Engine: document trust for workbooks opened from files

Active content such as macros must not run only because a workbook was
opened. DocState gets a trust state: Local for workbooks made in the
session (new workbooks and samples) and FromFile for anything opened
with file.open. Active content in a FromFile workbook asks before it
runs. A second window on a workbook shares its trust.

The clipboard carries the trust of its source document. Pasting
formulas, formats (conditional formats hold formulas) or validation
from a FromFile workbook into another workbook makes that workbook
FromFile too; pasting values, column widths or notes carries nothing
active and changes nothing. Sheet moves and copies stay inside one
workbook, so its trust is unchanged. document.inspect reports the trust.

crates/engine/src/cmd/edit.rs

@@ -676,7 +676,7 @@ fn copy_impl(s: &mut Session, p: &Json, cut: bool) -> Result<Json> {
     // The HTML rendering is for the host clipboard (UI); it can reach 4 MB, so agents and
     // scripts get it only when they ask for it.
     let html = if p.get("html").and_then(Json::as_bool) == Some(true) { crate::io::range_html(&wb, sheet, range, &text) } else { None };
-    let clip = Clipboard { wb, sheet, range, cut, doc_uid: d.uid, text: text.clone(), areas, selected };
+    let clip = Clipboard { wb, sheet, range, cut, doc_uid: d.uid, text: text.clone(), areas, selected, trust: d.trust };
     s.clipboard = Some(clip);
     let mut result = json!({"range": range.a1(), "text": text});
     if let Some(html) = html {
@@ -1183,6 +1183,12 @@ fn paste_special(s: &mut Session, p: &Json) -> Result<Json> {
         *cx.sel = crate::Selection { active: at, anchor: at, ranges: vec![RangeRef::new(at, end)] };
         Ok(())
     })?;
+    // Formulas, formats (conditional formats hold formulas) and validation from an untrusted file
+    // leave the destination untrusted; plain values, column widths and notes carry nothing active.
+    if !same_doc && !matches!(what, What::Values | What::ValuesAndNumberFormats | What::ColumnWidths | What::Comments) {
+        let d = s.doc_mut()?;
+        d.trust = d.trust.receive(clip.trust);
+    }
     if cut_move {
         s.clipboard = None;
     }

crates/engine/src/cmd/extra.rs

@@ -782,6 +782,7 @@ fn new_window(s: &mut Session, _: &Json) -> Result<Json> {
     let d = s.doc()?.clone();
     let mut copy = crate::DocState::new((*d.wb).clone(), d.path.clone(), format!("{}:2", d.display_title()));
     copy.selection = d.selection.clone();
+    copy.trust = d.trust;
     let i = s.add_document(copy);
     Ok(json!({"index": i}))
 }

crates/engine/src/cmd/file.rs

@@ -80,6 +80,8 @@ fn open(s: &mut Session, p: &Json) -> Result<Json> {
     if crate::io::FileKind::from_path(&name).is_none() && gridcraft_xlsx::sniff(&bytes) == gridcraft_xlsx::Format::Xlsx {
         doc.content_kind = Some(crate::io::FileKind::Xlsx);
     }
+    // Someone else may have made the file: its active content asks before it runs.
+    doc.trust = crate::Trust::FromFile;
     let i = s.add_document(doc);
     // The decrypted-workbook notice is for the info bar, not a message box.
     let shown: Vec<&str> = warnings.iter().map(String::as_str).filter(|w| *w != crate::io::DECRYPTED_NOTICE).collect();

crates/engine/src/cmd/inspect.rs

@@ -7,7 +7,7 @@ use super::*;
 
 pub fn specs() -> Vec<CommandSpec> {
     vec![
-        cmd!(query "document.inspect", "Inspect Workbook", [], None, "{} → sheets, selection, names, tables, charts, dirty, history", has_doc, inspect),
+        cmd!(query "document.inspect", "Inspect Workbook", [], None, "{} → sheets, selection, names, tables, charts, dirty, trust (local|fromFile), history", has_doc, inspect),
         cmd!(query "sheet.read", "Read Range", [], None, "{range?: \"A1:D10\" (default: used range), sheet?, formulas?: bool, formatted?: bool} → rows of values", has_doc, read),
         cmd!(query "cell.get", "Get Cell", [], None, "{cell?, sheet?} → value, formula, display text, style, comment, link", has_doc, cell_get),
         cmd!(query "selection.stats", "Selection Statistics", [], None, "{} → count, sum, average, min, max", has_doc, sel_stats),
@@ -63,6 +63,7 @@ fn inspect(s: &mut Session, _: &Json) -> Result<Json> {
         "title": d.display_title(),
         "path": d.path,
         "dirty": d.is_dirty(),
+        "trust": d.trust,
         "activeSheet": wb.active_sheet,
         "sheets": sheets,
         "selection": d.selection.a1(),