|
1
|
|
|
<?php |
|
2
|
|
|
|
|
3
|
|
|
/** |
|
4
|
|
|
* Utility class for secure file erasure. |
|
5
|
|
|
*/ |
|
6
|
|
|
|
|
7
|
|
|
namespace CryptoManana\Utilities; |
|
8
|
|
|
|
|
9
|
|
|
use \CryptoManana\Core\Abstractions\Containers\AbstractRandomnessInjectable as RandomnessContainer; |
|
10
|
|
|
use \CryptoManana\Core\Interfaces\Randomness\FileErasureInterface as SecureFileErasure; |
|
11
|
|
|
use \CryptoManana\Core\Traits\CommonValidations\FileNameValidationTrait as ValidateFileNames; |
|
12
|
|
|
|
|
13
|
|
|
/** |
|
14
|
|
|
* Class FileShredder - Utility class for file shredding. |
|
15
|
|
|
* |
|
16
|
|
|
* @package CryptoManana\Utilities |
|
17
|
|
|
* |
|
18
|
|
|
* @property \CryptoManana\Core\Abstractions\Randomness\AbstractGenerator $randomnessSource The randomness generator. |
|
19
|
|
|
*/ |
|
20
|
|
|
class FileShredder extends RandomnessContainer implements SecureFileErasure |
|
21
|
|
|
{ |
|
22
|
|
|
/** |
|
23
|
|
|
* File name and path validations. |
|
24
|
|
|
* |
|
25
|
|
|
* {@internal Reusable implementation of the common file name validation. }} |
|
26
|
|
|
*/ |
|
27
|
|
|
use ValidateFileNames; |
|
28
|
|
|
|
|
29
|
|
|
/** |
|
30
|
|
|
* Internal method for calculating the file size in bytes. |
|
31
|
|
|
* |
|
32
|
|
|
* @param string $filename The filename and location. |
|
33
|
|
|
* |
|
34
|
|
|
* @return int The file size in bytes. |
|
35
|
|
|
* @throws \Exception Validation errors. |
|
36
|
|
|
*/ |
|
37
|
2 |
|
protected function calculateFileSize($filename) |
|
38
|
|
|
{ |
|
39
|
2 |
|
$sizeInBytes = filesize($filename); |
|
40
|
|
|
|
|
41
|
|
|
// @codeCoverageIgnoreStart |
|
42
|
|
|
if ($sizeInBytes === false) { |
|
43
|
|
|
throw new \RuntimeException('The operating system could not obtain the correct size of the file.'); |
|
44
|
|
|
} |
|
45
|
|
|
// @codeCoverageIgnoreEnd |
|
46
|
|
|
|
|
47
|
2 |
|
return $sizeInBytes; |
|
48
|
|
|
} |
|
49
|
|
|
|
|
50
|
|
|
/** |
|
51
|
|
|
* Internal method for shredding the physical file based on the DOD 5220.22-M (3 passes) standard. |
|
52
|
|
|
* |
|
53
|
|
|
* @param string $filename The filename and location. |
|
54
|
|
|
* |
|
55
|
|
|
* @return bool The file shredding operation result. |
|
56
|
|
|
* @throws \Exception Validation or filesystem errors. |
|
57
|
|
|
*/ |
|
58
|
2 |
|
protected function fileShredding($filename) |
|
59
|
|
|
{ |
|
60
|
2 |
|
$sizeInBytes = $this->calculateFileSize($filename); |
|
61
|
|
|
|
|
62
|
2 |
|
$written = true; |
|
63
|
|
|
|
|
64
|
2 |
|
for ($i = 1; $i <= 3; $i++) { |
|
65
|
2 |
|
for ($j = 0; $j < $sizeInBytes; $j++) { |
|
66
|
2 |
|
$flag = ($j === 0) ? LOCK_EX : (FILE_APPEND | LOCK_EX); |
|
67
|
|
|
|
|
68
|
2 |
|
if ($i === 1) { |
|
69
|
2 |
|
$written = file_put_contents($filename, "\x0", $flag); |
|
70
|
2 |
|
} elseif ($i === 2) { |
|
71
|
2 |
|
$written = file_put_contents($filename, "\x1", $flag); |
|
72
|
2 |
|
} elseif ($i === 3) { |
|
73
|
2 |
|
$written = file_put_contents($filename, $this->randomnessSource->getBytes(1), $flag); |
|
74
|
|
|
} |
|
75
|
|
|
|
|
76
|
|
|
// @codeCoverageIgnoreStart |
|
77
|
|
|
if ($written === false) { |
|
78
|
|
|
throw new \RuntimeException('Problem with writing to the filesystem'); |
|
79
|
|
|
} |
|
80
|
|
|
// @codeCoverageIgnoreEnd |
|
81
|
|
|
} |
|
82
|
|
|
|
|
83
|
|
|
// Sleep for 15 milliseconds for the disk verify the written data and sync buffers |
|
84
|
2 |
|
usleep(15000); |
|
85
|
|
|
} |
|
86
|
|
|
|
|
87
|
2 |
|
$written = file_put_contents($filename, '', LOCK_EX); |
|
88
|
|
|
|
|
89
|
2 |
|
return (unlink($filename) === true && $written !== false); |
|
90
|
|
|
} |
|
91
|
|
|
|
|
92
|
|
|
/** |
|
93
|
|
|
* Data erasure and wiping of a file. |
|
94
|
|
|
* |
|
95
|
|
|
* @param string $filename The filename and location. |
|
96
|
|
|
* |
|
97
|
|
|
* @throws \Exception Validation errors. |
|
98
|
|
|
* |
|
99
|
|
|
* @internal Files that are bigger than 2 GB may not be deletable or behave irrationally for x86 platforms. |
|
100
|
|
|
*/ |
|
101
|
6 |
|
public function eraseFile($filename) |
|
102
|
|
|
{ |
|
103
|
6 |
|
if (!is_string($filename)) { |
|
104
|
2 |
|
throw new \InvalidArgumentException('The file path must be of type string.'); |
|
105
|
|
|
} |
|
106
|
|
|
|
|
107
|
4 |
|
$this->validateFileNamePath($filename); |
|
108
|
|
|
|
|
109
|
|
|
// @codeCoverageIgnoreStart |
|
110
|
|
|
if ($this->fileShredding($filename) === false) { |
|
111
|
|
|
throw new \RuntimeException('Failed to delete the file from the filesystem.'); |
|
112
|
|
|
} |
|
113
|
|
|
// @codeCoverageIgnoreEnd |
|
114
|
2 |
|
} |
|
115
|
|
|
} |
|
116
|
|
|
|
TonyKaravasilev /
CryptoManana
