Skip to content

Instantly share code, notes, and snippets.

@jefft

jefft/grubvalidator.sh

Created August 5, 2020 06:53
Show Gist options
  • Save jefft/76cf6c5f6605eee55df6079223d8ba1c to your computer and use it in GitHub Desktop.
Save jefft/76cf6c5f6605eee55df6079223d8ba1c to your computer and use it in GitHub Desktop.
Download ZIP

Revisions

  1. jefft created this gist Aug 5, 2020.
    36 changes: 36 additions & 0 deletions grubvalidator.sh
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,36 @@
    #!/bin/bash
    # Script to check whether a Debian/Ubuntu system will experience boot problems from https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1889556 / https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1889509
    # https://www.redradishtech.com/display/~jturner/2020/07/30/symbol+%27grub_calloc%27+not+found+--+how+to+fix+on+AWS

    pass()
    {
    echo "All good. $*"
    exit
    }

    fail()
    {
    echo >&2 "Reboot may fail! $*"
    exit 1
    }

    if [[ -d /sys/firmware/efi ]]; then
    pass "System uses EFI, not BIOS, so is not affected"
    fi

    if zgrep -q "LP: #1889556" /usr/share/doc/grub-pc/changelog.Debian.gz; then
    pass "grub version has fixed the bug #1889556"
    fi

    command -v debconf-get-selections >/dev/null || sudo apt-get install debconf-utils
    devices="$(sudo debconf-get-selections | awk '$1=="grub-pc" && $2 == "grub-pc/install_devices" {print $4}')"

    if [[ -z $devices ]]; then
    pass "Although your grub is vulnerable to the bug, your debconf system has no preset devices to install grub onto. You will be prompted for a device when next running dpkg-reconfigure grub-pc"
    fi

    for device in $devices; do
    [[ -e $device ]] || fail "Your grub version does not fix the bug, and grub is configured to install to nonexistent device $device. Please upgrade grub and/or 'dpkg-reconfigure grub-pc' until you are sure grub is installed on the correct boot device"
    done

    fail "Your grub version does not fix the bug. Please run 'dpkg-reconfigure grub-pc', select the correct boot device, and verify that grub gets installed on it without error."