Bug 1966443: Ignore NULs in clipboard paste and DND drop operations r=stransky,geckoview-reviewers,mac-reviewers,bradwerth,tcampbell

Windows and GTK null-terminate text flavors in clipboard and DND operations.
For other platforms, it sanitizes text to ensure that there are no surprise
NUL characters in it, since NSStrings and Java strings in general can.

On a related note, GTK expects text to be obtained with gtk_selection_data_get_text,
not gtk_selection_data_get_data (and it guarantees null-termination), so
this patch makes that change as well.

Differential Revision: https://phabricator.services.mozilla.com/D256877

Author: davidp3

widget/android/nsClipboard.cpp

@@ -124,7 +124,8 @@ nsClipboard::GetNativeClipboardData(const nsACString& aFlavor,
     if (!text) {
       return nsCOMPtr<nsISupports>{};
     }
-    nsString buffer = text->ToString();
+    nsAutoString buffer(text->ToString());
+    buffer.StripChar(char16_t(0));
     if (buffer.IsEmpty()) {
       return nsCOMPtr<nsISupports>{};
     }

widget/cocoa/nsClipboard.mm

@@ -219,9 +219,11 @@
     bool isRTF = [pboardType
         isEqualToString:[UTIHelper stringFromPboardType:NSPasteboardTypeRTF]];
     if (isRTF) {
-      stringData = [pString dataUsingEncoding:NSASCIIStringEncoding];
+      stringData = [pString dataUsingEncoding:NSASCIIStringEncoding
+                         allowLossyConversion:YES];
     } else {
-      stringData = [pString dataUsingEncoding:NSUnicodeStringEncoding];
+      stringData = [pString dataUsingEncoding:NSUnicodeStringEncoding
+                         allowLossyConversion:YES];
     }
     unsigned int dataLength = [stringData length];
     void* clipboardDataPtr = malloc(dataLength);

widget/cocoa/nsCocoaUtils.mm

@@ -1664,7 +1664,10 @@ PanGestureInput panEvent(
   NSString* availableType =
       [aItem availableTypeFromArray:[NSArray arrayWithObjects:(id)aType, nil]];
   if (availableType && IsValidPasteboardType(availableType, aAllowFileURL)) {
-    return [aItem stringForType:(id)availableType];
+    NSString* str = [aItem stringForType:(id)availableType];
+    // Sanitize (remove NULs, etc) to align with other platforms.
+    return [NSString stringWithCString:[str UTF8String]
+                              encoding:NSUTF8StringEncoding];
   }
 
   return nil;

widget/gtk/nsDragService.cpp

@@ -248,10 +248,7 @@ bool DragData::IsFileFlavor() const {
 }
 
 bool DragData::IsTextFlavor() const {
-  return mDataFlavor == nsDragSession::sTextMimeAtom ||
-         mDataFlavor == nsDragSession::sTextPlainUTF8TypeAtom ||
-         mDataFlavor == nsDragSession::sUTF8STRINGMimeAtom ||
-         mDataFlavor == nsDragSession::sSTRINGMimeAtom;
+  return nsDragSession::IsTextFlavor(mDataFlavor);
 }
 
 bool DragData::IsURIFlavor() const {
@@ -1574,8 +1571,15 @@ void nsDragSession::TargetDataReceived(GtkWidget* aWidget,
     LOGDRAGSERVICE("  TargetDataReceived(): URI data, MIME %s",
                    GUniquePtr<gchar>(gdk_atom_name(target)).get());
   } else {
-    const guchar* data = gtk_selection_data_get_data(aSelectionData);
-    gint len = gtk_selection_data_get_length(aSelectionData);
+    const guchar* data = nullptr;
+    gint len = -1;
+    if (IsTextFlavor(target)) {
+      data = gtk_selection_data_get_text(aSelectionData);
+      len = data ? g_utf8_strlen(reinterpret_cast<const gchar*>(data), -1) : -1;
+    } else {
+      data = gtk_selection_data_get_data(aSelectionData);
+      len = gtk_selection_data_get_length(aSelectionData);
+    }
     if (len < 0 && !data) {
       LOGDRAGSERVICE(" TargetDataReceived() failed");
       return;
@@ -2341,10 +2345,7 @@ void nsDragSession::SourceDataGet(GtkWidget* aWidget, GdkDragContext* aContext,
     return;
   }
 
-  if (requestedFlavor == sTextMimeAtom ||
-      requestedFlavor == sTextPlainUTF8TypeAtom ||
-      requestedFlavor == sUTF8STRINGMimeAtom ||
-      requestedFlavor == sSTRINGMimeAtom) {
+  if (IsTextFlavor(requestedFlavor)) {
     if (!SourceDataGetText(item, nsDependentCString(kTextMime),
                            /* aNeedToDoConversionToPlainText */ true,
                            aSelectionData)) {
@@ -2989,4 +2990,12 @@ nsAutoCString nsDragSession::GetDebugTag() const {
   return tag;
 }
 
+/* static */
+bool nsDragSession::IsTextFlavor(GdkAtom aFlavor) {
+  return aFlavor == nsDragSession::sTextMimeAtom ||
+         aFlavor == nsDragSession::sTextPlainUTF8TypeAtom ||
+         aFlavor == nsDragSession::sUTF8STRINGMimeAtom ||
+         aFlavor == nsDragSession::sSTRINGMimeAtom;
+}
+
 #undef LOGDRAGSERVICE

widget/gtk/nsDragService.h

@@ -131,6 +131,8 @@ class nsDragSession : public nsBaseDragSession, public nsIObserver {
 
   static int GetLoopDepth() { return sEventLoopDepth; };
 
+  static bool IsTextFlavor(GdkAtom aFlavor);
+
  protected:
   // mScheduledTask indicates what signal has been received from GTK and
   // so what needs to be dispatched when the scheduled task is run.  It is