From af66cde5dd1bbd5462a281152ca7b87df9f50aa9 Mon Sep 17 00:00:00 2001
From: Andrey Arapov <andrey.arapov@nixaid.com>
Date: Tue, 22 Sep 2015 10:27:25 +0200
Subject: [PATCH] Initial release

---
 ocdec.sh | 179 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 179 insertions(+)
 create mode 100644 ocdec.sh

diff --git a/ocdec.sh b/ocdec.sh
new file mode 100644
index 0000000..499b500
--- /dev/null
+++ b/ocdec.sh
@@ -0,0 +1,179 @@
+#!/usr/bin/env bash
+#set -x
+#  Script: ocdec.sh
+#  Author: Andrey Arapov
+#  Email: andrey.arapov@nixaid.com
+#
+#  Copyright (C) 2015 Andrey Arapov
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+#
+#
+# Version: 1.0.0 - Initial release (22 September 2015)
+#
+# Tested with:
+# - ownCloud 8.1.3
+#
+# Limitations:
+# - with some files (binary ones) it is running really slow
+#
+#
+# === Usage notes
+#
+# Current directory should be the ownCloud data directory !
+# You can find it this way:
+# grep -i datadirectory /srv/pathto/owncloud/config/config.php
+#  'datadirectory' => '/srv/ownclouddata/',
+#
+# Make sure you have exported env. variable, e.g.
+# export userLoginPass='s3cr3tpass'
+#
+#
+# === Usage Example - Decrypt just 1 file
+#
+# export userLoginPass='s3cr3tpass'
+# cd /srv/ownclouddata
+# /tmp/ocdec.sh testuser1/files/secretfile.txt
+#
+#
+# === Usage Example 2 - Decrypt Everything!
+#
+# 1. Create directory structure for decrypted data
+#
+# export USER=testuser1
+# export userLoginPass='s3cr3tpass'
+# cd /srv/ownclouddata
+# find ${USER}/files -type d |cut -sd / -f 2- |xargs -I@ mkdir -p "${USER}-DECRYPTED/@"
+#
+#
+# 2. Decrypt the data
+#
+# cd /srv/ownclouddata
+# find ${USER}/files -type f |xargs -I@ sh -c '/tmp/ocdec.sh "@" > "${USER}-DECRYPTED/$(echo @|cut -sd / -f 2-)"'
+#
+# Now all your data is decrypted & available at the ${USER}-DECRYPTED/ path !
+#
+#
+
+
+# Beginning of a script
+
+#
+# Get User Private Key
+#
+# arg1: username
+# arg2: password
+function decryptUserPrivateKey() {
+  USER=$1
+  userLoginPass=$2
+  userPrivKeyPath="$USER/files_encryption/OC_DEFAULT_MODULE/$USER.privateKey"
+  if [ ! -r "$userPrivKeyPath" ]; then
+    echo "decryptUserPrivateKey():: File "$userPrivKeyPath" does not exist or not enough permissions! Aborting."
+    return 1
+  fi
+
+  encPrivKeyContentsALL="$(cat "$userPrivKeyPath")"
+  # Some non-GNU versions of sed do not support pattern matches. In that case use: perl -pne 's/(00iv00.*)?00iv00.*/$1 /'
+  encPrivKeyContentsBASE64="$( sed -r 's/^HBEGIN:.+:HEND-*//;s/(00iv00.*)?00iv00.*{16}xx/\1/' <(echo "${encPrivKeyContentsALL}") )"
+  plainPrivKeyIV="$( sed -r 's/^HBEGIN.*00iv00//;s/xx$//' <(echo "${encPrivKeyContentsALL}") )"
+  userLoginPassHEX=$(echo -n $userLoginPass |od -An -tx1 |tr -dc '[:xdigit:]')
+  plainPrivKeyIVHEX=$(echo -n $plainPrivKeyIV |od -An -tx1 |tr -dc '[:xdigit:]')
+
+  echo "$( openssl enc -AES-256-CFB -d -nosalt -base64 -A -K $userLoginPassHEX -iv $plainPrivKeyIVHEX -in <(echo $encPrivKeyContentsBASE64) )"
+}
+
+#
+# Decrypt the file
+#
+# arg1: username
+# arg2: path to an encrypted file (e.g. 'files/secretfile.txt' or 'files/Photos/Squirrel.jpg')
+# arg3: user Private Key in plaintext
+function decryptFile() {
+  USER="$1"
+  encFilePath="$2"
+  plainUserPrivKey="$3"
+
+  if [ ! -r "${USER}/$encFilePath" ]; then
+    echo "decryptFile():: File "${USER}/$encFilePath" does not exist or not enough permissions! Aborting."
+    return 1
+  fi
+  if ! grep -q "^HBEGIN:" "${USER}/$encFilePath"; then
+    echo "decryptFile():: File "${USER}/$encFilePath" does not seem to be encrypted! Aborting."
+    return 1
+  fi
+
+  # --- Get the FileKey ---
+  userFileShareKeyPath="${USER}/files_encryption/keys/${encFilePath}/OC_DEFAULT_MODULE/${USER}.shareKey"
+  encFileKeyPath="${USER}/files_encryption/keys/${encFilePath}/OC_DEFAULT_MODULE/fileKey"
+
+  decUserFileShareKeyHEX="$( openssl rsautl -decrypt -inkey <(echo "$plainUserPrivKey") -in "$userFileShareKeyPath" |od -An -tx1 |tr -dc '[:xdigit:]' )"
+  if [ -z "$decUserFileShareKeyHEX" ];then echo "decryptFile():: The User Private Key is not good. Are you sure your ownCloud User Login password is correct?"; return 1; fi
+
+  decFileKeyContent="$( openssl rc4 -d -in "$encFileKeyPath" -iv 0 -K $decUserFileShareKeyHEX )"
+  decFileKeyContentHEX="$( echo -n $decFileKeyContent |od -An -tx1 |tr -dc '[:xdigit:]' )"
+  # --- Get the FileKey ---
+
+  # --- Decrypt the file ---
+  # TODO: to figure out how to speed-up the decryption process
+  encFileContentsALL="$(cat "${USER}/$encFilePath")"
+  encFileContentsNOHEAD=$(echo -n "$encFileContentsALL" | sed -r 's/^HBEGIN:.+:HEND-*//')
+  N=0
+  for IV in $(echo -n "$encFileContentsNOHEAD" |grep -E -o '00iv00.{16}xx' |sed -r 's/^00iv00//;s/xx$//'); do
+    N=$[N+1]
+    encFileContentsBASE64=$(echo -n "$encFileContentsNOHEAD" |awk -F '00iv00................xx' -v N=$N '{print $N}')
+    plainFileIVHEX=$(echo -n "$IV" |od -An -tx1 |tr -dc '[:xdigit:]')
+    openssl enc -AES-256-CFB -d -nosalt -base64 -A -K $decFileKeyContentHEX -iv $plainFileIVHEX -in <(echo "$encFileContentsBASE64")
+    #php -r "echo openssl_decrypt('$encFileContentsBASE64', 'AES-256-CFB', '$decFileKeyContent', false, '$IV');"
+  done
+  # --- Decrypt the file ---
+}
+
+# Get a username from the path (arg1)
+USER="$(echo $1 |cut -sd / -f 1)"
+
+# Strip off the username from the path (arg1)
+FILETD="$(echo $1 |cut -sd / -f 2-)"
+
+if [ ! -r "$USER" ]; then
+  echo "User directory cannot be found! Are you sure you are in ownCloud's data directory?"
+  exit 1
+fi
+
+if [ -z "$userLoginPass" ]; then
+  echo "Please set userLoginPass environment variable!"
+  exit 1
+fi
+
+if [ ! -r "$1" ]; then
+  echo "File specified $1 does not exist or not enough permissions to access it!"
+  exit 1
+fi
+
+#
+# TODO: Add checks for available tools installed: openssl, sed, cat, od, tr, mawk
+#
+
+#
+# 1) Locate and decrypt User Private Key
+#
+# TODO: to decrypt User Private Key only once when running this script in a loop (decrypting multiple files)
+plainUserPrivKey="$(decryptUserPrivateKey $USER $userLoginPass)";
+
+#
+# 2) Decrypt the shareKey, then the fileKey, then the file and output the plaintext
+#
+decryptFile $USER "$FILETD" "$plainUserPrivKey"
+
+# End of a script