desktop-mode / includes / portal.php

portal.php in OpenStation: Desktop Windows, Dock & Virtual Desktops for WP Admin 1.1.1, at includes/portal.php

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1	<?php
2	/**
3	* OpenStation — `/openstation` Portal Entry Point.
4	*
5	* Registers `/openstation` as a shareable URL that behaves like the
6	* front door of the desktop UI:
7	* 1. Logged-out users are bounced through `wp-login.php` with a
8	* redirect back to `/openstation/`.
9	* 2. Logged-in users with basic admin-read capability have the
10	* `desktop_mode_mode` user-meta toggle auto-enabled on first visit,
11	* then are forwarded into `wp-admin` at whichever window was
12	* last focused in their saved session (or the dashboard as
13	* fallback).
14	*
15	* The URL is served virtually (no rewrite rules, no `.htaccess`
16	* surgery) by intercepting `parse_request` before WordPress routes the
17	* URL to 404. This keeps the plugin drop-in.
18	*
19	* @package OpenStation
20	*/
21
22	defined( 'ABSPATH' ) \|\| exit;
23
24	/** The URL path that triggers the portal handler. */
25	const OPENSTATION_PORTAL_PATH = 'openstation';
26
27	/**
28	* The pre-rebrand portal path, still accepted.
29	*
30	* The portal was reachable at `/desktop-mode/` before the rename, and
31	* that address is the kind of thing people bookmark or pin. It is not
32	* canonical: {@see openstation_portal_url()} always emits the current
33	* path, and a visit here forwards into wp-admin exactly as the canonical
34	* path does, so the address bar self-corrects on the next hop.
35	*
36	* The VALUE keeps its pre-rebrand spelling on purpose: it is a
37	* persisted or externally-visible identifier, so renaming it would
38	* orphan data already written by live installs (or break a live
39	* URL). The mismatch between this constant's name and its value is
40	* deliberate — it is NOT a half-finished rename.
41	*/
42	const OPENSTATION_PORTAL_PATH_LEGACY = 'desktop-mode';
43
44	/**
45	* Query var the admin shell reads to know it was entered via the portal.
46	*
47	* The VALUE keeps its pre-rebrand spelling on purpose: it is a
48	* persisted or externally-visible identifier, so renaming it would
49	* orphan data already written by live installs (or break a live
50	* URL). The mismatch between this constant's name and its value is
51	* deliberate — it is NOT a half-finished rename.
52	*/
53	const OPENSTATION_PORTAL_FLAG = 'desktop_mode_portal';
54
55	/**
56	* Query var set on portal redirects whose landing page came from an
57	* explicit `?target=…` URL the user (or a redirect chain originating
58	* from a click) provided — as opposed to the portal picking the
59	* session's focused window or the default-window fallback.
60	*
61	* The shell uses this to distinguish "user expressed navigation intent
62	* toward this URL" (open it) from "portal had to forward somewhere"
63	* (don't disturb the restored session).
64	*
65	* The VALUE keeps its pre-rebrand spelling on purpose: it is a
66	* persisted or externally-visible identifier, so renaming it would
67	* orphan data already written by live installs (or break a live
68	* URL). The mismatch between this constant's name and its value is
69	* deliberate — it is NOT a half-finished rename.
70	*/
71	const OPENSTATION_PORTAL_INTENT_FLAG = 'desktop_mode_portal_intent';
72
73	/**
74	* Query var set by the window-title-bar "Detach" action. Tells the
75	* admin_init redirect to skip portal forwarding for this request so the
76	* user can view the page as classic wp-admin in a new tab even when
77	* OpenStation is globally enabled for their account.
78	*
79	* The VALUE keeps its pre-rebrand spelling on purpose: it is a
80	* persisted or externally-visible identifier, so renaming it would
81	* orphan data already written by live installs (or break a live
82	* URL). The mismatch between this constant's name and its value is
83	* deliberate — it is NOT a half-finished rename.
84	*/
85	const OPENSTATION_CLASSIC_FLAG = 'desktop_mode_classic';
86
87	/**
88	* Returns the canonical portal URL, e.g. `https://example.com/openstation/`.
89	*
90	* @return string
91	*/
92	function openstation_portal_url() {
93	return home_url( '/' . OPENSTATION_PORTAL_PATH . '/' );
94	}
95
96	/**
97	* Intercepts requests to `/openstation` and forwards them into the admin.
98	*
99	* Hooks on `parse_request` — early enough to pre-empt 404 handling but
100	* late enough that `is_user_logged_in()` is reliable.
101	*
102	* @param WP $wp Current WordPress environment instance.
103	*/
104	function openstation_handle_portal_request( $wp ) {
105	unset( $wp );
106
107	if ( ! openstation_is_portal_request() ) {
108	return;
109	}
110
111	// Logged-out: bounce through login, returning to the portal URL.
112	if ( ! is_user_logged_in() ) {
113	wp_safe_redirect( wp_login_url( openstation_portal_url() ) );
114	exit;
115	}
116
117	// Require basic admin-read capability so subscribers of sites that
118	// blocked `read` from admin don't land in a broken window.
119	if ( ! current_user_can( 'read' ) ) {
120	wp_die(
121	esc_html__( 'Sorry, you are not allowed to access the WordPress desktop.', 'desktop-mode' ),
122	'',
123	array( 'response' => 403 )
124	);
125	}
126
127	$user_id = get_current_user_id();
128
129	/**
130	* Filters whether visiting the `/openstation` portal should auto-enable
131	* OpenStation for the current user.
132	*
133	* Default: true — the portal is an explicit opt-in action, so flipping
134	* the user meta mirrors the intent of visiting the URL.
135	*
136	* @param bool $auto_enable Whether to auto-enable OpenStation.
137	* @param int $user_id The current user's ID.
138	*/
139	$auto_enable = apply_filters( 'openstation_portal_auto_enable', true, $user_id );
140
141	// CSRF guard: only flip user-meta when the request is a same-origin
142	// top-level navigation. The portal is a GET URL by design (users
143	// follow shared `/openstation/` links), so we can't require a nonce
144	// — but we can require that the navigation originated from the
145	// same site (or a typed/bookmarked URL with no Referer/Sec-Fetch-
146	// Site). Off-origin hits still redirect into admin so shared
147	// links keep working; they just don't silently mutate user-meta.
148	if ( $auto_enable && openstation_portal_is_same_origin_navigation() && '1' !== get_user_meta( $user_id, 'desktop_mode_mode', true ) ) {
149	update_user_meta( $user_id, 'desktop_mode_mode', '1' );
150	}
151
152	// Pick the landing page. Priority:
153	// 1. Explicit `target` query arg, if same-origin wp-admin URL.
154	// This is how `openstation_redirect_plain_admin_to_portal` preserves
155	// the user's navigation intent when they follow a link to a
156	// specific admin page (e.g. profile.php).
157	// 2. Last-focused window from the saved session.
158	// 3. Dashboard fallback.
159	$target = '';
160	$has_intent = false;
161	if ( ! empty( $_GET['target'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
162	// `esc_url_raw`, NOT `sanitize_text_field`: the latter strips
163	// every `%XX` percent-encoded sequence from its input as an XSS
164	// safeguard, which mangles request URIs that legitimately carry
165	// encoded slashes (e.g. `plugin=dir%2Ffile.php`). The downstream
166	// `openstation_sanitize_portal_target` validates the URL
167	// rigorously (scheme rejection, traversal rejection, and a
168	// hardcoded allowlist of canonical wp-admin filenames — see
169	// `openstation_admin_target_allowlist()`) so we don't lose
170	// any real safety by skipping `sanitize_text_field` here.
171	$target = openstation_sanitize_portal_target( esc_url_raw( wp_unslash( $_GET['target'] ) ) ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended
172	if ( '' !== $target ) {
173	$has_intent = true;
174	}
175	}
176	if ( '' === $target ) {
177	$target = openstation_portal_entry_url( $user_id );
178	}
179
180	// Flag the forward so the shell can stamp the address bar back to
181	// /openstation/ via history.replaceState once it has loaded.
182	$target = add_query_arg( OPENSTATION_PORTAL_FLAG, '1', $target );
183
184	// Second flag: the redirect resolved from an explicit `target`, so
185	// the shell should treat the resulting `currentPage` as user
186	// intent and auto-open it on top of the restored session. Without
187	// this, a bare `/openstation/` visit and a portal-redirected
188	// admin-bar click would be indistinguishable downstream.
189	if ( $has_intent ) {
190	$target = add_query_arg( OPENSTATION_PORTAL_INTENT_FLAG, '1', $target );
191	}
192
193	wp_safe_redirect( $target );
194	exit;
195	}
196	add_action( 'parse_request', 'openstation_handle_portal_request' );
197
198	/**
199	* Decides whether the current request to the portal can mutate
200	* user-meta safely (same-origin) or should only redirect (cross-
201	* origin, possibly CSRF).
202	*
203	* Logic mirrors the `Sec-Fetch-Site` heuristic browsers use:
204	*
205	* - `Sec-Fetch-Site: same-origin \| same-site \| none` → trusted
206	* (the request originated from this site, or from a typed URL
207	* / bookmark with no referrer info).
208	* - `Sec-Fetch-Site: cross-site` → untrusted (a third-party page
209	* pointed the user at the portal — could be an `<img>` tag).
210	* - Header missing (older browsers): fall back to `Referer` —
211	* same host or empty referrer is trusted, anything else isn't.
212	*
213	* @return bool
214	*/
215	function openstation_portal_is_same_origin_navigation() {
216	if ( ! empty( $_SERVER['HTTP_SEC_FETCH_SITE'] ) ) {
217	$site = strtolower( sanitize_text_field( wp_unslash( $_SERVER['HTTP_SEC_FETCH_SITE'] ) ) );
218	return in_array( $site, array( 'same-origin', 'same-site', 'none' ), true );
219	}
220
221	if ( empty( $_SERVER['HTTP_REFERER'] ) ) {
222	return true;
223	}
224
225	$referer_host = wp_parse_url( esc_url_raw( wp_unslash( $_SERVER['HTTP_REFERER'] ) ), PHP_URL_HOST );
226	$home_host = wp_parse_url( home_url(), PHP_URL_HOST );
227
228	if ( ! is_string( $referer_host ) \|\| '' === $referer_host ) {
229	return true;
230	}
231
232	return is_string( $home_host ) && strtolower( $referer_host ) === strtolower( $home_host );
233	}
234
235	/**
236	* Detects whether the current request is for the portal URL.
237	*
238	* Strips any query string and trailing slash and compares against
239	* `/openstation` relative to the site's home path. The pre-rebrand
240	* `/desktop-mode` path is accepted too, so bookmarks made before the
241	* rename still land in the shell.
242	*
243	* @return bool
244	*/
245	function openstation_is_portal_request() {
246	if ( empty( $_SERVER['REQUEST_URI'] ) ) {
247	return false;
248	}
249
250	// `esc_url_raw` instead of `sanitize_text_field` so percent-encoded
251	// chars in the URI (notably `%2F` from query-arg slashes) survive
252	// long enough for `wp_parse_url` to split path / query correctly.
253	$uri = esc_url_raw( wp_unslash( $_SERVER['REQUEST_URI'] ) );
254	$path = wp_parse_url( $uri, PHP_URL_PATH );
255	if ( ! is_string( $path ) ) {
256	return false;
257	}
258
259	$home_path = wp_parse_url( home_url( '/' ), PHP_URL_PATH );
260	$home_path = is_string( $home_path ) ? rtrim( $home_path, '/' ) : '';
261
262	$path = '/' . ltrim( rtrim( $path, '/' ), '/' );
263
264	return in_array(
265	$path,
266	array(
267	$home_path . '/' . OPENSTATION_PORTAL_PATH,
268	$home_path . '/' . OPENSTATION_PORTAL_PATH_LEGACY,
269	),
270	true
271	);
272	}
273
274	/**
275	* Forwards plain `/wp-admin/...` requests to the `/openstation/` portal
276	* when the current user has OpenStation enabled.
277	*
278	* Why: when OpenStation is on, `/openstation/` is meant to be the one
279	* canonical address. A user who bookmarks `/wp-admin/plugins.php` or
280	* follows an old admin link should still land in the shell, not in
281	* vanilla admin with the shell glued over the top. Running through the
282	* portal unifies the address bar and honors the saved session's focused
283	* window.
284	*
285	* Narrowly scoped to bail on every automated or sub-request entry point
286	* — AJAX, REST, cron, admin-post.php, non-GET methods — so the hook
287	* can't corrupt a form submission or break an API call.
288	*
289	* Disable via the `openstation_admin_redirect_to_portal` filter (return
290	* false). Passthrough kicks in automatically when the current request
291	* is chromeless or already carries the portal flag.
292	*/
293	function openstation_redirect_plain_admin_to_portal() {
294	if ( ! openstation_is_enabled() ) {
295	return;
296	}
297	if ( openstation_is_chromeless_request() ) {
298	return;
299	}
300	if ( wp_doing_ajax() \|\| wp_doing_cron() ) {
301	return;
302	}
303	if ( defined( 'REST_REQUEST' ) && REST_REQUEST ) {
304	return;
305	}
306	if ( ! empty( $_SERVER['REQUEST_METHOD'] ) && 'GET' !== strtoupper( sanitize_text_field( wp_unslash( $_SERVER['REQUEST_METHOD'] ) ) ) ) {
307	return;
308	}
309
310	// The portal handler adds this flag after it forwards into admin.
311	// Bailing here keeps us out of an infinite redirect loop.
312	if ( ! empty( $_GET[ OPENSTATION_PORTAL_FLAG ] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
313	return;
314	}
315
316	// The "Detach to new tab" button tags its URL with this flag so the
317	// user can view one admin page classically without disabling desktop
318	// mode account-wide. Only affects the single request — subsequent
319	// navigations inside the tab lose the flag and follow normal rules.
320	if ( ! empty( $_GET[ OPENSTATION_CLASSIC_FLAG ] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
321	return;
322	}
323
324	// admin-post.php and admin-ajax.php handle form submissions and JSON
325	// endpoints; redirecting them would break the call.
326	global $pagenow;
327	if ( in_array( $pagenow, array( 'admin-post.php', 'admin-ajax.php' ), true ) ) {
328	return;
329	}
330
331	/**
332	* Filters whether plain admin URLs should redirect to the portal
333	* when OpenStation is active.
334	*
335	* @param bool $redirect Whether to redirect. Default true.
336	* @param int $user_id The current user's ID.
337	*/
338	$redirect = apply_filters( 'openstation_admin_redirect_to_portal', true, get_current_user_id() );
339	if ( ! $redirect ) {
340	return;
341	}
342
343	// Preserve the original target on the portal redirect. Without this,
344	// navigating to a specific admin page (profile.php, plugins.php, any
345	// deep link) loses the user's intent — the portal would forward them
346	// to whichever window was last focused instead of the page they asked
347	// for. The portal handler reads `target`, validates it's same-origin
348	// wp-admin, and uses it as the entry URL.
349	$portal_url = openstation_portal_url();
350	// `esc_url_raw` instead of `sanitize_text_field`: the latter strips
351	// every `%XX` percent-encoded sequence, which corrupts URIs whose
352	// query string legitimately carries an encoded slash — e.g. WP's
353	// own `plugins.php?action=activate&plugin=dir%2Ffile.php` activate
354	// link. The portal handler will validate this target downstream.
355	$target = isset( $_SERVER['REQUEST_URI'] ) ? esc_url_raw( wp_unslash( $_SERVER['REQUEST_URI'] ) ) : '';
356	if ( is_string( $target ) && '' !== $target ) {
357	$portal_url = add_query_arg( 'target', rawurlencode( $target ), $portal_url );
358	}
359
360	wp_safe_redirect( $portal_url );
361	exit;
362	}
363	add_action( 'admin_init', 'openstation_redirect_plain_admin_to_portal' );
364
365	/**
366	* Resolves the admin URL the portal should forward to for a given user.
367	*
368	* Looks up the user's session and returns the URL of the window flagged
369	* as `focused`. If the session is empty, has no focused window, or the
370	* focused window's URL isn't same-origin admin, falls back to the
371	* dashboard.
372	*
373	* The portal navigates the TOP window, not an iframe, so any chromeless
374	* `openstation_chromeless=1` flag baked into the stored URL is stripped — a leftover
375	* flag would land the user in a standalone chromeless page (no admin
376	* bar, no toggle, no way out) instead of the shell.
377	*
378	* @param int $user_id The user whose session to consult.
379	* @return string The admin URL to redirect to.
380	*/
381	function openstation_portal_entry_url( $user_id ) {
382	$session = openstation_get_session( $user_id );
383
384	// User's configured default-window preference. When disabled, we
385	// still have to forward SOMEWHERE (the portal is an HTTP redirect),
386	// so we land on the Dashboard URL — but the shell detects the
387	// `enabled=false` state via the config and skips the auto-open,
388	// leaving the user with an empty desktop as they chose.
389	$default_window = openstation_get_default_window( $user_id );
390	$fallback = $default_window['url'];
391
392	// Native marker (e.g. "native:os-settings") is not a
393	// redirectable URL. The portal MUST forward somewhere — the
394	// redirect happens at HTTP level — so we land on the admin home
395	// and let the shell pick up `defaultWindow.url` from the config
396	// after init and call nativeWindows.openById( <slug> ).
397	if ( is_string( $fallback ) && 0 === strpos( $fallback, 'native:' ) ) {
398	$fallback = admin_url();
399	}
400
401	if ( empty( $session['focused'] ) \|\| empty( $session['windows'] ) ) {
402	return $fallback;
403	}
404
405	foreach ( $session['windows'] as $win ) {
406	if ( ! isset( $win['id'], $win['url'] ) ) {
407	continue;
408	}
409	if ( $win['id'] !== $session['focused'] ) {
410	continue;
411	}
412	if ( ! openstation_url_is_same_admin( $win['url'] ) ) {
413	return $fallback;
414	}
415	return remove_query_arg( array( 'openstation_chromeless', OPENSTATION_PORTAL_FLAG ), $win['url'] );
416	}
417
418	return $fallback;
419	}
420
421	/**
422	* Validates and normalizes a `target` query arg on the portal URL.
423	*
424	* Accepts a raw request-URI-shaped string (path + optional query, e.g.
425	* `/wp-admin/profile.php?foo=bar`) and returns a fully-qualified admin
426	* URL if — and only if — it resolves to a same-origin `wp-admin/` path.
427	* Everything else returns an empty string so the caller falls back to
428	* the saved-session entry URL.
429	*
430	* Strips `openstation_chromeless` and the portal flag from the query so the target
431	* doesn't chain us into a chromeless standalone load or an infinite
432	* redirect loop.
433	*
434	* @param string $raw Raw value from `$_GET['target']` (already unslashed).
435	* @return string A safe absolute admin URL, or '' if the input is invalid.
436	*/
437	function openstation_sanitize_portal_target( $raw ) {
438	if ( ! is_string( $raw ) \|\| '' === $raw ) {
439	return '';
440	}
441
442	// Reject URIs with a scheme or protocol-relative prefix — we only
443	// accept relative paths so there's no way to redirect off-site.
444	if ( preg_match( '#^([a-z][a-z0-9+.-]*:\|//)#i', $raw ) ) {
445	return '';
446	}
447
448	// Must be an absolute path starting with /.
449	if ( '/' !== $raw[0] ) {
450	return '';
451	}
452
453	$path = wp_parse_url( $raw, PHP_URL_PATH );
454	$query = wp_parse_url( $raw, PHP_URL_QUERY );
455	if ( ! is_string( $path ) \|\| '' === $path ) {
456	return '';
457	}
458
459	$admin_path = wp_parse_url( admin_url(), PHP_URL_PATH );
460	$admin_path = is_string( $admin_path ) ? $admin_path : '/wp-admin/';
461	if ( 0 !== strpos( $path, $admin_path ) ) {
462	return '';
463	}
464
465	$file = substr( $path, strlen( $admin_path ) );
466	$file = ltrim( (string) $file, '/' );
467	if ( '' === $file ) {
468	$file = 'index.php';
469	}
470
471	// Resolve against the hardcoded allowlist of canonical wp-admin
472	// filenames (see `openstation_admin_target_allowlist()`). A
473	// regex alone would accept a plausible-looking filename that
474	// isn't a real core admin page (e.g. `custom_admin_page.php`)
475	// and effectively become an open redirect to a 404 page served
476	// under the admin path; the explicit allowlist closes that.
477	$target = openstation_resolve_admin_target( $file );
478	if ( is_wp_error( $target ) ) {
479	return '';
480	}
481
482	if ( is_string( $query ) && '' !== $query ) {
483	parse_str( $query, $args );
484	unset( $args['openstation_chromeless'], $args[ OPENSTATION_PORTAL_FLAG ], $args[ OPENSTATION_PORTAL_INTENT_FLAG ], $args['target'] );
485	if ( ! empty( $args ) ) {
486	$target = add_query_arg( $args, $target );
487	}
488	}
489
490	return $target;
491	}
492