701 lines
19 KiB
PHP
701 lines
19 KiB
PHP
<?php
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/**
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* ownCloud
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*
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* @author Sam Tuke, Frank Karlitschek
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* @copyright 2012 Sam Tuke samtuke@owncloud.com,
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* Frank Karlitschek frank@owncloud.org
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
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* License as published by the Free Software Foundation; either
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* version 3 of the License, or any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU AFFERO GENERAL PUBLIC LICENSE for more details.
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*
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* You should have received a copy of the GNU Affero General Public
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* License along with this library. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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# Bugs
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# ----
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# Sharing a file to a user without encryption set up will not provide them with access but won't notify the sharer
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# Deleting files if keyfile is missing fails
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# When encryption app is disabled files become unreadable
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# Timeouts on first login due to encryption of very large files
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# MultiKeyEncrypt() may be failing
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# Missing features
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# ----------------
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# Unshare a file
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# Re-use existing keyfiles so they don't need version control
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# Make sure user knows if large files weren't encrypted
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# Trashbin support
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// Old Todo:
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// - Crypt/decrypt button in the userinterface
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// - Setting if crypto should be on by default
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// - Add a setting "Don´t encrypt files larger than xx because of performance
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// reasons"
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namespace OCA\Encryption;
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/**
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* @brief Class for utilities relating to encrypted file storage system
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* @param OC_FilesystemView $view expected to have OC '/' as root path
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* @param string $userId ID of the logged in user
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* @param int $client indicating status of client side encryption. Currently
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* unused, likely to become obsolete shortly
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*/
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class Util {
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// Web UI:
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//// DONE: files created via web ui are encrypted
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//// DONE: file created & encrypted via web ui are readable in web ui
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//// DONE: file created & encrypted via web ui are readable via webdav
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// WebDAV:
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//// DONE: new data filled files added via webdav get encrypted
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//// DONE: new data filled files added via webdav are readable via webdav
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//// DONE: reading unencrypted files when encryption is enabled works via
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//// webdav
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//// DONE: files created & encrypted via web ui are readable via webdav
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// Legacy support:
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//// DONE: add method to check if file is encrypted using new system
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//// DONE: add method to check if file is encrypted using old system
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//// DONE: add method to fetch legacy key
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//// DONE: add method to decrypt legacy encrypted data
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// Admin UI:
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//// DONE: changing user password also changes encryption passphrase
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//// TODO: add support for optional recovery in case of lost passphrase / keys
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//// TODO: add admin optional required long passphrase for users
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//// TODO: add UI buttons for encrypt / decrypt everything
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//// TODO: implement flag system to allow user to specify encryption by folder, subfolder, etc.
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// Sharing:
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//// TODO: add support for encrypting to multiple public keys
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//// TODO: add support for decrypting to multiple private keys
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// Integration testing:
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//// TODO: test new encryption with versioning
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//// TODO: test new encryption with sharing
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//// TODO: test new encryption with proxies
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private $view; // OC_FilesystemView object for filesystem operations
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private $userId; // ID of the currently logged-in user
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private $pwd; // User Password
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private $client; // Client side encryption mode flag
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private $publicKeyDir; // Dir containing all public user keys
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private $encryptionDir; // Dir containing user's files_encryption
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private $keyfilesPath; // Dir containing user's keyfiles
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private $shareKeysPath; // Dir containing env keys for shared files
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private $publicKeyPath; // Path to user's public key
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private $privateKeyPath; // Path to user's private key
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public function __construct( \OC_FilesystemView $view, $userId, $client = false ) {
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$this->view = $view;
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$this->userId = $userId;
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$this->client = $client;
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$this->userDir = '/' . $this->userId;
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$this->userFilesDir = '/' . $this->userId . '/' . 'files';
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$this->publicKeyDir = '/' . 'public-keys';
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$this->encryptionDir = '/' . $this->userId . '/' . 'files_encryption';
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$this->keyfilesPath = $this->encryptionDir . '/' . 'keyfiles';
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$this->shareKeysPath = $this->encryptionDir . '/' . 'share-keys';
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$this->publicKeyPath = $this->publicKeyDir . '/' . $this->userId . '.public.key'; // e.g. data/public-keys/admin.public.key
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$this->privateKeyPath = $this->encryptionDir . '/' . $this->userId . '.private.key'; // e.g. data/admin/admin.private.key
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}
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public function ready() {
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if(
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!$this->view->file_exists( $this->encryptionDir )
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or !$this->view->file_exists( $this->keyfilesPath )
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or !$this->view->file_exists( $this->shareKeysPath )
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or !$this->view->file_exists( $this->publicKeyPath )
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or !$this->view->file_exists( $this->privateKeyPath )
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) {
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return false;
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} else {
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return true;
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}
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}
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/**
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* @brief Sets up user folders and keys for serverside encryption
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* @param $passphrase passphrase to encrypt server-stored private key with
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*/
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public function setupServerSide( $passphrase = null ) {
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// Create user dir
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if( !$this->view->file_exists( $this->userDir ) ) {
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$this->view->mkdir( $this->userDir );
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}
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// Create user files dir
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if( !$this->view->file_exists( $this->userFilesDir ) ) {
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$this->view->mkdir( $this->userFilesDir );
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}
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// Create shared public key directory
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if( !$this->view->file_exists( $this->publicKeyDir ) ) {
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$this->view->mkdir( $this->publicKeyDir );
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}
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// Create encryption app directory
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if( !$this->view->file_exists( $this->encryptionDir ) ) {
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$this->view->mkdir( $this->encryptionDir );
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}
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// Create mirrored keyfile directory
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if( !$this->view->file_exists( $this->keyfilesPath ) ) {
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$this->view->mkdir( $this->keyfilesPath );
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}
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// Create mirrored share env keys directory
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if( !$this->view->file_exists( $this->shareKeysPath ) ) {
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$this->view->mkdir( $this->shareKeysPath );
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}
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// Create user keypair
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if (
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! $this->view->file_exists( $this->publicKeyPath )
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or ! $this->view->file_exists( $this->privateKeyPath )
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) {
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// Generate keypair
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$keypair = Crypt::createKeypair();
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\OC_FileProxy::$enabled = false;
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// Save public key
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$this->view->file_put_contents( $this->publicKeyPath, $keypair['publicKey'] );
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// Encrypt private key with user pwd as passphrase
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$encryptedPrivateKey = Crypt::symmetricEncryptFileContent( $keypair['privateKey'], $passphrase );
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// Save private key
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$this->view->file_put_contents( $this->privateKeyPath, $encryptedPrivateKey );
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\OC_FileProxy::$enabled = true;
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}
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return true;
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}
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/**
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* @brief Find all files and their encryption status within a directory
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* @param string $directory The path of the parent directory to search
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* @return mixed false if 0 found, array on success. Keys: name, path
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* @note $directory needs to be a path relative to OC data dir. e.g.
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* /admin/files NOT /backup OR /home/www/oc/data/admin/files
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*/
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public function findEncFiles( $directory ) {
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// Disable proxy - we don't want files to be decrypted before
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// we handle them
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\OC_FileProxy::$enabled = false;
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$found = array( 'plain' => array(), 'encrypted' => array(), 'legacy' => array() );
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if (
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$this->view->is_dir( $directory )
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&& $handle = $this->view->opendir( $directory )
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) {
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while ( false !== ( $file = readdir( $handle ) ) ) {
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if (
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$file != "."
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&& $file != ".."
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) {
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$filePath = $directory . '/' . $this->view->getRelativePath( '/' . $file );
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$relPath = $this->stripUserFilesPath( $filePath );
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// If the path is a directory, search
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// its contents
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if ( $this->view->is_dir( $filePath ) ) {
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$this->findEncFiles( $filePath );
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// If the path is a file, determine
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// its encryption status
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} elseif ( $this->view->is_file( $filePath ) ) {
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// Disable proxies again, some-
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// where they got re-enabled :/
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\OC_FileProxy::$enabled = false;
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$data = $this->view->file_get_contents( $filePath );
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// If the file is encrypted
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// NOTE: If the userId is
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// empty or not set, file will
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// detected as plain
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// NOTE: This is inefficient;
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// scanning every file like this
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// will eat server resources :(
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if (
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Keymanager::getFileKey( $this->view, $this->userId, $file )
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&& Crypt::isCatfile( $data )
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) {
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$found['encrypted'][] = array( 'name' => $file, 'path' => $filePath );
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// If the file uses old
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// encryption system
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} elseif ( Crypt::isLegacyEncryptedContent( $this->view->file_get_contents( $filePath ), $relPath ) ) {
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$found['legacy'][] = array( 'name' => $file, 'path' => $filePath );
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// If the file is not encrypted
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} else {
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$found['plain'][] = array( 'name' => $file, 'path' => $filePath );
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}
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}
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}
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}
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\OC_FileProxy::$enabled = true;
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if ( empty( $found ) ) {
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return false;
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} else {
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return $found;
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}
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}
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\OC_FileProxy::$enabled = true;
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return false;
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}
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/**
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* @brief Check if a given path identifies an encrypted file
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* @return true / false
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*/
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public function isEncryptedPath( $path ) {
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// Disable encryption proxy so data retreived is in its
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// original form
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\OC_FileProxy::$enabled = false;
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$data = $this->view->file_get_contents( $path );
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\OC_FileProxy::$enabled = true;
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return Crypt::isCatfile( $data );
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}
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/**
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* @brief Format a path to be relative to the /user/files/ directory
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*/
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public function stripUserFilesPath( $path ) {
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$trimmed = ltrim( $path, '/' );
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$split = explode( '/', $trimmed );
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$sliced = array_slice( $split, 2 );
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$relPath = implode( '/', $sliced );
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return $relPath;
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}
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/**
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* @brief Format a shared path to be relative to the /user/files/ directory
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* @note Expects a path like /uid/files/Shared/filepath
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*/
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public function stripSharedFilePath( $path ) {
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$trimmed = ltrim( $path, '/' );
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$split = explode( '/', $trimmed );
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$sliced = array_slice( $split, 3 );
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$relPath = implode( '/', $sliced );
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return $relPath;
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}
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public function isSharedPath( $path ) {
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$trimmed = ltrim( $path, '/' );
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$split = explode( '/', $trimmed );
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if ( $split[2] == "Shared" ) {
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return true;
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} else {
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return false;
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}
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}
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/**
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* @brief Encrypt all files in a directory
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* @param string $publicKey the public key to encrypt files with
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* @param string $dirPath the directory whose files will be encrypted
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* @note Encryption is recursive
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*/
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public function encryptAll( $publicKey, $dirPath, $legacyPassphrase = null, $newPassphrase = null ) {
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if ( $found = $this->findEncFiles( $dirPath ) ) {
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// Disable proxy to prevent file being encrypted twice
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\OC_FileProxy::$enabled = false;
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// Encrypt unencrypted files
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foreach ( $found['plain'] as $plainFile ) {
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// Fetch data from file
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$plainData = $this->view->file_get_contents( $plainFile['path'] );
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// Encrypt data, generate catfile
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$encrypted = Crypt::keyEncryptKeyfile( $plainData, $publicKey );
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$relPath = $this->stripUserFilesPath( $plainFile['path'] );
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// Save keyfile
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Keymanager::setFileKey( $this->view, $relPath, $this->userId, $encrypted['key'] );
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// Overwrite the existing file with the encrypted one
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$this->view->file_put_contents( $plainFile['path'], $encrypted['data'] );
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$size = strlen( $encrypted['data'] );
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// Add the file to the cache
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\OC\Files\Filesystem::putFileInfo( $plainFile['path'], array( 'encrypted'=>true, 'size' => $size ), '' );
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}
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// Encrypt legacy encrypted files
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if (
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! empty( $legacyPassphrase )
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&& ! empty( $newPassphrase )
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) {
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foreach ( $found['legacy'] as $legacyFile ) {
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// Fetch data from file
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$legacyData = $this->view->file_get_contents( $legacyFile['path'] );
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// Recrypt data, generate catfile
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$recrypted = Crypt::legacyKeyRecryptKeyfile( $legacyData, $legacyPassphrase, $publicKey, $newPassphrase );
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$relPath = $this->stripUserFilesPath( $legacyFile['path'] );
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// Save keyfile
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Keymanager::setFileKey( $this->view, $relPath, $this->userId, $recrypted['key'] );
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// Overwrite the existing file with the encrypted one
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$this->view->file_put_contents( $legacyFile['path'], $recrypted['data'] );
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$size = strlen( $recrypted['data'] );
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// Add the file to the cache
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\OC\Files\Filesystem::putFileInfo( $legacyFile['path'], array( 'encrypted'=>true, 'size' => $size ), '' );
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}
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}
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\OC_FileProxy::$enabled = true;
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// If files were found, return true
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return true;
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} else {
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// If no files were found, return false
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return false;
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}
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}
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/**
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* @brief Return important encryption related paths
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* @param string $pathName Name of the directory to return the path of
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* @return string path
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*/
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public function getPath( $pathName ) {
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switch ( $pathName ) {
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case 'publicKeyDir':
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return $this->publicKeyDir;
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break;
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case 'encryptionDir':
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return $this->encryptionDir;
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break;
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case 'keyfilesPath':
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return $this->keyfilesPath;
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break;
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case 'publicKeyPath':
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return $this->publicKeyPath;
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break;
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case 'privateKeyPath':
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return $this->privateKeyPath;
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break;
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}
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}
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/**
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* @brief get path of a file.
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* @param $fileId id of the file
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* @return path of the file
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*/
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public static function fileIdToPath( $fileId ) {
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$query = \OC_DB::prepare( 'SELECT `path`'
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.' FROM `*PREFIX*filecache`'
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.' WHERE `fileid` = ?' );
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$result = $query->execute( array( $fileId ) );
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$row = $result->fetchRow();
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return substr( $row['path'], 5 );
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}
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/**
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* @brief Filter an array of UIDs to return only ones ready for sharing
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* @param array $unfilteredUsers users to be checked for sharing readiness
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* @return array $userIds filtered users
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*/
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public function filterShareReadyUsers( $unfilteredUsers ) {
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// This array will collect the filtered IDs
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$userIds = array();
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// Loop through users and create array of UIDs that need new keyfiles
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foreach ( $unfilteredUsers as $user ) {
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$util = new Util( $this->view, $user );
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// Check that the user is encryption capable, or is the
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// public system user 'ownCloud' (for public shares)
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if (
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$util->ready()
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or $user == 'ownCloud'
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) {
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// Construct array of just UIDs for Keymanager{}
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$userIds[] = $user;
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} else {
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// Log warning; we can't do necessary setup here
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// because we don't have the user passphrase
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// TODO: Provide user feedback indicating that
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// sharing failed
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\OC_Log::write( 'Encryption library', '"'.$user.'" is not setup for encryption', \OC_Log::WARN );
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}
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}
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return $userIds;
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}
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/**
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* @brief Expand given path to all sub files & folders
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* @param Session $session
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* @param string $path path which needs to be updated
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* @return array $pathsArray all found file paths
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* @note Paths of directories excluded, only *file* paths are returned
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*/
|
||
public function getPaths( $path ) {
|
||
|
||
// Default return value is success
|
||
$result = true;
|
||
|
||
// Make path include 'files' dir for OC_FSV operations
|
||
$fPath = 'files' . $path;
|
||
|
||
// If we're handling a single file
|
||
if ( ! $this->view->is_dir( $fPath ) ) {
|
||
|
||
$pathsArray[] = $path;
|
||
|
||
// If we're handling a folder (recursively)
|
||
} else {
|
||
|
||
$subFiles = $this->view->getDirectoryContent( $fPath );
|
||
|
||
foreach ( $subFiles as $file ) {
|
||
|
||
$filePath = substr( $file['path'], 5 );
|
||
|
||
// If this is a nested file
|
||
if ( ! $this->view->is_dir( $fPath ) ) {
|
||
|
||
// Add the file path to array
|
||
$pathsArray[] = $path;
|
||
|
||
} else {
|
||
|
||
// If this is a nested folder
|
||
$dirPaths = $this->getPaths( $filePath );
|
||
|
||
// Add all subfiles & folders to the array
|
||
$pathsArray = array_merge( $dirPaths, $pathsArray );
|
||
|
||
}
|
||
}
|
||
|
||
}
|
||
|
||
return $pathsArray;
|
||
|
||
}
|
||
|
||
/**
|
||
* @brief Encrypt keyfile to multiple users
|
||
* @param array $users list of users which should be able to access the file
|
||
* @param string $filePath path of the file to be shared
|
||
*/
|
||
public function setSharedFileKeyfiles( Session $session, array $users, $filePath ) {
|
||
|
||
// Make sure users are capable of sharing
|
||
$filteredUids = $this->filterShareReadyUsers( $users );
|
||
|
||
// Get public keys for each user, ready for generating sharekeys
|
||
$userPubKeys = Keymanager::getPublicKeys( $this->view, $filteredUids ); // TODO: check this includes the owner's public key
|
||
|
||
\OC_FileProxy::$enabled = false;
|
||
|
||
// Get the current users's private key for decrypting existing keyfile
|
||
$privateKey = $session->getPrivateKey();
|
||
|
||
$fileOwner = \OC\Files\Filesystem::getOwner( $filePath );
|
||
|
||
// Get the encrypted keyfile
|
||
// NOTE: the keyfile format depends on how it was encrypted! At
|
||
// this stage we don't know how it was encrypted
|
||
$encKeyfile = Keymanager::getFileKey( $this->view, $this->userId, $filePath );
|
||
|
||
// We need to decrypt the keyfile
|
||
// Has the file been shared yet?
|
||
if (
|
||
$this->userId == $fileOwner
|
||
&& ! Keymanager::getShareKey( $this->view, $this->userId, $filePath ) // NOTE: we can't use isShared() here because it's a post share hook so it always returns true
|
||
) {
|
||
|
||
// The file has no shareKey, and its keyfile must be
|
||
// decrypted conventionally
|
||
$plainKeyfile = Crypt::keyDecrypt( $encKeyfile, $privateKey );
|
||
|
||
|
||
} else {
|
||
|
||
// The file has a shareKey and must use it for decryption
|
||
$shareKey = Keymanager::getShareKey( $this->view, $this->userId, $filePath );
|
||
|
||
$plainKeyfile = Crypt::multiKeyDecrypt( $encKeyfile, $shareKey, $privateKey );
|
||
|
||
}
|
||
|
||
// Re-enc keyfile to (additional) sharekeys
|
||
$multiEncKey = Crypt::multiKeyEncrypt( $plainKeyfile, $userPubKeys );
|
||
|
||
// Save the recrypted key to it's owner's keyfiles directory
|
||
// Save new sharekeys to all necessary user directory
|
||
if (
|
||
! Keymanager::setFileKey( $this->view, $filePath, $fileOwner, $multiEncKey['data'] )
|
||
|| ! Keymanager::setShareKeys( $this->view, $filePath, $multiEncKey['keys'] )
|
||
) {
|
||
|
||
trigger_error( "SET Share keys failed" );
|
||
|
||
}
|
||
|
||
// Delete existing keyfile
|
||
// Do this last to ensure file is recoverable in case of error
|
||
// Keymanager::deleteFileKey( $this->view, $this->userId, $params['fileTarget'] );
|
||
|
||
\OC_FileProxy::$enabled = true;
|
||
|
||
return true;
|
||
}
|
||
|
||
}
|