OpenSSLCrypto::getKey() - Code Metrics - silverstripe/silverstripe-hybridsessions - Measure and Improve Code Quality continuously with Scrutinizer

OpenSSLCrypto::getKey() A
last analyzed 2019-11-21 03:21 UTC

↳ Parent: OpenSSLCrypto

Complexity

Conditions	1
Paths	1

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
dl	0
loc	4
rs	10
c	0
b	0
f	0
cc	1
nc	1
nop	0

<?php

namespace SilverStripe\HybridSessions\Crypto;

/**
 * Some cryptography used for Session cookie encryption.
 *
 */
class OpenSSLCrypto implements CryptoHandler
{
    protected $key;

    protected $salt;

    protected $saltedKey;

    /**
     * @return string
     */
    public function getKey()
    {
        return $this->key;
    }

    /**
     * @return string
     */
    public function getSalt()
    {
        return $this->salt;
    }

    /**
     * @param string $key a per-site secret string which is used as the base encryption key.
     * @param string $salt a per-session random string which is used as a salt to generate a per-session key
     *
     * The base encryption key needs to stay secret. If an attacker ever gets it, they can read their session,
     * and even modify & re-sign it.
     *
     * The salt is a random per-session string that is used with the base encryption key to create a per-session key.
     * This (amongst other things) makes sure an attacker can't use a known-plaintext attack to guess the key.
     *
     * Normally we could create a salt on encryption, send it to the client as part of the session (it doesn't
     * need to remain secret), then use the returned salt to decrypt. But we already have the Session ID which makes
     * a great salt, so no need to generate & handle another one.
     */
    public function __construct($key, $salt)
    {
        $this->key = $key;
        $this->salt = $salt;
        $this->saltedKey = hash_pbkdf2('sha256', $this->key, $this->salt, 1000, 0, true);
    }

    /**
     * Encrypt and then sign some cleartext
     *
     * @param string $cleartext - The cleartext to encrypt and sign
     * @return string - The encrypted-and-signed message as base64 ASCII.
     */
    public function encrypt($cleartext)
    {
        $cipher = "AES-256-CBC";
        $ivlen = openssl_cipher_iv_length($cipher);
        $iv = openssl_random_pseudo_bytes($ivlen);
        $ciphertext_raw = openssl_encrypt($cleartext, $cipher, $this->saltedKey, $options = OPENSSL_RAW_DATA, $iv);
        $hmac = hash_hmac('sha256', $ciphertext_raw, $this->saltedKey, $as_binary = true);
        $ciphertext = base64_encode($iv . $hmac . $ciphertext_raw);
$myVar = 'Value';
$higher = false;

if (rand(1, 6) > 3) {
    $higher = true;
} else {
    $higher = false;
}

        return base64_encode($iv . $hmac . $ciphertext_raw);
    }

    /**
     * Check the signature on an encrypted-and-signed message, and if valid
     * decrypt the content
     *
     * @param string $data - The encrypted-and-signed message as base64 ASCII
     *
     * @return bool|string - The decrypted cleartext or false if signature failed
     */
    public function decrypt($data)
    {
        $c = base64_decode($data);
        $cipher = "AES-256-CBC";
        $ivlen = openssl_cipher_iv_length($cipher);
        $iv = substr($c, 0, $ivlen);
        $hmac = substr($c, $ivlen, $sha2len = 32);
        $ciphertext_raw = substr($c, $ivlen + $sha2len);
        $cleartext = openssl_decrypt($ciphertext_raw, $cipher, $this->saltedKey, $options = OPENSSL_RAW_DATA, $iv);
        $calcmac = hash_hmac('sha256', $ciphertext_raw, $this->saltedKey, $as_binary = true);

        if (hash_equals($hmac, $calcmac)) {
            return $cleartext;
        }

        return false;
class Author {
    private $name;

    public function __construct($name) {
        $this->name = $name;
    }

    public function getName() {
        return $this->name;
    }
}

abstract class Post {
    public function getAuthor() {
        return 'Johannes';
    }
}

class BlogPost extends Post {
    public function getAuthor() {
        return new Author('Johannes');
    }
}

class ForumPost extends Post { /* ... */ }

function my_function(Post $post) {
    echo strtoupper($post->getAuthor());
}
    }
}


1			<?php
2
3			namespace SilverStripe\HybridSessions\Crypto;
4
5			/**
6			* Some cryptography used for Session cookie encryption.
7			*
8			*/
9			class OpenSSLCrypto implements CryptoHandler
10			{
11			protected $key;
12
13			protected $salt;
14
15			protected $saltedKey;
16
17			/**
18			* @return string
19			*/
20			public function getKey()
21			{
22			return $this->key;
23			}
24
25			/**
26			* @return string
27			*/
28			public function getSalt()
29			{
30			return $this->salt;
31			}
32
33			/**
34			* @param string $key a per-site secret string which is used as the base encryption key.
35			* @param string $salt a per-session random string which is used as a salt to generate a per-session key
36			*
37			* The base encryption key needs to stay secret. If an attacker ever gets it, they can read their session,
38			* and even modify & re-sign it.
39			*
40			* The salt is a random per-session string that is used with the base encryption key to create a per-session key.
41			* This (amongst other things) makes sure an attacker can't use a known-plaintext attack to guess the key.
42			*
43			* Normally we could create a salt on encryption, send it to the client as part of the session (it doesn't
44			* need to remain secret), then use the returned salt to decrypt. But we already have the Session ID which makes
45			* a great salt, so no need to generate & handle another one.
46			*/
47			public function __construct($key, $salt)
48			{
49			$this->key = $key;
50			$this->salt = $salt;
51			$this->saltedKey = hash_pbkdf2('sha256', $this->key, $this->salt, 1000, 0, true);
52			}
53
54			/**
55			* Encrypt and then sign some cleartext
56			*
57			* @param string $cleartext - The cleartext to encrypt and sign
58			* @return string - The encrypted-and-signed message as base64 ASCII.
59			*/
60			public function encrypt($cleartext)
61			{
62			$cipher = "AES-256-CBC";
63			$ivlen = openssl_cipher_iv_length($cipher);
64			$iv = openssl_random_pseudo_bytes($ivlen);
65			$ciphertext_raw = openssl_encrypt($cleartext, $cipher, $this->saltedKey, $options = OPENSSL_RAW_DATA, $iv);
66			$hmac = hash_hmac('sha256', $ciphertext_raw, $this->saltedKey, $as_binary = true);
67			$ciphertext = base64_encode($iv . $hmac . $ciphertext_raw);
			0 ignored issues – show Unused Code introduced 2017-09-20 05:27 UTC by Report Bug Copy Issue Report `$ciphertext` is not used, you could remove the assignment. This check looks for variable assignements that are either overwritten by other assignments or where the variable is not used subsequently. $myVar = 'Value'; $higher = false; if (rand(1, 6) > 3) { $higher = true; } else { $higher = false; } Both the `$myVar` assignment in line 1 and the `$higher` assignment in line 2 are dead. The first because `$myVar` is never used and the second because `$higher` is always overwritten for every possible time line. Loading history...
68
69			return base64_encode($iv . $hmac . $ciphertext_raw);
70			}
71
72			/**
73			* Check the signature on an encrypted-and-signed message, and if valid
74			* decrypt the content
75			*
76			* @param string $data - The encrypted-and-signed message as base64 ASCII
77			*
78			* @return bool\|string - The decrypted cleartext or false if signature failed
79			*/
80			public function decrypt($data)
81			{
82			$c = base64_decode($data);
83			$cipher = "AES-256-CBC";
84			$ivlen = openssl_cipher_iv_length($cipher);
85			$iv = substr($c, 0, $ivlen);
86			$hmac = substr($c, $ivlen, $sha2len = 32);
87			$ciphertext_raw = substr($c, $ivlen + $sha2len);
88			$cleartext = openssl_decrypt($ciphertext_raw, $cipher, $this->saltedKey, $options = OPENSSL_RAW_DATA, $iv);
89			$calcmac = hash_hmac('sha256', $ciphertext_raw, $this->saltedKey, $as_binary = true);
90
91			if (hash_equals($hmac, $calcmac)) {
92			return $cleartext;
93			}
94
95			return false;
			0 ignored issues – show Bug Best Practice introduced 2017-09-20 05:27 UTC by Report Bug Copy Issue Report The return type of `return false;` (`false`) is incompatible with the return type declared by the interface `SilverStripe\HybridSessi...\CryptoHandler::decrypt` of type `string`. If you return a value from a function or method, it should be a sub-type of the type that is given by the parent type f.e. an interface, or abstract method. This is more formally defined by the Lizkov substitution principle, and guarantees that classes that depend on the parent type can use any instance of a child type interchangably. This principle also belongs to the SOLID principles for object oriented design. Let’s take a look at an example: class Author { private $name; public function __construct($name) { $this->name = $name; } public function getName() { return $this->name; } } abstract class Post { public function getAuthor() { return 'Johannes'; } } class BlogPost extends Post { public function getAuthor() { return new Author('Johannes'); } } class ForumPost extends Post { /* ... */ } function my_function(Post $post) { echo strtoupper($post->getAuthor()); } Our function `my_function` expects a `Post` object, and outputs the author of the post. The base class `Post` returns a simple string and outputting a simple string will work just fine. However, the child class `BlogPost` which is a sub-type of `Post` instead decided to return an `object`, and is therefore violating the SOLID principles. If a `BlogPost` were passed to `my_function`, PHP would not complain, but ultimately fail when executing the `strtoupper` call in its body. Loading history...
96			}
97			}
98

silverstripe / silverstripe-hybridsessions

OpenSSLCrypto::getKey() A last analyzed 2019-11-21 03:21 UTC

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OpenSSLCrypto::getKey() A
last analyzed 2019-11-21 03:21 UTC