62 lines
1.8 KiB
PHP
62 lines
1.8 KiB
PHP
<?php
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declare(strict_types=1);
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/*
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* The MIT License (MIT)
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*
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* Copyright (c) 2014-2020 Spomky-Labs
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*
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* This software may be modified and distributed under the terms
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* of the MIT license. See the LICENSE file for details.
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*/
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namespace Jose\Component\KeyManagement\Analyzer;
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use Base64Url\Base64Url;
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use Brick\Math\BigInteger;
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use Jose\Component\Core\JWK;
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use Jose\Component\Core\Util\Ecc\NistCurve;
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use RuntimeException;
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final class ES256KeyAnalyzer implements KeyAnalyzer
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{
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/**
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* @throws RuntimeException if the component "web-token/jwt-util-ecc" is missing
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*/
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public function __construct()
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{
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if (!class_exists(NistCurve::class)) {
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throw new RuntimeException('Please install web-token/jwt-util-ecc to use this key analyzer');
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}
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}
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public function analyze(JWK $jwk, MessageBag $bag): void
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{
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if ('EC' !== $jwk->get('kty')) {
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return;
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}
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if (!$jwk->has('crv')) {
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$bag->add(Message::high('Invalid key. The components "crv" is missing.'));
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return;
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}
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if ('P-256' !== $jwk->get('crv')) {
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return;
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}
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$x = Base64Url::decode($jwk->get('x'));
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$xLength = 8 * mb_strlen($x, '8bit');
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$y = Base64Url::decode($jwk->get('y'));
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$yLength = 8 * mb_strlen($y, '8bit');
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if ($yLength !== $xLength || 256 !== $yLength) {
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$bag->add(Message::high('Invalid key. The components "x" and "y" size shall be 256 bits.'));
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}
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$xBI = BigInteger::fromBase(bin2hex($x), 16);
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$yBI = BigInteger::fromBase(bin2hex($y), 16);
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$curve = NistCurve::curve256();
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if (!$curve->contains($xBI, $yBI)) {
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$bag->add(Message::high('Invalid key. The point is not on the curve.'));
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}
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}
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}
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