heads/initrd/bin/kexec-save-default

#!/bin/sh
# Save these options to be the persistent default
set -e -o pipefail
. /tmp/config
. /etc/functions

while getopts "b:d:p:i:" arg; do
	case $arg in
		b) bootdir="$OPTARG" ;;
		d) paramsdev="$OPTARG" ;;
		p) paramsdir="$OPTARG" ;;
		i) index="$OPTARG" ;;
	esac
done

if [ -z "$bootdir" -o -z "$index" ]; then
	die "Usage: $0 -b /boot -i menu_option "
fi

if [ -z "$paramsdev" ]; then
	paramsdev="$bootdir"
fi

if [ -z "$paramsdir" ]; then
	paramsdir="$bootdir"
fi

bootdir="${bootdir%%/}"
paramsdev="${paramsdev%%/}"
paramsdir="${paramsdir%%/}"

TMP_MENU_FILE="/tmp/kexec/kexec_menu.txt"
ENTRY_FILE="$paramsdir/kexec_default.$index.txt"
HASH_FILE="$paramsdir/kexec_default_hashes.txt"

if [ ! -r "$TMP_MENU_FILE" ]; then
	die "No menu options available, please run kexec-select-boot"
fi

entry=`head -n $index $TMP_MENU_FILE | tail -1`
if [ -z "$entry" ]; then
	die "Invalid menu index $index"
fi

KEY_DEVICES="$paramsdir/kexec_key_devices.txt"
KEY_LVM="$paramsdir/kexec_key_lvm.txt"
save_key="n"
if [[ "$CONFIG_TPM" = "y" && "$CONFIG_TPM_NO_LUKS_DISK_UNLOCK" != "y" ]]; then
	if [ ! -r "$KEY_DEVICES" ]; then
		read \
			-n 1 \
			-p "Do you wish to add a disk encryption to the TPM [y/N]: " \
			add_key_confirm
		echo

		if [ "$add_key_confirm" = "y" \
			-o "$add_key_confirm" = "Y" ]; then
			lvm_suggest="e.g. qubes_dom0 or blank"
			devices_suggest="e.g. /dev/sda2 or blank"
			save_key="y"
		fi
	else
		read \
			-n 1 \
			-p "Do you want to reseal a disk key to the TPM [y/N]: " \
			change_key_confirm
		echo

		if [ "$change_key_confirm" = "y" \
			-o "$change_key_confirm" = "Y" ]; then
			old_lvm_volume_group=""
			if [ -r "$KEY_LVM" ]; then
				old_lvm_volume_group=`cat $KEY_LVM` || true
				old_key_devices=`cat $KEY_DEVICES \
				| cut -d\  -f1 \
				| grep -v "$old_lvm_volume_group" \
				| xargs` || true
			else
				old_key_devices=`cat $KEY_DEVICES \
				| cut -d\  -f1 | xargs` || true
			fi

			lvm_suggest="was '$old_lvm_volume_group'"
			devices_suggest="was '$old_key_devices'"
			save_key="y"
		fi
	fi

	if [ "$save_key" = "y" ]; then
		echo "+++ LVM volume groups (lvm vgscan): "
		lvm vgscan || true

		read \
			-p "Encrypted LVM group? ($lvm_suggest): " \
			lvm_volume_group

		echo "+++ Block devices (blkid): "
		blkid || true

		read \
			-p "Encrypted devices? ($devices_suggest): " \
			key_devices

		save_key_params="-s -p $paramsdev"
		if [ -n "$lvm_volume_group" ]; then
			save_key_params="$save_key_params -l $lvm_volume_group $key_devices"
		else
			save_key_params="$save_key_params $key_devices"
		fi
		echo "Running kexec-save-key with params: $save_key_params"
		kexec-save-key $save_key_params \
			|| die "Failed to save the disk key"
	fi
fi

# try to switch to rw mode
mount -o rw,remount $paramsdev

if [ ! -d $paramsdir ]; then
	mkdir -p $paramsdir \
	|| die "Failed to create params directory"
fi
rm $paramsdir/kexec_default.*.txt 2>/dev/null || true
echo "$entry" > $ENTRY_FILE
( cd $bootdir && kexec-boot -b "$bootdir" -e "$entry" -f| \
	xargs sha256sum > $HASH_FILE \
) || die "Failed to create hashes of boot files"
if [ ! -r $ENTRY_FILE -o ! -r $HASH_FILE ]; then
	die "Failed to write default config"
fi

if [ "$save_key" = "y" ]; then
	# logic to parse OS initrd to extract crypttab, its filepaths and its OS defined options
	mkdir -p /tmp/initrd_extract
	cd /tmp/initrd_extract
	# Get initrd filename selected to be default initrd that OS could be using to configure LUKS on boot by deploying crypttab files
	current_default_initrd=$(cat /boot/kexec_default_hashes.txt | grep initr | awk -F " " {'print $NF'} | sed 's/\.\//\/boot\//g')
	
	# Get crypttab files paths from initrd
	echo "Checking current selected default boot's $current_default_initrd for existing crypttab files..."
	# First either decompress or use the original if it's not compressed
	initrd_decompressed="/tmp/initrd_extract/initrd_decompressed.cpio"
	zcat < "$current_default_initrd" > "$initrd_decompressed" 2> /dev/null || initrd_decompressed="$current_default_initrd"
	crypttab_files=$(cpio --list --quiet < "$initrd_decompressed" | grep crypttab 2> /dev/null) || true
	
	if [ ! -z "$crypttab_files" ]; then
		echo "Extracting current selected default boot's $current_default_initrd for found crypttab files analysis..."
		cpio -id --quiet < $initrd_decompressed $crypttab_files 2> /dev/null
		rm -f $bootdir/kexec_initrd_crypttab_overrides.txt || true
		
		#Parsing each crypttab file found
		echo "$crypttab_files" | while read filepath; do
			# Keep only non-commented lines
			current_filepath_entries=$(cat "$filepath" | grep -v "^#")
			# Modify each retained crypttab line to contain to be injected /secret.key at next default boots
			modified_filepath_entries=$(echo "$current_filepath_entries" | sed 's/none/\/secret.key/g')
			echo "$modified_filepath_entries" | while read single_modified_filepath_entry; do
				# Append each found filepath:entry into additional kexec_ file that will be part of detached signed digest
				echo "$filepath:$single_modified_filepath_entry" >> $bootdir/kexec_initrd_crypttab_overrides.txt
			done
		done

		cd - > /dev/null

		#insert current default boot's initrd crypttab locations into tracking file to be overwritten into initramfs at kexec-inject-key
		echo "The following OS crypttab file:entry were modified from default boot's initrd:"
		cat $bootdir/kexec_initrd_crypttab_overrides.txt
		echo "Heads added /secret.key in those entries and saved them under $bootdir/kexec_initrd_crypttab_overrides.txt"
		echo "Those overrides will be part of detached signed digests and used to prepare cpio injected at kexec of selected default boot entry."
	else
		echo "No crypttab file found in extracted initrd. Removing $bootdir/kexec_initrd_crypttab_overrides.txt"
		rm -f "$bootdir/kexec_initrd_crypttab_overrides.txt" || true
	fi
	# Cleanup
	rm -rf /tmp/initrd_extract || true
fi

# sign and auto-roll config counter
extparam=
if [ "$CONFIG_TPM" = "y" ]; then
	extparam=-r
fi
kexec-sign-config -p $paramsdir $extparam \
|| die "Failed to sign default config"

# switch back to ro mode
mount -o ro,remount $paramsdev