From 8e74f73bf46c3dc6ed96e1e0db04db88e7761521 Mon Sep 17 00:00:00 2001
From: Christian Hesse <mail@eworm.de>
Date: Mon, 27 May 2013 10:50:21 +0200
Subject: Initial import

---
 bin/ykfde     | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 hook/ykfde    | 36 +++++++++++++++++++++++
 install/ykfde | 13 +++++++++
 3 files changed, 140 insertions(+)
 create mode 100644 bin/ykfde
 create mode 100644 hook/ykfde
 create mode 100644 install/ykfde

diff --git a/bin/ykfde b/bin/ykfde
new file mode 100644
index 0000000..56e75a7
--- /dev/null
+++ b/bin/ykfde
@@ -0,0 +1,91 @@
+#!/bin/sh
+
+function help() {
+	echo "usage: ${0} [OPTIONS]"
+	echo
+	echo "where OPTIONS are:"
+	echo " -1         use Yubico key slot 1"
+	echo " -2         use Yubico key slot 2"
+	echo " -d DEVICE  add key to device DEVICE"
+	echo " -h         show this help"
+	echo " -k         keep challenge, just add a new slot"
+}
+
+DIR="/tmp/.ykfde-${$}/"
+PASS=""
+SLOT="1"
+KEEP="0"
+
+while getopts "12d:hk" opt; do
+	case ${opt} in
+		1)
+			SLOT="1"
+			;;
+		2)
+			SLOT="2"
+			echo "Do not forget to add 'ykfde_slot=2' to your boot parameters!"
+			;;
+		d)
+			DEVICE="${OPTARG}"
+			;;
+		h)
+			help
+			exit 0
+			;;
+		k)
+			KEEP="1"
+			;;
+	esac
+done
+
+if [ -z "${DEVICE}" ]; then
+	echo "No device given." >&2
+	help
+	exit 1
+elif [ ! -b "${DEVICE}" ]; then
+	echo "Device '${DEVICE}' does not exist or is not a block device." >&2
+	exit 1
+elif ! cryptsetup isLuks "${DEVICE}" 2>/dev/null; then
+	echo "Device '${DEVICE}' does not exist." >&2
+	exit 1
+fi
+
+install -d -m0700 "${DIR}"
+echo "Please give extra password if you want to activate two factor"
+echo -n "authentication, just ENTER for none: "
+stty -echo
+read PASS
+stty echo
+echo
+
+if [ -n "${PASS}" ]; then
+	echo "Do not forget to add 'ykfde_twofactor=y' to your boot parameters!"
+fi
+
+# generate challenge
+if [ "${KEEP}" = "1" ] && [ -s "/etc/ykfde-challenge" ]; then
+	echo "User requested to keep challenge, not generating a new one."
+	ln -s "/etc/ykfde-challenge" "${DIR}/ykfde-challenge"
+else
+	makepasswd --chars=$((64-${#PASS})) | tr -d '\n' > "${DIR}/ykfde-challenge"
+fi
+
+# generate response and add key to LUKS device
+if ! ykchalresp -${SLOT} "${PASS}$(cat ${DIR}/ykfde-challenge)" > "${DIR}/ykfde-response"; then
+	# ykchalresp should have shouted, so do not complain here
+	exit 1
+fi
+if ! cryptsetup luksAddKey "${DEVICE}" "${DIR}/ykfde-response"; then
+	# cryptsetup should have shouted, ...
+	exit 1
+fi
+
+# shred response and install challenge
+shred --remove "${DIR}/ykfde-response"
+if [ "${KEEP}" != "1" ] && [ -s "${DIR}/ykfde-challenge" ] && [ ! -L "${DIR}/ykfde-challenge" ]; then
+	install -D -m 0400 "${DIR}/ykfde-challenge" "/etc/ykfde-challenge"
+fi
+rm -rf "${DIR}"
+
+echo "Please do not forget to remove old keys when changing challenge!"
+echo "Now run 'mkinitcpio' to build a new initramfs!"
diff --git a/hook/ykfde b/hook/ykfde
new file mode 100644
index 0000000..be75694
--- /dev/null
+++ b/hook/ykfde
@@ -0,0 +1,36 @@
+#!/bin/sh
+
+run_hook() {
+	ykfde_slot="${ykfde_slot:-1}"
+	ykfde_count=0
+
+	if [ -s /ykfde-challenge ]; then
+		modprobe -a -q usbhid >/dev/null 2>&1
+
+		if [ "${ykfde_twofactor}" = "y" ]; then
+			echo -n "Please give two factor key for Yubikey: "
+			stty -echo
+			read TWOFACTOR
+			stty echo
+			echo
+		else
+			TWOFACTOR=""
+		fi
+
+		# Any chance to get this more efficient? Without polling and without long sleep times would be great.
+		while ! ykchalresp -${ykfde_slot} "${TWOFACTOR}$(cat /ykfde-challenge)" > /crypto_keyfile.bin 2>/dev/null; do
+			if [ $((ykfde_count++)) -gt 10 ]; then
+				msg ":: No Yubikey presend, fallback to interactive mode"
+				rm -f /ykfde-challenge
+				return 1
+			fi
+			sleep 0.3
+		done
+
+		msg ":: Created crypto keyfile using Yubikey, handing over to encrypt hook"
+		rm -f /ykfde-challenge
+	else
+		msg ":: No challenge found, falling back to interactive mode"
+		return 1
+	fi
+}
diff --git a/install/ykfde b/install/ykfde
new file mode 100644
index 0000000..bbf5bd2
--- /dev/null
+++ b/install/ykfde
@@ -0,0 +1,13 @@
+#!/bin/sh
+
+build() {
+	add_runscript
+	add_binary ykchalresp
+	add_file /etc/ykfde-challenge /
+	add_module 'usbhid'
+}
+
+help() {
+	echo "This hook adds support for opening LUKS devices with Yubico key."
+	echo "Please use command 'ykfde' to prepare."
+}
-- 
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