heads/initrd/bin/kexec-save-default

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

TRACE "Under /bin/kexec-save-default"

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="$paramsdir/kexec_default_hashes.txt"
PRIMHASH_FILE="$paramsdir/kexec_primhdl_hash.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 "LVM group containing Encrypted LVs (retype to keep)? ($lvm_suggest): " \
			lvm_volume_group

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

		read \
			-p "Encrypted devices (retype to keep)? ($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

if [ "$CONFIG_TPM2_TOOLS" = "y" ]; then
	sha256sum /tmp/primary.handle > "$PRIMHASH_FILE" \
		|| die "ERROR: Failed to Hash TPM2 primary key handle!"
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

		#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 $bootdir/kexec_initrd_crypttab_overrides.txt"
		echo "+++ Those overrides will be part of detached signed digests and used to prepare cpio injected at kexec of selected default boot entry."
	else
		echo "+++ No crypttab file found in extracted initrd. A generic crypttab will be generated"
		if [ -e "$bootdir/kexec_initrd_crypttab_overrides.txt" ]; then
			echo "+++ Removing $bootdir/kexec_initrd_crypttab_overrides.txt"
			rm -f "$bootdir/kexec_initrd_crypttab_overrides.txt"
		fi
	fi

	# Cleanup
	cd /
	rm -rf /tmp/initrd_extract || true
fi

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

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