server/apps/files_encryption/lib/keymanager.php
Bjoern Schiessle 0c24c7c420 only check if the key file exists to decide if it is an encrypted file or not.
This solves problems with external storage which doesn't support fseek
2013-11-20 11:02:22 +01:00

532 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';
$key = false;
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
if ($view->file_exists($path)) {
$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 (Helper::isPartialFilePath($targetPath)) {
$result = $view->file_put_contents(
$basePath . '/' . Helper::stripPartialFileExtension($targetPath) . '.key', $catfile);
} else {
$result = $view->file_put_contents($basePath . '/' . $targetPath . '.key', $catfile);
}
\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* @brief retrieve keyfile for an encrypted file
* @param \OC_FilesystemView $view
* @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, $filePath) {
$util = new Util($view, \OCP\User::getUser());
list($owner, $filename) = $util->getUidAndFilename($filePath);
$filename = Helper::stripPartialFileExtension($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 => $shareKey) {
// try reusing key file if part file
if (Helper::isPartialFilePath($shareKeyPath)) {
$writePath = $basePath . '/' . Helper::stripPartialFileExtension($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);
$filename = Helper::stripPartialFileExtension($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;
}
}