Populate initiator origin in DragDownloadFileUI::InitiateDownload.

This CL propagates the initiator origin via
`content::DragDownloadFile::DragDownloadFileUI::InitiateDownload`
into `download::DownloadUrlParameters::set_initiator`.

Note that the initiator origin comes from trustworthy, browser-side data:

- `RenderFrameHostImpl::StartDragging` passes `GetLastCommittedOrigin()`
  into `RenderViewHostDelegateView::StartDragging`
- `WebContentsViewAura::StartDragging` stores the origin into into
  `ui::OSExchangeDataProviderFactory` using a call to
  `ui::OSExchangeDataProviderFactory::MarkRendererTaintedFromOrigin`.
  On Windows this CL takes the origin from
  `OSExchangeDataProviderFactory` and passes it directly into
  `DragDownloadFile`'s constructor.
- `WebContentsViewMac::StartDragging` ends up storing the origin in
  `WebDragSource` from `web_drag_source_mac.mm`.  On Mac this CL takes
  this origin and also passes it (indirectly, via mojo) into
  `DragDownloadFile`'s constructor.

@lukasza has manually tested this CL on Windows using the repro steps
from https://crbug.com/40060358 (@dcheng has kindly tried the repro
steps on Mac).  Note that `DragDownloadFile` is used on Windows and Mac,
but not on Linux (i.e. the repro wouldn't have worked on Linux).

Fixed: 40060358
Change-Id: I24b180473e140cbb8a56640444f2f4a306aa42fc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5692867
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Łukasz Anforowicz <lukasza@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1327773}

content/app_shim_remote_cocoa/web_drag_source_mac.mm

@@ -280,7 +280,8 @@
     base::FilePath filePath =
         base::apple::NSURLToFilePath([NSURL URLWithString:dropDestination]);
     filePath = filePath.Append(_downloadFileName);
-    _host->DragPromisedFileTo(filePath, _dropData, _downloadURL, &filePath);
+    _host->DragPromisedFileTo(filePath, _dropData, _downloadURL, _sourceOrigin,
+                              &filePath);
 
     // The process of writing the file may have altered the value of
     // `filePath` if, say, an existing file at the drop site already had that

content/app_shim_remote_cocoa/window_occlusion_browsertest_mac.mm

@@ -313,6 +313,7 @@ class WebContentsNSViewHostStub
   bool DragPromisedFileTo(const ::base::FilePath& file_path,
                           const ::content::DropData& drop_data,
                           const ::GURL& download_url,
+                          const ::url::Origin& source_origin,
                           ::base::FilePath* out_file_path) override {
     return false;
   }
@@ -320,6 +321,7 @@ class WebContentsNSViewHostStub
   void DragPromisedFileTo(const ::base::FilePath& file_path,
                           const ::content::DropData& drop_data,
                           const ::GURL& download_url,
+                          const ::url::Origin& source_origin,
                           DragPromisedFileToCallback callback) override {}
 
   void EndDrag(uint32_t drag_operation,

content/browser/download/drag_download_file.cc

@@ -38,6 +38,7 @@ class DragDownloadFile::DragDownloadFileUI
   DragDownloadFileUI(const GURL& url,
                      const Referrer& referrer,
                      const std::string& referrer_encoding,
+                     std::optional<url::Origin> initiator_origin,
                      int render_process_id,
                      int render_frame_id,
                      OnCompleted on_completed)
@@ -45,6 +46,7 @@ class DragDownloadFile::DragDownloadFileUI
         url_(url),
         referrer_(referrer),
         referrer_encoding_(referrer_encoding),
+        initiator_origin_(initiator_origin),
         render_process_id_(render_process_id),
         render_frame_id_(render_frame_id) {
     DCHECK(on_completed_);
@@ -95,6 +97,7 @@ class DragDownloadFile::DragDownloadFileUI
     params->set_referrer_policy(
         Referrer::ReferrerPolicyForUrlRequest(referrer_.policy));
     params->set_referrer_encoding(referrer_encoding_);
+    params->set_initiator(initiator_origin_);
     params->set_callback(base::BindOnce(&DragDownloadFileUI::OnDownloadStarted,
                                         weak_ptr_factory_.GetWeakPtr()));
     params->set_file_path(file_path);
@@ -174,6 +177,7 @@ class DragDownloadFile::DragDownloadFileUI
   GURL url_;
   Referrer referrer_;
   std::string referrer_encoding_;
+  std::optional<url::Origin> initiator_origin_;
   int render_process_id_;
   int render_frame_id_;
   raw_ptr<download::DownloadItem> download_item_ = nullptr;
@@ -187,13 +191,14 @@ DragDownloadFile::DragDownloadFile(const base::FilePath& file_path,
                                    const GURL& url,
                                    const Referrer& referrer,
                                    const std::string& referrer_encoding,
+                                   std::optional<url::Origin> initiator_origin,
                                    WebContents* web_contents)
     : file_path_(file_path), file_(std::move(file)) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   RenderFrameHost* host = web_contents->GetPrimaryMainFrame();
   drag_ui_ = new DragDownloadFileUI(
-      url, referrer, referrer_encoding, host->GetProcess()->GetID(),
-      host->GetRoutingID(),
+      url, referrer, referrer_encoding, initiator_origin,
+      host->GetProcess()->GetID(), host->GetRoutingID(),
       base::BindOnce(&DragDownloadFile::DownloadCompleted,
                      weak_ptr_factory_.GetWeakPtr()));
   DCHECK(!file_path_.empty());

content/browser/download/drag_download_file.h

@@ -40,6 +40,7 @@ class CONTENT_EXPORT DragDownloadFile : public ui::DownloadFileProvider {
                    const GURL& url,
                    const Referrer& referrer,
                    const std::string& referrer_encoding,
+                   std::optional<url::Origin> initiator_origin,
                    WebContents* web_contents);
 
   DragDownloadFile(const DragDownloadFile&) = delete;

content/browser/download/drag_download_file_browsertest.cc

@@ -2,14 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "content/browser/download/drag_download_file.h"
+
 #include "base/files/file_path.h"
+#include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/memory/raw_ptr.h"
 #include "base/memory/ref_counted.h"
 #include "base/path_service.h"
 #include "base/run_loop.h"
+#include "base/threading/thread_restrictions.h"
 #include "content/browser/download/download_manager_impl.h"
-#include "content/browser/download/drag_download_file.h"
 #include "content/browser/download/drag_download_util.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/browser_task_traits.h"
@@ -100,9 +103,9 @@ IN_PROC_BROWSER_TEST_F(DragDownloadFileTest, DragDownloadFileTest_NetError) {
   ASSERT_TRUE(embedded_test_server()->ShutdownAndWaitUntilComplete());
   Referrer referrer;
   std::string referrer_encoding;
-  auto file = std::make_unique<DragDownloadFile>(name, base::File(), url,
-                                                 referrer, referrer_encoding,
-                                                 shell()->web_contents());
+  auto file = std::make_unique<DragDownloadFile>(
+      name, base::File(), url, referrer, referrer_encoding, std::nullopt,
+      shell()->web_contents());
   scoped_refptr<MockDownloadFileObserver> observer(
       new MockDownloadFileObserver());
   EXPECT_CALL(*observer.get(), OnDownloadAborted())
@@ -119,9 +122,9 @@ IN_PROC_BROWSER_TEST_F(DragDownloadFileTest, DragDownloadFileTest_Complete) {
   GURL url = embedded_test_server()->GetURL("/download/download-test.lib");
   Referrer referrer;
   std::string referrer_encoding;
-  auto file = std::make_unique<DragDownloadFile>(name, base::File(), url,
-                                                 referrer, referrer_encoding,
-                                                 shell()->web_contents());
+  auto file = std::make_unique<DragDownloadFile>(
+      name, base::File(), url, referrer, referrer_encoding, std::nullopt,
+      shell()->web_contents());
   scoped_refptr<MockDownloadFileObserver> observer(
       new MockDownloadFileObserver());
   EXPECT_CALL(*observer.get(), OnDownloadCompleted(_))
@@ -132,15 +135,48 @@ IN_PROC_BROWSER_TEST_F(DragDownloadFileTest, DragDownloadFileTest_Complete) {
   RunUntilSucceed();
 }
 
+IN_PROC_BROWSER_TEST_F(DragDownloadFileTest, DragDownloadFileTest_Initiator) {
+  base::FilePath name(
+      downloads_directory().AppendASCII("DragDownloadFileTest_Initiator.txt"));
+  GURL url = embedded_test_server()->GetURL("/echoheader?sec-fetch-site");
+  url::Origin initiator =
+      url::Origin::Create(GURL("https://initiator.example.com"));
+  Referrer referrer;
+  std::string referrer_encoding;
+  auto file = std::make_unique<DragDownloadFile>(
+      name, base::File(), url, referrer, referrer_encoding, initiator,
+      shell()->web_contents());
+  base::FilePath downloaded_path;
+  scoped_refptr<MockDownloadFileObserver> observer(
+      new MockDownloadFileObserver());
+  EXPECT_CALL(*observer.get(), OnDownloadCompleted(_))
+      .WillOnce([&](const base::FilePath& file_path) {
+        downloaded_path = file_path;
+        this->Succeed();
+      });
+  ON_CALL(*observer.get(), OnDownloadAborted())
+      .WillByDefault(InvokeWithoutArgs(this, &DragDownloadFileTest::FailFast));
+  file->Start(observer.get());
+  RunUntilSucceed();
+
+  std::string actual_sec_fetch_site_value;
+  {
+    base::ScopedAllowBlockingForTesting allow_blocking;
+    ASSERT_TRUE(
+        base::ReadFileToString(downloaded_path, &actual_sec_fetch_site_value));
+  }
+  EXPECT_EQ("cross-site", actual_sec_fetch_site_value);
+}
+
 IN_PROC_BROWSER_TEST_F(DragDownloadFileTest, DragDownloadFileTest_ClosePage) {
   base::FilePath name(
       downloads_directory().AppendASCII("DragDownloadFileTest_Complete.txt"));
   GURL url = embedded_test_server()->GetURL("/download/download-test.lib");
   Referrer referrer;
   std::string referrer_encoding;
-  auto file = std::make_unique<DragDownloadFile>(name, base::File(), url,
-                                                 referrer, referrer_encoding,
-                                                 shell()->web_contents());
+  auto file = std::make_unique<DragDownloadFile>(
+      name, base::File(), url, referrer, referrer_encoding, std::nullopt,
+      shell()->web_contents());
   scoped_refptr<MockDownloadFileObserver> observer(
       new MockDownloadFileObserver());
   ON_CALL(*observer.get(), OnDownloadAborted())

content/browser/web_contents/web_contents_view_aura.cc

@@ -232,7 +232,7 @@ void PrepareDragForDownload(const DropData& drop_data,
   auto download_file = std::make_unique<DragDownloadFile>(
       download_path, base::File(), download_url,
       Referrer(page_url, drop_data.referrer_policy), page_encoding,
-      web_contents);
+      provider->GetRendererTaintedOrigin(), web_contents);
   ui::DownloadFileInfo file_download(base::FilePath(),
                                      std::move(download_file));
   provider->SetDownloadFileInfo(&file_download);

content/browser/web_contents/web_contents_view_mac.h

@@ -169,6 +169,7 @@ class WebContentsViewMac : public WebContentsView,
   bool DragPromisedFileTo(const base::FilePath& file_path,
                           const DropData& drop_data,
                           const GURL& download_url,
+                          const url::Origin& source_origin,
                           base::FilePath* out_file_path) override;
   void EndDrag(uint32_t drag_opeation,
                const gfx::PointF& local_point,
@@ -184,6 +185,7 @@ class WebContentsViewMac : public WebContentsView,
   void DragPromisedFileTo(const base::FilePath& file_path,
                           const DropData& drop_data,
                           const GURL& download_url,
+                          const url::Origin& source_origin,
                           DragPromisedFileToCallback callback) override;
 
   // Return the list of child RenderWidgetHostViewMacs. This will remove any

content/browser/web_contents/web_contents_view_mac.mm

@@ -521,6 +521,7 @@ bool WebContentsViewMac::PerformDragOperation(DraggingInfoPtr dragging_info,
 bool WebContentsViewMac::DragPromisedFileTo(const base::FilePath& file_path,
                                             const DropData& drop_data,
                                             const GURL& download_url,
+                                            const url::Origin& source_origin,
                                             base::FilePath* out_file_path) {
   *out_file_path = file_path;
   // This is called by -namesOfPromisedFilesDroppedAtDestination, which is
@@ -539,7 +540,7 @@ bool WebContentsViewMac::DragPromisedFileTo(const base::FilePath& file_path,
         *out_file_path, std::move(file), download_url,
         content::Referrer(web_contents_->GetLastCommittedURL(),
                           drop_data.referrer_policy),
-        web_contents_->GetEncoding(), web_contents_);
+        web_contents_->GetEncoding(), source_origin, web_contents_);
 
     DragDownloadFile* downloader = drag_file_downloader.get();
     // The finalizer will take care of closing and deletion.
@@ -616,9 +617,11 @@ void WebContentsViewMac::DragPromisedFileTo(
     const base::FilePath& file_path,
     const DropData& drop_data,
     const GURL& download_url,
+    const url::Origin& source_origin,
     DragPromisedFileToCallback callback) {
   base::FilePath actual_file_path;
-  DragPromisedFileTo(file_path, drop_data, download_url, &actual_file_path);
+  DragPromisedFileTo(file_path, drop_data, download_url, source_origin,
+                     &actual_file_path);
   std::move(callback).Run(actual_file_path);
 }
 

content/common/web_contents_ns_view_bridge.mojom

@@ -145,7 +145,8 @@ interface WebContentsNSViewHost {
   [Sync]
   DragPromisedFileTo(mojo_base.mojom.FilePath file_path,
                      content.mojom.DropData drop_data,
-                     url.mojom.Url download_url) =>
+                     url.mojom.Url download_url,
+                     url.mojom.Origin source_origin) =>
                          (mojo_base.mojom.FilePath file_path);
 
   // Called in to the -draggedImage: method being called on the NSView.