PhpBackend.php

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<?php
namespace TYPO3\CMS\Rsaauth\Backend;

/*
 * This file is part of the TYPO3 CMS project.
 *
 * It is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License, either version 2
 * of the License, or any later version.
 *
 * For the full copyright and license information, please read the
 * LICENSE.txt file that was distributed with this source code.
 *
 * The TYPO3 project - inspiring people to share!
 */

class PhpBackend extends AbstractBackend
{
    public function createNewKeyPair()
    {
        $keyPair = \TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\TYPO3\CMS\Rsaauth\Keypair::class);
        if ($keyPair->isReady()) {
            return $keyPair;
        }

        $privateKey = @openssl_pkey_new();
        if ($privateKey !== false) {
            // Create private key as string
            $privateKeyStr = '';
            openssl_pkey_export($privateKey, $privateKeyStr);
            // Prepare public key information
            $exportedData = '';
            $csr = openssl_csr_new([
                'localityName' => 'foo',
                'organizationName' => 'bar',
            ], $privateKey);
            openssl_csr_export($csr, $exportedData, false);
            // Get public key (in fact modulus) and exponent
            $publicKey = $this->extractPublicKeyModulus($exportedData);
            $exponent = $this->extractExponent($exportedData);

            $keyPair->setExponent($exponent);
            $keyPair->setPrivateKey($privateKeyStr);
            $keyPair->setPublicKey($publicKey);
            // Clean up all resources
            openssl_free_key($privateKey);
        } else {
            $keyPair = null;
        }

        return $keyPair;
    }

    public function decrypt($privateKey, $data)
    {
        $result = '';
        if (!@openssl_private_decrypt(base64_decode($data), $result, $privateKey)) {
            $result = null;
        }
        return $result;
    }

    public function isAvailable()
    {
        $result = false;
        if (is_callable('openssl_pkey_new')) {
            // PHP extension has to be configured properly. It
            // can be installed and available but will not work unless
            // properly configured. So we check if it works.
            $testKey = @openssl_pkey_new();
            if (is_resource($testKey)) {
                openssl_free_key($testKey);
                $result = true;
            }
        }
        return $result;
    }

    protected function extractExponent($data)
    {
        $index = strpos($data, 'Exponent: ');
        // We do not check for '$index === FALSE' because the exponent is
        // always there!
        return (int)substr($data, $index + 10);
    }

    protected function extractPublicKeyModulus($data)
    {
        $fragment = preg_replace('/.*Modulus.*?\\n(.*)Exponent:.*/ms', '\\1', $data);
        $fragment = preg_replace('/[\\s\\n\\r:]/', '', $fragment);
        return trim(strtoupper(substr($fragment, 2)));
    }
}