72 lines
1.6 KiB
PHP
72 lines
1.6 KiB
PHP
<?php
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/**
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* SSH2 Signature Handler
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*
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* PHP version 5
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*
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* Handles signatures in the format used by SSH2
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*
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* @author Jim Wigginton <terrafrost@php.net>
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* @copyright 2016 Jim Wigginton
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* @license http://www.opensource.org/licenses/mit-license.html MIT License
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* @link http://phpseclib.sourceforge.net
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*/
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declare(strict_types=1);
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namespace phpseclib3\Crypt\DSA\Formats\Signature;
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use phpseclib3\Common\Functions\Strings;
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use phpseclib3\Math\BigInteger;
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/**
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* SSH2 Signature Handler
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*
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* @author Jim Wigginton <terrafrost@php.net>
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*/
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abstract class SSH2
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{
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/**
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* Loads a signature
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*/
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public static function load(string $sig)
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{
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if (!is_string($sig)) {
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return false;
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}
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$result = Strings::unpackSSH2('ss', $sig);
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if ($result === false) {
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return false;
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}
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[$type, $blob] = $result;
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if ($type != 'ssh-dss' || strlen($blob) != 40) {
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return false;
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}
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return [
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'r' => new BigInteger(substr($blob, 0, 20), 256),
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's' => new BigInteger(substr($blob, 20), 256)
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];
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}
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/**
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* Returns a signature in the appropriate format
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*
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* @return string
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*/
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public static function save(BigInteger $r, BigInteger $s)
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{
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if ($r->getLength() > 160 || $s->getLength() > 160) {
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return false;
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}
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return Strings::packSSH2(
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'ss',
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'ssh-dss',
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str_pad($r->toBytes(), 20, "\0", STR_PAD_LEFT) .
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str_pad($s->toBytes(), 20, "\0", STR_PAD_LEFT)
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);
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}
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}
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