From 92162898567c5b19e0119b63484e3beb228c5490 Mon Sep 17 00:00:00 2001
From: Sam Tuke <samtuke@owncloud.com>
Date: Tue, 24 Jul 2012 17:53:12 +0100
Subject: [PATCH] Wrote new methods for testing if a file is encrypted using
AES or Blowfish Added more unit tests for crypt class Added new method for
generating 16 character pseudo-random initialisation vectors Started writing
new methods for handling legacy keys and en/de/re cryption Added comments to
lib/filecache.php explaining expected $path type
---
apps/files_encryption/lib/crypt.php | 98 ++++++++++++++-
apps/files_encryption/lib/util.php | 118 ++++++++++++++++++
apps/files_encryption/tests/encryption.php | 44 ++++++-
.../tests/legacy-encrypted-text.txt | Bin 0 -> 3360 bytes
lib/filecache.php | 10 +-
5 files changed, 261 insertions(+), 9 deletions(-)
create mode 100644 apps/files_encryption/tests/legacy-encrypted-text.txt
diff --git a/apps/files_encryption/lib/crypt.php b/apps/files_encryption/lib/crypt.php
index 098074c228..668101014a 100644
--- a/apps/files_encryption/lib/crypt.php
+++ b/apps/files_encryption/lib/crypt.php
@@ -50,6 +50,66 @@ class Crypt {
}
+ /**
+ * @brief Check if a file's contents contains an IV and is symmetrically encrypted
+ * @return true / false
+ */
+ public static function isEncryptedContent( $content ) {
+
+ if ( !$content ) {
+
+ return false;
+
+ }
+
+ // Fetch encryption metadata from end of file
+ $meta = substr( $content, -22 );
+
+ // Fetch IV from end of file
+ $iv = substr( $meta, -16 );
+
+ // Fetch identifier from start of metadata
+ $identifier = substr( $meta, 0, 6 );
+
+ if ( $identifier == '00iv00') {
+
+ return true;
+
+ } else {
+
+ return false;
+
+ }
+
+ }
+
+ /**
+ * @brief Check if a file is encrypted via legacy system
+ * @return true / false
+ */
+ public static function isLegacyEncryptedContent( $content, $path ) {
+
+ // Fetch all file metadata from DB
+ $metadata = \OC_FileCache_Cached::get( $content, '' );
+
+ // If a file is flagged with encryption in DB, but isn't a valid content + IV combination, it's probably using the legacy encryption system
+ if (
+ $content
+ and isset( $metadata['encrypted'] )
+ and $metadata['encrypted'] === true
+ and !self::isEncryptedContent( $content )
+ ) {
+
+ return true;
+
+ } else {
+
+ return false;
+
+ }
+
+ }
+
/**
* @brief Symmetrically encrypt a string
* @returns encrypted file
@@ -106,13 +166,12 @@ class Crypt {
}
- $random = openssl_random_pseudo_bytes( 13 );
-
- $iv = substr( base64_encode( $random ), 0, -4 );
+ $iv = self::generateIv();
if ( $encryptedContent = self::encrypt( $plainContent, $iv, $passphrase ) ) {
- $combinedKeyfile = $encryptedContent .= $iv;
+ // Combine content to encrypt with IV identifier and actual IV
+ $combinedKeyfile = $encryptedContent . '00iv00' . $iv;
return $combinedKeyfile;
@@ -143,9 +202,11 @@ class Crypt {
}
+ // Fetch IV from end of file
$iv = substr( $keyfileContent, -16 );
- $encryptedContent = substr( $keyfileContent, 0, -16 );
+ // Remove IV and IV identifier text to expose encrypted content
+ $encryptedContent = substr( $keyfileContent, 0, -22 );
if ( $plainContent = self::decrypt( $encryptedContent, $iv, $passphrase ) ) {
@@ -269,6 +330,33 @@ class Crypt {
}
+ /**
+ * @brief Generate a pseudo random 1024kb ASCII key
+ * @returns $key Generated key
+ */
+ public static function generateIv() {
+
+ if ( $random = openssl_random_pseudo_bytes( 13, $strong ) ) {
+
+ if ( !$strong ) {
+
+ // If OpenSSL indicates randomness is insecure, log error
+ \OC_Log::write( 'Encryption library', 'Insecure symmetric key was generated using openssl_random_pseudo_bytes()' , \OC_Log::WARN );
+
+ }
+
+ $iv = substr( base64_encode( $random ), 0, -4 );
+
+ return $iv;
+
+ } else {
+
+ return false;
+
+ }
+
+ }
+
/**
* @brief Generate a pseudo random 1024kb ASCII key
* @returns $key Generated key
diff --git a/apps/files_encryption/lib/util.php b/apps/files_encryption/lib/util.php
index 62b435583e..5185ad351d 100644
--- a/apps/files_encryption/lib/util.php
+++ b/apps/files_encryption/lib/util.php
@@ -37,6 +37,23 @@ namespace OCA_Encryption;
class Util {
+ # DONE: add method to check if file is encrypted using new system
+ # DONE: add method to check if file is encrypted using old system
+ # TODO: add method to encrypt all user files using new system
+ # TODO: add method to decrypt all user files using new system
+ # TODO: add method to encrypt all user files using old system
+ # TODO: add method to decrypt all user files using old system
+ # TODO: fix / test the crypt stream proxy class
+ # TODO: add support for optional recovery user in case of lost passphrase / keys
+ # TODO: add admin optional required long passphrase for users
+ # TODO: implement flag system to allow user to specify encryption by folder, subfolder, etc.
+ # TODO: add UI buttons for encrypt / decrypt everything?
+
+ # TODO: test new encryption with webdav
+ # TODO: test new encryption with versioning
+ # TODO: test new encryption with sharing
+ # TODO: test new encryption with proxies
+
private $view; // OC_FilesystemView object for filesystem operations
private $pwd; // User Password
private $client; // Client side encryption mode flag
@@ -73,6 +90,10 @@ class Util {
}
+ /**
+ * @brief Sets up encryption folders and keys for a user
+ * @param $passphrase passphrase to encrypt server-stored private key with
+ */
public function setup( $passphrase = null ) {
$publicKeyFileName = 'encryption.public.key';
@@ -129,5 +150,102 @@ class Util {
}
}
+
+ /**
+ * @brief Fetch the legacy encryption key from user files
+ * @param string $login used to locate the legacy key
+ * @param string $passphrase used to decrypt the legacy key
+ * @return true / false
+ *
+ * if the key is left out, the default handeler will be used
+ */
+ public function getLegacyKey( $login, $passphrase ) {
+
+ OC_FileProxy::$enabled = false;
+
+ if (
+ $login
+ and $passphrase
+ and $key = $this->view->file_get_contents( '/' . $login . '/encryption.key' )
+ ) {
+
+ OC_FileProxy::$enabled = true;
+
+ return $this->legacyDecrypt( $key, $passphrase );
+
+ } else {
+
+ OC_FileProxy::$enabled = true;
+
+ return false;
+
+ }
+
+ }
+
+ /**
+ * @brief Get the blowfish encryption handeler for a key
+ * @param $key string (optional)
+ * @return Crypt_Blowfish blowfish object
+ *
+ * if the key is left out, the default handeler will be used
+ */
+ public function getBlowfish( $key = '' ) {
+
+ if( $key ){
+
+ return new Crypt_Blowfish($key);
+
+ } else {
+
+ return false;
+
+ }
+
+ }
+
+ /**
+ * @brief encrypts content using legacy blowfish system
+ * @param $content the cleartext message you want to encrypt
+ * @param $key the encryption key (optional)
+ * @returns encrypted content
+ *
+ * This function encrypts an content
+ */
+ public static function legacyEncrypt( $content, $key='') {
+ $bf = self::getBlowfish($key);
+ return $bf->encrypt($content);
+ }
+
+ /**
+ * @brief decryption of an content
+ * @param $content the cleartext message you want to decrypt
+ * @param $key the encryption key (optional)
+ * @returns cleartext content
+ *
+ * This function decrypts an content
+ */
+ public static function legacyDecrypt( $content, $key = '' ) {
+
+ $bf = $this->getBlowfish( $key );
+
+ $data = $bf->decrypt( $content );
+
+ return $data;
+
+ }
+
+ /**
+ * @brief Re-encryptes a legacy blowfish encrypted file using AES with integrated IV
+ * @param $legacyContent the legacy encrypted content to re-encrypt
+ * @returns cleartext content
+ *
+ * This function decrypts an content
+ */
+ public function legacyRecrypt( $legacyContent ) {
+
+ # TODO: write me
+
+ }
}
diff --git a/apps/files_encryption/tests/encryption.php b/apps/files_encryption/tests/encryption.php
index 600e00fd3e..9246e71526 100644
--- a/apps/files_encryption/tests/encryption.php
+++ b/apps/files_encryption/tests/encryption.php
@@ -1,19 +1,22 @@
<?php
/**
- * Copyright (c) 2012 Robin Appelman <icewind@owncloud.com>
+ * Copyright (c) 2012 Sam Tuke <samtuke@owncloud.com>, and
+ * Robin Appelman <icewind@owncloud.com>
* This file is licensed under the Affero General Public License version 3 or
* later.
* See the COPYING-README file.
*/
require realpath( dirname(__FILE__).'/../lib/crypt.php' );
+//require realpath( dirname(__FILE__).'/../../../lib/filecache.php' );
class Test_Encryption extends UnitTestCase {
-
+
function setUp() {
// set content for encrypting / decrypting in tests
$this->data = realpath( dirname(__FILE__).'/../lib/crypt.php' );
+ $this->legacyEncryptedData = realpath( dirname(__FILE__).'/legacy-encrypted-text.txt' );
}
@@ -25,10 +28,22 @@ class Test_Encryption extends UnitTestCase {
$key = OCA_Encryption\Crypt::generateKey();
+ $this->assertTrue( $key );
+
$this->assertTrue( strlen( $key ) > 1000 );
}
+ function testGenerateIv() {
+
+ $iv = OCA_Encryption\Crypt::generateIv();
+
+ $this->assertTrue( $iv );
+
+ $this->assertTrue( strlen( $iv ) == 16 );
+
+ }
+
function testEncrypt() {
$random = openssl_random_pseudo_bytes( 13 );
@@ -85,6 +100,31 @@ class Test_Encryption extends UnitTestCase {
}
+ function testIsEncryptedContent() {
+
+ $this->assertFalse( OCA_Encryption\Crypt::isEncryptedContent( $this->data ) );
+
+ $this->assertFalse( OCA_Encryption\Crypt::isEncryptedContent( $this->legacyEncryptedData ) );
+
+ $keyfileContent = OCA_Encryption\Crypt::symmetricEncryptFileContent( $this->data, 'hat' );
+
+ $this->assertTrue( OCA_Encryption\Crypt::isEncryptedContent( $keyfileContent ) );
+
+ }
+
+// // Cannot use this test for now due to hidden dependencies in OC_FileCache
+// function testIsLegacyEncryptedContent() {
+//
+// $keyfileContent = OCA_Encryption\Crypt::symmetricEncryptFileContent( $this->legacyEncryptedData, 'hat' );
+//
+// $this->assertFalse( OCA_Encryption\Crypt::isLegacyEncryptedContent( $keyfileContent, '/files/admin/test.txt' ) );
+//
+// OC_FileCache::put( '/admin/files/legacy-encrypted-test.txt', $this->legacyEncryptedData );
+//
+// $this->assertTrue( OCA_Encryption\Crypt::isLegacyEncryptedContent( $this->legacyEncryptedData, '/files/admin/test.txt' ) );
+//
+// }
+
function testMultiKeyEncrypt() {
# TODO: search in keyfile for actual content as IV will ensure this test always passes
diff --git a/apps/files_encryption/tests/legacy-encrypted-text.txt b/apps/files_encryption/tests/legacy-encrypted-text.txt
new file mode 100644
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GIT binary patch
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diff --git a/lib/filecache.php b/lib/filecache.php
index d956f34dc4..8894c8a3eb 100644
--- a/lib/filecache.php
+++ b/lib/filecache.php
@@ -23,10 +23,16 @@
* provide caching for filesystem info in the database
*
* not used by OC_Filesystem for reading filesystem info,
- * instread apps should use OC_FileCache::get where possible
+ * instead apps should use OC_FileCache::get where possible
+ *
+ * It will try to keep the data up to date but changes from outside
+ * ownCloud can invalidate the cache
+ *
+ * Methods that take $path and $root params expect $path to be relative, like
+ * /admin/files/file.txt, if $root is false
*
- * It will try to keep the data up to date but changes from outside ownCloud can invalidate the cache
*/
+
class OC_FileCache{
/**
* get the filesystem info from the cache
--
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