nextcloud/apps/files_encryption/lib/keymanager.php

573 lines
15 KiB
PHP
Executable File

<?php
/**
* ownCloud
*
* @author Bjoern Schiessle
* @copyright 2012 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\Encryption;
/**
* @brief Class to manage storage and retrieval of encryption keys
* @note Where a method requires a view object, it's root must be '/'
*/
class Keymanager {
/**
* @brief retrieve the ENCRYPTED private key from a user
*
* @param \OC_FilesystemView $view
* @param string $user
* @return string private key or false (hopefully)
* @note the key returned by this method must be decrypted before use
*/
public static function getPrivateKey(\OC_FilesystemView $view, $user) {
$path = '/' . $user . '/' . 'files_encryption' . '/' . $user . '.private.key';
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
$key = $view->file_get_contents($path);
\OC_FileProxy::$enabled = $proxyStatus;
return $key;
}
/**
* @brief retrieve public key for a specified user
* @param \OC_FilesystemView $view
* @param $userId
* @return string public key or false
*/
public static function getPublicKey(\OC_FilesystemView $view, $userId) {
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
$result = $view->file_get_contents('/public-keys/' . $userId . '.public.key');
\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* @brief Retrieve a user's public and private key
* @param \OC_FilesystemView $view
* @param $userId
* @return array keys: privateKey, publicKey
*/
public static function getUserKeys(\OC_FilesystemView $view, $userId) {
return array(
'publicKey' => self::getPublicKey($view, $userId),
'privateKey' => self::getPrivateKey($view, $userId)
);
}
/**
* @brief Retrieve public keys for given users
* @param \OC_FilesystemView $view
* @param array $userIds
* @return array of public keys for the specified users
*/
public static function getPublicKeys(\OC_FilesystemView $view, array $userIds) {
$keys = array();
foreach ($userIds as $userId) {
$keys[$userId] = self::getPublicKey($view, $userId);
}
return $keys;
}
/**
* @brief store file encryption key
*
* @param \OC_FilesystemView $view
* @param string $path relative path of the file, including filename
* @param $userId
* @param $catfile
* @internal param string $key
* @return bool true/false
* @note The keyfile is not encrypted here. Client code must
* asymmetrically encrypt the keyfile before passing it to this method
*/
public static function setFileKey(\OC_FilesystemView $view, $path, $userId, $catfile) {
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
//here we need the currently logged in user, while userId can be a different user
$util = new Util($view, \OCP\User::getUser());
list($owner, $filename) = $util->getUidAndFilename($path);
// in case of system wide mount points the keys are stored directly in the data directory
if ($util->isSystemWideMountPoint($filename)) {
$basePath = '/files_encryption/keyfiles';
} else {
$basePath = '/' . $owner . '/files_encryption/keyfiles';
}
$targetPath = self::keySetPreparation($view, $filename, $basePath, $owner);
if (!$view->is_dir($basePath . '/' . $targetPath)) {
// create all parent folders
$info = pathinfo($basePath . '/' . $targetPath);
$keyfileFolderName = $view->getLocalFolder($info['dirname']);
if (!file_exists($keyfileFolderName)) {
mkdir($keyfileFolderName, 0750, true);
}
}
// try reusing key file if part file
if (self::isPartialFilePath($targetPath)) {
$result = $view->file_put_contents(
$basePath . '/' . self::fixPartialFilePath($targetPath) . '.key', $catfile);
} else {
$result = $view->file_put_contents($basePath . '/' . $targetPath . '.key', $catfile);
}
\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* @brief Remove .path extension from a file path
* @param string $path Path that may identify a .part file
* @return string File path without .part extension
* @note this is needed for reusing keys
*/
public static function fixPartialFilePath($path) {
if (preg_match('/\.part$/', $path) || preg_match('/\.etmp$/', $path)) {
$newLength = strlen($path) - 5;
$fPath = substr($path, 0, $newLength);
return $fPath;
} else {
return $path;
}
}
/**
* @brief Check if a path is a .part file
* @param string $path Path that may identify a .part file
* @return bool
*/
public static function isPartialFilePath($path) {
if (preg_match('/\.part$/', $path) || preg_match('/\.etmp$/', $path)) {
return true;
} else {
return false;
}
}
/**
* @brief retrieve keyfile for an encrypted file
* @param \OC_FilesystemView $view
* @param $userId
* @param $filePath
* @internal param \OCA\Encryption\file $string name
* @return string file key or false
* @note The keyfile returned is asymmetrically encrypted. Decryption
* of the keyfile must be performed by client code
*/
public static function getFileKey(\OC_FilesystemView $view, $userId, $filePath) {
$util = new Util($view, \OCP\User::getUser());
list($owner, $filename) = $util->getUidAndFilename($filePath);
$filename = self::fixPartialFilePath($filename);
$filePath_f = ltrim($filename, '/');
// in case of system wide mount points the keys are stored directly in the data directory
if ($util->isSystemWideMountPoint($filename)) {
$keyfilePath = '/files_encryption/keyfiles/' . $filePath_f . '.key';
} else {
$keyfilePath = '/' . $owner . '/files_encryption/keyfiles/' . $filePath_f . '.key';
}
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
if ($view->file_exists($keyfilePath)) {
$result = $view->file_get_contents($keyfilePath);
} else {
$result = false;
}
\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* @brief Delete a keyfile
*
* @param \OC_FilesystemView $view
* @param string $userId username
* @param string $path path of the file the key belongs to
* @return bool Outcome of unlink operation
* @note $path must be relative to data/user/files. e.g. mydoc.txt NOT
* /data/admin/files/mydoc.txt
*/
public static function deleteFileKey(\OC_FilesystemView $view, $userId, $path) {
$trimmed = ltrim($path, '/');
$util = new Util($view, \OCP\User::getUser());
if($util->isSystemWideMountPoint($path)) {
$keyPath = '/files_encryption/keyfiles/' . $trimmed;
} else {
$keyPath = '/' . $userId . '/files_encryption/keyfiles/' . $trimmed;
}
$result = false;
if ($view->is_dir($keyPath)) {
$result = $view->unlink($keyPath);
} else {
if ($view->file_exists($keyPath . '.key')) {
$result = $view->unlink($keyPath . '.key');
}
}
if (!$result) {
\OCP\Util::writeLog('Encryption library',
'Could not delete keyfile; does not exist: "' . $keyPath, \OCP\Util::ERROR);
}
return $result;
}
/**
* @brief store private key from the user
* @param string $key
* @return bool
* @note Encryption of the private key must be performed by client code
* as no encryption takes place here
*/
public static function setPrivateKey($key) {
$user = \OCP\User::getUser();
$view = new \OC_FilesystemView('/' . $user . '/files_encryption');
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
if (!$view->file_exists(''))
$view->mkdir('');
$result = $view->file_put_contents($user . '.private.key', $key);
\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* @brief store share key
*
* @param \OC_FilesystemView $view
* @param string $path where the share key is stored
* @param $shareKey
* @return bool true/false
* @note The keyfile is not encrypted here. Client code must
* asymmetrically encrypt the keyfile before passing it to this method
*/
private static function setShareKey(\OC_FilesystemView $view, $path, $shareKey) {
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
$result = $view->file_put_contents($path, $shareKey);
\OC_FileProxy::$enabled = $proxyStatus;
if (is_int($result) && $result > 0) {
return true;
} else {
return false;
}
}
/**
* @brief store multiple share keys for a single file
* @param \OC_FilesystemView $view
* @param $path
* @param array $shareKeys
* @return bool
*/
public static function setShareKeys(\OC_FilesystemView $view, $path, array $shareKeys) {
// $shareKeys must be an array with the following format:
// [userId] => [encrypted key]
// Here we need the currently logged in user, while userId can be a different user
$util = new Util($view, \OCP\User::getUser());
list($owner, $filename) = $util->getUidAndFilename($path);
// in case of system wide mount points the keys are stored directly in the data directory
if ($util->isSystemWideMountPoint($filename)) {
$basePath = '/files_encryption/share-keys';
} else {
$basePath = '/' . $owner . '/files_encryption/share-keys';
}
$shareKeyPath = self::keySetPreparation($view, $filename, $basePath, $owner);
$result = true;
foreach ($shareKeys as $userId => $shareKey) {
// try reusing key file if part file
if (self::isPartialFilePath($shareKeyPath)) {
$writePath = $basePath . '/' . self::fixPartialFilePath($shareKeyPath) . '.' . $userId . '.shareKey';
} else {
$writePath = $basePath . '/' . $shareKeyPath . '.' . $userId . '.shareKey';
}
if (!self::setShareKey($view, $writePath, $shareKey)) {
// If any of the keys are not set, flag false
$result = false;
}
}
// Returns false if any of the keys weren't set
return $result;
}
/**
* @brief retrieve shareKey for an encrypted file
* @param \OC_FilesystemView $view
* @param string $userId
* @param string $filePath
* @internal param \OCA\Encryption\file $string name
* @return string file key or false
* @note The sharekey returned is encrypted. Decryption
* of the keyfile must be performed by client code
*/
public static function getShareKey(\OC_FilesystemView $view, $userId, $filePath) {
// try reusing key file if part file
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
//here we need the currently logged in user, while userId can be a different user
$util = new Util($view, \OCP\User::getUser());
list($owner, $filename) = $util->getUidAndFilename($filePath);
$filename = self::fixPartialFilePath($filename);
// in case of system wide mount points the keys are stored directly in the data directory
if ($util->isSystemWideMountPoint($filename)) {
$shareKeyPath = '/files_encryption/share-keys/' . $filename . '.' . $userId . '.shareKey';
} else {
$shareKeyPath = '/' . $owner . '/files_encryption/share-keys/' . $filename . '.' . $userId . '.shareKey';
}
if ($view->file_exists($shareKeyPath)) {
$result = $view->file_get_contents($shareKeyPath);
} else {
$result = false;
}
\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* @brief delete all share keys of a given file
* @param \OC_FilesystemView $view
* @param string $userId owner of the file
* @param string $filePath path to the file, relative to the owners file dir
*/
public static function delAllShareKeys(\OC_FilesystemView $view, $userId, $filePath) {
$util = new util($view, $userId);
if ($util->isSystemWideMountPoint($filePath)) {
$baseDir = '/files_encryption/share-keys/';
} else {
$baseDir = $userId . '/files_encryption/share-keys/';
}
if ($view->is_dir($userId . '/files/' . $filePath)) {
$view->unlink($baseDir . $filePath);
} else {
$localKeyPath = $view->getLocalFile($baseDir . $filePath);
$escapedPath = Helper::escapeGlobPattern($localKeyPath);
$matches = glob($escapedPath . '*.shareKey');
foreach ($matches as $ma) {
$result = unlink($ma);
if (!$result) {
\OCP\Util::writeLog('Encryption library',
'Keyfile or shareKey could not be deleted for file "' . $filePath . '"', \OCP\Util::ERROR);
}
}
}
}
/**
* @brief Delete a single user's shareKey for a single file
*/
public static function delShareKey(\OC_FilesystemView $view, $userIds, $filePath) {
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
//here we need the currently logged in user, while userId can be a different user
$util = new Util($view, \OCP\User::getUser());
list($owner, $filename) = $util->getUidAndFilename($filePath);
if ($util->isSystemWideMountPoint($filename)) {
$shareKeyPath = \OC\Files\Filesystem::normalizePath('/files_encryption/share-keys/' . $filename);
} else {
$shareKeyPath = \OC\Files\Filesystem::normalizePath('/' . $owner . '/files_encryption/share-keys/' . $filename);
}
if ($view->is_dir($shareKeyPath)) {
$localPath = \OC\Files\Filesystem::normalizePath($view->getLocalFolder($shareKeyPath));
self::recursiveDelShareKeys($localPath, $userIds);
} else {
foreach ($userIds as $userId) {
if (!$view->unlink($shareKeyPath . '.' . $userId . '.shareKey')) {
\OCP\Util::writeLog('Encryption library',
'Could not delete shareKey; does not exist: "' . $shareKeyPath . '.' . $userId
. '.shareKey"', \OCP\Util::ERROR);
}
}
}
\OC_FileProxy::$enabled = $proxyStatus;
}
/**
* @brief recursively delete share keys from given users
*
* @param string $dir directory
* @param array $userIds user ids for which the share keys should be deleted
*/
private static function recursiveDelShareKeys($dir, $userIds) {
foreach ($userIds as $userId) {
$extension = '.' . $userId . '.shareKey';
$escapedDir = Helper::escapeGlobPattern($dir);
$escapedExtension = Helper::escapeGlobPattern($extension);
$matches = glob($escapedDir . '/*' . $escapedExtension);
}
/** @var $matches array */
foreach ($matches as $ma) {
if (!unlink($ma)) {
\OCP\Util::writeLog('Encryption library',
'Could not delete shareKey; does not exist: "' . $ma . '"', \OCP\Util::ERROR);
}
}
$subdirs = $directories = glob($escapedDir . '/*', GLOB_ONLYDIR);
foreach ($subdirs as $subdir) {
self::recursiveDelShareKeys($subdir, $userIds);
}
}
/**
* @brief Make preparations to vars and filesystem for saving a keyfile
*/
public static function keySetPreparation(\OC_FilesystemView $view, $path, $basePath, $userId) {
$targetPath = ltrim($path, '/');
$path_parts = pathinfo($targetPath);
// If the file resides within a subdirectory, create it
if (
isset($path_parts['dirname'])
&& !$view->file_exists($basePath . '/' . $path_parts['dirname'])
) {
$sub_dirs = explode(DIRECTORY_SEPARATOR, $basePath . '/' . $path_parts['dirname']);
$dir = '';
foreach ($sub_dirs as $sub_dir) {
$dir .= '/' . $sub_dir;
if (!$view->is_dir($dir)) {
$view->mkdir($dir);
}
}
}
return $targetPath;
}
}