← All changes | inc/submit-token.php +39 -11 2.11.1 → 2.12.8 View file →

		@@ -54,8 +54,31 @@
54	54	*/
55	55	public const DEFAULT_ACCEPTED_WINDOWS = 4;
56	56
57	57	/**
	58	+ * Namespace for tokens that authorise a form submission.
	59	+ *
	60	+ * The value is the historical payload prefix, so existing tokens keep verifying
	61	+ * across an upgrade — changing it would reject every token already embedded in
	62	+ * cached HTML.
	63	+ *
	64	+ * @since 2.12.6
	65	+ */
	66	+ public const NAMESPACE_SUBMIT = 'srfm_submit';
	67	+
	68	+ /**
	69	+ * Namespace for tokens that authorise the page-view beacon.
	70	+ *
	71	+ * Separate from NAMESPACE_SUBMIT so the two cannot stand in for each other: a
	72	+ * view token scraped from the page must not authorise a submission, and the
	73	+ * view endpoint must not double as an oracle for whether a submit token is
	74	+ * still inside an accepted window.
	75	+ *
	76	+ * @since 2.12.6
	77	+ */
	78	+ public const NAMESPACE_VIEW = 'srfm_view';
	79	+
	80	+ /**
58	81	* Generate a submission token for a given form.
59	82	*
60	83	* The token encodes the form ID and the current half-day window, signed
61	84	* with the site's auth salt. It is safe to embed in cached HTML because
		@@ -61,13 +84,15 @@
61	84	* with the site's auth salt. It is safe to embed in cached HTML because
62	85	* `verify()` accepts several consecutive past windows.
63	86	*
64	87	* @since 2.6.0
65		- * @param int $form_id The form post ID.
	88	+ * @since 2.12.6 Added the $namespace parameter.
	89	+ * @param int $form_id The form post ID.
	90	+ * @param string $namespace Purpose the token is minted for. Defaults to form submission.
66	91	* @return string 64-character lowercase hex HMAC-SHA256 token.
67	92	*/
68		- public static function generate( int $form_id ): string {
69		- return self::sign( $form_id, self::current_window() );
	93	+ public static function generate( int $form_id, string $namespace = self::NAMESPACE_SUBMIT ): string {
	94	+ return self::sign( $form_id, self::current_window(), $namespace );
70	95	}
71	96
72	97	/**
73	98	* Verify a token submitted with a form.
		@@ -75,13 +100,15 @@
75	100	* Checks the token against every accepted window, from newest to oldest,
76	101	* using constant-time comparison throughout.
77	102	*
78	103	* @since 2.6.0
79		- * @param string $token Token value received from the client.
80		- * @param int $form_id Form post ID extracted from the request body.
	104	+ * @since 2.12.6 Added the $namespace parameter.
	105	+ * @param string $token Token value received from the client.
	106	+ * @param int $form_id Form post ID extracted from the request body.
	107	+ * @param string $namespace Purpose the token must have been minted for.
81	108	* @return bool True if the token is valid for the given form, false otherwise.
82	109	*/
83		- public static function verify( string $token, int $form_id ): bool {
	110	+ public static function verify( string $token, int $form_id, string $namespace = self::NAMESPACE_SUBMIT ): bool {
84	111	if ( '' === $token || $form_id <= 0 ) {
85	112	return false;
86	113	}
87	114
		@@ -90,9 +117,9 @@
90	117	$accepted = max( 1, min( 14, (int) apply_filters( 'srfm_submit_token_accepted_windows', self::DEFAULT_ACCEPTED_WINDOWS ) ) );
91	118
92	119	// Walk backwards through accepted windows; current window first.
93	120	for ( $offset = 0; $offset < $accepted; $offset++ ) {
94		- if ( hash_equals( self::sign( $form_id, self::current_window() - $offset ), $token ) ) {
	121	+ if ( hash_equals( self::sign( $form_id, self::current_window() - $offset, $namespace ), $token ) ) {
95	122	return true;
96	123	}
97	124	}
98	125
		@@ -119,18 +146,19 @@
119	146	* the window index so that tokens cannot be repurposed across forms or
120	147	* replayed across time windows.
121	148	*
122	149	* @since 2.6.0
123		- * @param int $form_id Post ID of the form.
124		- * @param int $window Half-day window index.
	150	+ * @param int $form_id Post ID of the form.
	151	+ * @param int $window Half-day window index.
	152	+ * @param string $namespace Purpose prefix; keeps tokens for one action from authorising another.
125	153	* @return string 64-character lowercase hex digest.
126	154	*/
127		- private static function sign( int $form_id, int $window ): string {
	155	+ private static function sign( int $form_id, int $window, string $namespace = self::NAMESPACE_SUBMIT ): string {
128	156	// Derive a plugin-specific sub-key from the site's auth salt so this
129	157	// system has an independent key surface from WordPress session cookies.
130	158	// Rotating wp-config.php secrets invalidates all outstanding tokens, which
131	159	// is intentional — a cache purge should follow any secret key rotation.
132	160	$signing_key = hash_hmac( 'sha256', 'srfm-submit-token-v1', wp_salt( 'auth' ) );
133		- $payload = implode( '|', [ 'srfm_submit', $form_id, $window ] );
	161	+ $payload = implode( '|', [ $namespace, $form_id, $window ] );
134	162	return hash_hmac( 'sha256', $payload, $signing_key );
135	163	}
136	164	}