FileEncrypter::setMode() - Code Metrics - Inspection of "Merge branch 'release/0.0.1'" - wubbajack/filecrypt - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Branch — master (2ce3bf)

by Christoper

created 2016-01-02 23:10 UTC

FileEncrypter::setMode() A

↳ Parent: FileEncrypter

Complexity

Conditions	1
Paths	1

Size

Total Lines	7
Code Lines	4

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	1

Metric	Value
c	1
b	0
f	1
dl	0
loc	7
rs	9.4286
cc	1
eloc	4
nc	1
nop	1

<?php namespace Wubbajack\Encryption;

use Wubbajack\Encryption\Exceptions\EncryptException;
use Wubbajack\Encryption\Exceptions\DecryptException;

/**
 * File Encryptor class.
 *
 * The file encryptor class by default encrypts using the AES standard.
 * Please note that it says RIJNDAEL_128 which refers to the block size and not the key size.
 * Refer to the following URL's for more details on this
 * https://www.leaseweb.com/labs/2014/02/aes-php-mcrypt-key-padding/
 * http://stackoverflow.com/questions/6770370/aes-256-encryption-in-php
 *
 *
 * @author  Chris Stolk <[email protected]>
 * @package Wubbajack\Encryption
 * @license MIT <https://opensource.org/licenses/MIT>
 * @since   0.0.1
 */
class FileEncrypter
{

    const CHUNK_BYTES = 8192;

    /**
     * The encryption key.
     *
     * @var string
     */
    protected $key;

    /**
     * The algorithm used for encryption.
     *
     * @var string
     */
    protected $cipher = MCRYPT_RIJNDAEL_128;

    /**
     * The mode used for encryption.
     *
     * @var string
     */
    protected $mode = MCRYPT_MODE_CBC;

    /**
     * The block size of the cipher.
     *
     * @var int
     */
    protected $block = 16;

    /**
     * FileEncrypter constructor.
     *
     * @param $key
     */
    public function __construct($key)
    {
        $this->key = $key;
    }

    /**
     * Set the encryption key.
     *
     * @param  string  $key
     * @return void
     */
    public function setKey($key)
    {
        $this->key = (string) $key;
    }

    /**
     * Set the encryption cipher.
     *
     * @param  string  $cipher
     * @return $this
     */
    public function setCipher($cipher)
    {
        $this->cipher = $cipher;
        $this->updateBlockSize();

        return $this;
    }

    /**
     * Set the encryption mode.
     *
     * @param  string $mode
     * @return $this
     */
    public function setMode($mode)
    {
        $this->mode = $mode;
        $this->updateBlockSize();

        return $this;
    }

    /**
     * Encrypts a file and returns the checksum of the encrypted file.
     * You can use the checksum to verify integrity as this method of encryption (symmetrical)
     * doesn't allow for easy integrity verification.
     *
     * It's not required but highly recommended as an attacker can shift bytes and thus changes the data
     * on the encrypted file.
     *
     * @param string $source
     * @param string $target
     * @return string The checksum of the encrypted file
     * @throws EncryptException
     */
    public function encrypt($source, $target)
    {
        $iv = mcrypt_create_iv($this->getIvSize(), $this->getRandomizer());

        try {
            $this->encryptFile($source, $target, $iv);
        } catch (\Exception $e) {
            throw new EncryptException('Unable to encrypt file', 0, $e);
        }

        // Returns the encrypted file object, sets the padding and the source file checksum for later checking
        return EncryptedFile::create(
            $iv,
            $this->calculateChecksum($source),
            $this->calculatePadding($source, $target),
            $target
        );
    }

    /**
     * Decrypts the source file to a target file. The checksum is an optional parameter
     * that can be used to verify integrity of the file some ciphers offer no integrity check of their own.
     *
     * It's an optional parameter but be warned, the file may have been tampered with by an attacker.
     *
     * @param EncryptedFile $encryptedFile
     * @param string        $target
     * @return string Path to the target file
     * @throws DecryptException
     */
    public function decrypt(EncryptedFile $encryptedFile, $target)
    {
        // Get the path to the source file
        $source = $encryptedFile->getFile()->getRealPath();

        try {
            $this->decryptFile($source, $target, $encryptedFile->getIv(), $encryptedFile->getPadding());
        } catch (\Exception $e) {
            throw new DecryptException('Unable to decrypt file', 0, $e);
        }

        // Verify the integrity of the decrypted file checking the checksum against the checksum of the original source file
        if (!$this->verifyChecksum($target, $encryptedFile->getChecksum())) {
            unlink($target);
            throw new DecryptException('Invalid checksum on decrypted file');
        }

        return $target;
    }

    /**
     * Decrypts a file in a stream, performing the callback on each successive decrypted block.
     * If the checksum is provided it checks it against the encrypted file for integrity.
     *
     * The callback can accept two arguments:
     *  - $data   - A chunk of decrypted data
     *  - $stream - The resource stream that is decrypting
     *
     * @param EncryptedFile $encryptedFile
     * @param \Closure      $callback
     * @throws DecryptException
     */
    public function streamDecrypt(EncryptedFile $encryptedFile, \Closure $callback)
    {
        // Get the path to the encrypted file
        $source = $encryptedFile->getFile()->getRealPath();

        // Check if callback is a closure
        if (!($callback instanceof \Closure)) {
            throw new DecryptException('Callback must be callable');
        }

        // Get the decryption stream
        $stream = $this->createDecryptionStream($source, $this->getOptions($encryptedFile->getIv()));

        // Run the callback while the file pointer isn't at the end
        while (!feof($stream)) {
            $callback(fread($stream, self::CHUNK_BYTES), $stream);
        }
    }

    /**
     * Encrypts the file
     *
     * @param string $source_file
     * @param string $target_file
     * @param string $iv
     *
     * @return void
     */
    protected function encryptFile($source_file, $target_file, $iv)

    {
        // We start by setting up both the source and target streams
        // and applying all the necessary stream filters for encryption.

        $source  = fopen($source_file, 'r');
        $target  = $this->createEncryptionStream($target_file, $this->getOptions($iv));

        // We copy the source into the target stream, passing through the encryption filter
        $this->copyStream($source, $target);

        // Close the source file and target files
        fclose($source);
        fclose($target);
    }

    /**
     * Decrypts a source file into a target file
     *
     * @param string $source
     * @param string $target
     * @param string $iv
     * @param int    $padding
     *
     * @return void
     */
    protected function decryptFile($source, $target, $iv, $padding = 0)

    {
        // We create a stream with a decryption filter appended to it
        $source = $this->createDecryptionStream($source, $this->getOptions($iv));
        $target = fopen($target, 'w+');

        // We copy the source into the target, decrypting it in the process
        $this->copyStream($source, $target, $padding);

        // Close both source and target
        fclose($source);
        fclose($target);
    }

    /**
     * Creates a stream that encrypts when written to
     *
     * @param string $target
     * @param array  $options
     *
     * @return resource
     * @throws EncryptException
     */
    protected function createEncryptionStream($target, array $options)
    {
        // Open up the resources to both the source and target
        $stream = fopen($target, 'w+');

        // Append the stream write filter with the correct encryption cipher
        stream_filter_append($stream, $this->getEncryptionFilterName(), STREAM_FILTER_WRITE, $options);

        // Returns the target stream
        return $stream;
    }

    /**
     * Creates a stream that is decrypted when read from
     *
     * @param string $source
     * @param array  $options
     *
     * @return resource
     */
    protected function createDecryptionStream($source, array $options)
    {
        $stream = fopen($source, 'rb');

        // Append the stream read filter with the decryption cipher
        stream_filter_append($stream, $this->getDecryptionFilterName(), STREAM_FILTER_READ, $options);

        // Returns the target stream
        return $stream;
    }

    /**
     * Copies a source stream to a target stream.
     * If the padding parameter is set it will remove said amount of bytes from the end of the file.
     *
     * This method does not use stream_copy_to_stream on purpose because this way we have more control
     * over the process of moving data from one stream to another.
     *
     * @param resource $source
     * @param resource $target
     * @param null|int $padding
     *
     * @return void
     */
    protected function copyStream($source, $target, $padding = null)
    {
        // Ensure that both pointers are at the start of the file
        while (!feof($source)) {
            $data = fread($source, self::CHUNK_BYTES);

            // If eof is reached and padding is set, remove it from the file
            if (feof($source) && $padding) {
0   == false // true
0   == null  // true
123 == false // false
123 == null  // false

// It is often better to use strict comparison
0 === false // false
0 === null  // false
                $data = substr($data, 0, -$padding);
            }

            fwrite($target, $data);
        }
    }

    /**
     * Returns the options for the stream filter
     * @param null $iv If no IV is set, one will be created
     *
     * @return array Returns an array with 'mode','key' and 'iv'
     */
    protected function getOptions($iv = null)
    {
        if ($iv === null) {
            mcrypt_create_iv($this->getIvSize(), $this->getRandomizer());
        }

        return [
            'mode' => $this->mode,
            'key'  => $this->key,
            'iv'   => $iv,
        ];
    }

    /**
     * Get the IV size for the cipher.
     *
     * @return int
     */
    protected function getIvSize()
    {
        return mcrypt_get_iv_size($this->cipher, $this->mode);
    }

    /**
     * Returns the encryption cipher for the stream filter
     *
     * @return string
     */
    protected function getEncryptionFilterName()
    {
        return 'mcrypt.'. $this->cipher;
    }

    /**
     * Returns the decryption cipher for the stream filter
     *
     * @return string
     */
    protected function getDecryptionFilterName()
    {
        return 'mdecrypt.'. $this->cipher;
    }

    /**
     * Get the random data source available for the OS.
     *
     * @return int
     */
    protected function getRandomizer()
    {
        if (defined('MCRYPT_DEV_URANDOM')) {
            return MCRYPT_DEV_URANDOM;
        }

        if (defined('MCRYPT_DEV_RANDOM')) {
            return MCRYPT_DEV_RANDOM;
        }

        mt_srand();

        return MCRYPT_RAND;
    }

    /**
     * Compares the given checksum with the actual file checksum.
     * Returns true if they match, false if not
     *
     * @param string $file
     * @param string $checksum
     * @return bool
     */
    protected function verifyChecksum($file, $checksum)
    {
        return strcmp($checksum, $this->calculateChecksum($file)) === 0;
    }

    /**
     * Update the block size for the current cipher and mode.
     *
     * @return void
     */
    protected function updateBlockSize()
    {
        $this->block = mcrypt_get_iv_size($this->cipher, $this->mode);
    }

    /**
     * Calculates the padding that was added during encryption
     *
     * @param string $source Path the the source file
     * @param string $target Path to the target file
     * @return int
     */
    protected function calculatePadding($source, $target)
    {
        return filesize($target) - filesize($source);
    }

    /**
     * Calculates the checksum of the file
     *
     * @param string $file
     * @return string
     */
    protected function calculateChecksum($file)
    {
        return sha1_file($file);
    }
}


1		<?php namespace Wubbajack\Encryption;
2
3		use Wubbajack\Encryption\Exceptions\EncryptException;
4		use Wubbajack\Encryption\Exceptions\DecryptException;
5
6		/**
7		* File Encryptor class.
8		*
9		* The file encryptor class by default encrypts using the AES standard.
10		* Please note that it says RIJNDAEL_128 which refers to the block size and not the key size.
11		* Refer to the following URL's for more details on this
12		* https://www.leaseweb.com/labs/2014/02/aes-php-mcrypt-key-padding/
13		* http://stackoverflow.com/questions/6770370/aes-256-encryption-in-php
14		*
15		*
16		* @author Chris Stolk <[email protected]>
17		* @package Wubbajack\Encryption
18		* @license MIT <https://opensource.org/licenses/MIT>
19		* @since 0.0.1
20		*/
21		class FileEncrypter
22		{
23
24		const CHUNK_BYTES = 8192;
25
26		/**
27		* The encryption key.
28		*
29		* @var string
30		*/
31		protected $key;
32
33		/**
34		* The algorithm used for encryption.
35		*
36		* @var string
37		*/
38		protected $cipher = MCRYPT_RIJNDAEL_128;
39
40		/**
41		* The mode used for encryption.
42		*
43		* @var string
44		*/
45		protected $mode = MCRYPT_MODE_CBC;
46
47		/**
48		* The block size of the cipher.
49		*
50		* @var int
51		*/
52		protected $block = 16;
53
54		/**
55		* FileEncrypter constructor.
56		*
57		* @param $key
58		*/
59		public function __construct($key)
60		{
61		$this->key = $key;
62		}
63
64		/**
65		* Set the encryption key.
66		*
67		* @param string $key
68		* @return void
69		*/
70		public function setKey($key)
71		{
72		$this->key = (string) $key;
73		}
74
75		/**
76		* Set the encryption cipher.
77		*
78		* @param string $cipher
79		* @return $this
80		*/
81		public function setCipher($cipher)
82		{
83		$this->cipher = $cipher;
84		$this->updateBlockSize();
85
86		return $this;
87		}
88
89		/**
90		* Set the encryption mode.
91		*
92		* @param string $mode
93		* @return $this
94		*/
95		public function setMode($mode)
96		{
97		$this->mode = $mode;
98		$this->updateBlockSize();
99
100		return $this;
101		}
102
103		/**
104		* Encrypts a file and returns the checksum of the encrypted file.
105		* You can use the checksum to verify integrity as this method of encryption (symmetrical)
106		* doesn't allow for easy integrity verification.
107		*
108		* It's not required but highly recommended as an attacker can shift bytes and thus changes the data
109		* on the encrypted file.
110		*
111		* @param string $source
112		* @param string $target
113		* @return string The checksum of the encrypted file
114		* @throws EncryptException
115		*/
116		public function encrypt($source, $target)
117		{
118		$iv = mcrypt_create_iv($this->getIvSize(), $this->getRandomizer());
119
120		try {
121		$this->encryptFile($source, $target, $iv);
122		} catch (\Exception $e) {
123		throw new EncryptException('Unable to encrypt file', 0, $e);
124		}
125
126		// Returns the encrypted file object, sets the padding and the source file checksum for later checking
127		return EncryptedFile::create(
128		$iv,
129		$this->calculateChecksum($source),
130		$this->calculatePadding($source, $target),
131		$target
132		);
133		}
134
135		/**
136		* Decrypts the source file to a target file. The checksum is an optional parameter
137		* that can be used to verify integrity of the file some ciphers offer no integrity check of their own.
138		*
139		* It's an optional parameter but be warned, the file may have been tampered with by an attacker.
140		*
141		* @param EncryptedFile $encryptedFile
142		* @param string $target
143		* @return string Path to the target file
144		* @throws DecryptException
145		*/
146		public function decrypt(EncryptedFile $encryptedFile, $target)
147		{
148		// Get the path to the source file
149		$source = $encryptedFile->getFile()->getRealPath();
150
151		try {
152		$this->decryptFile($source, $target, $encryptedFile->getIv(), $encryptedFile->getPadding());
153		} catch (\Exception $e) {
154		throw new DecryptException('Unable to decrypt file', 0, $e);
155		}
156
157		// Verify the integrity of the decrypted file checking the checksum against the checksum of the original source file
158		if (!$this->verifyChecksum($target, $encryptedFile->getChecksum())) {
159		unlink($target);
160		throw new DecryptException('Invalid checksum on decrypted file');
161		}
162
163		return $target;
164		}
165
166		/**
167		* Decrypts a file in a stream, performing the callback on each successive decrypted block.
168		* If the checksum is provided it checks it against the encrypted file for integrity.
169		*
170		* The callback can accept two arguments:
171		* - $data - A chunk of decrypted data
172		* - $stream - The resource stream that is decrypting
173		*
174		* @param EncryptedFile $encryptedFile
175		* @param \Closure $callback
176		* @throws DecryptException
177		*/
178		public function streamDecrypt(EncryptedFile $encryptedFile, \Closure $callback)
179		{
180		// Get the path to the encrypted file
181		$source = $encryptedFile->getFile()->getRealPath();
182
183		// Check if callback is a closure
184		if (!($callback instanceof \Closure)) {
185		throw new DecryptException('Callback must be callable');
186		}
187
188		// Get the decryption stream
189		$stream = $this->createDecryptionStream($source, $this->getOptions($encryptedFile->getIv()));
190
191		// Run the callback while the file pointer isn't at the end
192		while (!feof($stream)) {
193		$callback(fread($stream, self::CHUNK_BYTES), $stream);
194		}
195		}
196
197		/**
198		* Encrypts the file
199		*
200		* @param string $source_file
201		* @param string $target_file
202		* @param string $iv
203		*
204		* @return void
205		*/
206	View Code Duplication	protected function encryptFile($source_file, $target_file, $iv)
		1 ignored issue – show Duplication introduced 2016-01-02 22:53 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
207		{
208		// We start by setting up both the source and target streams
209		// and applying all the necessary stream filters for encryption.
210
211		$source = fopen($source_file, 'r');
212		$target = $this->createEncryptionStream($target_file, $this->getOptions($iv));
213
214		// We copy the source into the target stream, passing through the encryption filter
215		$this->copyStream($source, $target);
216
217		// Close the source file and target files
218		fclose($source);
219		fclose($target);
220		}
221
222		/**
223		* Decrypts a source file into a target file
224		*
225		* @param string $source
226		* @param string $target
227		* @param string $iv
228		* @param int $padding
229		*
230		* @return void
231		*/
232	View Code Duplication	protected function decryptFile($source, $target, $iv, $padding = 0)
		1 ignored issue – show Duplication introduced 2016-01-02 22:53 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
233		{
234		// We create a stream with a decryption filter appended to it
235		$source = $this->createDecryptionStream($source, $this->getOptions($iv));
236		$target = fopen($target, 'w+');
237
238		// We copy the source into the target, decrypting it in the process
239		$this->copyStream($source, $target, $padding);
240
241		// Close both source and target
242		fclose($source);
243		fclose($target);
244		}
245
246		/**
247		* Creates a stream that encrypts when written to
248		*
249		* @param string $target
250		* @param array $options
251		*
252		* @return resource
253		* @throws EncryptException
254		*/
255		protected function createEncryptionStream($target, array $options)
256		{
257		// Open up the resources to both the source and target
258		$stream = fopen($target, 'w+');
259
260		// Append the stream write filter with the correct encryption cipher
261		stream_filter_append($stream, $this->getEncryptionFilterName(), STREAM_FILTER_WRITE, $options);
262
263		// Returns the target stream
264		return $stream;
265		}
266
267		/**
268		* Creates a stream that is decrypted when read from
269		*
270		* @param string $source
271		* @param array $options
272		*
273		* @return resource
274		*/
275		protected function createDecryptionStream($source, array $options)
276		{
277		$stream = fopen($source, 'rb');
278
279		// Append the stream read filter with the decryption cipher
280		stream_filter_append($stream, $this->getDecryptionFilterName(), STREAM_FILTER_READ, $options);
281
282		// Returns the target stream
283		return $stream;
284		}
285
286		/**
287		* Copies a source stream to a target stream.
288		* If the padding parameter is set it will remove said amount of bytes from the end of the file.
289		*
290		* This method does not use stream_copy_to_stream on purpose because this way we have more control
291		* over the process of moving data from one stream to another.
292		*
293		* @param resource $source
294		* @param resource $target
295		* @param null\|int $padding
296		*
297		* @return void
298		*/
299		protected function copyStream($source, $target, $padding = null)
300		{
301		// Ensure that both pointers are at the start of the file
302		while (!feof($source)) {
303		$data = fread($source, self::CHUNK_BYTES);
304
305		// If eof is reached and padding is set, remove it from the file
306		if (feof($source) && $padding) {
		0 ignored issues – show Bug Best Practice introduced 2016-01-02 22:53 UTC by Report Bug Copy Issue Report The expression `$padding` of type `null\|integer` is loosely compared to `true`; this is ambiguous if the integer can be zero. You might want to explicitly use `!== null` instead. In PHP, under loose comparison (like `==`, or `!=`, or `switch` conditions), values of different types might be equal. For `integer` values, zero is a special case, in particular the following results might be unexpected: 0 == false // true 0 == null // true 123 == false // false 123 == null // false // It is often better to use strict comparison 0 === false // false 0 === null // false Loading history...
307		$data = substr($data, 0, -$padding);
308		}
309
310		fwrite($target, $data);
311		}
312		}
313
314		/**
315		* Returns the options for the stream filter
316		* @param null $iv If no IV is set, one will be created
317		*
318		* @return array Returns an array with 'mode','key' and 'iv'
319		*/
320		protected function getOptions($iv = null)
321		{
322		if ($iv === null) {
323		mcrypt_create_iv($this->getIvSize(), $this->getRandomizer());
324		}
325
326		return [
327		'mode' => $this->mode,
328		'key' => $this->key,
329		'iv' => $iv,
330		];
331		}
332
333		/**
334		* Get the IV size for the cipher.
335		*
336		* @return int
337		*/
338		protected function getIvSize()
339		{
340		return mcrypt_get_iv_size($this->cipher, $this->mode);
341		}
342
343		/**
344		* Returns the encryption cipher for the stream filter
345		*
346		* @return string
347		*/
348		protected function getEncryptionFilterName()
349		{
350		return 'mcrypt.'. $this->cipher;
351		}
352
353		/**
354		* Returns the decryption cipher for the stream filter
355		*
356		* @return string
357		*/
358		protected function getDecryptionFilterName()
359		{
360		return 'mdecrypt.'. $this->cipher;
361		}
362
363		/**
364		* Get the random data source available for the OS.
365		*
366		* @return int
367		*/
368		protected function getRandomizer()
369		{
370		if (defined('MCRYPT_DEV_URANDOM')) {
371		return MCRYPT_DEV_URANDOM;
372		}
373
374		if (defined('MCRYPT_DEV_RANDOM')) {
375		return MCRYPT_DEV_RANDOM;
376		}
377
378		mt_srand();
379
380		return MCRYPT_RAND;
381		}
382
383		/**
384		* Compares the given checksum with the actual file checksum.
385		* Returns true if they match, false if not
386		*
387		* @param string $file
388		* @param string $checksum
389		* @return bool
390		*/
391		protected function verifyChecksum($file, $checksum)
392		{
393		return strcmp($checksum, $this->calculateChecksum($file)) === 0;
394		}
395
396		/**
397		* Update the block size for the current cipher and mode.
398		*
399		* @return void
400		*/
401		protected function updateBlockSize()
402		{
403		$this->block = mcrypt_get_iv_size($this->cipher, $this->mode);
404		}
405
406		/**
407		* Calculates the padding that was added during encryption
408		*
409		* @param string $source Path the the source file
410		* @param string $target Path to the target file
411		* @return int
412		*/
413		protected function calculatePadding($source, $target)
414		{
415		return filesize($target) - filesize($source);
416		}
417
418		/**
419		* Calculates the checksum of the file
420		*
421		* @param string $file
422		* @return string
423		*/
424		protected function calculateChecksum($file)
425		{
426		return sha1_file($file);
427		}
428		}
429

wubbajack / filecrypt

Branch — master (2ce3bf)

FileEncrypter::setMode() A

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