From 735de3b38abbd6564082a819377673ee593744a6 Mon Sep 17 00:00:00 2001
From: Kenny Root <kroot@google.com>
Date: Thu, 30 Sep 2010 14:11:39 -0700
Subject: Hash keys with MD5; track IBinders not IInterface

Using a plaintext password doesn't work unless it's a certain length, so
just hash the plaintext password with MD5 to make it the right length
for the twofish encryption.

Tracking the IInterface doesn't make much sense since it's different
each time, so track the IBinder instead. That way we can unlinkToDeath
the binder when the last thing it's holding onto goes away.

Change-Id: Id828d25b4d74f27e9d8b4bfb3909c964469cc473
---
 tools/obbtool/mkobb.sh | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

(limited to 'tools/obbtool')

diff --git a/tools/obbtool/mkobb.sh b/tools/obbtool/mkobb.sh
index f4cae9a..1987696 100755
--- a/tools/obbtool/mkobb.sh
+++ b/tools/obbtool/mkobb.sh
@@ -21,7 +21,7 @@
 MOUNTDIR=/tmp
 
 # Presets. Changing these will probably break your OBB on the device
-CRYPTO=blowfish
+CRYPTO=twofish
 FS=vfat
 MKFS=mkfs.vfat
 LOSETUP=losetup
@@ -122,7 +122,12 @@ onexit() {
         rmdir ${temp_mount}
     fi
     if [ "x${loop_dev}" != "x" ]; then \
-        ${LOSETUPBIN} -d ${loop_dev}
+        if [ ${use_crypto} -eq 1 ]; then \
+            dmsetup remove -f ${loop_dev}
+            ${LOSETUPBIN} -d ${old_loop_dev}
+        else \
+            ${LOSETUPBIN} -d ${loop_dev}
+        fi
     fi
     if [ "x${tempfile}" != "x" -a -f "${tempfile}" ]; then \
         rm -f ${tempfile}
@@ -202,7 +207,7 @@ trap onexit ERR
 
 tempfile=$(tempfile -d ${outdir}) || ( echo "ERROR: couldn't create temporary file in ${outdir}"; exit 1 )
 
-block_count=`du --apparent-size --block-size=512 ${directory} | awk '{ print $1; }'`
+block_count=`du -s --apparent-size --block-size=512 ${directory} | awk '{ print $1; }'`
 if [ $? -ne 0 ]; then \
     echo "ERROR: Couldn't read size of input directory ${directory}"
     exit 1
@@ -216,12 +221,14 @@ fi
 
 loop_dev=$(${LOSETUPBIN} -f) || ( echo "ERROR: losetup wouldn't tell us the next unused device"; exit 1 )
 
+${LOSETUPBIN} ${loop_dev} ${tempfile} || ( echo "ERROR: couldn't create loopback device"; exit 1 )
+
 if [ ${use_crypto} -eq 1 ]; then \
-    keyfile=$(tempfile -d ${outdir}) || ( echo "ERROR: could not create temporary key file"; exit 1 )
-    ${LOSETUPBIN} -p 5 -e ${CRYPTO} ${loop_dev} ${tempfile} 5< ${keyfile} || ( echo "ERROR: couldn't create loopback device"; exit 1 )
-    rm -f ${keyfile}
-else \
-    ${LOSETUPBIN} ${loop_dev} ${tempfile} || ( echo "ERROR: couldn't create loopback device"; exit 1 )
+    hashed_key=`echo -n "${key}" | md5sum | awk '{ print $1 }'`
+    unique_dm_name=`basename ${tempfile}`
+    echo "0 `blockdev --getsize ${loop_dev}` crypt ${CRYPTO} ${hashed_key} 0 ${loop_dev} 0" | dmsetup create ${unique_dm_name}
+    old_loop_dev=${loop_dev}
+    loop_dev=/dev/mapper/${unique_dm_name}
 fi
 
 #
@@ -252,7 +259,12 @@ echo "Successfully created \`${filename}'"
 #
 umount ${temp_mount}
 rmdir ${temp_mount}
-${LOSETUPBIN} -d ${loop_dev}
+if [ ${use_crypto} -eq 1 ]; then \
+    dmsetup remove -f ${loop_dev}
+    ${LOSETUPBIN} -d ${old_loop_dev}
+else \
+    ${LOSETUPBIN} -d ${loop_dev}
+fi
 mv ${tempfile} ${filename}
 
 trap - ERR
-- 
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