defender-security / lib / packages / FG / ASN1 / Universal / Integer.php

Integer.php in Defender Security – Malware Scanner, Login Security & Firewall 6.3.0, at lib/packages/FG/ASN1/Universal/Integer.php

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1	<?php
2	/*
3	* This file is part of the PHPASN1 library.
4	*
5	* Copyright © Friedrich Große <[email protected]>
6	*
7	* For the full copyright and license information, please view the LICENSE
8	* file that was distributed with this source code.
9	*/
10
11	namespace WP_DEFENDER_VENDOR\FG\ASN1\Universal;
12
13	use Exception;
14	use WP_DEFENDER_VENDOR\FG\Utility\BigInteger;
15	use WP_DEFENDER_VENDOR\FG\ASN1\Exception\ParserException;
16	use WP_DEFENDER_VENDOR\FG\ASN1\ASNObject;
17	use WP_DEFENDER_VENDOR\FG\ASN1\Parsable;
18	use WP_DEFENDER_VENDOR\FG\ASN1\Identifier;
19
20	class Integer extends ASNObject implements Parsable
21	{
22	/** @var int */
23	private $value;
24
25	/**
26	* @param int $value
27	*
28	* @throws Exception if the value is not numeric
29	*/
30	public function __construct($value)
31	{
32	if (is_numeric($value) == false) {
33	throw new Exception("Invalid VALUE [{$value}] for ASN1_INTEGER");
34	}
35	$this->value = $value;
36	}
37
38	public function getType()
39	{
40	return Identifier::INTEGER;
41	}
42
43	public function getContent()
44	{
45	return $this->value;
46	}
47
48	protected function calculateContentLength()
49	{
50	return strlen($this->getEncodedValue());
51	}
52
53	protected function getEncodedValue()
54	{
55	$value = BigInteger::create($this->value, 10);
56	$negative = $value->compare(0) < 0;
57	if ($negative) {
58	$value = $value->absoluteValue();
59	$limit = 0x80;
60	} else {
61	$limit = 0x7f;
62	}
63
64	$mod = 0xff+1;
65	$values = [];
66	while($value->compare($limit) > 0) {
67	$values[] = $value->modulus($mod)->toInteger();
68	$value = $value->shiftRight(8);
69	}
70
71	$values[] = $value->modulus($mod)->toInteger();
72	$numValues = count($values);
73
74	if ($negative) {
75	for ($i = 0; $i < $numValues; $i++) {
76	$values[$i] = 0xff - $values[$i];
77	}
78	for ($i = 0; $i < $numValues; $i++) {
79	$values[$i] += 1;
80	if ($values[$i] <= 0xff) {
81	break;
82	}
83	assert($i != $numValues - 1);
84	$values[$i] = 0;
85	}
86	if ($values[$numValues - 1] == 0x7f) {
87	$values[] = 0xff;
88	}
89	}
90	$values = array_reverse($values);
91	$r = pack("C*", ...$values);
92	return $r;
93	}
94
95	private static function ensureMinimalEncoding($binaryData, $offsetIndex)
96	{
97	// All the first nine bits cannot equal 0 or 1, which would
98	// be non-minimal encoding for positive and negative integers respectively
99	if ((ord($binaryData[$offsetIndex]) == 0x00 && (ord($binaryData[$offsetIndex+1]) & 0x80) == 0) \|\|
100	(ord($binaryData[$offsetIndex]) == 0xff && (ord($binaryData[$offsetIndex+1]) & 0x80) == 0x80)) {
101	throw new ParserException("Integer not minimally encoded", $offsetIndex);
102	}
103	}
104
105	public static function fromBinary(&$binaryData, &$offsetIndex = 0)
106	{
107	$parsedObject = new static(0);
108	self::parseIdentifier($binaryData[$offsetIndex], $parsedObject->getType(), $offsetIndex++);
109	$contentLength = self::parseContentLength($binaryData, $offsetIndex, 1);
110
111	if ($contentLength > 1) {
112	self::ensureMinimalEncoding($binaryData, $offsetIndex);
113	}
114	$isNegative = (ord($binaryData[$offsetIndex]) & 0x80) != 0x00;
115	$number = BigInteger::create(ord($binaryData[$offsetIndex++]) & 0x7F);
116
117	for ($i = 0; $i < $contentLength - 1; $i++) {
118	$number = $number->multiply(0x100)->add(ord($binaryData[$offsetIndex++]));
119	}
120
121	if ($isNegative) {
122	$number = $number->subtract(BigInteger::create(2)->toPower(8 * $contentLength - 1));
123	}
124
125	$parsedObject = new static((string)$number);
126	$parsedObject->setContentLength($contentLength);
127
128	return $parsedObject;
129	}
130	}
131