xref: /dokuwiki/vendor/paragonie/constant_time_encoding/src/Base64.php (revision 8e88a29b81301f78509349ab1152bb09c229123e) 
1<?php
2declare(strict_types=1);
3namespace ParagonIE\ConstantTime;
4
5use InvalidArgumentException;
6use Override;
7use RangeException;
8use SensitiveParameter;
9use SodiumException;
10use TypeError;
11use function extension_loaded;
12use function pack;
13use function rtrim;
14use function sodium_base642bin;
15use function sodium_bin2base64;
16use function strlen;
17use function substr;
18use function unpack;
19use const SODIUM_BASE64_VARIANT_ORIGINAL;
20use const SODIUM_BASE64_VARIANT_ORIGINAL_NO_PADDING;
21use const SODIUM_BASE64_VARIANT_URLSAFE;
22use const SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING;
23
24/**
25 *  Copyright (c) 2016 - 2022 Paragon Initiative Enterprises.
26 *  Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com)
27 *
28 *  Permission is hereby granted, free of charge, to any person obtaining a copy
29 *  of this software and associated documentation files (the "Software"), to deal
30 *  in the Software without restriction, including without limitation the rights
31 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
32 *  copies of the Software, and to permit persons to whom the Software is
33 *  furnished to do so, subject to the following conditions:
34 *
35 *  The above copyright notice and this permission notice shall be included in all
36 *  copies or substantial portions of the Software.
37 *
38 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
39 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
40 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
41 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
42 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
43 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
44 *  SOFTWARE.
45 */
46
47/**
48 * Class Base64
49 * [A-Z][a-z][0-9]+/
50 *
51 * @package ParagonIE\ConstantTime
52 */
53abstract class Base64 implements EncoderInterface
54{
55    /**
56     * Encode into Base64
57     *
58     * Base64 character set "[A-Z][a-z][0-9]+/"
59     *
60     * @param string $binString
61     * @return string
62     *
63     * @throws TypeError
64     */
65    #[Override]
66    public static function encode(
67        #[SensitiveParameter]
68        string $binString
69    ): string {
70        if (extension_loaded('sodium')) {
71            $variant = match(static::class) {
72                Base64::class => SODIUM_BASE64_VARIANT_ORIGINAL,
73                Base64UrlSafe::class => SODIUM_BASE64_VARIANT_URLSAFE,
74                default => 0,
75            };
76            if ($variant > 0) {
77                try {
78                    return sodium_bin2base64($binString, $variant);
79                } catch (SodiumException $ex) {
80                    throw new RangeException($ex->getMessage(), $ex->getCode(), $ex);
81                }
82            }
83        }
84        return static::doEncode($binString, true);
85    }
86
87    /**
88     * Encode into Base64, no = padding
89     *
90     * Base64 character set "[A-Z][a-z][0-9]+/"
91     *
92     * @param string $src
93     * @return string
94     *
95     * @throws TypeError
96     * @api
97     */
98    public static function encodeUnpadded(
99        #[SensitiveParameter]
100        string $src
101    ): string {
102        if (extension_loaded('sodium')) {
103            $variant = match(static::class) {
104                Base64::class => SODIUM_BASE64_VARIANT_ORIGINAL_NO_PADDING,
105                Base64UrlSafe::class => SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING,
106                default => 0,
107            };
108            if ($variant > 0) {
109                try {
110                    return sodium_bin2base64($src, $variant);
111                } catch (SodiumException $ex) {
112                    throw new RangeException($ex->getMessage(), $ex->getCode(), $ex);
113                }
114            }
115        }
116        return static::doEncode($src, false);
117    }
118
119    /**
120     * @param string $src
121     * @param bool $pad   Include = padding?
122     * @return string
123     *
124     * @throws TypeError
125     */
126    protected static function doEncode(
127        #[SensitiveParameter]
128        string $src,
129        bool $pad = true
130    ): string {
131        $dest = '';
132        $srcLen = strlen($src);
133        // Main loop (no padding):
134        for ($i = 0; $i + 3 <= $srcLen; $i += 3) {
135            /** @var array<int, int> $chunk */
136            $chunk = unpack('C*', substr($src, $i, 3));
137            $b0 = $chunk[1];
138            $b1 = $chunk[2];
139            $b2 = $chunk[3];
140
141            $dest .=
142                static::encode6Bits(               $b0 >> 2       ) .
143                static::encode6Bits((($b0 << 4) | ($b1 >> 4)) & 63) .
144                static::encode6Bits((($b1 << 2) | ($b2 >> 6)) & 63) .
145                static::encode6Bits(  $b2                     & 63);
146        }
147        // The last chunk, which may have padding:
148        if ($i < $srcLen) {
149            /** @var array<int, int> $chunk */
150            $chunk = unpack('C*', substr($src, $i, $srcLen - $i));
151            $b0 = $chunk[1];
152            if ($i + 1 < $srcLen) {
153                $b1 = $chunk[2];
154                $dest .=
155                    static::encode6Bits($b0 >> 2) .
156                    static::encode6Bits((($b0 << 4) | ($b1 >> 4)) & 63) .
157                    static::encode6Bits(($b1 << 2) & 63);
158                if ($pad) {
159                    $dest .= '=';
160                }
161            } else {
162                $dest .=
163                    static::encode6Bits( $b0 >> 2) .
164                    static::encode6Bits(($b0 << 4) & 63);
165                if ($pad) {
166                    $dest .= '==';
167                }
168            }
169        }
170        return $dest;
171    }
172
173    /**
174     * decode from base64 into binary
175     *
176     * Base64 character set "./[A-Z][a-z][0-9]"
177     *
178     * @param string $encodedString
179     * @param bool $strictPadding
180     * @return string
181     *
182     * @throws RangeException
183     * @throws TypeError
184     */
185    #[Override]
186    public static function decode(
187        #[SensitiveParameter]
188        string $encodedString,
189        bool $strictPadding = false
190    ): string {
191        // Remove padding
192        $srcLen = strlen($encodedString);
193        if ($srcLen === 0) {
194            return '';
195        }
196
197        if ($strictPadding) {
198            if (($srcLen & 3) === 0) {
199                if ($encodedString[$srcLen - 1] === '=') {
200                    $srcLen--;
201                    if ($encodedString[$srcLen - 1] === '=') {
202                        $srcLen--;
203                    }
204                }
205            }
206            if (($srcLen & 3) === 1) {
207                throw new RangeException(
208                    'Incorrect padding'
209                );
210            }
211            if ($encodedString[$srcLen - 1] === '=') {
212                throw new RangeException(
213                    'Incorrect padding'
214                );
215            }
216            if (extension_loaded('sodium')) {
217                $variant = match(static::class) {
218                    Base64::class => SODIUM_BASE64_VARIANT_ORIGINAL_NO_PADDING,
219                    Base64UrlSafe::class => SODIUM_BASE64_VARIANT_URLSAFE_NO_PADDING,
220                    default => 0,
221                };
222                if ($variant > 0) {
223                    try {
224                        return sodium_base642bin(substr($encodedString, 0, $srcLen), $variant);
225                    } catch (SodiumException $ex) {
226                        throw new RangeException($ex->getMessage(), $ex->getCode(), $ex);
227                    }
228                }
229            }
230        } else {
231            // Just remove all padding.
232            $encodedString = rtrim($encodedString, '=');
233            $srcLen = strlen($encodedString);
234        }
235
236        $err = 0;
237        $dest = '';
238        // Main loop (no padding):
239        for ($i = 0; $i + 4 <= $srcLen; $i += 4) {
240            /** @var array<int, int> $chunk */
241            $chunk = unpack('C*', substr($encodedString, $i, 4));
242            $c0 = static::decode6Bits($chunk[1]);
243            $c1 = static::decode6Bits($chunk[2]);
244            $c2 = static::decode6Bits($chunk[3]);
245            $c3 = static::decode6Bits($chunk[4]);
246
247            $dest .= pack(
248                'CCC',
249                ((($c0 << 2) | ($c1 >> 4)) & 0xff),
250                ((($c1 << 4) | ($c2 >> 2)) & 0xff),
251                ((($c2 << 6) |  $c3      ) & 0xff)
252            );
253            $err |= ($c0 | $c1 | $c2 | $c3) >> 8;
254        }
255        // The last chunk, which may have padding:
256        if ($i < $srcLen) {
257            /** @var array<int, int> $chunk */
258            $chunk = unpack('C*', substr($encodedString, $i, $srcLen - $i));
259            $c0 = static::decode6Bits($chunk[1]);
260
261            if ($i + 2 < $srcLen) {
262                $c1 = static::decode6Bits($chunk[2]);
263                $c2 = static::decode6Bits($chunk[3]);
264                $dest .= pack(
265                    'CC',
266                    ((($c0 << 2) | ($c1 >> 4)) & 0xff),
267                    ((($c1 << 4) | ($c2 >> 2)) & 0xff)
268                );
269                $err |= ($c0 | $c1 | $c2) >> 8;
270                if ($strictPadding) {
271                    $err |= ($c2 << 6) & 0xff;
272                }
273            } elseif ($i + 1 < $srcLen) {
274                $c1 = static::decode6Bits($chunk[2]);
275                $dest .= pack(
276                    'C',
277                    ((($c0 << 2) | ($c1 >> 4)) & 0xff)
278                );
279                $err |= ($c0 | $c1) >> 8;
280                if ($strictPadding) {
281                    $err |= ($c1 << 4) & 0xff;
282                }
283            } elseif ($strictPadding) {
284                $err |= 1;
285            }
286        }
287        $check = ($err === 0);
288        if (!$check) {
289            throw new RangeException(
290                'Base64::decode() only expects characters in the correct base64 alphabet'
291            );
292        }
293        return $dest;
294    }
295
296    /**
297     * @param string $encodedString
298     * @return string
299     * @api
300     */
301    public static function decodeNoPadding(
302        #[SensitiveParameter]
303        string $encodedString
304    ): string {
305        $srcLen = strlen($encodedString);
306        if ($srcLen === 0) {
307            return '';
308        }
309        if (($srcLen & 3) === 0) {
310            // If $strLen is not zero, and it is divisible by 4, then it's at least 4.
311            if ($encodedString[$srcLen - 1] === '=' || $encodedString[$srcLen - 2] === '=') {
312                throw new InvalidArgumentException(
313                    "decodeNoPadding() doesn't tolerate padding"
314                );
315            }
316        }
317        return static::decode(
318            $encodedString,
319            true
320        );
321    }
322
323    /**
324     * Uses bitwise operators instead of table-lookups to turn 6-bit integers
325     * into 8-bit integers.
326     *
327     * Base64 character set:
328     * [A-Z]      [a-z]      [0-9]      +     /
329     * 0x41-0x5a, 0x61-0x7a, 0x30-0x39, 0x2b, 0x2f
330     *
331     * @param int $src
332     * @return int
333     */
334    protected static function decode6Bits(int $src): int
335    {
336        $ret = -1;
337
338        // if ($src > 0x40 && $src < 0x5b) $ret += $src - 0x41 + 1; // -64
339        $ret += (((0x40 - $src) & ($src - 0x5b)) >> 8) & ($src - 64);
340
341        // if ($src > 0x60 && $src < 0x7b) $ret += $src - 0x61 + 26 + 1; // -70
342        $ret += (((0x60 - $src) & ($src - 0x7b)) >> 8) & ($src - 70);
343
344        // if ($src > 0x2f && $src < 0x3a) $ret += $src - 0x30 + 52 + 1; // 5
345        $ret += (((0x2f - $src) & ($src - 0x3a)) >> 8) & ($src + 5);
346
347        // if ($src == 0x2b) $ret += 62 + 1;
348        $ret += (((0x2a - $src) & ($src - 0x2c)) >> 8) & 63;
349
350        // if ($src == 0x2f) ret += 63 + 1;
351        $ret += (((0x2e - $src) & ($src - 0x30)) >> 8) & 64;
352
353        return $ret;
354    }
355
356    /**
357     * Uses bitwise operators instead of table-lookups to turn 8-bit integers
358     * into 6-bit integers.
359     *
360     * @param int $src
361     * @return string
362     */
363    protected static function encode6Bits(int $src): string
364    {
365        $diff = 0x41;
366
367        // if ($src > 25) $diff += 0x61 - 0x41 - 26; // 6
368        $diff += ((25 - $src) >> 8) & 6;
369
370        // if ($src > 51) $diff += 0x30 - 0x61 - 26; // -75
371        $diff -= ((51 - $src) >> 8) & 75;
372
373        // if ($src > 61) $diff += 0x2b - 0x30 - 10; // -15
374        $diff -= ((61 - $src) >> 8) & 15;
375
376        // if ($src > 62) $diff += 0x2f - 0x2b - 1; // 3
377        $diff += ((62 - $src) >> 8) & 3;
378
379        return pack('C', $src + $diff);
380    }
381}
382