summaryrefslogtreecommitdiff
blob: 66921f610ff0df50363d6ecc3a6e819c572ce162 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
<?php

// These constants can be set in wp-config.php to ensure sites behind proxies will still work.
// Setting these constants, though, is *not* the preferred method. It's better to configure
// the proxy to send the X-Forwarded-Port header.
defined( 'JETPACK_SIGNATURE__HTTP_PORT'  ) or define( 'JETPACK_SIGNATURE__HTTP_PORT' , 80  );
defined( 'JETPACK_SIGNATURE__HTTPS_PORT' ) or define( 'JETPACK_SIGNATURE__HTTPS_PORT', 443 );
defined( 'JETPACK__WPCOM_JSON_API_HOST' )  or define( 'JETPACK__WPCOM_JSON_API_HOST', 'public-api.wordpress.com' );

class Jetpack_Signature {
	public $token;
	public $secret;

	function __construct( $access_token, $time_diff = 0 ) {
		$secret = explode( '.', $access_token );
		if ( 2 != count( $secret ) )
			return;

		$this->token  = $secret[0];
		$this->secret = $secret[1];
		$this->time_diff = $time_diff;
	}

	function sign_current_request( $override = array() ) {
		if ( isset( $override['scheme'] ) ) {
			$scheme = $override['scheme'];
			if ( !in_array( $scheme, array( 'http', 'https' ) ) ) {
				return new Jetpack_Error( 'invalid_sheme', 'Invalid URL scheme' );
			}
		} else {
			if ( is_ssl() ) {
				$scheme = 'https';
			} else {
				$scheme = 'http';
			}
		}

		$host_port = isset( $_SERVER['HTTP_X_FORWARDED_PORT'] ) ? $_SERVER['HTTP_X_FORWARDED_PORT'] : $_SERVER['SERVER_PORT'];

		if ( is_ssl() ) {
			// 443: Standard Port
			// 80: Assume we're behind a proxy without X-Forwarded-Port. Hardcoding "80" here means most sites
			//     with SSL termination proxies (self-served, Cloudflare, etc.) don't need to fiddle with
			//     the JETPACK_SIGNATURE__HTTPS_PORT constant. The code also implies we can't talk to a
			//     site at https://example.com:80/ (which would be a strange configuration).
			// JETPACK_SIGNATURE__HTTPS_PORT: Set this constant in wp-config.php to the back end webserver's port
			//                                if the site is behind a proxy running on port 443 without
			//                                X-Forwarded-Port and the back end's port is *not* 80. It's better,
			//                                though, to configure the proxy to send X-Forwarded-Port.
			$port = in_array( $host_port, array( 443, 80, JETPACK_SIGNATURE__HTTPS_PORT ) ) ? '' : $host_port;
		} else {
			// 80: Standard Port
			// JETPACK_SIGNATURE__HTTPS_PORT: Set this constant in wp-config.php to the back end webserver's port
			//                                if the site is behind a proxy running on port 80 without
			//                                X-Forwarded-Port. It's better, though, to configure the proxy to
			//                                send X-Forwarded-Port.
			$port = in_array( $host_port, array( 80, JETPACK_SIGNATURE__HTTP_PORT ) ) ? '' : $host_port;
		}

		$url = "{$scheme}://{$_SERVER['HTTP_HOST']}:{$port}" . stripslashes( $_SERVER['REQUEST_URI'] );

		if ( array_key_exists( 'body', $override ) && !is_null( $override['body'] ) ) {
			$body = $override['body'];
		} else if ( 'POST' == strtoupper( $_SERVER['REQUEST_METHOD'] ) ) {
			$body = isset( $GLOBALS['HTTP_RAW_POST_DATA'] ) ? $GLOBALS['HTTP_RAW_POST_DATA'] : null;

			// Convert the $_POST to the body, if the body was empty. This is how arrays are hashed
			// and encoded on the Jetpack side.
			if ( defined( 'IS_WPCOM' ) && IS_WPCOM ) {
				if ( empty( $body ) && is_array( $_POST ) && count( $_POST ) > 0 ) {
					$body = $_POST;
				}
			}

		} else {
			$body = null;
		}

		$a = array();
		foreach ( array( 'token', 'timestamp', 'nonce', 'body-hash' ) as $parameter ) {
			if ( isset( $override[$parameter] ) ) {
				$a[$parameter] = $override[$parameter];
			} else {
				$a[$parameter] = isset( $_GET[$parameter] ) ? stripslashes( $_GET[$parameter] ) : '';
			}
		}

		$method = isset( $override['method'] ) ? $override['method'] : $_SERVER['REQUEST_METHOD'];
		return $this->sign_request( $a['token'], $a['timestamp'], $a['nonce'], $a['body-hash'], $method, $url, $body, true );
	}

	// body_hash v. body-hash is annoying.  Refactor to accept an array?
	function sign_request( $token = '', $timestamp = 0, $nonce = '', $body_hash = '', $method = '', $url = '', $body = null, $verify_body_hash = true ) {
		if ( !$this->secret ) {
			return new Jetpack_Error( 'invalid_secret', 'Invalid secret' );
		}

		if ( !$this->token ) {
			return new Jetpack_Error( 'invalid_token', 'Invalid token' );
		}

		list( $token ) = explode( '.', $token );

		if ( 0 !== strpos( $token, "$this->token:" ) ) {
			return new Jetpack_Error( 'token_mismatch', 'Incorrect token' );
		}

		// If we got an array at this point, let's encode it, so we can see what it looks like as a string.
		if ( is_array( $body ) ) {
			if ( count( $body ) > 0 ) {
				$body = json_encode( $body );

			} else {
				$body = '';
			}
		}

		$required_parameters = array( 'token', 'timestamp', 'nonce', 'method', 'url' );
		if ( !is_null( $body ) ) {
			$required_parameters[] = 'body_hash';
			if ( !is_string( $body ) ) {
				return new Jetpack_Error( 'invalid_body', 'Body is malformed.' );
			}
		}

		foreach ( $required_parameters as $required ) {
			if ( !is_scalar( $$required ) ) {
				return new Jetpack_Error( 'invalid_signature', sprintf( 'The required "%s" parameter is malformed.', str_replace( '_', '-', $required ) ) );
			}

			if ( !strlen( $$required ) ) {
				return new Jetpack_Error( 'invalid_signature', sprintf( 'The required "%s" parameter is missing.', str_replace( '_', '-', $required ) ) );
			}
		}

		if ( empty( $body ) ) {
			if ( $body_hash ) {
				return new Jetpack_Error( 'invalid_body_hash', 'The body hash does not match.' );
			}
		} else {
			if ( $verify_body_hash && jetpack_sha1_base64( $body ) !== $body_hash ) {
				return new Jetpack_Error( 'invalid_body_hash', 'The body hash does not match.' );
			}
		}

		$parsed = parse_url( $url );
		if ( !isset( $parsed['host'] ) ) {
			return new Jetpack_Error( 'invalid_signature', sprintf( 'The required "%s" parameter is malformed.', 'url' ) );
		}

		if ( $parsed['host'] === JETPACK__WPCOM_JSON_API_HOST ) {
			$parsed['host'] = 'public-api.wordpress.com';
		}

		if ( !empty( $parsed['port'] ) ) {
			$port = $parsed['port'];
		} else {
			if ( 'http' == $parsed['scheme'] ) {
				$port = 80;
			} else if ( 'https' == $parsed['scheme'] ) {
				$port = 443;
			} else {
				return new Jetpack_Error( 'unknown_scheme_port', "The scheme's port is unknown" );
			}
		}

		if ( !ctype_digit( "$timestamp" ) || 10 < strlen( $timestamp ) ) { // If Jetpack is around in 275 years, you can blame mdawaffe for the bug.
			return new Jetpack_Error( 'invalid_signature', sprintf( 'The required "%s" parameter is malformed.', 'timestamp' ) );
		}

		$local_time = $timestamp - $this->time_diff;
		if ( $local_time < time() - 600 || $local_time > time() + 300 ) {
			return new Jetpack_Error( 'invalid_signature', 'The timestamp is too old.' );
		}

		if ( 12 < strlen( $nonce ) || preg_match( '/[^a-zA-Z0-9]/', $nonce ) ) {
			return new Jetpack_Error( 'invalid_signature', sprintf( 'The required "%s" parameter is malformed.', 'nonce' ) );
		}

		$normalized_request_pieces = array(
			$token,
			$timestamp,
			$nonce,
			$body_hash,
			strtoupper( $method ),
			strtolower( $parsed['host'] ),
			$port,
			$parsed['path'],
			// Normalized Query String
		);

		$normalized_request_pieces = array_merge( $normalized_request_pieces, $this->normalized_query_parameters( isset( $parsed['query'] ) ? $parsed['query'] : '' ) );

		$normalized_request_string = join( "\n", $normalized_request_pieces ) . "\n";

		return base64_encode( hash_hmac( 'sha1', $normalized_request_string, $this->secret, true ) );
	}

	function normalized_query_parameters( $query_string ) {
		parse_str( $query_string, $array );
		if ( get_magic_quotes_gpc() )
			$array = stripslashes_deep( $array );

		unset( $array['signature'] );

		$names  = array_keys( $array );
		$values = array_values( $array );

		$names  = array_map( array( $this, 'encode_3986' ), $names  );
		$values = array_map( array( $this, 'encode_3986' ), $values );

		$pairs  = array_map( array( $this, 'join_with_equal_sign' ), $names, $values );

		sort( $pairs );

		return $pairs;
	}

	function encode_3986( $string ) {
		$string = rawurlencode( $string );
		return str_replace( '%7E', '~', $string ); // prior to PHP 5.3, rawurlencode was RFC 1738
	}

	function join_with_equal_sign( $name, $value ) {
		return "{$name}={$value}";
	}
}

function jetpack_sha1_base64( $text ) {
	return base64_encode( sha1( $text, true ) );
}