server/apps/files_encryption/lib/keymanager.php
Vincent Petry 1e631754d7 Fix share key finding algorithm in various cases
Instead of inaccurate pattern matching, use the list of users who we
know have access to the file to build the list of share keys.

This covers the following cases:

- Move/copy files into a subfolder within a share
- Unsharing from a user
- Deleting files directlry / moving share keys to trashbin
2014-09-23 12:33:07 +02:00

616 lines
17 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;
/**
* Class to manage storage and retrieval of encryption keys
* @note Where a method requires a view object, it's root must be '/'
*/
class Keymanager {
/**
* retrieve the ENCRYPTED private key from a user
*
* @param \OC\Files\View $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\Files\View $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;
}
/**
* retrieve public key for a specified user
* @param \OC\Files\View $view
* @param string $userId
* @return string public key or false
*/
public static function getPublicKey(\OC\Files\View $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;
}
/**
* Retrieve a user's public and private key
* @param \OC\Files\View $view
* @param string $userId
* @return array keys: privateKey, publicKey
*/
public static function getUserKeys(\OC\Files\View $view, $userId) {
return array(
'publicKey' => self::getPublicKey($view, $userId),
'privateKey' => self::getPrivateKey($view, $userId)
);
}
/**
* Retrieve public keys for given users
* @param \OC\Files\View $view
* @param array $userIds
* @return array of public keys for the specified users
*/
public static function getPublicKeys(\OC\Files\View $view, array $userIds) {
$keys = array();
foreach ($userIds as $userId) {
$keys[$userId] = self::getPublicKey($view, $userId);
}
return $keys;
}
/**
* store file encryption key
*
* @param \OC\Files\View $view
* @param \OCA\Encryption\Util $util
* @param string $path relative path of the file, including filename
* @param string $catfile keyfile content
* @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\Files\View $view, $util, $path, $catfile) {
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
list($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, $basePath);
// try reusing key file if part file
if (Helper::isPartialFilePath($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;
}
/**
* retrieve keyfile for an encrypted file
* @param \OC\Files\View $view
* @param \OCA\Encryption\Util $util
* @param string|false $filePath
* @internal param \OCA\Encryption\file $string name
* @return string file key or false
* @note The keyfile returned is asymmetrically encrypted. Decryption
* of the keyfile must be performed by client code
*/
public static function getFileKey($view, $util, $filePath) {
list($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;
}
/**
* Delete a keyfile
*
* @param \OC\Files\View $view
* @param string $path path of the file the key belongs to
* @param string $userId the user to whom the file belongs
* @return bool Outcome of unlink operation
* @note $path must be relative to data/user/files. e.g. mydoc.txt NOT
* /data/admin/files/mydoc.txt
*/
public static function deleteFileKey($view, $path, $userId=null) {
$trimmed = ltrim($path, '/');
if ($trimmed === '') {
\OCP\Util::writeLog('Encryption library',
'Can\'t delete file-key empty path given!', \OCP\Util::ERROR);
return false;
}
if ($userId === null) {
$userId = Helper::getUser($path);
}
$util = new Util($view, $userId);
if($util->isSystemWideMountPoint($path)) {
$keyPath = '/files_encryption/keyfiles/' . $trimmed;
} else {
$keyPath = '/' . $userId . '/files_encryption/keyfiles/' . $trimmed;
}
$result = false;
$fileExists = $view->file_exists('/' . $userId . '/files/' . $trimmed);
if ($view->is_dir($keyPath) && !$fileExists) {
\OCP\Util::writeLog('files_encryption', 'deleteFileKey: delete file key: ' . $keyPath, \OCP\Util::DEBUG);
$result = $view->unlink($keyPath);
} elseif ($view->file_exists($keyPath . '.key') && !$fileExists) {
\OCP\Util::writeLog('files_encryption', 'deleteFileKey: delete file key: ' . $keyPath, \OCP\Util::DEBUG);
$result = $view->unlink($keyPath . '.key');
}
if ($fileExists) {
\OCP\Util::writeLog('Encryption library',
'Did not delete the file key, file still exists: ' . '/' . $userId . '/files/' . $trimmed, \OCP\Util::ERROR);
} elseif (!$result) {
\OCP\Util::writeLog('Encryption library',
'Could not delete keyfile; does not exist: "' . $keyPath, \OCP\Util::ERROR);
}
return $result;
}
/**
* 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, $user = '') {
if ($user === '') {
$user = \OCP\User::getUser();
}
$header = Crypt::generateHeader();
$view = new \OC\Files\View('/' . $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', $header . $key);
\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* write private system key (recovery and public share key) to disk
*
* @param string $key encrypted key
* @param string $keyName name of the key file
* @return boolean
*/
public static function setPrivateSystemKey($key, $keyName) {
$header = Crypt::generateHeader();
$view = new \OC\Files\View('/owncloud_private_key');
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
if (!$view->file_exists('')) {
$view->mkdir('');
}
$result = $view->file_put_contents($keyName, $header . $key);
\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* store share key
*
* @param \OC\Files\View $view
* @param string $path where the share key is stored
* @param string $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\Files\View $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;
}
}
/**
* store multiple share keys for a single file
* @param \OC\Files\View $view
* @param \OCA\Encryption\Util $util
* @param string $path
* @param array $shareKeys
* @return bool
*/
public static function setShareKeys(\OC\Files\View $view, $util, $path, array $shareKeys) {
// $shareKeys must be an array with the following format:
// [userId] => [encrypted key]
list($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);
$result = true;
foreach ($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;
}
/**
* retrieve shareKey for an encrypted file
* @param \OC\Files\View $view
* @param string $userId
* @param \OCA\Encryption\Util $util
* @param string $filePath
* @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\Files\View $view, $userId, $util, $filePath) {
// try reusing key file if part file
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
list($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;
}
/**
* delete all share keys of a given file
* @param \OC\Files\View $view
* @param string $userId owner of the file
* @param string $filePath path to the file, relative to the owners file dir
*/
public static function delAllShareKeys($view, $userId, $filePath) {
$filePath = ltrim($filePath, '/');
if ($view->file_exists('/' . $userId . '/files/' . $filePath)) {
\OCP\Util::writeLog('Encryption library',
'File still exists, stop deleting share keys!', \OCP\Util::ERROR);
return false;
}
if ($filePath === '') {
\OCP\Util::writeLog('Encryption library',
'Can\'t delete share-keys empty path given!', \OCP\Util::ERROR);
return false;
}
$util = new util($view, $userId);
if ($util->isSystemWideMountPoint($filePath)) {
$baseDir = '/files_encryption/share-keys/';
} else {
$baseDir = $userId . '/files_encryption/share-keys/';
}
$result = true;
if ($view->is_dir($baseDir . $filePath)) {
\OCP\Util::writeLog('files_encryption', 'delAllShareKeys: delete share keys: ' . $baseDir . $filePath, \OCP\Util::DEBUG);
$result = $view->unlink($baseDir . $filePath);
} else {
$sharingEnabled = \OCP\Share::isEnabled();
$users = $util->getSharingUsersArray($sharingEnabled, $filePath);
foreach($users as $user) {
$keyName = $baseDir . $filePath . '.' . $user . '.shareKey';
if ($view->file_exists($keyName)) {
\OCP\Util::writeLog(
'files_encryption',
'dellAllShareKeys: delete share keys: "' . $keyName . '"',
\OCP\Util::DEBUG
);
$result &= $view->unlink($keyName);
}
}
}
return (bool)$result;
}
/**
* Delete a single user's shareKey for a single file
*
* @param \OC\Files\View $view relative to data/
* @param array $userIds list of users we want to remove
* @param string $filename the owners name of the file for which we want to remove the users relative to data/user/files
* @param string $owner owner of the file
*/
public static function delShareKey($view, $userIds, $filename, $owner) {
$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
$util = new Util($view, $owner);
if ($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($shareKeyPath)) {
self::recursiveDelShareKeys($shareKeyPath, $userIds, $owner, $view);
} else {
foreach ($userIds as $userId) {
if ($userId === $owner && $view->file_exists('/' . $owner . '/files/' . $filename)) {
\OCP\Util::writeLog('files_encryption', 'Tried to delete owner key, but the file still exists!', \OCP\Util::FATAL);
continue;
}
$result = $view->unlink($shareKeyPath . '.' . $userId . '.shareKey');
\OCP\Util::writeLog('files_encryption', 'delShareKey: delete share key: ' . $shareKeyPath . '.' . $userId . '.shareKey' , \OCP\Util::DEBUG);
if (!$result) {
\OCP\Util::writeLog('Encryption library',
'Could not delete shareKey; does not exist: "' . $shareKeyPath . '.' . $userId
. '.shareKey"', \OCP\Util::ERROR);
}
}
}
\OC_FileProxy::$enabled = $proxyStatus;
}
/**
* recursively delete share keys from given users
*
* @param string $dir directory
* @param array $userIds user ids for which the share keys should be deleted
* @param string $owner owner of the file
* @param \OC\Files\View $view view relative to data/
*/
private static function recursiveDelShareKeys($dir, $userIds, $owner, $view) {
$dirContent = $view->opendir($dir);
$dirSlices = explode('/', ltrim($dir, '/'));
$realFileDir = '/' . $owner . '/files/' . implode('/', array_slice($dirSlices, 3)) . '/';
if (is_resource($dirContent)) {
while (($file = readdir($dirContent)) !== false) {
if (!\OC\Files\Filesystem::isIgnoredDir($file)) {
if ($view->is_dir($dir . '/' . $file)) {
self::recursiveDelShareKeys($dir . '/' . $file, $userIds, $owner, $view);
} else {
foreach ($userIds as $userId) {
$fileNameFromShareKey = self::getFilenameFromShareKey($file, $userId);
if (!$fileNameFromShareKey) {
continue;
}
$realFile = $realFileDir . $fileNameFromShareKey;
if ($userId === $owner &&
$view->file_exists($realFile)) {
\OCP\Util::writeLog('files_encryption', 'original file still exists, keep owners share key!', \OCP\Util::ERROR);
continue;
}
\OCP\Util::writeLog('files_encryption', 'recursiveDelShareKey: delete share key: ' . $file, \OCP\Util::DEBUG);
$view->unlink($dir . '/' . $file);
}
}
}
}
closedir($dirContent);
}
}
/**
* Make preparations to vars and filesystem for saving a keyfile
* @param string|boolean $path
* @param string $basePath
*/
protected static function keySetPreparation(\OC\Files\View $view, $path, $basePath) {
$targetPath = ltrim($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('/', $basePath . '/' . $path_parts['dirname']);
$dir = '';
foreach ($sub_dirs as $sub_dir) {
$dir .= '/' . $sub_dir;
if (!$view->is_dir($dir)) {
$view->mkdir($dir);
}
}
}
return $targetPath;
}
/**
* extract filename from share key name
* @param string $shareKey (filename.userid.sharekey)
* @param string $userId
* @return string|false filename or false
*/
protected static function getFilenameFromShareKey($shareKey, $userId) {
$expectedSuffix = '.' . $userId . '.' . 'shareKey';
$suffixLen = strlen($expectedSuffix);
$suffix = substr($shareKey, -$suffixLen);
if ($suffix !== $expectedSuffix) {
return false;
}
return substr($shareKey, 0, -$suffixLen);
}
}