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live-custom-ubuntu-from-scr…/scripts/chroot_build.sh
Marcos Tischer Vallim daba0cd44e feat: secure boot noble
2024-09-10 04:55:17 -03:00

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#!/bin/bash
set -e # exit on error
set -o pipefail # exit on pipeline error
set -u # treat unset variable as error
SCRIPT_DIR="$(dirname "$(readlink -f "$0")")"
CMD=(setup_host install_pkg build_image finish_up)
function help() {
# if $1 is set, use $1 as headline message in help()
if [ -z ${1+x} ]; then
echo -e "This script builds Ubuntu from scratch"
echo -e
else
echo -e $1
echo
fi
echo -e "Supported commands : ${CMD[*]}"
echo -e
echo -e "Syntax: $0 [start_cmd] [-] [end_cmd]"
echo -e "\trun from start_cmd to end_end"
echo -e "\tif start_cmd is omitted, start from first command"
echo -e "\tif end_cmd is omitted, end with last command"
echo -e "\tenter single cmd to run the specific command"
echo -e "\tenter '-' as only argument to run all commands"
echo -e
exit 0
}
function find_index() {
local ret;
local i;
for ((i=0; i<${#CMD[*]}; i++)); do
if [ "${CMD[i]}" == "$1" ]; then
index=$i;
return;
fi
done
help "Command not found : $1"
}
function check_host() {
if [ $(id -u) -ne 0 ]; then
echo "This script should be run as 'root'"
exit 1
fi
export HOME=/root
export LC_ALL=C
}
function setup_host() {
echo "=====> running setup_host ..."
cat <<EOF > /etc/apt/sources.list
deb $TARGET_UBUNTU_MIRROR $TARGET_UBUNTU_VERSION main restricted universe multiverse
deb-src $TARGET_UBUNTU_MIRROR $TARGET_UBUNTU_VERSION main restricted universe multiverse
deb $TARGET_UBUNTU_MIRROR $TARGET_UBUNTU_VERSION-security main restricted universe multiverse
deb-src $TARGET_UBUNTU_MIRROR $TARGET_UBUNTU_VERSION-security main restricted universe multiverse
deb $TARGET_UBUNTU_MIRROR $TARGET_UBUNTU_VERSION-updates main restricted universe multiverse
deb-src $TARGET_UBUNTU_MIRROR $TARGET_UBUNTU_VERSION-updates main restricted universe multiverse
EOF
echo "$TARGET_NAME" > /etc/hostname
# we need to install systemd first, to configure machine id
apt-get update
apt-get install -y libterm-readline-gnu-perl systemd-sysv
#configure machine id
dbus-uuidgen > /etc/machine-id
ln -fs /etc/machine-id /var/lib/dbus/machine-id
# don't understand why, but multiple sources indicate this
dpkg-divert --local --rename --add /sbin/initctl
ln -s /bin/true /sbin/initctl
}
# Load configuration values from file
function load_config() {
if [[ -f "$SCRIPT_DIR/config.sh" ]]; then
. "$SCRIPT_DIR/config.sh"
elif [[ -f "$SCRIPT_DIR/default_config.sh" ]]; then
. "$SCRIPT_DIR/default_config.sh"
else
>&2 echo "Unable to find default config file $SCRIPT_DIR/default_config.sh, aborting."
exit 1
fi
}
function install_pkg() {
echo "=====> running install_pkg ... will take a long time ..."
apt-get -y upgrade
# install live packages
apt-get install -y \
sudo \
ubuntu-standard \
casper \
discover \
laptop-detect \
os-prober \
network-manager \
net-tools \
wireless-tools \
wpagui \
locales \
grub-common \
grub-gfxpayload-lists \
grub-pc \
grub-pc-bin \
grub2-common \
grub-efi-amd64-signed \
shim-signed \
mtools \
binutils
case $TARGET_UBUNTU_VERSION in
"focal" | "bionic")
apt-get install -y lupin-casper
;;
*)
echo "Package lupin-casper is not needed. Skipping."
;;
esac
# install kernel
apt-get install -y --no-install-recommends $TARGET_KERNEL_PACKAGE
# graphic installer - ubiquity
apt-get install -y \
ubiquity \
ubiquity-casper \
ubiquity-frontend-gtk \
ubiquity-slideshow-ubuntu \
ubiquity-ubuntu-artwork
# Call into config function
customize_image
# remove unused and clean up apt cache
apt-get autoremove -y
# final touch
dpkg-reconfigure locales
# network manager
cat <<EOF > /etc/NetworkManager/NetworkManager.conf
[main]
rc-manager=none
plugins=ifupdown,keyfile
dns=systemd-resolved
[ifupdown]
managed=false
EOF
dpkg-reconfigure network-manager
apt-get clean -y
}
function build_image() {
echo "=====> running build_image ..."
rm -rf /image
mkdir -p /image/{casper,isolinux,install}
pushd /image
# copy kernel files
cp /boot/vmlinuz-**-**-generic casper/vmlinuz
cp /boot/initrd.img-**-**-generic casper/initrd
# memtest86
wget --progress=dot https://memtest.org/download/v7.00/mt86plus_7.00.binaries.zip -O install/memtest86.zip
unzip -p install/memtest86.zip memtest64.bin > install/memtest86+.bin
unzip -p install/memtest86.zip memtest64.efi > install/memtest86+.efi
rm -f install/memtest86.zip
# grub
touch ubuntu
cat <<EOF > isolinux/grub.cfg
search --set=root --file /ubuntu
insmod all_video
set default="0"
set timeout=30
menuentry "Try Ubuntu FS without installing" {
linux /casper/vmlinuz boot=casper nopersistent toram quiet splash ---
initrd /casper/initrd
}
menuentry "Install Ubuntu FS" {
linux /casper/vmlinuz boot=casper only-ubiquity quiet splash ---
initrd /casper/initrd
}
menuentry "Check disc for defects" {
linux /casper/vmlinuz boot=casper integrity-check quiet splash ---
initrd /casper/initrd
}
grub_platform
if [ "\$grub_platform" = "efi" ]; then
menuentry 'UEFI Firmware Settings' {
fwsetup
}
menuentry "Test memory Memtest86+ (UEFI)" {
linux /install/memtest86+.efi
}
else
menuentry "Test memory Memtest86+ (BIOS)" {
linux16 /install/memtest86+.bin
}
fi
EOF
# generate manifest
dpkg-query -W --showformat='${Package} ${Version}\n' | sudo tee casper/filesystem.manifest
cp -v casper/filesystem.manifest casper/filesystem.manifest-desktop
for pkg in $TARGET_PACKAGE_REMOVE; do
sudo sed -i "/$pkg/d" casper/filesystem.manifest-desktop
done
# create diskdefines
cat <<EOF > README.diskdefines
#define DISKNAME ${GRUB_LIVEBOOT_LABEL}
#define TYPE binary
#define TYPEbinary 1
#define ARCH amd64
#define ARCHamd64 1
#define DISKNUM 1
#define DISKNUM1 1
#define TOTALNUM 0
#define TOTALNUM0 1
EOF
# create certificates
rm -rf /certificates
mkdir /certificates
pushd /certificates
# create the certificate template
cat <<EOF > config.conf
[ req ]
default_bits = 2048
default_md = sha256
distinguished_name = dn
prompt = no
[ dn ]
C = BR
ST = SP
L = Campinas
O = Scratch, Labs
OU = Labs
CN = \${ENV::CN}
[ root ]
basicConstraints = critical,CA:TRUE
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid:always,issuer
keyUsage = critical,digitalSignature,keyEncipherment,keyCertSign,cRLSign
[ ca ]
basicConstraints = critical,CA:TRUE,pathlen:0
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid:always,issuer:always
keyUsage = critical,digitalSignature,keyEncipherment,keyCertSign,cRLSign
[ db ]
subjectKeyIdentifier = hash
basicConstraints = critical,CA:FALSE
keyUsage = critical,keyEncipherment,dataEncipherment
authorityKeyIdentifier = keyid,issuer:always
EOF
# create the Root CA certificate
CN="Root, CA" \
openssl req -x509 -newkey rsa:2048 -nodes \
-keyout root.key \
-days 3650 \
-config config.conf \
-extensions root \
-out root.pem
# create the intermediate CA certificate
CN="Ubuntu live from scratch, CA" \
openssl req -newkey rsa:2048 -nodes \
-keyout ca.key \
-config config.conf \
-out ca.pem
# create Database (DB) request certificate
CN="Ubuntu live from scratch, Database" \
openssl req -newkey rsa:2048 -nodes \
-keyout db.key \
-config config.conf \
-out db.pem
# sign the intermediate CA certificate with the Root CA certificate
CN="Ubuntu live from scratch, CA" \
openssl x509 -req \
-extfile config.conf \
-extensions ca \
-in ca.pem \
-CA root.pem \
-CAkey root.key \
-CAcreateserial \
-out ca.pem \
-days 3650 -sha256
# sign Database (DB) certificate using your own CA
CN="Ubuntu live from scratch, Database" \
openssl x509 -req \
-extfile config.conf \
-extensions db \
-in db.pem \
-CA ca.pem \
-CAkey ca.key \
-CAcreateserial \
-out db.pem \
-days 3650 -sha256
# create the intermediate CA certificate chain
cat ca.pem root.pem > ca-chain.pem
# verify the signatures
openssl verify -CAfile ca-chain.pem db.pem
# create DER version of our public key (CA)
openssl x509 -outform DER -in ca.pem -out ca.cer
popd # return to image directory
# grub version/release
GRUB_VERSION=`grub-mkstandalone -V | tr -s ' ' | cut -d' ' -f3 | cut -d'-' -f1`
GRUB_RELEASE=`grub-mkstandalone -V | tr -s ' ' | cut -d' ' -f3`
# create SBAT file
cat <<EOF > isolinux/sbat.csv
sbat,1,SBAT Version,sbat,1,https://github.com/rhboot/shim/blob/main/SBAT.md
grub,1,Free Software Foundation,grub,$GRUB_VERSION,https://www.gnu.org/software/grub/
grub.ubuntu,1,Ubuntu,grub2,$GRUB_RELEASE,https://www.ubuntu.com/
EOF
# create a grub UEFI image
grub-mkstandalone \
--format=x86_64-efi \
--output=isolinux/grubx64.efi \
--locales="" \
--fonts="" \
"boot/grub/grub.cfg=isolinux/grub.cfg"
# fix secure boot grub
sed -i 's/SecureBoot/SecureB00t/' isolinux/grubx64.efi
# add .sbat sections
objcopy --add-section .sbat=isolinux/sbat.csv isolinux/grubx64.efi --change-section-address .sbat=10000000
# UEFI secure boot signing
sbsign --key /certificates/db.key --cert /certificates/db.pem --output isolinux/grubx64.efi isolinux/grubx64.efi
# Copy Shim and MOK
cp /usr/lib/shim/shimx64.efi.signed.previous isolinux/bootx64.efi
cp /usr/lib/shim/mmx64.efi isolinux/mmx64.efi
# create a FAT16 UEFI boot disk image containing the EFI bootloader
(
cd isolinux && \
dd if=/dev/zero of=efiboot.img bs=1M count=10 && \
mkfs.vfat -F 16 efiboot.img && \
LC_CTYPE=C mmd -i efiboot.img certificates efi efi/boot && \
LC_CTYPE=C mcopy -i efiboot.img ./bootx64.efi ::efi/boot/bootx64.efi && \
LC_CTYPE=C mcopy -i efiboot.img ./mmx64.efi ::efi/boot/mmx64.efi && \
LC_CTYPE=C mcopy -i efiboot.img ./grubx64.efi ::efi/boot/grubx64.efi && \
LC_CTYPE=C mcopy -i efiboot.img /certificates/ca.cer ::certificates/
)
# create a grub BIOS image
grub-mkstandalone \
--format=i386-pc \
--output=isolinux/core.img \
--install-modules="linux16 linux normal iso9660 biosdisk memdisk search tar ls" \
--modules="linux16 linux normal iso9660 biosdisk search" \
--locales="" \
--fonts="" \
"boot/grub/grub.cfg=isolinux/grub.cfg"
# combine a bootable Grub cdboot.img
cat /usr/lib/grub/i386-pc/cdboot.img isolinux/core.img > isolinux/bios.img
# generate md5sum.txt
/bin/bash -c "(find . -type f -print0 | xargs -0 md5sum | grep -v -e 'md5sum.txt' -e 'bios.img' -e 'efiboot.img' > md5sum.txt)"
popd # return initial directory
}
function finish_up() {
echo "=====> finish_up"
# truncate machine id (why??)
truncate -s 0 /etc/machine-id
# remove diversion (why??)
rm /sbin/initctl
dpkg-divert --rename --remove /sbin/initctl
rm -rf /tmp/* ~/.bash_history
}
# ============= main ================
load_config
check_host
# check number of args
if [[ $# == 0 || $# > 3 ]]; then help; fi
# loop through args
dash_flag=false
start_index=0
end_index=${#CMD[*]}
for ii in "$@";
do
if [[ $ii == "-" ]]; then
dash_flag=true
continue
fi
find_index $ii
if [[ $dash_flag == false ]]; then
start_index=$index
else
end_index=$(($index+1))
fi
done
if [[ $dash_flag == false ]]; then
end_index=$(($start_index + 1))
fi
# loop through the commands
for ((ii=$start_index; ii<$end_index; ii++)); do
${CMD[ii]}
done
echo "$0 - Initial build is done!"