This file is indexed.

/usr/share/php/ParagonIE/ConstantTime/Hex.php is in php-constant-time 2.2.0-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
<?php
declare(strict_types=1);
namespace ParagonIE\ConstantTime;

/**
 *  Copyright (c) 2016 - 2017 Paragon Initiative Enterprises.
 *  Copyright (c) 2014 Steve "Sc00bz" Thomas (steve at tobtu dot com)
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a copy
 *  of this software and associated documentation files (the "Software"), to deal
 *  in the Software without restriction, including without limitation the rights
 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *  copies of the Software, and to permit persons to whom the Software is
 *  furnished to do so, subject to the following conditions:
 *
 *  The above copyright notice and this permission notice shall be included in all
 *  copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 *  SOFTWARE.
 */

/**
 * Class Hex
 * @package ParagonIE\ConstantTime
 */
abstract class Hex implements EncoderInterface
{
    /**
     * Convert a binary string into a hexadecimal string without cache-timing
     * leaks
     *
     * @param string $bin_string (raw binary)
     * @return string
     */
    public static function encode(string $bin_string): string
    {
        $hex = '';
        $len = Binary::safeStrlen($bin_string);
        for ($i = 0; $i < $len; ++$i) {
            $chunk = \unpack('C', Binary::safeSubstr($bin_string, $i, 2));
            $c = $chunk[1] & 0xf;
            $b = $chunk[1] >> 4;
            $hex .= pack(
                'CC',
                (87 + $b + ((($b - 10) >> 8) & ~38)),
                (87 + $c + ((($c - 10) >> 8) & ~38))
            );
        }
        return $hex;
    }

    /**
     * Convert a binary string into a hexadecimal string without cache-timing
     * leaks, returning uppercase letters (as per RFC 4648)
     *
     * @param string $bin_string (raw binary)
     * @return string
     */
    public static function encodeUpper(string $bin_string): string
    {
        $hex = '';
        $len = Binary::safeStrlen($bin_string);
        for ($i = 0; $i < $len; ++$i) {
            $chunk = \unpack('C', Binary::safeSubstr($bin_string, $i, 2));
            $c = $chunk[1] & 0xf;
            $b = $chunk[1] >> 4;
            $hex .= pack(
                'CC',
                (55 + $b + ((($b - 10) >> 8) & ~6)),
                (55 + $c + ((($c - 10) >> 8) & ~6))
            );
        }
        return $hex;
    }

    /**
     * Convert a hexadecimal string into a binary string without cache-timing
     * leaks
     *
     * @param string $hex_string
     * @param bool $strictPadding
     * @return string (raw binary)
     * @throws \RangeException
     */
    public static function decode(string $hexString, bool $strictPadding = false): string
    {
        $hex_pos = 0;
        $bin = '';
        $c_acc = 0;
        $hex_len = Binary::safeStrlen($hexString);
        $state = 0;
        if (($hex_len & 1) !== 0) {
            if ($strictPadding) {
                throw new \RangeException(
                    'Expected an even number of hexadecimal characters'
                );
            } else {
                $hexString = '0' . $hexString;
                ++$hex_len;
            }
        }

        $chunk = \unpack('C*', $hexString);
        while ($hex_pos < $hex_len) {
            ++$hex_pos;
            $c = $chunk[$hex_pos];
            $c_num = $c ^ 48;
            $c_num0 = ($c_num - 10) >> 8;
            $c_alpha = ($c & ~32) - 55;
            $c_alpha0 = (($c_alpha - 10) ^ ($c_alpha - 16)) >> 8;
            if (($c_num0 | $c_alpha0) === 0) {
                throw new \RangeException(
                    'hexEncode() only expects hexadecimal characters'
                );
            }
            $c_val = ($c_num0 & $c_num) | ($c_alpha & $c_alpha0);
            if ($state === 0) {
                $c_acc = $c_val * 16;
            } else {
                $bin .= \pack('C', $c_acc | $c_val);
            }
            $state ^= 1;
        }
        return $bin;
    }
}