nextcloud/apps/files_encryption/lib/keymanager.php

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<?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 {
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/**
* @brief retrieve the ENCRYPTED private key from a 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 = $view->file_get_contents( $path );
return $key;
}
/**
* @brief retrieve public key for a specified user
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* @param \OC_FilesystemView $view
* @param $userId
* @return string public key or false
*/
public static function getPublicKey( \OC_FilesystemView $view, $userId ) {
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$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
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$result = $view->file_get_contents( '/public-keys/' . $userId . '.public.key' );
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\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* @brief Retrieve a user's public and private key
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* @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 string $path relative path of the file, including filename
* @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 );
$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 );
}
}
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// 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;
}
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/**
* @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( $path ) {
if (preg_match('/\.part$/', $path)) {
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$newLength = strlen($path) - 5;
$fPath = substr($path, 0, $newLength);
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return $fPath;
} else {
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return $path;
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}
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}
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/**
* @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 ) ) {
return true;
} else {
return false;
}
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}
/**
* @brief retrieve keyfile for an encrypted file
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* @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 ) {
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// try reusing key file if part file
if ( self::isPartialFilePath( $filePath ) ) {
$result = self::getFileKey( $view, $userId, self::fixPartialFilePath( $filePath ) );
if ( $result ) {
return $result;
}
}
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$util = new Util($view, \OCP\User::getUser());
list($owner, $filename) = $util->getUidAndFilename($filePath);
$filePath_f = ltrim( $filename, '/' );
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$keyfilePath = '/' . $owner . '/files_encryption/keyfiles/' . $filePath_f . '.key';
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$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
if ( $view->file_exists( $keyfilePath ) ) {
$result = $view->file_get_contents( $keyfilePath );
} else {
$result = false;
}
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\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* @brief Delete a keyfile
*
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* @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, '/' );
$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 ) {
\OC_Log::write( 'Encryption library', 'Could not delete keyfile; does not exist: "' . $keyPath, \OC_Log::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( '/' . $user . '/files_encryption' );
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$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
if ( !$view->file_exists( '' ) ) $view->mkdir( '' );
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$result = $view->file_put_contents( $user . '.private.key', $key );
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\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* @brief store private keys from the user
*
* @param string privatekey
* @param string publickey
* @return bool true/false
*/
public static function setUserKeys($privatekey, $publickey) {
return ( self::setPrivateKey( $privatekey ) && self::setPublicKey( $publickey ) );
}
/**
* @brief store public key of the user
*
* @param string key
* @return bool true/false
*/
public static function setPublicKey( $key ) {
$view = new \OC_FilesystemView( '/public-keys' );
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$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
if ( !$view->file_exists( '' ) ) $view->mkdir( '' );
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$result = $view->file_put_contents( \OCP\User::getUser() . '.public.key', $key );
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\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* @brief store share key
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*
* @param string $path relative path of the file, including filename
* @param string $key
* @param null $view
* @param string $dbClassName
* @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 setShareKey( \OC_FilesystemView $view, $path, $userId, $shareKey ) {
// 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 );
$basePath = '/' . $owner . '/files_encryption/share-keys';
$shareKeyPath = self::keySetPreparation( $view, $filename, $basePath, $owner );
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// try reusing key file if part file
if(self::isPartialFilePath($shareKeyPath)) {
$writePath = $basePath . '/' . self::fixPartialFilePath($shareKeyPath) . '.' . $userId . '.shareKey';
} else {
$writePath = $basePath . '/' . $shareKeyPath . '.' . $userId . '.shareKey';
}
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$proxyStatus = \OC_FileProxy::$enabled;
\OC_FileProxy::$enabled = false;
$result = $view->file_put_contents( $writePath, $shareKey );
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\OC_FileProxy::$enabled = $proxyStatus;
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if (
is_int( $result )
&& $result > 0
) {
return true;
} else {
return false;
}
}
/**
* @brief store multiple share keys for a single file
* @return bool
*/
public static function setShareKeys( \OC_FilesystemView $view, $path, array $shareKeys ) {
// $shareKeys must be an array with the following format:
// [userId] => [encrypted key]
$result = true;
foreach ( $shareKeys as $userId => $shareKey ) {
if ( ! self::setShareKey( $view, $path, $userId, $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, $filePath ) {
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// try reusing key file if part file
if(self::isPartialFilePath($filePath)) {
$result = self::getShareKey($view, $userId, self::fixPartialFilePath($filePath));
if($result) {
return $result;
}
}
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$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);
$shareKeyPath = '/' . $owner . '/files_encryption/share-keys/' . $filename . '.' . $userId . '.shareKey';
if ( $view->file_exists( $shareKeyPath ) ) {
$result = $view->file_get_contents( $shareKeyPath );
} else {
$result = false;
}
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\OC_FileProxy::$enabled = $proxyStatus;
return $result;
}
/**
* @brief delete all share keys of a given file
* @param \OC_FilesystemView $view
* @param type $userId owner of the file
* @param type $filePath path to the file, relative to the owners file dir
*/
public static function delAllShareKeys(\OC_FilesystemView $view, $userId, $filePath) {
if ($view->is_dir($userId.'/files/'.$filePath)) {
$view->unlink($userId.'/files_encryption/share-keys/'.$filePath);
} else {
$localKeyPath = $view->getLocalFile($userId.'/files_encryption/share-keys/'.$filePath);
$matches = glob(preg_quote($localKeyPath).'*.shareKey');
foreach ($matches as $ma) {
unlink($ma);
}
}
}
/**
* @brief Delete a single user's shareKey for a single file
*/
public static function delShareKey( \OC_FilesystemView $view, $userIds, $filePath ) {
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$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);
$shareKeyPath = '/' . $owner . '/files_encryption/share-keys/' . $filename;
$result = false;
if ( $view->is_dir($shareKeyPath) ) {
$localPath = \OC_Filesystem::normalizePath($view->getLocalFolder($shareKeyPath));
$result = self::recursiveDelShareKeys($localPath, $userIds);
} else {
foreach ($userIds as $userId) {
$view->unlink($shareKeyPath.'.'.$userId.'.shareKey');
}
$result = true;
}
if ( ! $result ) {
\OC_Log::write( 'Encryption library', 'Could not delete shareKey; does not exist: "' . $shareKeyPath, \OC_Log::ERROR );
}
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\OC_FileProxy::$enabled = $proxyStatus;
return $result;
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}
/**
* @brief recursively delete share keys from given users
*
* @param type $dir directory
* @param type $userIds user ids for which the share keys should be deleted
*/
private static function recursiveDelShareKeys($dir, $userIds) {
foreach ($userIds as $userId) {
$completePath = $dir.'/.*'.'.'.$userId.'.shareKey';
$matches = glob(preg_quote($dir).'/*'.preg_quote('.'.$userId.'.shareKey'));
}
foreach ($matches as $ma) {
unlink($ma);
}
$subdirs = $directories = glob(preg_quote($dir) . '/*' , GLOB_ONLYDIR);
foreach ( $subdirs as $subdir ) {
self::recursiveDelShareKeys($subdir, $userIds);
}
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return true;
}
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/**
* @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
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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);
}
}
}
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return $targetPath;
}
/**
* @brief change password of private encryption key
*
* @param string $oldpasswd old password
* @param string $newpasswd new password
* @return bool true/false
*/
public static function changePasswd($oldpasswd, $newpasswd) {
if ( \OCP\User::checkPassword(\OCP\User::getUser(), $newpasswd) ) {
return Crypt::changekeypasscode($oldpasswd, $newpasswd);
}
return false;
}
/**
* @brief Fetch the legacy encryption key from user files
* @param string $login used to locate the legacy key
* @param string $passphrase used to decrypt the legacy key
* @return true / false
*
* if the key is left out, the default handeler will be used
*/
public function getLegacyKey() {
$user = \OCP\User::getUser();
$view = new \OC_FilesystemView( '/' . $user );
return $view->file_get_contents( 'encryption.key' );
}
}