fix(engine): link watch and Link Info read within the asking caller's roots

crates/engine/src/cmd/links.rs

@@ -1338,8 +1338,10 @@ fn placement_json(o: PlacementOptions) -> Value {
 
 /// Link Info's fields of the linked file `l` (of object `id` of `st`) into `out`.
 fn file_fields(st: &crate::DocState, id: NodeId, l: &LinkInfo, out: &mut Value) {
-    // Within what the caller that opened the document may read, whoever asks.
-    crate::file_access::confine(st.opened_by.as_ref(), || file_fields_here(st, id, l, out));
+    // A confined caller reads within its own roots; anyone else within what the caller that
+    // opened the document may read (never wider than the caller asking now).
+    let roots = crate::file_access::current().or_else(|| st.opened_by.clone());
+    crate::file_access::confine(roots.as_ref(), || file_fields_here(st, id, l, out));
 }
 
 fn file_fields_here(st: &crate::DocState, id: NodeId, l: &LinkInfo, out: &mut Value) {

crates/engine/src/link_watch.rs

@@ -69,6 +69,9 @@ impl Session {
         }
         let Some(st) = self.active() else { return };
         let (uid, files, doc_path) = (st.uid, crate::cmd::links::linked_groups(&st.doc), st.path.clone());
+        // A confined caller's roots, else what the caller that opened the document may read (the
+        // desktop frame is unconfined).
+        let opened_by = st.opened_by.clone();
         if files.is_empty() {
             return;
         }
@@ -76,7 +79,11 @@ impl Session {
         let out = slot.clone();
         let scope = crate::file_access::ScopeHandle::capture();
         let spawned = std::thread::Builder::new().name("link-watch".into()).spawn(move || {
-            let stamps = scope.run(|| files.into_iter().map(|(p, ids)| (p.clone(), ids, stamp(&p, doc_path.as_deref()))).collect());
+            let stamps = scope.run(|| {
+                crate::file_access::confine(crate::file_access::current().or(opened_by).as_ref(), || {
+                    files.into_iter().map(|(p, ids)| (p.clone(), ids, stamp(&p, doc_path.as_deref()))).collect()
+                })
+            });
             *out.lock().unwrap_or_else(PoisonError::into_inner) = Some((uid, stamps));
         });
         if spawned.is_ok() {
@@ -141,7 +148,8 @@ impl Session {
         let mode = if update { "automatically" } else { self.prefs.update_links.as_str() };
         match mode {
             "automatically" => {
-                let r = self.execute("links.update", &json!({"ids": ids}))?;
+                let roots = crate::file_access::current().or_else(|| self.active().and_then(|d| d.opened_by.clone()));
+                let r = crate::file_access::confine(roots.as_ref(), || self.execute("links.update", &json!({"ids": ids})))?;
                 // Not readable yet (still being written): the next look tries again.
                 let unread: BTreeSet<u64> = r["missing"].as_array().map(|a| a.iter().filter_map(Value::as_u64).collect()).unwrap_or_default();
                 for (path, ids) in &changed {

crates/engine/src/tests/linkspanel.rs

@@ -278,6 +278,24 @@ fn link_info_has_the_file_and_placement_details() {
     assert_eq!((i["status"].as_str(), i["linked"].as_bool(), i["fileName"].as_str()), (Some("embedded"), Some(false), None));
 }
 
+/// Link Info reads within the opener's roots for an unconfined caller, and never past a confined
+/// caller's own roots.
+#[test]
+fn link_info_stays_within_the_asking_callers_roots() {
+    let dir = Folder::new("info-roots");
+    let other = Folder::new("info-other");
+    let pic = dir.file("photo.png");
+    write(&pic, &png(60, 30, RED));
+    let mut s = session();
+    let id = place(&mut s, &pic);
+    let roots = |p: &std::path::Path| crate::file_access::AutomationRoots::new(&[p], &[]).unwrap().unwrap();
+    s.active_mut().unwrap().opened_by = Some(roots(&dir.0));
+    assert_eq!(run(&mut s, "links.info", json!({"id": id.0}))["status"], "ok");
+    let narrow = roots(&other.0);
+    let i = crate::file_access::confine(Some(&narrow), || run(&mut s, "links.info", json!({"id": id.0})));
+    assert_ne!(i["status"], "ok", "{i}");
+}
+
 /// A 600×300 pt image at the centre of the artboard, its placement options set to `options`,
 /// relinked to a 300×100 px file → the image's id and session.
 fn relinked(name: &str, options: Value) -> (Session, NodeId, Folder) {