grub_conf

Grub is a boot loader on the Linux platform used to load and then transfer control to an operating system kernel, after which that kernel initializes the rest of the operating system. Use the grub_conf InSpec audit resource to test boot loader configuration settings that are defined in the grub.conf configuration file.


Syntax

A grub_conf resource block declares a list of settings in a grub.conf file:

describe grub_conf('path', 'kernel') do
  its('setting') { should eq 'value' }
end

or:

describe grub_conf('path') do
  its('default') { should eq '0' } #
  its('setting') { should eq 'value' }
end

where

  • 'service_name' is a service listed in the grub.conf file
  • 'path' is the path to the grub.conf file
  • 'kernel' specifies the default kernel (by using 'default') or a specific kernel; 'default' defines the position in the list of kernels at which the default kernel is defined, i.e. should eq '0' for the first kernel listed or 'path', 'default' to use the default kernel as specified in the grub.conf file
  • 'value' is the value that is expected


Examples

The following examples show how to use this InSpec audit resource.

Test a grub.conf file

A Grub configuration file located at /etc/grub.conf is similar to the following:

# grub.conf generated by anaconda
#
# Note:  You do not need to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/hda6
#          initrd /initrd-version.img
#boot=/dev/hda
default=0
timeout=10
splashimage=(hd0,0)/grub/splash.xpm.gz
title Red Hat Enterprise Linux ES (2.6.32-573.7.1.el6.x86_64)
    root (hd0,0)
    kernel /vmlinuz-2.6.32-573.7.1.el6.x86_64 ro root=/dev/hda6
    initrd /initrd-2.6.32-573.7.1.el6.x86_64.img
title Red Hat Enterprise Linux ES (2.6.32-358.14.1.el6.x86_64)
    root (hd0,0)
    kernel /vmlinuz-2.6.32-358.14.1.el6.x86_64 ro root=/dev/hda6 ramdisk_size=400000
    initrd /initrd-2.6.32-358.14.1.el6.x86_64.img

This file defines two versions of RedHat Enterprise Linux, with version 2.6.32-573.7.1.el6.x86_64 specified as the default.

The following test verifies the kernel, ensures that kernel is the default kernel, its initial RAM disk (initrd), and the timeout:

describe grub_conf('/etc/grub.conf',  'default') do
  its('kernel') { should include '/vmlinuz-2.6.32-573.7.1.el6.x86_64' }
  its('initrd') { should include '/initrd-2.6.32-573.7.1.el6.x86_64.img' }
  its('default') { should_not eq '1' }
  its('timeout') { should eq '10' }
end

The following test verifies the ramdisk_size for the non-deault kernel:

describe grub_conf('/etc/grub.conf',  'Red Hat Enterprise Linux ES (2.6.32-358.14.1.el6.x86_64)') do
   its('kernel') { should include 'ramdisk_size=400000' }
 end

Test a configuration file and boot configuration

describe grub_conf('/etc/grub.conf',  'default') do
  its('kernel') { should include '/vmlinuz-2.6.32-573.7.1.el6.x86_64' }
  its('initrd') { should include '/initramfs-2.6.32-573.el6.x86_64.img=1' }
  its('default') { should_not eq '1' }
  its('timeout') { should eq '5' }
end

Test a specific kernel

grub_conf('/etc/grub.conf',  'CentOS (2.6.32-573.12.1.el6.x86_64)') do
  its('kernel') { should include 'audit=1' }
end


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