Bug 1730194 - Prevent Copy button to send information to Cloud Clipboard and Clipboard History on Windows r=dimi,johannh,cmartin

Differential Revision: https://phabricator.services.mozilla.com/D125831

browser/components/aboutlogins/AboutLoginsChild.jsm

@@ -121,7 +121,7 @@ class AboutLoginsChild extends JSWindowActorChild {
         break;
       }
       case "AboutLoginsCopyLoginDetail": {
-        ClipboardHelper.copyString(event.detail);
+        ClipboardHelper.copyString(event.detail, ClipboardHelper.Sensitive);
         break;
       }
       case "AboutLoginsCreateLogin": {

modules/libpref/init/StaticPrefList.yaml

@@ -1481,6 +1481,15 @@
 #endif
   mirror: always
 
+#ifdef XP_WIN
+  # allow to copy clipboard data to Clipboard History/Cloud
+  # (used on sensitive data in about:logins and Private Browsing)
+-   name: clipboard.copyPrivateDataToClipboardCloudOrHistory
+    type: bool
+    value: false
+    mirror: always
+#endif
+
 #---------------------------------------------------------------------------
 # Prefs starting with "consoleservice."
 #---------------------------------------------------------------------------

widget/nsClipboardHelper.cpp

@@ -36,7 +36,8 @@ nsClipboardHelper::~nsClipboardHelper() {
 
 NS_IMETHODIMP
 nsClipboardHelper::CopyStringToClipboard(const nsAString& aString,
-                                         int32_t aClipboardID) {
+                                         int32_t aClipboardID,
+                                         SensitiveData aSensitive) {
   nsresult rv;
 
   // get the clipboard
@@ -69,6 +70,9 @@ nsClipboardHelper::CopyStringToClipboard(const nsAString& aString,
   NS_ENSURE_TRUE(trans, NS_ERROR_FAILURE);
 
   trans->Init(nullptr);
+  if (aSensitive == SensitiveData::Sensitive) {
+    trans->SetIsPrivateData(true);
+  }
 
   // Add the text data flavor to the transferable
   rv = trans->AddDataFlavor(kUnicodeMime);
@@ -102,11 +106,13 @@ nsClipboardHelper::CopyStringToClipboard(const nsAString& aString,
 }
 
 NS_IMETHODIMP
-nsClipboardHelper::CopyString(const nsAString& aString) {
+nsClipboardHelper::CopyString(const nsAString& aString,
+                              SensitiveData aSensitive) {
   nsresult rv;
 
   // copy to the global clipboard. it's bad if this fails in any way.
-  rv = CopyStringToClipboard(aString, nsIClipboard::kGlobalClipboard);
+  rv = CopyStringToClipboard(aString, nsIClipboard::kGlobalClipboard,
+                             aSensitive);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // unix also needs us to copy to the selection clipboard. this will
@@ -118,7 +124,7 @@ nsClipboardHelper::CopyString(const nsAString& aString) {
   // if this fails in any way other than "not being unix", we'll get
   // the assertion we need in CopyStringToClipboard, and we needn't
   // assert again here.
-  CopyStringToClipboard(aString, nsIClipboard::kSelectionClipboard);
+  CopyStringToClipboard(aString, nsIClipboard::kSelectionClipboard, aSensitive);
 
   return NS_OK;
 }

widget/nsIClipboardHelper.idl

@@ -18,19 +18,28 @@
 [scriptable, uuid(438307fd-0c68-4d79-922a-f6cc9550cd02)]
 interface nsIClipboardHelper : nsISupports
 {
+  cenum SensitiveData : 8 {
+    NotSensitive = 0,
+    Sensitive = 1,
+  };
+
   /**
    * copy string to given clipboard
    *
    * @param aString, the string to copy to the clipboard
    * @param aClipboardID, the ID of the clipboard to copy to
    *        (eg. kSelectionClipboard -- see nsIClipboard.idl)
+   * @param aSensitive, optional flag to indicate that data is sensitive, like a password.
+   *        That will exclude data from Cloud Clipboard/Clipboard History on Windows.
    */
-  void copyStringToClipboard(in AString aString, in long aClipboardID);
+  void copyStringToClipboard(in AString aString, in long aClipboardID,
+                             [optional, default(NotSensitive)] in nsIClipboardHelper_SensitiveData aSensitive);
 
   /**
    * copy string to (default) clipboard
    *
    * @param aString, the string to copy to the clipboard
    */
-  void copyString(in AString aString);
+  void copyString(in AString aString,
+                  [optional, default(NotSensitive)] in nsIClipboardHelper_SensitiveData aSensitive);
 };

widget/windows/nsClipboard.cpp

@@ -15,6 +15,7 @@
 #include <thread>
 #include <chrono>
 
+#include "mozilla/StaticPrefs_clipboard.h"
 #include "nsArrayUtils.h"
 #include "nsCOMPtr.h"
 #include "nsDataObj.h"
@@ -147,6 +148,29 @@ nsresult nsClipboard::CreateNativeDataObject(nsITransferable* aTransferable,
   return res;
 }
 
+static nsresult StoreValueInDataObject(nsDataObj* aObj,
+                                       LPCWSTR aClipboardFormat, DWORD value) {
+  HGLOBAL hGlobalMemory = ::GlobalAlloc(GMEM_MOVEABLE, sizeof(DWORD));
+  if (!hGlobalMemory) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+  DWORD* pdw = (DWORD*)::GlobalLock(hGlobalMemory);
+  *pdw = value;
+  ::GlobalUnlock(hGlobalMemory);
+
+  STGMEDIUM stg;
+  stg.tymed = TYMED_HGLOBAL;
+  stg.pUnkForRelease = nullptr;
+  stg.hGlobal = hGlobalMemory;
+
+  FORMATETC fe;
+  SET_FORMATETC(fe, ::RegisterClipboardFormat(aClipboardFormat), 0,
+                DVASPECT_CONTENT, -1, TYMED_HGLOBAL)
+  aObj->SetData(&fe, &stg, TRUE);
+
+  return NS_OK;
+}
+
 //-------------------------------------------------------------------------
 nsresult nsClipboard::SetupNativeDataObject(nsITransferable* aTransferable,
                                             IDataObject* aDataObj) {
@@ -253,6 +277,23 @@ nsresult nsClipboard::SetupNativeDataObject(nsITransferable* aTransferable,
     }
   }
 
+  if (!StaticPrefs::clipboard_copyPrivateDataToClipboardCloudOrHistory()) {
+    // Let Clipboard know that data is sensitive and must not be copied to
+    // the Cloud Clipboard, Clipboard History and similar.
+    // https://docs.microsoft.com/en-us/windows/win32/dataxchg/clipboard-formats#cloud-clipboard-and-clipboard-history-formats
+    if (aTransferable->GetIsPrivateData()) {
+      nsresult rv =
+          StoreValueInDataObject(dObj, TEXT("CanUploadToCloudClipboard"), 0);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv =
+          StoreValueInDataObject(dObj, TEXT("CanIncludeInClipboardHistory"), 0);
+      NS_ENSURE_SUCCESS(rv, rv);
+      rv = StoreValueInDataObject(
+          dObj, TEXT("ExcludeClipboardContentFromMonitorProcessing"), 0);
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+
   return NS_OK;
 }