
    cmd_exec('id').to_s.include? 'context='
  rescue
    raise 'Could not determine SELinux status'
  end

  #
  # Returns true if SELinux is in enforcing mode
  #
  # @return [Boolean]
  #
  def selinux_enforcing?
    return false unless selinux_installed?

    sestatus = cmd_exec('/usr/sbin/sestatus').to_s.strip
    raise unless sestatus.include?('SELinux')

    return true if sestatus =~ /Current mode:\s*enforcing/
    false
  rescue
    raise 'Could not determine SELinux status'
  end

  #
  # Returns true if Yama is installed
  #
  # @return [Boolean]
  #
  def yama_installed?
    ptrace_scope = cmd_exec('cat /proc/sys/kernel/yama/ptrace_scope').to_s.strip
    return true if ptrace_scope =~ /\A\d\z/
    false
  rescue
    raise 'Could not determine Yama status'
  end

  #
  # Returns true if Yama is enabled
  #
  # @return [Boolean]
  #
  def yama_enabled?
    return false unless yama_installed?
    !cmd_exec('cat /proc/sys/kernel/yama/ptrace_scope').to_s.strip.eql? '0'
  rescue
    raise 'Could not determine Yama status'
  end
end # Kernel
end # Linux
end # Post
end # Msf