dologin / src / secret.cls.php

secret.cls.php in DoLogin Security trunk, at src/secret.cls.php

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1	<?php
2	/**
3	* Salt-bound secret storage helpers.
4	*
5	* @since 4.7.4
6	* @package dologin
7	*/
8
9	namespace dologin;
10
11	defined( 'WPINC' ) \|\| exit;
12
13	class Secret {
14	const TOKEN_PREFIX = 'dologin:hmac:v1:';
15	const SODIUM_PREFIX = 'dologin:sealed:v1:s:';
16	const OPENSSL_PREFIX = 'dologin:sealed:v1:o:';
17
18	/**
19	* Create a non-reversible token verifier bound to the WordPress authentication salt.
20	*/
21	public static function token_hash( $purpose, $token ) {
22	if ( ! is_string( $purpose ) \|\| '' === $purpose \|\| ! is_string( $token ) \|\| '' === $token ) {
23	return false;
24	}
25	$key = hash_hmac( 'sha256', 'dologin-token-key-v1\|' . $purpose, wp_salt( 'auth' ), true );
26	return self::TOKEN_PREFIX . hash_hmac( 'sha256', $token, $key );
27	}
28
29	/**
30	* Verify a raw bearer token without storing the token itself.
31	*/
32	public static function verify_token( $purpose, $token, $stored ) {
33	if ( ! self::is_token_hash( $stored ) ) {
34	return false;
35	}
36	$expected = self::token_hash( $purpose, $token );
37	return is_string( $expected ) && hash_equals( $stored, $expected );
38	}
39
40	/**
41	* Whether a value is a versioned token verifier.
42	*/
43	public static function is_token_hash( $stored ) {
44	return is_string( $stored )
45	&& 1 === preg_match( '/^' . preg_quote( self::TOKEN_PREFIX, '/' ) . '[a-f0-9]{64}$/D', $stored );
46	}
47
48	/**
49	* Encrypt and authenticate a recoverable secret with a purpose-bound site key.
50	*/
51	public static function seal( $purpose, $plain ) {
52	if ( ! is_string( $purpose ) \|\| '' === $purpose \|\| ! is_string( $plain ) \|\| '' === $plain ) {
53	return false;
54	}
55
56	if ( function_exists( 'sodium_crypto_secretbox' )
57	&& defined( 'SODIUM_CRYPTO_SECRETBOX_NONCEBYTES' )
58	&& defined( 'SODIUM_CRYPTO_SECRETBOX_KEYBYTES' ) ) {
59	try {
60	$nonce = random_bytes( SODIUM_CRYPTO_SECRETBOX_NONCEBYTES );
61	$box = sodium_crypto_secretbox( $plain, $nonce, self::storage_key( $purpose, SODIUM_CRYPTO_SECRETBOX_KEYBYTES ) );
62	} catch ( \Exception $ex ) {
63	return false;
64	}
65	return self::SODIUM_PREFIX . base64_encode( $nonce . $box );
66	}
67
68	if ( function_exists( 'openssl_encrypt' ) && defined( 'OPENSSL_RAW_DATA' ) ) {
69	$cipher_name = 'aes-256-cbc';
70	$iv_length = openssl_cipher_iv_length( $cipher_name );
71	if ( ! is_int( $iv_length ) \|\| $iv_length <= 0 ) {
72	return false;
73	}
74	try {
75	$iv = random_bytes( $iv_length );
76	} catch ( \Exception $ex ) {
77	return false;
78	}
79	$keys = self::storage_key( $purpose, 64 );
80	$cipher = openssl_encrypt( $plain, $cipher_name, substr( $keys, 0, 32 ), OPENSSL_RAW_DATA, $iv );
81	if ( false === $cipher ) {
82	return false;
83	}
84	$tag = hash_hmac( 'sha256', self::OPENSSL_PREFIX . $purpose . '\|' . $iv . $cipher, substr( $keys, 32, 32 ), true );
85	return self::OPENSSL_PREFIX . base64_encode( $iv . $tag . $cipher );
86	}
87
88	return false;
89	}
90
91	/**
92	* Authenticate and decrypt a versioned secret.
93	*/
94	public static function open( $purpose, $stored ) {
95	if ( ! is_string( $purpose ) \|\| '' === $purpose \|\| ! is_string( $stored ) ) {
96	return false;
97	}
98
99	if ( 0 === strpos( $stored, self::SODIUM_PREFIX ) ) {
100	if ( ! function_exists( 'sodium_crypto_secretbox_open' )
101	\|\| ! defined( 'SODIUM_CRYPTO_SECRETBOX_NONCEBYTES' )
102	\|\| ! defined( 'SODIUM_CRYPTO_SECRETBOX_MACBYTES' )
103	\|\| ! defined( 'SODIUM_CRYPTO_SECRETBOX_KEYBYTES' ) ) {
104	return false;
105	}
106	$sealed = base64_decode( substr( $stored, strlen( self::SODIUM_PREFIX ) ), true );
107	if ( false === $sealed \|\| strlen( $sealed ) < SODIUM_CRYPTO_SECRETBOX_NONCEBYTES + SODIUM_CRYPTO_SECRETBOX_MACBYTES ) {
108	return false;
109	}
110	$nonce = substr( $sealed, 0, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES );
111	return sodium_crypto_secretbox_open( substr( $sealed, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES ), $nonce, self::storage_key( $purpose, SODIUM_CRYPTO_SECRETBOX_KEYBYTES ) );
112	}
113
114	if ( 0 === strpos( $stored, self::OPENSSL_PREFIX ) ) {
115	if ( ! function_exists( 'openssl_decrypt' ) \|\| ! defined( 'OPENSSL_RAW_DATA' ) ) {
116	return false;
117	}
118	$cipher_name = 'aes-256-cbc';
119	$iv_length = openssl_cipher_iv_length( $cipher_name );
120	$sealed = base64_decode( substr( $stored, strlen( self::OPENSSL_PREFIX ) ), true );
121	if ( ! is_int( $iv_length ) \|\| $iv_length <= 0 \|\| false === $sealed \|\| strlen( $sealed ) <= $iv_length + 32 ) {
122	return false;
123	}
124	$iv = substr( $sealed, 0, $iv_length );
125	$tag = substr( $sealed, $iv_length, 32 );
126	$cipher = substr( $sealed, $iv_length + 32 );
127	$keys = self::storage_key( $purpose, 64 );
128	$expected_tag = hash_hmac( 'sha256', self::OPENSSL_PREFIX . $purpose . '\|' . $iv . $cipher, substr( $keys, 32, 32 ), true );
129	if ( ! hash_equals( $expected_tag, $tag ) ) {
130	return false;
131	}
132	return openssl_decrypt( $cipher, $cipher_name, substr( $keys, 0, 32 ), OPENSSL_RAW_DATA, $iv );
133	}
134
135	return false;
136	}
137
138	/**
139	* Whether a value uses one of the supported encrypted formats.
140	*/
141	public static function is_sealed( $stored ) {
142	return is_string( $stored )
143	&& ( 0 === strpos( $stored, self::SODIUM_PREFIX ) \|\| 0 === strpos( $stored, self::OPENSSL_PREFIX ) );
144	}
145
146	/**
147	* Derive purpose-separated key material from the WordPress authentication salt.
148	*/
149	private static function storage_key( $purpose, $length ) {
150	$material = hash_hmac( 'sha512', 'dologin-storage-key-v1\|' . $purpose, wp_salt( 'auth' ), true );
151	return substr( $material, 0, $length );
152	}
153	}
154