fix: request permission on main thread

src/slic3r/plugin/PluginAuditManager.cpp

@@ -115,6 +115,9 @@ static const std::unordered_map<std::string, AuditEventCategory> audit_event_cat
     {"subprocess.Popen", AuditEventCategory::ProcessCreate},
     {"_winapi.CreateProcess", AuditEventCategory::ProcessCreate},
     {"_posixsubprocess.fork_exec", AuditEventCategory::ProcessCreate},
+
+    // threading
+    {"_thread.start_new_thread", AuditEventCategory::Threading},
 };
 
 // Returns the category event_name belongs to, or AuditEventCategory::None when it isn't audited.
@@ -735,6 +738,12 @@ std::vector<std::string> audit_targets(const std::string& event_name, AuditEvent
         }
         return targets;
     }
+    case AuditEventCategory::Threading:
+        // Thread creation exposes no user-supplied target. Use a fixed sentinel so the grant
+        // persists per plugin: the permission list matches targets by exact string, and the
+        // started function's repr embeds an address that changes every run.
+        targets.emplace_back("thread");
+        return targets;
     default:
         break;
     }
@@ -761,6 +770,7 @@ std::vector<std::string>* permission_list_for(AuditEventCategory category, Plugi
     case AuditEventCategory::Http:          return &permissions.network_http;
     case AuditEventCategory::Socket:        return &permissions.network_socket;
     case AuditEventCategory::ProcessCreate: return &permissions.process;
+    case AuditEventCategory::Threading:     return &permissions.threading;
     default:                                return nullptr;
     }
 }
@@ -832,11 +842,74 @@ wxString audit_message(AuditEventCategory category, const wxString& plugin_name,
         return wxString::Format(_L("Plugin \"%s\" is requesting to open a network connection to:\n%s"), plugin_name, target_list);
     case AuditEventCategory::ProcessCreate:
         return wxString::Format(_L("Plugin \"%s\" is requesting to run the following command(s):\n%s"), plugin_name, target_list);
+    case AuditEventCategory::Threading:
+        return wxString::Format(_L("Plugin \"%s\" is requesting permission to create a thread."), plugin_name);
     default:
         return wxString::Format(_L("Plugin \"%s\" is requesting permission for the Python audit event \"%s\"."), plugin_name, event_name);
     }
 }
 
+// Builds and shows the modal permission prompt. Must run on the GUI thread.
+bool prompt_for_targets(AuditEventCategory category, const std::string& plugin_name, const std::string& event_name,
+                        const std::vector<std::string>& unresolved)
+{
+    wxString target_list;
+    for (const auto& target : unresolved)
+        target_list += wxString::FromUTF8(target.c_str()) + "\n";
+
+    wxMessageDialog dialog(nullptr,
+                           audit_message(category, wxString::FromUTF8(plugin_name.c_str()),
+                                        wxString::FromUTF8(event_name.c_str()), target_list),
+                           _L("Plugin permission request"), wxYES_NO | wxICON_WARNING);
+    return dialog.ShowModal() == wxID_YES;
+}
+
+// Records a grant in the plugin's sidecar so it is not asked again. Reads the install state
+// freshly because the async prompt outlives the caller's stack copy of it.
+void persist_grant(const std::string& plugin_key, AuditEventCategory category, const std::vector<std::string>& targets)
+{
+    PluginInstallState state;
+    if (!PluginManager::instance().get_install_state(plugin_key, state))
+        return;
+
+    std::vector<std::string>* permission_list = permission_list_for(category, state.permissions);
+    if (!permission_list)
+        return;
+
+    for (const auto& target : targets)
+        persist_permission(plugin_key, state, *permission_list, target);
+}
+
+// Requests permission for an audited event, returning true when it is already granted or the user
+// approves an inline prompt.
+//
+// An audited event can fire on a thread the UI thread may itself be blocked waiting on: the
+// SlicingPipeline hook runs on the slicing worker thread (see PluginHooks.cpp), and
+// BackgroundSlicingProcess::stop()/stop_internal() park the UI thread until that worker stops.
+// Blocking the worker on a marshaled modal -- which is safe for the plugin-load worker that
+// request_filesystem_read_permissions runs on -- would therefore deadlock the application (the
+// invariant PluginHostUi.cpp documents for slicing-hook UI calls). Off the main thread the prompt
+// is therefore posted asynchronously and the current event denied (fail closed, like an unanswered
+// prompt); the grant is persisted once the user accepts, so a later attempt succeeds without
+// re-prompting.
+bool request_permission(AuditEventCategory category, const std::string& plugin_key, const std::string& plugin_name,
+                        const std::string& event_name, const std::vector<std::string>& unresolved)
+{
+    if (wxTheApp == nullptr || GUI::wxGetApp().is_closing())
+        return false;
+
+    if (wxIsMainThread())
+        return prompt_for_targets(category, plugin_name, event_name, unresolved);
+
+    GUI::wxGetApp().CallAfter([category, plugin_key, plugin_name, event_name, unresolved]() {
+        if (wxTheApp == nullptr || GUI::wxGetApp().is_closing())
+            return;
+        if (prompt_for_targets(category, plugin_name, event_name, unresolved))
+            persist_grant(plugin_key, category, unresolved);
+    });
+    return false;
+}
+
 int decide_audited_event(PluginAuditManager&             mgr,
                          PluginInstallState&              state,
                          const std::string&                plugin_key,
@@ -857,15 +930,7 @@ int decide_audited_event(PluginAuditManager&             mgr,
             return 0;
     }
 
-    wxString target_list;
+    if (!request_permission(category, plugin_key, plugin_name, event_name, unresolved))
-    for (const auto& target : unresolved)
-        target_list += wxString::FromUTF8(target.c_str()) + "\n";
-
-    wxMessageDialog dialog(nullptr,
-                           audit_message(category, wxString::FromUTF8(plugin_name.c_str()),
-                                        wxString::FromUTF8(event_name.c_str()), target_list),
-                           _L("Plugin permission request"), wxYES_NO | wxICON_WARNING);
-    if (dialog.ShowModal() != wxID_YES)
         return report_denied(mgr, event_name, {false, "audit permission required"});
 
     if (permission_list)

src/slic3r/plugin/PluginFsUtils.cpp

@@ -807,6 +807,7 @@ bool read_install_state(const boost::filesystem::path& plugin_dir, PluginInstall
             read_string_list("network_http", parsed.permissions.network_http);
             read_string_list("network_socket", parsed.permissions.network_socket);
             read_string_list("process", parsed.permissions.process);
+            read_string_list("threading", parsed.permissions.threading);
         }
 
         if (state.contains("enabled") && state["enabled"].is_boolean())
@@ -850,6 +851,7 @@ bool write_install_state(const boost::filesystem::path& plugin_dir, const Plugin
         {"network_http", state.permissions.network_http},
         {"network_socket", state.permissions.network_socket},
         {"process", state.permissions.process},
+        {"threading", state.permissions.threading},
     };
 
     nlohmann::json capabilities = nlohmann::json::array();

src/slic3r/plugin/PluginFsUtils.hpp

@@ -92,6 +92,7 @@ struct PluginPermissions
     std::vector<std::string> network_http;
     std::vector<std::string> network_socket;
     std::vector<std::string> process;
+    std::vector<std::string> threading;
 };
 
 struct PluginInstallState {

tests/slic3rutils/test_plugin_install.cpp

@@ -122,6 +122,7 @@ TEST_CASE("install-state sidecar is the source of truth for a cloud plugin's ins
     state.permissions.network_http  = {"https://api.example.com"};
     state.permissions.network_socket = {"192.168.45.6:443"};
     state.permissions.process        = {"/usr/bin/curl"};
+    state.permissions.threading      = {"thread"};
     REQUIRE(write_install_state(plugin_dir, state));
 
     // Permission data is persisted in the same sidecar as the installation metadata.
@@ -132,6 +133,7 @@ TEST_CASE("install-state sidecar is the source of truth for a cloud plugin's ins
     CHECK(persisted.permissions.network_http == state.permissions.network_http);
     CHECK(persisted.permissions.network_socket == state.permissions.network_socket);
     CHECK(persisted.permissions.process == state.permissions.process);
+    CHECK(persisted.permissions.threading == state.permissions.threading);
 
     // Reading the sidecar back onto a freshly-scanned descriptor (whose header version is still
     // 1.0.0) must surface the cloud-installed 1.2.0. This is what lets update_cloud_metadata compare