Windows Sandbox: Show Everyone-writable directory warning (#6283)

Show a warning when Auto Sandbox mode becomes enabled, if we detect
Everyone-writable directories, since they cannot be protected by the
current implementation of the Sandbox.

This PR also includes changes to how we detect Everyone-writable to be
*much* faster

codex-rs/tui/src/chatwidget.rs

@@ -2030,13 +2030,34 @@ impl ChatWidget {
                         preset: preset_clone.clone(),
                     });
                 })]
-            } else if cfg!(target_os = "windows")
-                && preset.id == "auto"
-                && codex_core::get_platform_sandbox().is_none()
-            {
-                vec![Box::new(|tx| {
-                    tx.send(AppEvent::ShowWindowsAutoModeInstructions);
-                })]
+            } else if preset.id == "auto" {
+                #[cfg(target_os = "windows")]
+                {
+                    if codex_core::get_platform_sandbox().is_none() {
+                        vec![Box::new(|tx| {
+                            tx.send(AppEvent::ShowWindowsAutoModeInstructions);
+                        })]
+                    } else if !self
+                        .config
+                        .notices
+                        .hide_world_writable_warning
+                        .unwrap_or(false)
+                        && self.windows_world_writable_flagged()
+                    {
+                        let preset_clone = preset.clone();
+                        vec![Box::new(move |tx| {
+                            tx.send(AppEvent::OpenWorldWritableWarningConfirmation {
+                                preset: Some(preset_clone.clone()),
+                            });
+                        })]
+                    } else {
+                        Self::approval_preset_actions(preset.approval, preset.sandbox.clone())
+                    }
+                }
+                #[cfg(not(target_os = "windows"))]
+                {
+                    Self::approval_preset_actions(preset.approval, preset.sandbox.clone())
+                }
             } else {
                 Self::approval_preset_actions(preset.approval, preset.sandbox.clone())
             };
@@ -2078,6 +2099,19 @@ impl ChatWidget {
         })]
     }
 
+    #[cfg(target_os = "windows")]
+    fn windows_world_writable_flagged(&self) -> bool {
+        use std::collections::HashMap;
+        let mut env_map: HashMap<String, String> = HashMap::new();
+        for (k, v) in std::env::vars() {
+            env_map.insert(k, v);
+        }
+        match codex_windows_sandbox::preflight_audit_everyone_writable(&self.config.cwd, &env_map) {
+            Ok(()) => false,
+            Err(_) => true,
+        }
+    }
+
     pub(crate) fn open_full_access_confirmation(&mut self, preset: ApprovalPreset) {
         let approval = preset.approval;
         let sandbox = preset.sandbox;
@@ -2142,6 +2176,95 @@ impl ChatWidget {
         });
     }
 
+    #[cfg(target_os = "windows")]
+    pub(crate) fn open_world_writable_warning_confirmation(
+        &mut self,
+        preset: Option<ApprovalPreset>,
+    ) {
+        let (approval, sandbox) = match &preset {
+            Some(p) => (Some(p.approval), Some(p.sandbox.clone())),
+            None => (None, None),
+        };
+        let mut header_children: Vec<Box<dyn Renderable>> = Vec::new();
+        let title_line = Line::from("Auto mode has unprotected directories").bold();
+        let info_line = Line::from(vec![
+            "Some important directories on this system are world-writable. ".into(),
+            "The Windows sandbox cannot protect writes to these locations in Auto mode."
+                .fg(Color::Red),
+        ]);
+        header_children.push(Box::new(title_line));
+        header_children.push(Box::new(
+            Paragraph::new(vec![info_line]).wrap(Wrap { trim: false }),
+        ));
+        let header = ColumnRenderable::with(header_children);
+
+        // Build actions ensuring acknowledgement happens before applying the new sandbox policy,
+        // so downstream policy-change hooks don't re-trigger the warning.
+        let mut accept_actions: Vec<SelectionAction> = Vec::new();
+        // Suppress the immediate re-scan once after user confirms continue.
+        accept_actions.push(Box::new(|tx| {
+            tx.send(AppEvent::SkipNextWorldWritableScan);
+        }));
+        if let (Some(approval), Some(sandbox)) = (approval, sandbox.clone()) {
+            accept_actions.extend(Self::approval_preset_actions(approval, sandbox));
+        }
+
+        let mut accept_and_remember_actions: Vec<SelectionAction> = Vec::new();
+        accept_and_remember_actions.push(Box::new(|tx| {
+            tx.send(AppEvent::UpdateWorldWritableWarningAcknowledged(true));
+            tx.send(AppEvent::PersistWorldWritableWarningAcknowledged);
+        }));
+        if let (Some(approval), Some(sandbox)) = (approval, sandbox) {
+            accept_and_remember_actions.extend(Self::approval_preset_actions(approval, sandbox));
+        }
+
+        let deny_actions: Vec<SelectionAction> = if preset.is_some() {
+            vec![Box::new(|tx| {
+                tx.send(AppEvent::OpenApprovalsPopup);
+            })]
+        } else {
+            Vec::new()
+        };
+
+        let items = vec![
+            SelectionItem {
+                name: "Continue".to_string(),
+                description: Some("Apply Auto mode for this session".to_string()),
+                actions: accept_actions,
+                dismiss_on_select: true,
+                ..Default::default()
+            },
+            SelectionItem {
+                name: "Continue and don't warn again".to_string(),
+                description: Some("Enable Auto mode and remember this choice".to_string()),
+                actions: accept_and_remember_actions,
+                dismiss_on_select: true,
+                ..Default::default()
+            },
+            SelectionItem {
+                name: "Cancel".to_string(),
+                description: Some("Go back without enabling Auto mode".to_string()),
+                actions: deny_actions,
+                dismiss_on_select: true,
+                ..Default::default()
+            },
+        ];
+
+        self.bottom_pane.show_selection_view(SelectionViewParams {
+            footer_hint: Some(standard_popup_hint_line()),
+            items,
+            header: Box::new(header),
+            ..Default::default()
+        });
+    }
+
+    #[cfg(not(target_os = "windows"))]
+    pub(crate) fn open_world_writable_warning_confirmation(
+        &mut self,
+        _preset: Option<ApprovalPreset>,
+    ) {
+    }
+
     #[cfg(target_os = "windows")]
     pub(crate) fn open_windows_auto_mode_instructions(&mut self) {
         use ratatui_macros::line;
@@ -2193,6 +2316,18 @@ impl ChatWidget {
         self.config.notices.hide_full_access_warning = Some(acknowledged);
     }
 
+    pub(crate) fn set_world_writable_warning_acknowledged(&mut self, acknowledged: bool) {
+        self.config.notices.hide_world_writable_warning = Some(acknowledged);
+    }
+
+    #[cfg_attr(not(target_os = "windows"), allow(dead_code))]
+    pub(crate) fn world_writable_warning_hidden(&self) -> bool {
+        self.config
+            .notices
+            .hide_world_writable_warning
+            .unwrap_or(false)
+    }
+
     /// Set the reasoning effort in the widget's config copy.
     pub(crate) fn set_reasoning_effort(&mut self, effort: Option<ReasoningEffortConfig>) {
         self.config.model_reasoning_effort = effort;