1 files changed, 59 insertions, 0 deletions
diff --git a/misc/luks-header-from-active b/misc/luks-header-from-active
new file mode 100755
index 0000000..a94ad33
--- /dev/null
+++ b/misc/luks-header-from-active
@@ -0,0 +1,59 @@
+#!/bin/bash
+
+# Try to get LUKS info and master key from active mapping and prepare parameters for cryptsetup.
+#
+# Copyright (C) 2010,2011,2012 Milan Broz <gmazyland@gmail.com>
+#
+# This copyrighted material is made available to anyone wishing to use,
+# modify, copy, or redistribute it subject to the terms and conditions
+# of the GNU General Public License v.2.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software Foundation,
+# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+umask 0077
+
+fail() { echo -e $1 ; exit 1 ; }
+field() { echo $(dmsetup table --target crypt --showkeys $DEVICE | sed 's/.*: //' | cut -d' ' -f$1) ; }
+field_uuid() { echo $(dmsetup info $1 --noheadings -c -o uuid) ; }
+field_device() {
+	TEMP=$(readlink /sys/dev/block/$1 | sed -e 's/.*\///')
+	if [  ${TEMP:0:3} = "dm-" -a -e /sys/block/$TEMP/dm/name ] ; then
+		TEMP=/dev/mapper/$(cat /sys/block/$TEMP/dm/name)
+	else
+		TEMP=/dev/$TEMP
+	fi
+	echo $TEMP
+}
+
+which readlink >/dev/null || fail "You need readlink (part of coreutils package)."
+which xxd >/dev/null || fail "You need xxd (part of vim package) installed to convert key."
+
+[ -z "$2" ] && fail "Recover LUKS header from active mapping, use:\n $0 crypt_mapped_device mk_file_name"
+
+DEVICE=$1
+MK_FILE=$2
+
+[ -z "$(field 4)" ] && fail "Mapping $1 not active or it is not crypt target."
+
+CIPHER=$(field 4)
+OFFSET=$(field 8)
+SYS_DEVICE=$(field 7)
+REAL_DEVICE=$(field_device $SYS_DEVICE)
+KEY=$(field 5)
+KEY_SIZE=$(( ${#KEY} / 2 * 8 ))
+SYS_UUID=$(field_uuid $DEVICE)
+UUID="${SYS_UUID:12:8}-${SYS_UUID:20:4}-${SYS_UUID:24:4}-${SYS_UUID:28:4}-${SYS_UUID:32:12}"
+
+#echo "CIPHER=$CIPHER OFFSET=$OFFSET SYS_DEVICE=$SYS_DEVICE REAL_DEVICE=$REAL_DEVICE KEY_SIZE=$KEY_SIZE KEY=$KEY UUID=$UUID SYS_UUID=$SYS_UUID"
+
+[ -z "$CIPHER" -o -z "$OFFSET" -o "$OFFSET" -le 383 -o \
+-z "$KEY" -o -z "$UUID" -o -z "$REAL_DEVICE" -o "${SYS_UUID:0:12}" != "CRYPT-LUKS1-" ] && \
+fail "Incompatible device, sorry."
+
+echo "Generating master key to file $MK_FILE."
+echo -E -n $KEY| xxd -r -p >$MK_FILE
+
+echo "You can now try to reformat LUKS device using:"
+echo "  cryptsetup luksFormat -c $CIPHER -s $KEY_SIZE --align-payload=$OFFSET --master-key-file=$MK_FILE --uuid=$UUID $REAL_DEVICE"