Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle 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 General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

namespace core;

use advanced_testcase;

/**

 * Test encryption.

 *

 * @package core

 * @copyright 2020 The Open University

 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 * @covers  \core\encryption

 */

final class encryption_test extends advanced_testcase {

    protected function setUp(): void {

        parent::setUp();

        require_once(__DIR__ . '/fixtures/testable_encryption.php');

    }

    /**

     * Return a list of supported encryption methods

     *

     * @return array[] Array of method options for test

     */

    public static function encryption_method_provider(): array {

        return [

            'Sodium' => [encryption::METHOD_SODIUM],

        ];

    }

    /**

     * Tests the create_keys and get_key functions.

     *

     * @param string $method Encryption method

     * @dataProvider encryption_method_provider

     */

    public function test_create_key(string $method): void {

        encryption::create_key($method);

        $key = testable_encryption::get_key($method);

        $this->assertEquals(32, strlen($key));

        $this->expectExceptionMessage('Key already exists');

        encryption::create_key($method);

    }

    /**

     * Tests encryption and decryption with empty strings.

     */

    public function test_encrypt_and_decrypt_empty(): void {

        $this->assertEquals('', encryption::encrypt(''));

        $this->assertEquals('', encryption::decrypt(''));

    }

    /**

     * Tests encryption when the keys weren't created yet.

     *

     * @param string $method Encryption method

     * @dataProvider encryption_method_provider

     */

    public function test_encrypt_nokeys(string $method): void {

        global $CFG;

        // Prevent automatic generation of keys.

        $CFG->nokeygeneration = true;

        $this->expectExceptionMessage('Key not found');

        encryption::encrypt('frogs', $method);

    }

    /**

     * Tests decryption when the data has a different encryption method

     */

    public function test_decrypt_wrongmethod(): void {

        $this->expectExceptionMessage('Data does not match a supported encryption method');

        encryption::decrypt('FAKE-CIPHER-METHOD:xx');

    }

    /**

     * Tests decryption when not enough data is supplied to get the IV and some data.

     *

     * @dataProvider encryption_method_provider

     * @param string $method Encryption method

     */

    public function test_decrypt_tooshort(string $method): void {

        switch ($method) {

            case encryption::METHOD_SODIUM:

                // Sodium needs 25 bytes at least as far as our code is concerned (24 bytes IV + 1

                // byte data); it splits out any authentication hashes itself.

                $justtooshort = '0123456789abcdef01234567';

                break;

        }

        $this->expectExceptionMessage('Insufficient data');

        encryption::decrypt($method . ':' .base64_encode($justtooshort));

    }

    /**

     * Tests decryption when data is not valid base64.

     *

     * @dataProvider encryption_method_provider

     * @param string $method Encryption method

     */

    public function test_decrypt_notbase64(string $method): void {

        $this->expectExceptionMessage('Invalid base64 data');

        encryption::decrypt($method . ':' . chr(160));

    }

    /**

     * Tests decryption when the keys weren't created yet.

     *

     * @dataProvider encryption_method_provider

     * @param string $method Encryption method

     */

    public function test_decrypt_nokeys(string $method): void {

        global $CFG;

        // Prevent automatic generation of keys.

        $CFG->nokeygeneration = true;

        $this->expectExceptionMessage('Key not found');

        encryption::decrypt($method . ':' . base64_encode(

                '0123456789abcdef0123456789abcdef0123456789abcdef0'));

    }

    /**

     * Test automatic generation of keys when needed.

     *

     * @dataProvider encryption_method_provider

     * @param string $method Encryption method

     */

    public function test_auto_key_generation(string $method): void {

        // Allow automatic generation (default).

        $encrypted = encryption::encrypt('frogs', $method);

        $this->assertEquals('frogs', encryption::decrypt($encrypted));

    }

    /**

     * Checks that invalid key causes failures.

     *

     * @dataProvider encryption_method_provider

     * @param string $method Encryption method

     */

    public function test_invalid_key(string $method): void {

        global $CFG;

        // Set the key to something bogus.

        $folder = $CFG->dataroot . '/secret/key';

        check_dir_exists($folder);

        file_put_contents(encryption::get_key_file($method), 'silly');

        switch ($method) {

            case encryption::METHOD_SODIUM:

                $this->expectExceptionMessageMatches('/(should|must) be SODIUM_CRYPTO_SECRETBOX_KEYBYTES bytes/');

                break;

        }

        encryption::encrypt('frogs', $method);

    }

    /**

     * Checks that modified data causes failures.

     *

     * @dataProvider encryption_method_provider

     * @param string $method Encryption method

     */

    public function test_modified_data(string $method): void {

        $encrypted = encryption::encrypt('frogs', $method);

        $mainbit = base64_decode(substr($encrypted, strlen($method) + 1));

        $mainbit = substr($mainbit, 0, 16) . 'X' . substr($mainbit, 16);

        $encrypted = $method . ':' . base64_encode($mainbit);

        $this->expectExceptionMessage('Integrity check failed');

        encryption::decrypt($encrypted);

    }

    /**

     * Tests encryption and decryption for real.

     *

     * @dataProvider encryption_method_provider

     * @param string $method Encryption method

     */

    public function test_encrypt_and_decrypt_realdata(string $method): void {

        // Encrypt short string.

        $encrypted = encryption::encrypt('frogs', $method);

        $this->assertNotEquals('frogs', $encrypted);

        $this->assertEquals('frogs', encryption::decrypt($encrypted));

        // Encrypt really long string (1 MB).

        $long = str_repeat('X', 1024 * 1024);

        $this->assertEquals($long, encryption::decrypt(encryption::encrypt($long, $method)));

    }

}