SecureString::verifyHmac() - Code Metrics - vanilla/garden - Measure and Improve Code Quality continuously with Scrutinizer

SecureString::verifyHmac() B
last analyzed 2017-08-29 15:20 UTC

↳ Parent: SecureString

Complexity

Conditions	5
Paths	5

Size

Total Lines	32
Code Lines	16

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	14
CRAP Score	5.0488

Importance

Changes

Metric	Value
cc	5
eloc	16
nc	5
nop	4
dl	0
loc	32
ccs	14
cts	16
cp	0.875
crap	5.0488
rs	8.439
c	0
b	0
f	0

<?php
/**
 * @author Todd Burry <[email protected]>
 * @copyright 2009-2014 Vanilla Forums Inc.
 * @license MIT
 */

namespace Garden;


/**
 * A class that provides functionality for encrypting and signing strings and then decoding those secure strings.
 */
class SecureString {
    const SEP = '.';
    const EOS = '-';
    const STRICT = 'strict';

    protected $timestampExpiry;

    /**
     * Initialize an instance of the {@link SecureString} class.
     */
    public function __construct() {
        $this->timestampExpiry = strtotime('1 day', 0);
    }

    /**
     * Get or set the timestamp expiry in seconds.
     *
     * @param int $value Set a new expiry value in seconds.
     * @return int Returns the current timestamp expiry.
     */
    public function timestampExpiry($value = 0) {
        if ($value) {
            $this->timestampExpiry = $value;
        }
        return $this->timestampExpiry;
    }

    /**
     * Encode a string using a secure specification.
     *
     * @param mixed $data The data to encode. This must be data that supports json serialization.
     * @param array $spec An array specifying how the string should be encoded.
     * The array should be in the form ['spec1' => 'password', 'spec2' => 'password'].
     * @param bool $throw Whether or not to throw an exception on error.
     * @return string|null Returns the encoded string or null if there is an error.
     */
    public function encode($data, array $spec, $throw = false) {
        $str = json_encode($data, JSON_UNESCAPED_SLASHES);

        $first = true;
        foreach ($spec as $name => $password) {
            if ($name === self::STRICT) {
                // Strict is just an option so continue.
                continue;
            }

            $supported = $this->supportedInfo($name, $throw);
            if ($supported === null) {
                return null;
            }

            list($encode,, $method, $encodeFirst) = $supported;

            if ($first) {
                if ($encodeFirst) {
                    $str = static::base64urlEncode($str);
                }
                $this->pushString($str, self::EOS);
            }

            switch ($encode) {
                case 'encrypt':
                    $str = $this->encrypt($str, $method, $password, '', $throw);
                    break;
                case 'hmac':
                    $str = $this->hmac($str, $method, $password, 0, $throw);
                    break;
                default:
                    return $this->exception($throw, "Invalid method $encode.", 500);

            }
            // Return on error.
            if (!$str) {
                return null;
            }

            $this->pushString($str, $name);

            $first = false;
        }

        return $str;
    }

    /**
     * Decode a string that was encoded using {@link SecureString::encode()}.
     *
     * @param string $str The encoded string.
     * @param array $spec An array specifying how the string should be encoded.
     * @param bool $throw Whether or not to throw an exception on error.
     * @return string|null Returns the decoded string or null of there was a problem.
     */
    public function decode($str, array $spec, $throw = false) {
        $decodeFirst = false;
        $wstr = $str; // wstr means working string
        $used = [];

        $strict = true;
        if (array_key_exists(self::STRICT, $spec)) {
            $strict = (bool)$spec[self::STRICT];
            unset($spec[self::STRICT]);
        }

        while ($token = $this->popString($wstr)) {
            if ($token === self::EOS) {
                if ($decodeFirst) {
                    $wstr = static::base64urlDecode($wstr);
                }
                break;
            }

            try {
                $supported = $this->supportedInfo($token, true);
            } catch (\Exception $ex) {
                return $this->exception($throw, $ex->getMessage(), 403);

            }

            if (!isset($spec[$token])) {
                return $this->exception($throw, "You did not provide a password for $token.", 403);

            }
            $password = $spec[$token];
            array_unshift($used, $token);

            list(, $decode, $method, $decodeFirst) = $supported;

            switch ($decode) {
                case 'decrypt':
                    $wstr = $this->decrypt($wstr, $method, $password, $throw);
                    break;
                case 'verifyHmac':
                    $wstr = $this->verifyHmac($wstr, $method, $password, $throw);
                    break;
                default:
                    return $this->exception($throw, "Invalid method $decode.", 500);

            }

            if ($wstr === null) {
                return null;
            }
        }

        // Make sure that the string was secured at all.
        if ($strict && array_keys($spec) != $used) {
            return $this->exception($throw, 'The string is not fully secure.', 403);

        } elseif (empty($used)) {
            return $this->exception($throw, 'The string is not secure.', 403);

        }

        $data = json_decode($wstr, true);
        if ($data === null) {
            return $this->exception($throw, 'The final string is not valid json.', 403);

        }

        return $data;
    }

    /**
     * Generate a random string suitable for use as an encryption or signature key.
     *
     * @param int $len The number of characters in the key.
     * @return string Returns a base64url encoded string representing the random key.
     */
    public static function generateRandomKey($len = 32) {
        $bytes = ceil($len * 3 / 4);

        return substr(self::base64urlEncode(openssl_random_pseudo_bytes($bytes)), 0, $len);
    }

    /**
     * Base64 Encode a string, but make it suitable to be passed in a url.
     *
     * @param string $str The string to encode.
     * @return string The encoded string.
     */
    protected static function base64urlEncode($str) {
        return trim(strtr(base64_encode($str), '+/', '-_'), '=');
    }

    /**
     * Decode a string that was encoded using base64UrlEncode().
     *
     * @param string $str The encoded string.
     * @return string The decoded string.
     */
    protected static function base64urlDecode($str) {
        return base64_decode(strtr($str, '-_', '+/'));
    }

    /**
     * Encrypt a string with {@link openssl_encrypt()}.
     *
     * @param string $str The string to encrypt.
     * @param string $method The encryption cipher.
     * @param string $password The encryption password.
     * @param string $iv The input vector.
     * @param bool $throw Whether or not to throw an exception on error.
     * @return string Returns the encrypted string.
     */
    protected function encrypt($str, $method, $password, $iv = '', $throw = false) {
        if ($iv === '') {
            $iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($method));
        }
        // Encrypt the string.
        $encrypted = openssl_encrypt($str, $method, $password, OPENSSL_RAW_DATA, $iv);

        if ($encrypted === false) {
            return $this->exception($throw, "Error encrypting the string.", 400);

        }

        $str = static::base64urlEncode($encrypted);
        $this->pushString($str, static::base64urlEncode($iv));

        return $str;
    }

    /**
     * Decrypt a string with {@link openssl_decrypt()}.
     *
     * @param string $str The base64 url encoded encrypted string.
     * @param string $method The encryption cipher.
     * @param string $password The password to decyrpt the string.
     * @param bool $throw Whether or not to decode the string on exception.
     * @return string|null Returns the decrypted string or null on error.
     */
    protected function decrypt($str, $method, $password, $throw = false) {
        $iv = static::base64urlDecode($this->popString($str));
        $encrypted = static::base64urlDecode($this->popString($str));

        try {
            $decrypted = openssl_decrypt($encrypted, $method, $password, true, $iv);
        } catch (\Exception $ex) {
            return $this->exception($throw, "Error decrypting the string.", 403);
        }

        if ($decrypted === false) {
            return $this->exception($throw, "Error decrypting the string.", 403);
        }

        return $decrypted;
    }

    /**
     * Get information about a supported spec name.
     *
     * @param string $name The name of the spec.
     * @param bool $throw Whether or not throw an exception on error.
     * @return array|null Returns an array in the form [encode, decode, method, encodeFirst].
     * Returns null on error.
     */
    protected function supportedInfo($name, $throw = false) {
        switch ($name) {
            case 'aes128':
            case 'aes256':
                $cipher = 'aes-'.substr($name, 3).'-cbc';
                return ['encrypt', 'decrypt', $cipher, false];
            case 'hsha1':
            case 'hsha256':
                $hash = substr($name, 1);
                return ['hmac', 'verifyHmac', $hash, true];
        }
        return $this->exception($throw, "Spec $name not supported.", 400);
    }

    /**
     * Sign a string with hmac and a hash method.
     *
     * @param string $str The string to sign.
     * @param string $method The hash method used to sign the string.
     * @param string $password The password used to hmac hash the string with.
     * @param int $timestamp The timestamp used to sign the string with or 0 to use the current time.
     * @param bool $throw Whether or not the throw an exception on error.
     * @return string Returns the string with signing information or null on error.
     */
    protected function hmac($str, $method, $password, $timestamp = 0, $throw = false) {
        if ($timestamp === 0) {
            $timestamp = time();
        }
        // Add the timestamp to the string.
        static::pushString($str, $timestamp);

        // Sign the string.
        $signature = hash_hmac($method, $str, $password, true);
        if ($signature === false) {
            return $this->exception($throw, "Invalid hash method $method.", 400);

        }

        // Add the signature to the string.
        static::pushString($str, static::base64urlEncode($signature));

        return $str;
    }

    /**
     * Verify the signature on a secure string.
     *
     * @param string $str The string to verify.
     * @param string $method The hashing algorithm that the string was signed with.
     * @param string $password The password used to sign the string.
     * @param bool $throw Whether or not to throw an exeptio on error.
     * @return bool Returns the string without the signing information or null on error.
     */
    protected function verifyHmac($str, $method, $password, $throw = false) {
        // Grab the signature from the string.
        $signature = $this->popString($str);
        if (!$signature) {
''   == false // true
''   == null  // true
'ab' == false // false
'ab' == null  // false

// It is often better to use strict comparison
'' === false // false
'' === null  // false
            return $this->exception($throw, "The signature is missing.", 403);
        }
        $signature = static::base64urlDecode($signature);

        // Recalculate the signature to compare.
        $calcSignature = hash_hmac($method, $str, $password, true);

        if (strlen($signature) !== strlen($calcSignature)) {
            return $this->exception($throw, "The signature is invalid.", 403);
        }

        // Do a double hmac comparison to prevent timing attacks.
        // https://www.isecpartners.com/blog/2011/february/double-hmac-verification.aspx
        $dblSignature = hash_hmac($method, $signature, $password, true);
        $dblCalcSignature = hash_hmac($method, $calcSignature, $password, true);

        if ($dblSignature !== $dblCalcSignature) {
            return $this->exception($throw, "The signature is invalid.", 403);
        }

        // Grab the timestamp and verify it.
        $timestamp = $this->popString($str);
        if (!$this->verifyTimestamp($timestamp, $throw)) {
            return null;
        }

        return $str;
    }

    /**
     * Verify that a timestamp hasn't expired.
     *
     * @param string $timestamp The unix timestamp to verify.
     * @param bool $throw Whether or not to throw an exception on error.
     * @return bool Returns true if the timestamp is valid or false otherwise.
     */
    protected function verifyTimestamp($timestamp, $throw = false) {
        if (!is_numeric($timestamp)) {
            return (bool)$this->exception($throw, "Invalid timestamp.", 403);
        }
        $intTimestamp = (int)$timestamp;
        $now = time();
        if ($intTimestamp + $this->timestampExpiry <= $now) {
            return (bool)$this->exception($throw, "The timestamp has expired.", 403);
        }

        return true;
    }

    /**
     * Pop a string off of the end of an encoded secure string.
     *
     * @param string &$str The main string to pop.
     * @return string|null Returns the popped string or null if {@link $str} is empty.
     */
    protected function popString(&$str) {
        if ($str === '') {
            return null;
        }

        $pos = strrpos($str, '.');
        if ($pos !== false) {
            $result = substr($str, $pos + 1);
            $str = substr($str, 0, $pos);
        } else {
            $result = $str;
            $str = '';
        }
        return $result;
    }

    /**
     * Pushes a string on to the end of an encoded secure string.
     *
     * @param string &$str The main string to push to.
     * @param string|array $item The string or array of strings to push on to the end of {@link $str}.
     */
    protected function pushString(&$str, $item) {
        if ($str) {
            $str .= static::SEP;
        }
        $str .= implode(static::SEP, (array)$item);
    }

    /**
     * Throw an exception or return false.
     *
     * @param bool $throw Whether or not to throw an exception.
     * @param string $message The exception message.
     * @param int $code The exception code.
     * @return bool Returns false if {@link $throw} is false.
     * @throws \Exception Throws an exception with {@link $message} and {@link $code}.
     */
    protected function exception($throw, $message, $code) {
        if ($throw) {
            throw new \Exception($message, $code);
        }
        return null;
    }

    /**
     * Twiddle a value in an encoded secure string to another value.
     *
     * This method is mainly for testing so that an invalid string can be created.
     *
     * @param string $string A valid cookie to twiddle.
     * @param int $index The index of the new value.
     * @param string $value The new value. This will be base64url encoded.
     * @param bool $encode Whether or not to base64 url encode the value.
     * @return string Returns the new encoded cookie.
     */
    public function twiddle($string, $index, $value, $encode = false) {
        $parts = explode(static::SEP, $string);

        if ($encode) {
            $value = static::base64urlEncode($value);
        }
        $parts[$index] = $value;

        return implode(static::SEP, $parts);
    }
}


1			<?php
2			/**
3			* @author Todd Burry <[email protected]>
4			* @copyright 2009-2014 Vanilla Forums Inc.
5			* @license MIT
6			*/
7
8			namespace Garden;
9
10
11			/**
12			* A class that provides functionality for encrypting and signing strings and then decoding those secure strings.
13			*/
14			class SecureString {
15			const SEP = '.';
16			const EOS = '-';
17			const STRICT = 'strict';
18
19			protected $timestampExpiry;
20
21			/**
22			* Initialize an instance of the {@link SecureString} class.
23			*/
24	440		public function __construct() {
25	440		$this->timestampExpiry = strtotime('1 day', 0);
26	440		}
27
28			/**
29			* Get or set the timestamp expiry in seconds.
30			*
31			* @param int $value Set a new expiry value in seconds.
32			* @return int Returns the current timestamp expiry.
33			*/
34	1		public function timestampExpiry($value = 0) {
35	1		if ($value) {
36	1		$this->timestampExpiry = $value;
37	1		}
38	1		return $this->timestampExpiry;
39			}
40
41			/**
42			* Encode a string using a secure specification.
43			*
44			* @param mixed $data The data to encode. This must be data that supports json serialization.
45			* @param array $spec An array specifying how the string should be encoded.
46			* The array should be in the form ['spec1' => 'password', 'spec2' => 'password'].
47			* @param bool $throw Whether or not to throw an exception on error.
48			* @return string\|null Returns the encoded string or null if there is an error.
49			*/
50	438		public function encode($data, array $spec, $throw = false) {
51	438		$str = json_encode($data, JSON_UNESCAPED_SLASHES);
52
53	438		$first = true;
54	438		foreach ($spec as $name => $password) {
55	438		if ($name === self::STRICT) {
56			// Strict is just an option so continue.
57	1		continue;
58			}
59
60	438		$supported = $this->supportedInfo($name, $throw);
61	438		if ($supported === null) {
62	1		return null;
63			}
64
65	437		list($encode,, $method, $encodeFirst) = $supported;
66
67	437		if ($first) {
68	437		if ($encodeFirst) {
69	195		$str = static::base64urlEncode($str);
70	195		}
71	437		$this->pushString($str, self::EOS);
72	437		}
73
74		View Code Duplication	switch ($encode) {
75	437		case 'encrypt':
76	290		$str = $this->encrypt($str, $method, $password, '', $throw);
77	290		break;
78	292		case 'hmac':
79	292		$str = $this->hmac($str, $method, $password, 0, $throw);
80	292		break;
81			default:
82			return $this->exception($throw, "Invalid method $encode.", 500);
			0 ignored issues – show Bug Compatibility introduced 2015-11-24 19:27 UTC by Report Bug Copy Issue Report The expression `$this->exception($throw,...thod {$encode}.", 500);` of type `boolean\|null` adds the type `boolean` to the return on line 82 which is incompatible with the return type documented by `Garden\SecureString::encode` of type `string\|null`. Loading history...
83			}
84			// Return on error.
85	437		if (!$str) {
86			return null;
87			}
88
89	437		$this->pushString($str, $name);
90
91	437		$first = false;
92	437		}
93
94	437		return $str;
95			}
96
97			/**
98			* Decode a string that was encoded using {@link SecureString::encode()}.
99			*
100			* @param string $str The encoded string.
101			* @param array $spec An array specifying how the string should be encoded.
102			* @param bool $throw Whether or not to throw an exception on error.
103			* @return string\|null Returns the decoded string or null of there was a problem.
104			*/
105	439		public function decode($str, array $spec, $throw = false) {
106	439		$decodeFirst = false;
107	439		$wstr = $str; // wstr means working string
108	439		$used = [];
109
110	439		$strict = true;
111	439		if (array_key_exists(self::STRICT, $spec)) {
112	2		$strict = (bool)$spec[self::STRICT];
113	2		unset($spec[self::STRICT]);
114	2		}
115
116	439		while ($token = $this->popString($wstr)) {
117	439		if ($token === self::EOS) {
118	147		if ($decodeFirst) {
119	65		$wstr = static::base64urlDecode($wstr);
120	65		}
121	147		break;
122			}
123
124			try {
125	438		$supported = $this->supportedInfo($token, true);
126	438		} catch (\Exception $ex) {
127	2		return $this->exception($throw, $ex->getMessage(), 403);
			0 ignored issues – show Bug Compatibility introduced 2015-11-24 19:27 UTC by Report Bug Copy Issue Report The expression `$this->exception($throw, $ex->getMessage(), 403);` of type `boolean\|null` adds the type `boolean` to the return on line 127 which is incompatible with the return type documented by `Garden\SecureString::decode` of type `string\|null`. Loading history...
128			}
129
130	437		if (!isset($spec[$token])) {
131	144		return $this->exception($throw, "You did not provide a password for $token.", 403);
			0 ignored issues – show Bug Compatibility introduced 2015-11-24 19:27 UTC by Report Bug Copy Issue Report The expression `$this->exception($throw,...d for {$token}.", 403);` of type `boolean\|null` adds the type `boolean` to the return on line 131 which is incompatible with the return type documented by `Garden\SecureString::decode` of type `string\|null`. Loading history...
132			}
133	293		$password = $spec[$token];
134	293		array_unshift($used, $token);
135
136	293		list(, $decode, $method, $decodeFirst) = $supported;
137
138		View Code Duplication	switch ($decode) {
139	293		case 'decrypt':
140	162		$wstr = $this->decrypt($wstr, $method, $password, $throw);
141	162		break;
142	180		case 'verifyHmac':
143	180		$wstr = $this->verifyHmac($wstr, $method, $password, $throw);
144	180		break;
145			default:
146			return $this->exception($throw, "Invalid method $decode.", 500);
			0 ignored issues – show Bug Compatibility introduced 2015-11-24 19:27 UTC by Report Bug Copy Issue Report The expression `$this->exception($throw,...thod {$decode}.", 500);` of type `boolean\|null` adds the type `boolean` to the return on line 146 which is incompatible with the return type documented by `Garden\SecureString::decode` of type `string\|null`. Loading history...
147			}
148
149	293		if ($wstr === null) {
150	146		return null;
151			}
152	147		}
153
154			// Make sure that the string was secured at all.
155	147		if ($strict && array_keys($spec) != $used) {
156	1		return $this->exception($throw, 'The string is not fully secure.', 403);
			0 ignored issues – show Bug Compatibility introduced 2015-11-24 19:27 UTC by Report Bug Copy Issue Report The expression `$this->exception($throw,...t fully secure.', 403);` of type `boolean\|null` adds the type `boolean` to the return on line 156 which is incompatible with the return type documented by `Garden\SecureString::decode` of type `string\|null`. Loading history...
157	147		} elseif (empty($used)) {
158	1		return $this->exception($throw, 'The string is not secure.', 403);
			0 ignored issues – show Bug Compatibility introduced 2015-11-24 19:27 UTC by Report Bug Copy Issue Report The expression `$this->exception($throw,... is not secure.', 403);` of type `boolean\|null` adds the type `boolean` to the return on line 158 which is incompatible with the return type documented by `Garden\SecureString::decode` of type `string\|null`. Loading history...
159			}
160
161	146		$data = json_decode($wstr, true);
162	146		if ($data === null) {
163			return $this->exception($throw, 'The final string is not valid json.', 403);
			0 ignored issues – show Bug Compatibility introduced 2015-11-24 19:27 UTC by Report Bug Copy Issue Report The expression `$this->exception($throw,...not valid json.', 403);` of type `boolean\|null` adds the type `boolean` to the return on line 163 which is incompatible with the return type documented by `Garden\SecureString::decode` of type `string\|null`. Loading history...
164			}
165
166	146		return $data;
167			}
168
169			/**
170			* Generate a random string suitable for use as an encryption or signature key.
171			*
172			* @param int $len The number of characters in the key.
173			* @return string Returns a base64url encoded string representing the random key.
174			*/
175	2		public static function generateRandomKey($len = 32) {
176	2		$bytes = ceil($len * 3 / 4);
177
178	2		return substr(self::base64urlEncode(openssl_random_pseudo_bytes($bytes)), 0, $len);
179			}
180
181			/**
182			* Base64 Encode a string, but make it suitable to be passed in a url.
183			*
184			* @param string $str The string to encode.
185			* @return string The encoded string.
186			*/
187	437		protected static function base64urlEncode($str) {
188	437		return trim(strtr(base64_encode($str), '+/', '-_'), '=');
189			}
190
191			/**
192			* Decode a string that was encoded using base64UrlEncode().
193			*
194			* @param string $str The encoded string.
195			* @return string The decoded string.
196			*/
197	293		protected static function base64urlDecode($str) {
198	293		return base64_decode(strtr($str, '-_', '+/'));
199			}
200
201			/**
202			* Encrypt a string with {@link openssl_encrypt()}.
203			*
204			* @param string $str The string to encrypt.
205			* @param string $method The encryption cipher.
206			* @param string $password The encryption password.
207			* @param string $iv The input vector.
208			* @param bool $throw Whether or not to throw an exception on error.
209			* @return string Returns the encrypted string.
210			*/
211	290	View Code Duplication	protected function encrypt($str, $method, $password, $iv = '', $throw = false) {
212	290		if ($iv === '') {
213	290		$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($method));
214	290		}
215			// Encrypt the string.
216	290		$encrypted = openssl_encrypt($str, $method, $password, OPENSSL_RAW_DATA, $iv);
217
218	290		if ($encrypted === false) {
219			return $this->exception($throw, "Error encrypting the string.", 400);
			0 ignored issues – show Bug Compatibility introduced 2015-11-24 19:27 UTC by Report Bug Copy Issue Report The expression `$this->exception($throw,...ing the string.', 400);` of type `boolean\|null` adds the type `boolean` to the return on line 219 which is incompatible with the return type documented by `Garden\SecureString::encrypt` of type `string`. Loading history...
220			}
221
222	290		$str = static::base64urlEncode($encrypted);
223	290		$this->pushString($str, static::base64urlEncode($iv));
224
225	290		return $str;
226			}
227
228			/**
229			* Decrypt a string with {@link openssl_decrypt()}.
230			*
231			* @param string $str The base64 url encoded encrypted string.
232			* @param string $method The encryption cipher.
233			* @param string $password The password to decyrpt the string.
234			* @param bool $throw Whether or not to decode the string on exception.
235			* @return string\|null Returns the decrypted string or null on error.
236			*/
237	162		protected function decrypt($str, $method, $password, $throw = false) {
238	162		$iv = static::base64urlDecode($this->popString($str));
239	162		$encrypted = static::base64urlDecode($this->popString($str));
240
241			try {
242	162		$decrypted = openssl_decrypt($encrypted, $method, $password, true, $iv);
243	162		} catch (\Exception $ex) {
244			return $this->exception($throw, "Error decrypting the string.", 403);
245			}
246
247	162		if ($decrypted === false) {
248	64		return $this->exception($throw, "Error decrypting the string.", 403);
249			}
250
251	98		return $decrypted;
252			}
253
254			/**
255			* Get information about a supported spec name.
256			*
257			* @param string $name The name of the spec.
258			* @param bool $throw Whether or not throw an exception on error.
259			* @return array\|null Returns an array in the form [encode, decode, method, encodeFirst].
260			* Returns null on error.
261			*/
262	439		protected function supportedInfo($name, $throw = false) {
263			switch ($name) {
264	439		case 'aes128':
265	439		case 'aes256':
266	291		$cipher = 'aes-'.substr($name, 3).'-cbc';
267	291		return ['encrypt', 'decrypt', $cipher, false];
268	295		case 'hsha1':
269	295		case 'hsha256':
270	292		$hash = substr($name, 1);
271	292		return ['hmac', 'verifyHmac', $hash, true];
272			}
273	3		return $this->exception($throw, "Spec $name not supported.", 400);
274			}
275
276			/**
277			* Sign a string with hmac and a hash method.
278			*
279			* @param string $str The string to sign.
280			* @param string $method The hash method used to sign the string.
281			* @param string $password The password used to hmac hash the string with.
282			* @param int $timestamp The timestamp used to sign the string with or 0 to use the current time.
283			* @param bool $throw Whether or not the throw an exception on error.
284			* @return string Returns the string with signing information or null on error.
285			*/
286	292	View Code Duplication	protected function hmac($str, $method, $password, $timestamp = 0, $throw = false) {
287	292		if ($timestamp === 0) {
288	292		$timestamp = time();
289	292		}
290			// Add the timestamp to the string.
291	292		static::pushString($str, $timestamp);
292
293			// Sign the string.
294	292		$signature = hash_hmac($method, $str, $password, true);
295	292		if ($signature === false) {
296			return $this->exception($throw, "Invalid hash method $method.", 400);
			0 ignored issues – show Bug Compatibility introduced 2015-11-24 19:27 UTC by Report Bug Copy Issue Report The expression `$this->exception($throw,...thod {$method}.", 400);` of type `boolean\|null` adds the type `boolean` to the return on line 296 which is incompatible with the return type documented by `Garden\SecureString::hmac` of type `string`. Loading history...
297			}
298
299			// Add the signature to the string.
300	292		static::pushString($str, static::base64urlEncode($signature));
301
302	292		return $str;
303			}
304
305			/**
306			* Verify the signature on a secure string.
307			*
308			* @param string $str The string to verify.
309			* @param string $method The hashing algorithm that the string was signed with.
310			* @param string $password The password used to sign the string.
311			* @param bool $throw Whether or not to throw an exeptio on error.
312			* @return bool Returns the string without the signing information or null on error.
313			*/
314	180		protected function verifyHmac($str, $method, $password, $throw = false) {
315			// Grab the signature from the string.
316	180		$signature = $this->popString($str);
317	180		if (!$signature) {
			0 ignored issues – show Bug Best Practice introduced 2015-11-24 19:27 UTC by Report Bug Copy Issue Report The expression `$signature` of type `string\|null` is loosely compared to `false`; this is ambiguous if the string can be empty. 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 `string` values, the empty string `''` is a special case, in particular the following results might be unexpected: '' == false // true '' == null // true 'ab' == false // false 'ab' == null // false // It is often better to use strict comparison '' === false // false '' === null // false Loading history...
318			return $this->exception($throw, "The signature is missing.", 403);
319			}
320	180		$signature = static::base64urlDecode($signature);
321
322			// Recalculate the signature to compare.
323	180		$calcSignature = hash_hmac($method, $str, $password, true);
324
325	180		if (strlen($signature) !== strlen($calcSignature)) {
326			return $this->exception($throw, "The signature is invalid.", 403);
327			}
328
329			// Do a double hmac comparison to prevent timing attacks.
330			// https://www.isecpartners.com/blog/2011/february/double-hmac-verification.aspx
331	180		$dblSignature = hash_hmac($method, $signature, $password, true);
332	180		$dblCalcSignature = hash_hmac($method, $calcSignature, $password, true);
333
334	180		if ($dblSignature !== $dblCalcSignature) {
335	81		return $this->exception($throw, "The signature is invalid.", 403);
336			}
337
338			// Grab the timestamp and verify it.
339	99		$timestamp = $this->popString($str);
340	99		if (!$this->verifyTimestamp($timestamp, $throw)) {
341	1		return null;
342			}
343
344	98		return $str;
345			}
346
347			/**
348			* Verify that a timestamp hasn't expired.
349			*
350			* @param string $timestamp The unix timestamp to verify.
351			* @param bool $throw Whether or not to throw an exception on error.
352			* @return bool Returns true if the timestamp is valid or false otherwise.
353			*/
354	99		protected function verifyTimestamp($timestamp, $throw = false) {
355	99		if (!is_numeric($timestamp)) {
356			return (bool)$this->exception($throw, "Invalid timestamp.", 403);
357			}
358	99		$intTimestamp = (int)$timestamp;
359	99		$now = time();
360	99		if ($intTimestamp + $this->timestampExpiry <= $now) {
361	1		return (bool)$this->exception($throw, "The timestamp has expired.", 403);
362			}
363
364	98		return true;
365			}
366
367			/**
368			* Pop a string off of the end of an encoded secure string.
369			*
370			* @param string &$str The main string to pop.
371			* @return string\|null Returns the popped string or null if {@link $str} is empty.
372			*/
373	439		protected function popString(&$str) {
374	439		if ($str === '') {
375			return null;
376			}
377
378	439		$pos = strrpos($str, '.');
379	439		if ($pos !== false) {
380	439		$result = substr($str, $pos + 1);
381	439		$str = substr($str, 0, $pos);
382	439		} else {
383	162		$result = $str;
384	162		$str = '';
385			}
386	439		return $result;
387			}
388
389			/**
390			* Pushes a string on to the end of an encoded secure string.
391			*
392			* @param string &$str The main string to push to.
393			* @param string\|array $item The string or array of strings to push on to the end of {@link $str}.
394			*/
395	437		protected function pushString(&$str, $item) {
396	437		if ($str) {
397	437		$str .= static::SEP;
398	437		}
399	437		$str .= implode(static::SEP, (array)$item);
400	437		}
401
402			/**
403			* Throw an exception or return false.
404			*
405			* @param bool $throw Whether or not to throw an exception.
406			* @param string $message The exception message.
407			* @param int $code The exception code.
408			* @return bool Returns false if {@link $throw} is false.
409			* @throws \Exception Throws an exception with {@link $message} and {@link $code}.
410			*/
411	295		protected function exception($throw, $message, $code) {
412	295		if ($throw) {
413	295		throw new \Exception($message, $code);
414			}
415	294		return null;
416			}
417
418			/**
419			* Twiddle a value in an encoded secure string to another value.
420			*
421			* This method is mainly for testing so that an invalid string can be created.
422			*
423			* @param string $string A valid cookie to twiddle.
424			* @param int $index The index of the new value.
425			* @param string $value The new value. This will be base64url encoded.
426			* @param bool $encode Whether or not to base64 url encode the value.
427			* @return string Returns the new encoded cookie.
428			*/
429	2		public function twiddle($string, $index, $value, $encode = false) {
430	2		$parts = explode(static::SEP, $string);
431
432	2		if ($encode) {
433			$value = static::base64urlEncode($value);
434			}
435	2		$parts[$index] = $value;
436
437	2		return implode(static::SEP, $parts);
438			}
439			}
440

vanilla / garden

SecureString::verifyHmac() B last analyzed 2017-08-29 15:20 UTC

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SecureString::verifyHmac() B
last analyzed 2017-08-29 15:20 UTC