Request permission on big paste

metainfo.xml

@@ -110,6 +110,7 @@
           <li>Expose current profile's name through env var `CONTOUR_PROFILE` (#1637)</li>
           <li>Add terminal tabs (#90)</li>
           <li>Add `SaveScreenshot` and `CopyScreenshot` action (#210)</li>
+          <li>Protect user from accidentally pasting too large input (#1198)</li>
           <li>Add binding to exit normal mode with `Esc` (#1604)</li>
           <li>Add config option to switch into insert mode after yank (#1604)</li>
           <li>Improves window size/resize handling on HiDPI monitor settings (#1628)</li>

src/contour/TerminalSession.cpp

@@ -368,6 +368,7 @@ void TerminalSession::executeRole(GuardedRole role, bool allow, bool remember)
         case GuardedRole::ShowHostWritableStatusLine:
             executeShowHostWritableStatusLine(allow, remember);
             break;
+        case GuardedRole::BigPaste: applyPendingPaste(allow, remember); break;
     }
 }
 
@@ -401,6 +402,7 @@ void TerminalSession::requestPermission(config::Permission allowedByConfig, Guar
                     case GuardedRole::ChangeFont: emit requestPermissionForFontChange(); break;
                     case GuardedRole::CaptureBuffer: emit requestPermissionForBufferCapture(); break;
                     case GuardedRole::ShowHostWritableStatusLine: emit requestPermissionForShowHostWritableStatusLine(); break;
+                    case GuardedRole::BigPaste: emit requestPermissionForPasteLargeFile(); break;
                         // clang-format on
                 }
             }
@@ -651,23 +653,65 @@ void TerminalSession::pasteFromClipboard(unsigned count, bool strip)
         sessionLog()("pasteFromClipboard: mime data contains {} formats.", md->formats().size());
         for (int i = 0; i < md->formats().size(); ++i)
             sessionLog()("pasteFromClipboard[{}]: {}\n", i, md->formats().at(i).toStdString());
-        string const text = strip_if(normalize_crlf(clipboard->text(QClipboard::Clipboard)), strip);
-        if (text.empty())
+
+        auto const text = clipboard->text(QClipboard::Clipboard);
+
+        // 1 MB hard limit
+        if (text.size() > 1024 * 1024)
+        {
+            sessionLog()("Clipboard contains huge text. Ignoring.");
+            _display->post([this]() {
+                emit showNotification("Screenshot", QString::fromStdString("Paste is too big"));
+            });
+            return;
+        }
+        // 512 KB soft limit to ask user for permission
+        if (text.size() > 1024 * 512)
+        {
+            _pendingBigPaste = clipboard;
+            emit requestPermissionForPasteLargeFile();
+            sessionLog()("Clipboard contains huge text. Requesting permission.");
+            return;
+        }
+
+        string const strippedText = strip_if(normalize_crlf(clipboard->text(QClipboard::Clipboard)), strip);
+        sessionLog()("Size of text: {}", strippedText.size());
+        if (strippedText.empty())
             sessionLog()("Clipboard does not contain text.");
         else if (count == 1)
-            terminal().sendPaste(string_view { text });
+            terminal().sendPaste(string_view { strippedText });
         else
         {
             string fullPaste;
             for (unsigned i = 0; i < count; ++i)
-                fullPaste += text;
+                fullPaste += strippedText;
             terminal().sendPaste(string_view { fullPaste });
         }
     }
     else
         sessionLog()("Could not access clipboard.");
 }
 
+void TerminalSession::applyPendingPaste(bool allow, bool remember)
+{
+    sessionLog()("applyPendingPaste: allow={}, remember={}", allow, remember);
+    if (remember)
+        _rememberedPermissions[GuardedRole::BigPaste] = allow;
+
+    if (!_pendingBigPaste)
+        return;
+
+    if (!allow)
+    {
+        _pendingBigPaste = std::nullopt;
+        return;
+    }
+
+    auto* clipboard = _pendingBigPaste.value();
+    auto text = clipboard->text(QClipboard::Clipboard);
+    terminal().sendPaste(string_view { text.toStdString() });
+}
+
 void TerminalSession::onSelectionCompleted()
 {
     switch (_config.onMouseSelection.value())

src/contour/TerminalSession.h

@@ -41,6 +41,7 @@ enum class GuardedRole : uint8_t
     ChangeFont,
     CaptureBuffer,
     ShowHostWritableStatusLine,
+    BigPaste,
 };
 
 /**
@@ -240,6 +241,7 @@ class TerminalSession: public QAbstractItemModel, public vtbackend::Terminal::Ev
     void detachDisplay(display::TerminalDisplay& display);
 
     Q_INVOKABLE void applyPendingFontChange(bool allow, bool remember);
+    Q_INVOKABLE void applyPendingPaste(bool allow, bool remember);
     Q_INVOKABLE void executePendingBufferCapture(bool allow, bool remember);
     Q_INVOKABLE void executeShowHostWritableStatusLine(bool allow, bool remember);
     Q_INVOKABLE void resizeTerminalToDisplaySize();
@@ -395,6 +397,7 @@ class TerminalSession: public QAbstractItemModel, public vtbackend::Terminal::Ev
     void onBell(float volume);
     void onAlert();
     void requestPermissionForFontChange();
+    void requestPermissionForPasteLargeFile();
     void requestPermissionForBufferCapture();
     void requestPermissionForShowHostWritableStatusLine();
     void showNotification(QString const& title, QString const& content);
@@ -470,6 +473,7 @@ class TerminalSession: public QAbstractItemModel, public vtbackend::Terminal::Ev
     };
     std::optional<CaptureBufferRequest> _pendingBufferCapture;
     std::optional<vtbackend::FontDef> _pendingFontChange;
+    std::optional<QClipboard*> _pendingBigPaste;
     PermissionCache _rememberedPermissions;
     std::unique_ptr<QThread> _exitWatcherThread;
 
@@ -494,6 +498,7 @@ struct std::formatter<contour::GuardedRole>: std::formatter<std::string_view>
             case contour::GuardedRole::ChangeFont: output = "Change Font"; break;
             case contour::GuardedRole::CaptureBuffer: output = "Capture Buffer"; break;
             case contour::GuardedRole::ShowHostWritableStatusLine:  output = "show Host Writable Statusline"; break;
+            case contour::GuardedRole::BigPaste:  output = "paste large number of characters"; break;
         }
         // clang-format on
         return formatter<string_view>::format(output, ctx);

src/contour/ui.template/Terminal.qml.in

@@ -135,6 +135,23 @@ ContourTerminal
         }
     }
 
+
+    RequestPermission {
+        id: requestLargeFilePaste
+        text: "The host application is going to paste large file, are you sure?"
+        onYesToAllClicked: vtWidget.session.applyPendingPaste(true, true);
+        onYesClicked: vtWidget.session.applyPendingPaste(true, false);
+        onNoToAllClicked: vtWidget.session.applyPendingPaste(false, true);
+        onNoClicked: vtWidget.session.applyPendingPaste(false, false);
+        onRejected: {
+            console.log("[Terminal] large file paste is rejected.", vtWidget.session)
+            if (vtWidget.session !== null)
+                vtWidget.session.applyPendingPaste(false, false);
+        }
+    }
+
+
+
     RequestPermission {
         id: requestBufferCaptureDialog
         text: "The host application is requesting to capture the terminal buffer."
@@ -265,6 +282,7 @@ ContourTerminal
         vt.requestPermissionForFontChange.connect(requestFontChangeDialog.open);
         vt.requestPermissionForBufferCapture.connect(requestBufferCaptureDialog.open);
         vt.requestPermissionForShowHostWritableStatusLine.connect(requestShowHostWritableStatusLine.open);
+        vt.requestPermissionForPasteLargeFile.connect(requestLargeFilePaste.open);
         forceActiveFocus();
 
         // TAB handling