nextcloud/apps/files_encryption/lib/util.php

1595 lines
44 KiB
PHP

<?php
/**
* ownCloud
*
* @copyright (C) 2014 ownCloud, Inc.
*
* @author Sam Tuke <samtuke@owncloud.com>,
* @author Frank Karlitschek <frank@owncloud.org>,
* @author Bjoern Schiessle <schiessle@owncloud.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
* License as published by the Free Software Foundation; either
* version 3 of the License, or any later version.
*
* This library 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 AFFERO GENERAL PUBLIC LICENSE for more details.
*
* You should have received a copy of the GNU Affero General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*/
namespace OCA\Files_Encryption;
/**
* Class for utilities relating to encrypted file storage system
* @param \OC\Files\View $view expected to have OC '/' as root path
* @param string $userId ID of the logged in user
* @param int $client indicating status of client side encryption. Currently
* unused, likely to become obsolete shortly
*/
class Util {
const MIGRATION_COMPLETED = 1; // migration to new encryption completed
const MIGRATION_IN_PROGRESS = -1; // migration is running
const MIGRATION_OPEN = 0; // user still needs to be migrated
private $view; // OC\Files\View object for filesystem operations
private $userId; // ID of the user we use to encrypt/decrypt files
private $keyId; // ID of the key we want to manipulate
private $client; // Client side encryption mode flag
private $publicKeyDir; // Dir containing all public user keys
private $encryptionDir; // Dir containing user's files_encryption
private $keysPath; // Dir containing all file related encryption keys
private $publicKeyPath; // Path to user's public key
private $privateKeyPath; // Path to user's private key
private $userFilesDir;
private $publicShareKeyId;
private $recoveryKeyId;
private $isPublic;
/**
* @param \OC\Files\View $view
* @param string $userId
* @param bool $client
*/
public function __construct($view, $userId, $client = false) {
$this->view = $view;
$this->client = $client;
$this->userId = $userId;
$appConfig = \OC::$server->getAppConfig();
$this->publicShareKeyId = $appConfig->getValue('files_encryption', 'publicShareKeyId');
$this->recoveryKeyId = $appConfig->getValue('files_encryption', 'recoveryKeyId');
$this->userDir = '/' . $this->userId;
$this->fileFolderName = 'files';
$this->userFilesDir =
'/' . $userId . '/' . $this->fileFolderName; // TODO: Does this need to be user configurable?
$this->publicKeyDir = Keymanager::getPublicKeyPath();
$this->encryptionDir = '/' . $this->userId . '/' . 'files_encryption';
$this->keysPath = $this->encryptionDir . '/' . 'keys';
$this->publicKeyPath =
$this->publicKeyDir . '/' . $this->userId . '.publicKey'; // e.g. data/public-keys/admin.publicKey
$this->privateKeyPath =
$this->encryptionDir . '/' . $this->userId . '.privateKey'; // e.g. data/admin/admin.privateKey
// make sure that the owners home is mounted
\OC\Files\Filesystem::initMountPoints($userId);
if (Helper::isPublicAccess()) {
$this->keyId = $this->publicShareKeyId;
$this->isPublic = true;
} else {
$this->keyId = $this->userId;
$this->isPublic = false;
}
}
/**
* @return bool
*/
public function ready() {
if (
!$this->view->file_exists($this->encryptionDir)
or !$this->view->file_exists($this->keysPath)
or !$this->view->file_exists($this->publicKeyPath)
or !$this->view->file_exists($this->privateKeyPath)
) {
return false;
} else {
return true;
}
}
/**
* check if the users private & public key exists
* @return boolean
*/
public function userKeysExists() {
if (
$this->view->file_exists($this->privateKeyPath) &&
$this->view->file_exists($this->publicKeyPath)) {
return true;
} else {
return false;
}
}
/**
* create a new public/private key pair for the user
*
* @param string $password password for the private key
*/
public function replaceUserKeys($password) {
$this->backupAllKeys('password_reset');
$this->view->unlink($this->publicKeyPath);
$this->view->unlink($this->privateKeyPath);
$this->setupServerSide($password);
}
/**
* Sets up user folders and keys for serverside encryption
*
* @param string $passphrase to encrypt server-stored private key with
* @return bool
*/
public function setupServerSide($passphrase = null) {
// Set directories to check / create
$setUpDirs = array(
$this->userDir,
$this->publicKeyDir,
$this->encryptionDir,
$this->keysPath
);
// Check / create all necessary dirs
foreach ($setUpDirs as $dirPath) {
if (!$this->view->file_exists($dirPath)) {
$this->view->mkdir($dirPath);
}
}
// Create user keypair
// we should never override a keyfile
if (
!$this->view->file_exists($this->publicKeyPath)
&& !$this->view->file_exists($this->privateKeyPath)
) {
// Generate keypair
$keypair = Crypt::createKeypair();
if ($keypair) {
\OC_FileProxy::$enabled = false;
// Encrypt private key with user pwd as passphrase
$encryptedPrivateKey = Crypt::symmetricEncryptFileContent($keypair['privateKey'], $passphrase, Helper::getCipher());
// Save key-pair
if ($encryptedPrivateKey) {
$header = crypt::generateHeader();
$this->view->file_put_contents($this->privateKeyPath, $header . $encryptedPrivateKey);
$this->view->file_put_contents($this->publicKeyPath, $keypair['publicKey']);
}
\OC_FileProxy::$enabled = true;
}
} else {
// check if public-key exists but private-key is missing
if ($this->view->file_exists($this->publicKeyPath) && !$this->view->file_exists($this->privateKeyPath)) {
\OCP\Util::writeLog('Encryption library',
'public key exists but private key is missing for "' . $this->keyId . '"', \OCP\Util::FATAL);
return false;
} else {
if (!$this->view->file_exists($this->publicKeyPath) && $this->view->file_exists($this->privateKeyPath)
) {
\OCP\Util::writeLog('Encryption library',
'private key exists but public key is missing for "' . $this->keyId . '"', \OCP\Util::FATAL);
return false;
}
}
}
return true;
}
/**
* @return string
*/
public function getPublicShareKeyId() {
return $this->publicShareKeyId;
}
/**
* Check whether pwd recovery is enabled for a given user
* @return bool 1 = yes, 0 = no, false = no record
*
* @note If records are not being returned, check for a hidden space
* at the start of the uid in db
*/
public function recoveryEnabledForUser() {
$recoveryMode = \OC::$server->getConfig()->getUserValue($this->userId, 'files_encryption', 'recovery_enabled', '0');
return ($recoveryMode === '1') ? true : false;
}
/**
* Enable / disable pwd recovery for a given user
* @param bool $enabled Whether to enable or disable recovery
* @return bool
*/
public function setRecoveryForUser($enabled) {
$value = $enabled ? '1' : '0';
try {
\OC::$server->getConfig()->setUserValue($this->userId, 'files_encryption', 'recovery_enabled', $value);
return true;
} catch(\OCP\PreConditionNotMetException $e) {
return false;
}
}
/**
* Find all files and their encryption status within a directory
* @param string $directory The path of the parent directory to search
* @param bool $found the founded files if called again
* @return array keys: plain, encrypted, broken
* @note $directory needs to be a path relative to OC data dir. e.g.
* /admin/files NOT /backup OR /home/www/oc/data/admin/files
*/
public function findEncFiles($directory, &$found = false) {
// Disable proxy - we don't want files to be decrypted before
// we handle them
\OC_FileProxy::$enabled = false;
if ($found === false) {
$found = array(
'plain' => array(),
'encrypted' => array(),
'broken' => array(),
);
}
if ($this->view->is_dir($directory) && $handle = $this->view->opendir($directory)){
if (is_resource($handle)) {
while (false !== ($file = readdir($handle))) {
if ($file !== "." && $file !== "..") {
$filePath = $directory . '/' . $this->view->getRelativePath('/' . $file);
$relPath = Helper::stripUserFilesPath($filePath);
// If the path is a directory, search
// its contents
if ($this->view->is_dir($filePath)) {
$this->findEncFiles($filePath, $found);
// If the path is a file, determine
// its encryption status
} elseif ($this->view->is_file($filePath)) {
// Disable proxies again, some-
// where they got re-enabled :/
\OC_FileProxy::$enabled = false;
$isEncryptedPath = $this->isEncryptedPath($filePath);
// If the file is encrypted
// NOTE: If the userId is
// empty or not set, file will
// detected as plain
// NOTE: This is inefficient;
// scanning every file like this
// will eat server resources :(
if ($isEncryptedPath) {
$fileKey = Keymanager::getFileKey($this->view, $this, $relPath);
$shareKey = Keymanager::getShareKey($this->view, $this->userId, $this, $relPath);
// if file is encrypted but now file key is available, throw exception
if ($fileKey === false || $shareKey === false) {
\OCP\Util::writeLog('encryption library', 'No keys available to decrypt the file: ' . $filePath, \OCP\Util::ERROR);
$found['broken'][] = array(
'name' => $file,
'path' => $filePath,
);
} else {
$found['encrypted'][] = array(
'name' => $file,
'path' => $filePath,
);
}
// If the file is not encrypted
} else {
$found['plain'][] = array(
'name' => $file,
'path' => $relPath
);
}
}
}
}
}
}
\OC_FileProxy::$enabled = true;
return $found;
}
/**
* Check if a given path identifies an encrypted file
* @param string $path
* @return boolean
*/
public function isEncryptedPath($path) {
// Disable encryption proxy so data retrieved is in its
// original form
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
$data = '';
// we only need 24 byte from the last chunk
if ($this->view->file_exists($path)) {
$handle = $this->view->fopen($path, 'r');
if (is_resource($handle)) {
// suppress fseek warining, we handle the case that fseek doesn't
// work in the else branch
if (@fseek($handle, -24, SEEK_END) === 0) {
$data = fgets($handle);
} else {
// if fseek failed on the storage we create a local copy from the file
// and read this one
fclose($handle);
$localFile = $this->view->getLocalFile($path);
$handle = fopen($localFile, 'r');
if (is_resource($handle) && fseek($handle, -24, SEEK_END) === 0) {
$data = fgets($handle);
}
}
fclose($handle);
}
}
// re-enable proxy
\OC_FileProxy::$enabled = $proxyStatus;
return Crypt::isCatfileContent($data);
}
/**
* get the file size of the unencrypted file
* @param string $path absolute path
* @return bool
*/
public function getFileSize($path) {
$result = 0;
// Disable encryption proxy to prevent recursive calls
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
// split the path parts
$pathParts = explode('/', $path);
if (isset($pathParts[2]) && $pathParts[2] === 'files' && $this->view->file_exists($path)
&& $this->isEncryptedPath($path)
) {
$cipher = 'AES-128-CFB';
$realSize = 0;
// get the size from filesystem
$size = $this->view->filesize($path);
// open stream
$stream = $this->view->fopen($path, "r");
if (is_resource($stream)) {
// if the file contains a encryption header we
// we set the cipher
// and we update the size
if ($this->containHeader($path)) {
$data = fread($stream,Crypt::BLOCKSIZE);
$header = Crypt::parseHeader($data);
$cipher = Crypt::getCipher($header);
$size -= Crypt::BLOCKSIZE;
}
// fast path, else the calculation for $lastChunkNr is bogus
if ($size === 0) {
\OC_FileProxy::$enabled = $proxyStatus;
return 0;
}
// calculate last chunk nr
// next highest is end of chunks, one subtracted is last one
// we have to read the last chunk, we can't just calculate it (because of padding etc)
$lastChunkNr = ceil($size/Crypt::BLOCKSIZE)-1;
// calculate last chunk position
$lastChunkPos = ($lastChunkNr * Crypt::BLOCKSIZE);
// get the content of the last chunk
if (@fseek($stream, $lastChunkPos, SEEK_CUR) === 0) {
$realSize+=$lastChunkNr*6126;
}
$lastChunkContentEncrypted='';
$count=Crypt::BLOCKSIZE;
while ($count>0) {
$data=fread($stream,Crypt::BLOCKSIZE);
$count=strlen($data);
$lastChunkContentEncrypted.=$data;
if(strlen($lastChunkContentEncrypted)>Crypt::BLOCKSIZE) {
$realSize+=6126;
$lastChunkContentEncrypted=substr($lastChunkContentEncrypted,Crypt::BLOCKSIZE);
}
}
fclose($stream);
$relPath = Helper::stripUserFilesPath($path);
$shareKey = Keymanager::getShareKey($this->view, $this->keyId, $this, $relPath);
if($shareKey===false) {
\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
$session = new Session($this->view);
$privateKey = $session->getPrivateKey();
$plainKeyfile = $this->decryptKeyfile($relPath, $privateKey);
$plainKey = Crypt::multiKeyDecrypt($plainKeyfile, $shareKey, $privateKey);
$lastChunkContent=Crypt::symmetricDecryptFileContent($lastChunkContentEncrypted, $plainKey, $cipher);
// calc the real file size with the size of the last chunk
$realSize += strlen($lastChunkContent);
// store file size
$result = $realSize;
}
}
\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* check if encrypted file contain a encryption header
*
* @param string $path
* @return boolean
*/
private function containHeader($path) {
// Disable encryption proxy to read the raw data
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
$isHeader = false;
$handle = $this->view->fopen($path, 'r');
if (is_resource($handle)) {
$firstBlock = fread($handle, Crypt::BLOCKSIZE);
$isHeader = Crypt::isHeader($firstBlock);
}
\OC_FileProxy::$enabled = $proxyStatus;
return $isHeader;
}
/**
* fix the file size of the encrypted file
* @param string $path absolute path
* @return boolean true / false if file is encrypted
*/
public function fixFileSize($path) {
$result = false;
// Disable encryption proxy to prevent recursive calls
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
$realSize = $this->getFileSize($path);
if ($realSize > 0) {
$cached = $this->view->getFileInfo($path);
$cached['encrypted'] = true;
// set the size
$cached['unencrypted_size'] = $realSize;
// put file info
$this->view->putFileInfo($path, $cached);
$result = true;
}
\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* encrypt versions from given file
* @param array $filelist list of encrypted files, relative to data/user/files
* @return boolean
*/
private function encryptVersions($filelist) {
$successful = true;
if (\OCP\App::isEnabled('files_versions')) {
foreach ($filelist as $filename) {
$versions = \OCA\Files_Versions\Storage::getVersions($this->userId, $filename);
foreach ($versions as $version) {
$path = '/' . $this->userId . '/files_versions/' . $version['path'] . '.v' . $version['version'];
$encHandle = fopen('crypt://' . $path . '.part', 'wb');
if ($encHandle === false) {
\OCP\Util::writeLog('Encryption library', 'couldn\'t open "' . $path . '", decryption failed!', \OCP\Util::FATAL);
$successful = false;
continue;
}
$plainHandle = $this->view->fopen($path, 'rb');
if ($plainHandle === false) {
\OCP\Util::writeLog('Encryption library', 'couldn\'t open "' . $path . '.part", decryption failed!', \OCP\Util::FATAL);
$successful = false;
continue;
}
stream_copy_to_stream($plainHandle, $encHandle);
fclose($encHandle);
fclose($plainHandle);
$this->view->rename($path . '.part', $path);
}
}
}
return $successful;
}
/**
* decrypt versions from given file
* @param string $filelist list of decrypted files, relative to data/user/files
* @return boolean
*/
private function decryptVersions($filelist) {
$successful = true;
if (\OCP\App::isEnabled('files_versions')) {
foreach ($filelist as $filename) {
$versions = \OCA\Files_Versions\Storage::getVersions($this->userId, $filename);
foreach ($versions as $version) {
$path = '/' . $this->userId . '/files_versions/' . $version['path'] . '.v' . $version['version'];
$encHandle = fopen('crypt://' . $path, 'rb');
if ($encHandle === false) {
\OCP\Util::writeLog('Encryption library', 'couldn\'t open "' . $path . '", decryption failed!', \OCP\Util::FATAL);
$successful = false;
continue;
}
$plainHandle = $this->view->fopen($path . '.part', 'wb');
if ($plainHandle === false) {
\OCP\Util::writeLog('Encryption library', 'couldn\'t open "' . $path . '.part", decryption failed!', \OCP\Util::FATAL);
$successful = false;
continue;
}
stream_copy_to_stream($encHandle, $plainHandle);
fclose($encHandle);
fclose($plainHandle);
$this->view->rename($path . '.part', $path);
}
}
}
return $successful;
}
/**
* Decrypt all files
* @return bool
*/
public function decryptAll() {
$found = $this->findEncFiles($this->userId . '/files');
$successful = true;
if ($found) {
$versionStatus = \OCP\App::isEnabled('files_versions');
\OC_App::disable('files_versions');
$decryptedFiles = array();
// Encrypt unencrypted files
foreach ($found['encrypted'] as $encryptedFile) {
//relative to data/<user>/file
$relPath = Helper::stripUserFilesPath($encryptedFile['path']);
//get file info
$fileInfo = \OC\Files\Filesystem::getFileInfo($relPath);
//relative to /data
$rawPath = $encryptedFile['path'];
//get timestamp
$timestamp = $fileInfo['mtime'];
//enable proxy to use OC\Files\View to access the original file
\OC_FileProxy::$enabled = true;
// Open enc file handle for binary reading
$encHandle = $this->view->fopen($rawPath, 'rb');
// Disable proxy to prevent file being encrypted again
\OC_FileProxy::$enabled = false;
if ($encHandle === false) {
\OCP\Util::writeLog('Encryption library', 'couldn\'t open "' . $rawPath . '", decryption failed!', \OCP\Util::FATAL);
$successful = false;
continue;
}
// Open plain file handle for binary writing, with same filename as original plain file
$plainHandle = $this->view->fopen($rawPath . '.part', 'wb');
if ($plainHandle === false) {
\OCP\Util::writeLog('Encryption library', 'couldn\'t open "' . $rawPath . '.part", decryption failed!', \OCP\Util::FATAL);
$successful = false;
continue;
}
// Move plain file to a temporary location
$size = stream_copy_to_stream($encHandle, $plainHandle);
if ($size === 0) {
\OCP\Util::writeLog('Encryption library', 'Zero bytes copied of "' . $rawPath . '", decryption failed!', \OCP\Util::FATAL);
$successful = false;
continue;
}
fclose($encHandle);
fclose($plainHandle);
$fakeRoot = $this->view->getRoot();
$this->view->chroot('/' . $this->userId . '/files');
$this->view->rename($relPath . '.part', $relPath);
//set timestamp
$this->view->touch($relPath, $timestamp);
$this->view->chroot($fakeRoot);
// Add the file to the cache
\OC\Files\Filesystem::putFileInfo($relPath, array(
'encrypted' => false,
'size' => $size,
'unencrypted_size' => 0,
'etag' => $fileInfo['etag']
));
$decryptedFiles[] = $relPath;
}
if ($versionStatus) {
\OC_App::enable('files_versions');
}
if (!$this->decryptVersions($decryptedFiles)) {
$successful = false;
}
// if there are broken encrypted files than the complete decryption
// was not successful
if (!empty($found['broken'])) {
$successful = false;
}
if ($successful) {
$this->backupAllKeys('decryptAll');
$this->view->deleteAll($this->keysPath);
}
\OC_FileProxy::$enabled = true;
}
return $successful;
}
/**
* Encrypt all files in a directory
* @param string $dirPath the directory whose files will be encrypted
* @return bool
* @note Encryption is recursive
*/
public function encryptAll($dirPath) {
$result = true;
$found = $this->findEncFiles($dirPath);
// Disable proxy to prevent file being encrypted twice
\OC_FileProxy::$enabled = false;
$versionStatus = \OCP\App::isEnabled('files_versions');
\OC_App::disable('files_versions');
$encryptedFiles = array();
// Encrypt unencrypted files
foreach ($found['plain'] as $plainFile) {
//get file info
$fileInfo = \OC\Files\Filesystem::getFileInfo($plainFile['path']);
//relative to data/<user>/file
$relPath = $plainFile['path'];
//relative to /data
$rawPath = '/' . $this->userId . '/files/' . $plainFile['path'];
// keep timestamp
$timestamp = $fileInfo['mtime'];
// Open plain file handle for binary reading
$plainHandle = $this->view->fopen($rawPath, 'rb');
// Open enc file handle for binary writing, with same filename as original plain file
$encHandle = fopen('crypt://' . $rawPath . '.part', 'wb');
if (is_resource($encHandle) && is_resource($plainHandle)) {
// Move plain file to a temporary location
$size = stream_copy_to_stream($plainHandle, $encHandle);
fclose($encHandle);
fclose($plainHandle);
$fakeRoot = $this->view->getRoot();
$this->view->chroot('/' . $this->userId . '/files');
$this->view->rename($relPath . '.part', $relPath);
// set timestamp
$this->view->touch($relPath, $timestamp);
$encSize = $this->view->filesize($relPath);
$this->view->chroot($fakeRoot);
// Add the file to the cache
\OC\Files\Filesystem::putFileInfo($relPath, array(
'encrypted' => true,
'size' => $encSize,
'unencrypted_size' => $size,
'etag' => $fileInfo['etag']
));
$encryptedFiles[] = $relPath;
} else {
\OCP\Util::writeLog('files_encryption', 'initial encryption: could not encrypt ' . $rawPath, \OCP\Util::FATAL);
$result = false;
}
}
\OC_FileProxy::$enabled = true;
if ($versionStatus) {
\OC_App::enable('files_versions');
}
$result = $result && $this->encryptVersions($encryptedFiles);
return $result;
}
/**
* Return important encryption related paths
* @param string $pathName Name of the directory to return the path of
* @return string path
*/
public function getPath($pathName) {
switch ($pathName) {
case 'publicKeyDir':
return $this->publicKeyDir;
break;
case 'encryptionDir':
return $this->encryptionDir;
break;
case 'keysPath':
return $this->keysPath;
break;
case 'publicKeyPath':
return $this->publicKeyPath;
break;
case 'privateKeyPath':
return $this->privateKeyPath;
break;
}
return false;
}
/**
* Returns whether the given user is ready for encryption.
* Also returns true if the given user is the public user
* or the recovery key user.
*
* @param string $user user to check
*
* @return boolean true if the user is ready, false otherwise
*/
private function isUserReady($user) {
if ($user === $this->publicShareKeyId
|| $user === $this->recoveryKeyId
) {
return true;
}
$util = new Util($this->view, $user);
return $util->ready();
}
/**
* Filter an array of UIDs to return only ones ready for sharing
* @param array $unfilteredUsers users to be checked for sharing readiness
* @return array as multi-dimensional array. keys: ready, unready
*/
public function filterShareReadyUsers($unfilteredUsers) {
// This array will collect the filtered IDs
$readyIds = $unreadyIds = array();
// Loop through users and create array of UIDs that need new keyfiles
foreach ($unfilteredUsers as $user) {
// Check that the user is encryption capable, or is the
// public system user (for public shares)
if ($this->isUserReady($user)) {
// Construct array of ready UIDs for Keymanager{}
$readyIds[] = $user;
} else {
// Construct array of unready UIDs for Keymanager{}
$unreadyIds[] = $user;
// Log warning; we can't do necessary setup here
// because we don't have the user passphrase
\OCP\Util::writeLog('Encryption library',
'"' . $user . '" is not setup for encryption', \OCP\Util::WARN);
}
}
return array(
'ready' => $readyIds,
'unready' => $unreadyIds
);
}
/**
* Decrypt a keyfile
* @param string $filePath
* @param string $privateKey
* @return false|string
*/
private function decryptKeyfile($filePath, $privateKey) {
// Get the encrypted keyfile
$encKeyfile = Keymanager::getFileKey($this->view, $this, $filePath);
// The file has a shareKey and must use it for decryption
$shareKey = Keymanager::getShareKey($this->view, $this->keyId, $this, $filePath);
$plainKeyfile = Crypt::multiKeyDecrypt($encKeyfile, $shareKey, $privateKey);
return $plainKeyfile;
}
/**
* Encrypt keyfile to multiple users
* @param Session $session
* @param array $users list of users which should be able to access the file
* @param string $filePath path of the file to be shared
* @return bool
*/
public function setSharedFileKeyfiles(Session $session, array $users, $filePath) {
// Make sure users are capable of sharing
$filteredUids = $this->filterShareReadyUsers($users);
// If we're attempting to share to unready users
if (!empty($filteredUids['unready'])) {
\OCP\Util::writeLog('Encryption library',
'Sharing to these user(s) failed as they are unready for encryption:"'
. print_r($filteredUids['unready'], 1), \OCP\Util::WARN);
return false;
}
// Get public keys for each user, ready for generating sharekeys
$userPubKeys = Keymanager::getPublicKeys($this->view, $filteredUids['ready']);
// Note proxy status then disable it
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
// Get the current users's private key for decrypting existing keyfile
$privateKey = $session->getPrivateKey();
try {
// Decrypt keyfile
$plainKeyfile = $this->decryptKeyfile($filePath, $privateKey);
// Re-enc keyfile to (additional) sharekeys
$multiEncKey = Crypt::multiKeyEncrypt($plainKeyfile, $userPubKeys);
} catch (Exception\EncryptionException $e) {
$msg = 'set shareFileKeyFailed (code: ' . $e->getCode() . '): ' . $e->getMessage();
\OCP\Util::writeLog('files_encryption', $msg, \OCP\Util::FATAL);
return false;
} catch (\Exception $e) {
$msg = 'set shareFileKeyFailed (unknown error): ' . $e->getMessage();
\OCP\Util::writeLog('files_encryption', $msg, \OCP\Util::FATAL);
return false;
}
// Save the recrypted key to it's owner's keyfiles directory
// Save new sharekeys to all necessary user directory
if (
!Keymanager::setFileKey($this->view, $this, $filePath, $multiEncKey['data'])
|| !Keymanager::setShareKeys($this->view, $this, $filePath, $multiEncKey['keys'])
) {
\OCP\Util::writeLog('Encryption library',
'Keyfiles could not be saved for users sharing ' . $filePath, \OCP\Util::ERROR);
return false;
}
// Return proxy to original status
\OC_FileProxy::$enabled = $proxyStatus;
return true;
}
/**
* Find, sanitise and format users sharing a file
* @note This wraps other methods into a portable bundle
* @param boolean $sharingEnabled
* @param string $filePath path relativ to current users files folder
*/
public function getSharingUsersArray($sharingEnabled, $filePath) {
$appConfig = \OC::$server->getAppConfig();
// Check if key recovery is enabled
if (
$appConfig->getValue('files_encryption', 'recoveryAdminEnabled')
&& $this->recoveryEnabledForUser()
) {
$recoveryEnabled = true;
} else {
$recoveryEnabled = false;
}
// Make sure that a share key is generated for the owner too
list($owner, $ownerPath) = $this->getUidAndFilename($filePath);
$ownerPath = Helper::stripPartialFileExtension($ownerPath);
// always add owner to the list of users with access to the file
$userIds = array($owner);
if ($sharingEnabled) {
// Find out who, if anyone, is sharing the file
$result = \OCP\Share::getUsersSharingFile($ownerPath, $owner);
$userIds = \array_merge($userIds, $result['users']);
if ($result['public']) {
$userIds[] = $this->publicShareKeyId;
}
}
// If recovery is enabled, add the
// Admin UID to list of users to share to
if ($recoveryEnabled) {
// Find recoveryAdmin user ID
$recoveryKeyId = $appConfig->getValue('files_encryption', 'recoveryKeyId');
// Add recoveryAdmin to list of users sharing
$userIds[] = $recoveryKeyId;
}
// check if it is a group mount
if (\OCP\App::isEnabled("files_external")) {
$mounts = \OC_Mount_Config::getSystemMountPoints();
foreach ($mounts as $mount) {
if ($mount['mountpoint'] == substr($ownerPath, 1, strlen($mount['mountpoint']))) {
$userIds = array_merge($userIds, $this->getUserWithAccessToMountPoint($mount['applicable']['users'], $mount['applicable']['groups']));
}
}
}
// Remove duplicate UIDs
$uniqueUserIds = array_unique($userIds);
return $uniqueUserIds;
}
private function getUserWithAccessToMountPoint($users, $groups) {
$result = array();
if (in_array('all', $users)) {
$result = \OCP\User::getUsers();
} else {
$result = array_merge($result, $users);
foreach ($groups as $group) {
$result = array_merge($result, \OC_Group::usersInGroup($group));
}
}
return $result;
}
/**
* set migration status
* @param int $status
* @param int $preCondition only update migration status if the previous value equals $preCondition
* @return boolean
*/
private function setMigrationStatus($status, $preCondition = null) {
// convert to string if preCondition is set
$preCondition = ($preCondition === null) ? null : (string)$preCondition;
try {
\OC::$server->getConfig()->setUserValue($this->userId, 'files_encryption', 'migration_status', (string)$status, $preCondition);
return true;
} catch(\OCP\PreConditionNotMetException $e) {
return false;
}
}
/**
* start migration mode to initially encrypt users data
* @return boolean
*/
public function beginMigration() {
$result = $this->setMigrationStatus(self::MIGRATION_IN_PROGRESS, self::MIGRATION_OPEN);
if ($result) {
\OCP\Util::writeLog('Encryption library', "Start migration to encryption mode for " . $this->userId, \OCP\Util::INFO);
} else {
\OCP\Util::writeLog('Encryption library', "Could not activate migration mode for " . $this->userId . ". Probably another process already started the initial encryption", \OCP\Util::WARN);
}
return $result;
}
public function resetMigrationStatus() {
return $this->setMigrationStatus(self::MIGRATION_OPEN);
}
/**
* close migration mode after users data has been encrypted successfully
* @return boolean
*/
public function finishMigration() {
$result = $this->setMigrationStatus(self::MIGRATION_COMPLETED);
if ($result) {
\OCP\Util::writeLog('Encryption library', "Finish migration successfully for " . $this->userId, \OCP\Util::INFO);
} else {
\OCP\Util::writeLog('Encryption library', "Could not deactivate migration mode for " . $this->userId, \OCP\Util::WARN);
}
return $result;
}
/**
* check if files are already migrated to the encryption system
* @return int|false migration status, false = in case of no record
* @note If records are not being returned, check for a hidden space
* at the start of the uid in db
*/
public function getMigrationStatus() {
$migrationStatus = false;
if (\OCP\User::userExists($this->userId)) {
$migrationStatus = \OC::$server->getConfig()->getUserValue($this->userId, 'files_encryption', 'migration_status', null);
if ($migrationStatus === null) {
\OC::$server->getConfig()->setUserValue($this->userId, 'files_encryption', 'migration_status', (string)self::MIGRATION_OPEN);
$migrationStatus = self::MIGRATION_OPEN;
}
}
return (int)$migrationStatus;
}
/**
* get uid of the owners of the file and the path to the file
* @param string $path Path of the file to check
* @throws \Exception
* @note $shareFilePath must be relative to data/UID/files. Files
* relative to /Shared are also acceptable
* @return array
*/
public function getUidAndFilename($path) {
$pathinfo = pathinfo($path);
$partfile = false;
$parentFolder = false;
if (array_key_exists('extension', $pathinfo) && $pathinfo['extension'] === 'part') {
// if the real file exists we check this file
$filePath = $this->userFilesDir . '/' .$pathinfo['dirname'] . '/' . $pathinfo['filename'];
if ($this->view->file_exists($filePath)) {
$pathToCheck = $pathinfo['dirname'] . '/' . $pathinfo['filename'];
} else { // otherwise we look for the parent
$pathToCheck = $pathinfo['dirname'];
$parentFolder = true;
}
$partfile = true;
} else {
$pathToCheck = $path;
}
$view = new \OC\Files\View($this->userFilesDir);
$fileOwnerUid = $view->getOwner($pathToCheck);
// handle public access
if ($this->isPublic) {
$filename = $path;
$fileOwnerUid = $this->userId;
return array(
$fileOwnerUid,
$filename
);
} else {
// Check that UID is valid
if (!\OCP\User::userExists($fileOwnerUid)) {
throw new \Exception(
'Could not find owner (UID = "' . var_export($fileOwnerUid, 1) . '") of file "' . $path . '"');
}
// NOTE: Bah, this dependency should be elsewhere
\OC\Files\Filesystem::initMountPoints($fileOwnerUid);
// If the file owner is the currently logged in user
if ($fileOwnerUid === $this->userId) {
// Assume the path supplied is correct
$filename = $path;
} else {
$info = $view->getFileInfo($pathToCheck);
$ownerView = new \OC\Files\View('/' . $fileOwnerUid . '/files');
// Fetch real file path from DB
$filename = $ownerView->getPath($info['fileid']);
if ($parentFolder) {
$filename = $filename . '/'. $pathinfo['filename'];
}
if ($partfile) {
$filename = $filename . '.' . $pathinfo['extension'];
}
}
return array(
$fileOwnerUid,
\OC\Files\Filesystem::normalizePath($filename)
);
}
}
/**
* go recursively through a dir and collect all files and sub files.
* @param string $dir relative to the users files folder
* @return array with list of files relative to the users files folder
*/
public function getAllFiles($dir, $mountPoint = '') {
$result = array();
$dirList = array($dir);
while ($dirList) {
$dir = array_pop($dirList);
$content = $this->view->getDirectoryContent(\OC\Files\Filesystem::normalizePath(
$this->userFilesDir . '/' . $dir));
foreach ($content as $c) {
// getDirectoryContent() returns the paths relative to the mount points, so we need
// to re-construct the complete path
$path = ($mountPoint !== '') ? $mountPoint . '/' . $c['path'] : $c['path'];
$path = \OC\Files\Filesystem::normalizePath($path);
if ($c['type'] === 'dir') {
$dirList[] = substr($path, strlen('/' . \OCP\User::getUser() . "/files"));
} else {
$result[] = substr($path, strlen('/' . \OCP\User::getUser() . "/files"));
}
}
}
return $result;
}
/**
* get owner of the shared files.
* @param int $id ID of a share
* @return string owner
*/
public function getOwnerFromSharedFile($id) {
$query = \OCP\DB::prepare('SELECT `parent`, `uid_owner` FROM `*PREFIX*share` WHERE `id` = ?', 1);
$result = $query->execute(array($id));
$source = null;
if (\OCP\DB::isError($result)) {
\OCP\Util::writeLog('Encryption library', \OC_DB::getErrorMessage($result), \OCP\Util::ERROR);
} else {
$source = $result->fetchRow();
}
$fileOwner = false;
if ($source && isset($source['parent'])) {
$parent = $source['parent'];
while (isset($parent)) {
$query = \OCP\DB::prepare('SELECT `parent`, `uid_owner` FROM `*PREFIX*share` WHERE `id` = ?', 1);
$result = $query->execute(array($parent));
$item = null;
if (\OCP\DB::isError($result)) {
\OCP\Util::writeLog('Encryption library', \OC_DB::getErrorMessage($result), \OCP\Util::ERROR);
} else {
$item = $result->fetchRow();
}
if ($item && isset($item['parent'])) {
$parent = $item['parent'];
} else {
$fileOwner = $item['uid_owner'];
break;
}
}
} else {
$fileOwner = $source['uid_owner'];
}
return $fileOwner;
}
/**
* @return string
*/
public function getUserId() {
return $this->userId;
}
/**
* @return string
*/
public function getKeyId() {
return $this->keyId;
}
/**
* @return string
*/
public function getUserFilesDir() {
return $this->userFilesDir;
}
/**
* @param string $password
* @return bool
*/
public function checkRecoveryPassword($password) {
$result = false;
$recoveryKey = Keymanager::getPrivateSystemKey($this->recoveryKeyId);
$decryptedRecoveryKey = Crypt::decryptPrivateKey($recoveryKey, $password);
if ($decryptedRecoveryKey) {
$result = true;
}
return $result;
}
/**
* @return string
*/
public function getRecoveryKeyId() {
return $this->recoveryKeyId;
}
/**
* add recovery key to all encrypted files
*/
public function addRecoveryKeys($path = '/') {
$dirContent = $this->view->getDirectoryContent($this->keysPath . '/' . $path);
foreach ($dirContent as $item) {
// get relative path from files_encryption/keyfiles/
$filePath = substr($item['path'], strlen('files_encryption/keys'));
if ($this->view->is_dir($this->userFilesDir . '/' . $filePath)) {
$this->addRecoveryKeys($filePath . '/');
} else {
$session = new Session(new \OC\Files\View('/'));
$sharingEnabled = \OCP\Share::isEnabled();
$usersSharing = $this->getSharingUsersArray($sharingEnabled, $filePath);
$this->setSharedFileKeyfiles($session, $usersSharing, $filePath);
}
}
}
/**
* remove recovery key to all encrypted files
*/
public function removeRecoveryKeys($path = '/') {
$dirContent = $this->view->getDirectoryContent($this->keysPath . '/' . $path);
foreach ($dirContent as $item) {
// get relative path from files_encryption/keyfiles
$filePath = substr($item['path'], strlen('files_encryption/keys'));
if ($this->view->is_dir($this->userFilesDir . '/' . $filePath)) {
$this->removeRecoveryKeys($filePath . '/');
} else {
$this->view->unlink($this->keysPath . '/' . $filePath . '/' . $this->recoveryKeyId . '.shareKey');
}
}
}
/**
* decrypt given file with recovery key and encrypt it again to the owner and his new key
* @param string $file
* @param string $privateKey recovery key to decrypt the file
*/
private function recoverFile($file, $privateKey) {
$sharingEnabled = \OCP\Share::isEnabled();
// Find out who, if anyone, is sharing the file
if ($sharingEnabled) {
$result = \OCP\Share::getUsersSharingFile($file, $this->userId, true);
$userIds = $result['users'];
$userIds[] = $this->recoveryKeyId;
if ($result['public']) {
$userIds[] = $this->publicShareKeyId;
}
} else {
$userIds = array(
$this->userId,
$this->recoveryKeyId
);
}
$filteredUids = $this->filterShareReadyUsers($userIds);
//decrypt file key
$encKeyfile = Keymanager::getFileKey($this->view, $this, $file);
$shareKey = Keymanager::getShareKey($this->view, $this->recoveryKeyId, $this, $file);
$plainKeyfile = Crypt::multiKeyDecrypt($encKeyfile, $shareKey, $privateKey);
// encrypt file key again to all users, this time with the new public key for the recovered use
$userPubKeys = Keymanager::getPublicKeys($this->view, $filteredUids['ready']);
$multiEncKey = Crypt::multiKeyEncrypt($plainKeyfile, $userPubKeys);
Keymanager::setFileKey($this->view, $this, $file, $multiEncKey['data']);
Keymanager::setShareKeys($this->view, $this, $file, $multiEncKey['keys']);
}
/**
* collect all files and recover them one by one
* @param string $path to look for files keys
* @param string $privateKey private recovery key which is used to decrypt the files
*/
private function recoverAllFiles($path, $privateKey) {
$dirContent = $this->view->getDirectoryContent($this->keysPath . '/' . $path);
foreach ($dirContent as $item) {
// get relative path from files_encryption/keyfiles
$filePath = substr($item['path'], strlen('files_encryption/keys'));
if ($this->view->is_dir($this->userFilesDir . '/' . $filePath)) {
$this->recoverAllFiles($filePath . '/', $privateKey);
} else {
$this->recoverFile($filePath, $privateKey);
}
}
}
/**
* recover users files in case of password lost
* @param string $recoveryPassword
*/
public function recoverUsersFiles($recoveryPassword) {
$encryptedKey = Keymanager::getPrivateSystemKey( $this->recoveryKeyId);
$privateKey = Crypt::decryptPrivateKey($encryptedKey, $recoveryPassword);
$this->recoverAllFiles('/', $privateKey);
}
/**
* create a backup of all keys from the user
*
* @param string $purpose (optional) define the purpose of the backup, will be part of the backup folder
*/
public function backupAllKeys($purpose = '') {
$this->userId;
$backupDir = $this->encryptionDir . '/backup.';
$backupDir .= ($purpose === '') ? date("Y-m-d_H-i-s") . '/' : $purpose . '.' . date("Y-m-d_H-i-s") . '/';
$this->view->mkdir($backupDir);
$this->view->copy($this->keysPath, $backupDir . 'keys/');
$this->view->copy($this->privateKeyPath, $backupDir . $this->userId . '.privateKey');
$this->view->copy($this->publicKeyPath, $backupDir . $this->userId . '.publicKey');
}
/**
* check if the file is stored on a system wide mount point
* @param string $path relative to /data/user with leading '/'
* @return boolean
*/
public function isSystemWideMountPoint($path) {
$normalizedPath = ltrim($path, '/');
if (\OCP\App::isEnabled("files_external")) {
$mounts = \OC_Mount_Config::getSystemMountPoints();
foreach ($mounts as $mount) {
if ($mount['mountpoint'] == substr($normalizedPath, 0, strlen($mount['mountpoint']))) {
if ($this->isMountPointApplicableToUser($mount)) {
return true;
}
}
}
}
return false;
}
/**
* check if mount point is applicable to user
*
* @param array $mount contains $mount['applicable']['users'], $mount['applicable']['groups']
* @return boolean
*/
protected function isMountPointApplicableToUser($mount) {
$uid = \OCP\User::getUser();
$acceptedUids = array('all', $uid);
// check if mount point is applicable for the user
$intersection = array_intersect($acceptedUids, $mount['applicable']['users']);
if (!empty($intersection)) {
return true;
}
// check if mount point is applicable for group where the user is a member
foreach ($mount['applicable']['groups'] as $gid) {
if (\OC_Group::inGroup($uid, $gid)) {
return true;
}
}
return false;
}
/**
* decrypt private key and add it to the current session
* @param array $params with 'uid' and 'password'
* @return mixed session or false
*/
public function initEncryption($params) {
$session = new Session($this->view);
// we tried to initialize the encryption app for this session
$session->setInitialized(Session::INIT_EXECUTED);
$encryptedKey = Keymanager::getPrivateKey($this->view, $params['uid']);
$privateKey = false;
if ($encryptedKey) {
$privateKey = Crypt::decryptPrivateKey($encryptedKey, $params['password']);
}
if ($privateKey === false) {
\OCP\Util::writeLog('Encryption library', 'Private key for user "' . $params['uid']
. '" is not valid! Maybe the user password was changed from outside if so please change it back to gain access', \OCP\Util::ERROR);
return false;
}
$session->setPrivateKey($privateKey);
$session->setInitialized(Session::INIT_SUCCESSFUL);
return $session;
}
/*
* remove encryption related keys from the session
*/
public function closeEncryptionSession() {
$session = new Session($this->view);
$session->closeSession();
}
}