From c2e4723f83cb7bb898feb2ca9cf385141720440f Mon Sep 17 00:00:00 2001
From: HappyZ <zhuyanzi@gmail.com>
Date: Wed, 25 Jul 2018 18:54:42 -0700
Subject: [PATCH] unpacker

---
 fw_updater_packer_unpacker/.gitignore         |   4 +-
 .../start_eufwupdater.sh                      | 128 ++++++++++++++++++
 fw_updater_packer_unpacker/unpacker.sh        | 125 +++++++++++++++++
 3 files changed, 255 insertions(+), 2 deletions(-)
 create mode 100755 fw_updater_packer_unpacker/start_eufwupdater.sh
 create mode 100755 fw_updater_packer_unpacker/unpacker.sh

diff --git a/fw_updater_packer_unpacker/.gitignore b/fw_updater_packer_unpacker/.gitignore
index 425855a..aa041d6 100644
--- a/fw_updater_packer_unpacker/.gitignore
+++ b/fw_updater_packer_unpacker/.gitignore
@@ -1,4 +1,4 @@
 *.pkg
 test/
-key1
-key2
\ No newline at end of file
+key.private
+key.pub
\ No newline at end of file
diff --git a/fw_updater_packer_unpacker/start_eufwupdater.sh b/fw_updater_packer_unpacker/start_eufwupdater.sh
new file mode 100755
index 0000000..a62bdb1
--- /dev/null
+++ b/fw_updater_packer_unpacker/start_eufwupdater.sh
@@ -0,0 +1,128 @@
+#!/bin/sh
+
+# $1 update package
+# $2 output directory
+# $3 pub key to verify sig
+# $4 pri key to decrypt data key
+
+SIG_FILE="$2/sig.dat"
+AES256_KEY="$2/aes256.key"
+IV="$2/iv"
+
+ANIM_SIG_FILE="$2/anim_sig.dat"
+ANIM_PID=0
+
+
+epd_cmd()
+{
+  epd_fb_test $@ >/dev/null 2>&1
+}
+
+
+########################################
+# file header check
+########################################
+HEAD_MARK=`head -c 4 $1`
+if [ $HEAD_MARK != "DPUP" ]
+then
+  echo "Invalid file"
+  exit 0
+fi
+
+
+DATA_OFFSET=`dd if=$1 bs=4 skip=1 count=1 2>/dev/null | od -A n -t d4 -v`
+BODY_SIZE=`dd if=$1 bs=4 skip=2 count=1 2>/dev/null | od -A n -t d4 -v`
+########################################
+# start animation for package check
+########################################
+ANIM_HEADER_OFFSET=$(( $DATA_OFFSET + $BODY_SIZE ))
+if [ -z "$ANIM_HEADER_OFFSET" ]
+then
+  ANIM_HEADER_OFFSET=0
+fi
+ANIM_HEADER_SIZE=`dd if=$1 bs=1 skip=$ANIM_HEADER_OFFSET count=4 2>/dev/null | od -A n -t d4 -v`
+if [ -z "$ANIM_HEADER_SIZE" ]
+then
+  ANIM_HEADER_SIZE=0
+fi
+ANIM_ARCH_SIZE=`dd if=$1 bs=1 skip=$(($ANIM_HEADER_OFFSET + 4)) count=4 2>/dev/null | od -A n -t d4 -v`
+ANIM_SIG_SIZE=`dd if=$1 bs=1 skip=$(($ANIM_HEADER_OFFSET + 8)) count=4 2>/dev/null | od -A n -t d4 -v`
+dd if=$1 of=$ANIM_SIG_FILE bs=1 skip=$(($ANIM_HEADER_OFFSET + 12)) count=$(($ANIM_SIG_SIZE)) 2>/dev/null
+ANIM_ARCH_OFFSET=$(($ANIM_HEADER_OFFSET + $ANIM_HEADER_SIZE))
+dd if=$1 bs=$ANIM_ARCH_OFFSET skip=1 2>/dev/null | head -c $(($ANIM_ARCH_SIZE)) | openssl dgst -sha256 -verify $3 -signature $ANIM_SIG_FILE 1>/dev/null
+if [ $? -eq 0 ]
+then
+  start_prepare_animation.sh $1 $2 $ANIM_ARCH_OFFSET $(($ANIM_ARCH_SIZE)) &
+  ANIM_PID=$!
+fi
+
+
+
+########################################
+# extract sig
+########################################
+SIG_SIZE=`dd if=$1 bs=4 skip=4 count=1 2>/dev/null | od -A n -t d4 -v`
+dd if=$1 of=$SIG_FILE bs=1 skip=20 count=$(($SIG_SIZE)) 2>/dev/null
+
+
+########################################
+# verify sig
+########################################
+dd if=$1 bs=$(($DATA_OFFSET)) skip=1 2>/dev/null | head -c $(($BODY_SIZE)) | openssl dgst -sha256 -verify $3 -signature $SIG_FILE 1>/dev/null
+if [ $? -ne 0 ]
+then
+  echo "Verify failed."
+  exit 0
+fi
+
+
+########################################
+# decrypt data key
+########################################
+ENC_KEY_OFFSET=$((20 + $SIG_SIZE))
+PAD_SIZE=$((16 - $SIG_SIZE % 16 ))
+if [ $PAD_SIZE -ne 16 ]
+then
+  ENC_KEY_OFFSET=$(( $ENC_KEY_OFFSET + $PAD_SIZE ))
+fi
+
+ENC_KEY_SIZE=`dd if=$1 bs=1 skip=${ENC_KEY_OFFSET} count=4 2>/dev/null | od -A n -t d4 -v`
+ENC_KEY_OFFSET=$(( $ENC_KEY_OFFSET + 4 ))
+dd if=$1 bs=1 skip=${ENC_KEY_OFFSET} count=$(($ENC_KEY_SIZE)) 2>/dev/null | openssl rsautl -decrypt -inkey $4 > ${AES256_KEY}
+
+
+########################################
+# extract iv
+########################################
+IV_OFFSET=$(($ENC_KEY_OFFSET + $ENC_KEY_SIZE))
+dd if=$1 of=$IV bs=1 skip=${IV_OFFSET} count=32 2>/dev/null
+
+
+########################################
+# decrypt data and extract directory tree
+########################################
+dd if=$1 bs=$(($DATA_OFFSET)) skip=1 2>/dev/null | head -c $(($BODY_SIZE)) | openssl enc -d -aes-256-cbc -K `cat ${AES256_KEY}` -iv `cat ${IV}` | tar -xz -C $2
+
+
+########################################
+# stop animation for package check
+########################################
+if [ $ANIM_PID -ne 0 ]
+then
+  kill $ANIM_PID
+  epd_cmd gray DU PART 0
+  epd_cmd wait 300000
+fi
+
+
+########################################
+# start updater
+########################################
+if [ -f ${2}/FwUpdater/eufwupdater.sh ]
+then
+  ${2}/FwUpdater/eufwupdater.sh
+  exit $?   # tentative
+else
+  echo "Invalid archive (No updater script)."
+  exit 0
+fi
\ No newline at end of file
diff --git a/fw_updater_packer_unpacker/unpacker.sh b/fw_updater_packer_unpacker/unpacker.sh
new file mode 100755
index 0000000..f4c895a
--- /dev/null
+++ b/fw_updater_packer_unpacker/unpacker.sh
@@ -0,0 +1,125 @@
+#!/bin/sh
+
+# Unpacker for DPT pkg
+# HappyZ
+# Thanks to anonymous contributer somewhere on earth
+
+# PKG FILE FORMAT
+# byte 1--4:          DPUP - file recognizer
+# byte 5--8:          data offset location A
+# byte 9--12:         total data content size D
+# byte 13--16:        nothing
+# byte 17--20:        sigfile size B
+# byte 21--(20+B):    sigfile data
+# byte (21+(-B%16)%16)--(25+(-B%16)%16):  encrypted data aes key size (BE) C
+# byte (+1)--(+C):    encrypted data aes key bytes
+# byte (+1)--(+32):   initial vector  --- up till now bytes shall equal to A
+# byte (A+1)--(A+D):  encrypted data
+# byte (+1)--(+4):    animation header size E
+# byte (+1)--(+4):    animation data size F
+# byte (+1)--(+4):    animation sigfile size G
+# byte (+1)--(+(-G%16)%16): animation sigfile --- here bytes shall be A+D+E
+# byte (A+D+E+1)--(A+D+E+F): animation data
+
+# zipped data format
+# FwUpdater
+# |- boot.img
+# |- boot.img.md5
+# |- system.img
+# |- system.img.md5
+# |- eufwupdater.sh
+# |- ...
+
+
+# params
+PKGFILE=$1  # pkg file
+OUTDIR=$2  # output folder
+SHA256KEY="./key.pub"
+DATAKEY_D="./key.private"
+
+# predefined outputs
+SIGFILE="$OUTDIR/signature"
+AESFILE="$OUTDIR/aes.key"
+IVFILE="$OUTDIR/init_vector"
+SIGFILE_ANIM="$OUTDIR/signature_animation"
+
+# commands
+ODUMP="od -A n -t d4 -v"
+
+
+# check if output folder does not exist, make one
+if [[ ! -d $OUTDIR ]]; then
+  mkdir $OUTDIR;
+fi
+if [[ ! -d $OUTDIR ]]; then  # check again
+  echo "! Err: looks like we cannot create this folder"
+  exit 0
+fi
+
+echo "* file header check.."
+if [ $(head -c 4 $PKGFILE) != "DPUP" ]; then
+  echo "! Err: this seems to be an invalid pkg"
+  exit 0
+fi
+
+echo "* getting data block size"
+OFFSET_DATA=`dd if=$PKGFILE bs=4 skip=1 count=1 2>/dev/null | $ODUMP`
+DATA_SIZE=`dd if=$PKGFILE bs=4 skip=2 count=1 2>/dev/null | $ODUMP`
+
+echo "* extract signature.."
+SIG_SIZE=`dd if=$PKGFILE bs=4 skip=4 count=1 2>/dev/null | $ODUMP`
+dd if=$PKGFILE of=$SIGFILE bs=1 skip=20 count=$((SIG_SIZE)) 2>/dev/null
+
+echo "* verify data with signature.."
+dd if=$PKGFILE bs=$((OFFSET_DATA)) skip=1 2>/dev/null | head -c $((DATA_SIZE)) | openssl dgst -sha256 -verify $SHA256KEY -signature $SIGFILE 1>/dev/null
+if [ $? -ne 0 ]; then
+  echo "! Err: failed to verify data with provided signature"
+  exit 0
+fi
+
+echo "* get encrypted data aes key.."
+OFFSET_DATAKEY_E=$((20 + SIG_SIZE + ((-(SIG_SIZE % 16)) % 16)))
+DATAKEY_E_SIZE=`dd if=$PKGFILE bs=1 skip=$OFFSET_DATAKEY_E count=4 2>/dev/null | $ODUMP`
+OFFSET_DATAKEY_E=$((OFFSET_DATAKEY_E + 4))
+echo "** decrypt it via $DATAKEY_D"
+dd if=$PKGFILE bs=1 skip=$OFFSET_DATAKEY_E count=$((DATAKEY_E_SIZE)) 2>/dev/null | openssl rsautl -decrypt -inkey $DATAKEY_D > $AESFILE
+
+echo "* extract 32-byte initial vector.."
+OFFSET_IV=$((OFFSET_DATAKEY_E + DATAKEY_E_SIZE))
+dd if=$PKGFILE of=$IVFILE bs=1 skip=$OFFSET_IV count=32 2>/dev/null
+
+echo "* decrypt data to zipped tar.."
+dd if=$PKGFILE bs=$((OFFSET_DATA)) skip=1 2>/dev/null | head -c $((DATA_SIZE)) | openssl enc -d -aes-256-cbc -K `cat $AESFILE` -iv `cat $IVFILE` > $OUTDIR/decrypted_pkg.tar.gz
+
+echo "* unzip data.."
+tar -xzf $OUTDIR/decrypted_pkg.tar.gz -C $OUTDIR
+
+echo "* checking if animation data followed by.."
+OFFSET_ANIM_HEADER=$((OFFSET_DATA + DATA_SIZE))
+ANIM_HEADER_SIZE=`dd if=$PKGFILE bs=1 skip=$OFFSET_ANIM_HEADER count=4 2>/dev/null | $ODUMP`
+if [ -z "$ANIM_HEADER_SIZE" ]; then
+  ANIM_HEADER_SIZE=0
+fi
+if [[ $((ANIM_HEADER_SIZE)) -gt 0 ]]; then
+  echo "** found animation block, getting animation data size.."
+  ANIM_DATA_SIZE=`dd if=$PKGFILE bs=1 skip=$((OFFSET_ANIM_HEADER + 4)) count=4 2>/dev/null | $ODUMP`
+
+  echo "** get animation signature.."
+  ANIM_SIG_SIZE=`dd if=$PKGFILE bs=1 skip=$((OFFSET_ANIM_HEADER + 8)) count=4 2>/dev/null | $ODUMP`
+  dd if=$PKGFILE of=$SIGFILE_ANIM bs=1 skip=$((OFFSET_ANIM_HEADER + 12)) count=$(($ANIM_SIG_SIZE)) 2>/dev/null
+
+  echo "** verify animation data with signature.."
+  OFFSET_ANIM_DATA=$((OFFSET_ANIM_HEADER + ANIM_HEADER_SIZE))
+  dd if=$PKGFILE bs=$((OFFSET_ANIM_DATA)) skip=1 2>/dev/null | head -c $((ANIM_DATA_SIZE)) | openssl dgst -sha256 -verify $SHA256KEY -signature $SIGFILE_ANIM
+  if [ $? -ne 0 ]; then
+    echo "! Err: failed to verify animation data with provided signature"
+    exit 0
+  fi
+
+  echo "** dump animation data to zipped tar.."
+  dd if=$PKGFILE bs=$((OFFSET_ANIM_DATA)) skip=1 2>/dev/null > $OUTDIR/decrypted_animation_pkg.tar.gz
+
+  echo "** unzip the tar.."
+  tar -xzf $OUTDIR/decrypted_animation_pkg.tar.gz -C $OUTDIR
+fi
+