From c4a533c3d5b2a4262182ab1fa47fb6804ccf6dc1 Mon Sep 17 00:00:00 2001
From: Milan Broz <gmazyland@gmail.com>
Date: Tue, 19 Jun 2012 14:43:10 +0200
Subject: [PATCH] Fix luks-header-from-active to not require header on device
 and add UUID setting.

---
 misc/luks-header-from-active | 40 +++++++++++++++++++++++++++-------------
 1 file changed, 27 insertions(+), 13 deletions(-)

diff --git a/misc/luks-header-from-active b/misc/luks-header-from-active
index 1efd5b4..5676ca8 100755
--- a/misc/luks-header-from-active
+++ b/misc/luks-header-from-active
@@ -2,7 +2,7 @@
 
 # Try to get LUKS info and master key from active mapping and prepare parameters for cryptsetup.
 #
-# Copyright (C) 2010,2011 Milan Broz <asi@ucw.cz>
+# Copyright (C) 2010,2011,2012 Milan Broz <asi@ucw.cz>
 #
 # This copyrighted material is made available to anyone wishing to use,
 # modify, copy, or redistribute it subject to the terms and conditions
@@ -12,11 +12,22 @@
 # 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_cryptsetup() { echo $(cryptsetup status $DEVICE | grep $1 | sed "s/.*$1:\s*//;s/\ .*//") ; }
-
+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"
@@ -26,20 +37,23 @@ MK_FILE=$2
 
 [ -z "$(field 4)" ] && fail "Mapping $1 not active or it is not crypt target."
 
-# FIXME:
-# - add UUID
-# - check for CRYPT-LUKS1-* DM-UUID
-
-CIPHER=$(field_cryptsetup cipher)
-OFFSET=$(field_cryptsetup offset)
-REAL_DEVICE=$(field_cryptsetup device)
-KEY_SIZE=$(field_cryptsetup keysize)
+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" ] && fail "Incompatible device, sorry."
+[ -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 $REAL_DEVICE"
+echo "  cryptsetup luksFormat -c $CIPHER -s $KEY_SIZE --align-payload=$OFFSET --master-key-file=$MK_FILE --uuid=$UUID $REAL_DEVICE"
-- 
2.7.4