Adding a DownloadRestrictions group policy.

chrome/browser/download/chrome_download_manager_delegate.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/download/chrome_download_manager_delegate.h"
 
 #include <string>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 31 matching lines @@
 #include "chrome/browser/ui/scoped_tabbed_browser_displayer.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/features.h"
 #include "chrome/common/pdf_uma.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/safe_browsing/file_type_policies.h"
 #include "chrome/grit/generated_resources.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "components/prefs/pref_member.h"
 #include "components/prefs/pref_service.h"
+#include "content/public/browser/download_interrupt_reasons.h"
 #include "content/public/browser/download_item.h"
 #include "content/public/browser/download_manager.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/page_navigator.h"
 #include "extensions/features/features.h"
 #include "net/base/filename_util.h"
 #include "net/base/mime_util.h"
 #include "ppapi/features/features.h"
 #include "ui/base/l10n/l10n_util.h"
 
@@ skipping 299 matching lines @@
     // In case the service was disabled between the download starting and now,
     // we need to restore the danger state.
     content::DownloadDangerType danger_type = item->GetDangerType();
     if (DownloadItemModel(item).GetDangerLevel() !=
             DownloadFileType::NOT_DANGEROUS &&
         (danger_type == content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS ||
          danger_type ==
              content::DOWNLOAD_DANGER_TYPE_MAYBE_DANGEROUS_CONTENT)) {
       DVLOG(2) << __func__
                << "() SB service disabled. Marking download as DANGEROUS FILE";
-      item->OnContentCheckCompleted(
-          content::DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE);
+      if (ShouldBlockFile(content::DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE)) {
+        item->OnContentCheckCompleted(
+            // Specifying a dangerous type here would take precendence over the
+            // blocking of the file.
+            content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS,
+            content::DOWNLOAD_INTERRUPT_REASON_FILE_BLOCKED);
+      } else {
+        item->OnContentCheckCompleted(
+            content::DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE,
+            content::DOWNLOAD_INTERRUPT_REASON_NONE);
+      }
       UMA_HISTOGRAM_ENUMERATION("Download.DangerousFile.Reason",
                                 SB_NOT_AVAILABLE, DANGEROUS_FILE_REASON_MAX);
       content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
                                        internal_complete_callback);
       return false;
     }
   } else if (!state->is_complete()) {
     // Don't complete the download until we have an answer.
     state->set_callback(internal_complete_callback);
     return false;
@@ skipping 333 matching lines @@
 
 #if defined(FULL_SAFE_BROWSING)
   safe_browsing::DownloadProtectionService* service =
       GetDownloadProtectionService();
   if (service) {
     bool is_content_check_supported =
         service->IsSupportedDownload(*download, suggested_path);
     DVLOG(2) << __func__ << "() Start SB URL check for download = "
              << download->DebugString(false);
     service->CheckDownloadUrl(download,
-                              base::Bind(&CheckDownloadUrlDone,
-                                         callback,
+                              base::Bind(&CheckDownloadUrlDone, callback,
                                          is_content_check_supported));
     return;
   }
 #endif
   callback.Run(content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS);
 }
 
 void ChromeDownloadManagerDelegate::GetFileMimeType(
     const base::FilePath& path,
     const GetFileMimeTypeCallback& callback) {
@@ skipping 50 matching lines @@
       case DownloadProtectionService::DANGEROUS_HOST:
         danger_type = content::DOWNLOAD_DANGER_TYPE_DANGEROUS_HOST;
         break;
       case DownloadProtectionService::POTENTIALLY_UNWANTED:
         danger_type = content::DOWNLOAD_DANGER_TYPE_POTENTIALLY_UNWANTED;
         break;
     }
     DCHECK_NE(danger_type,
               content::DOWNLOAD_DANGER_TYPE_MAYBE_DANGEROUS_CONTENT);
 
-    if (danger_type != content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS)
-      item->OnContentCheckCompleted(danger_type);
+    if (danger_type != content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS) {
+      if (ShouldBlockFile(danger_type)) {
+        item->OnContentCheckCompleted(
+            // Specifying a dangerous type here would take precendence over the
+            // blocking of the file.
+            content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS,
+            content::DOWNLOAD_INTERRUPT_REASON_FILE_BLOCKED);
+      } else {
+        item->OnContentCheckCompleted(danger_type,
+                                      content::DOWNLOAD_INTERRUPT_REASON_NONE);
+      }
+    }
   }
 
   SafeBrowsingState* state = static_cast<SafeBrowsingState*>(
       item->GetUserData(&kSafeBrowsingUserDataKey));
   state->CompleteDownload();
 }
 #endif  // FULL_SAFE_BROWSING
 
 // content::NotificationObserver implementation.
 void ChromeDownloadManagerDelegate::Observe(
@@ skipping 26 matching lines @@
         target_info->is_filetype_handled_safely)
       DownloadItemModel(item).SetShouldPreferOpeningInBrowser(true);
 
 #if defined(OS_LINUX) || defined(OS_CHROMEOS)
     if (item->GetOriginalMimeType() == "application/x-x509-user-cert")
       DownloadItemModel(item).SetShouldPreferOpeningInBrowser(true);
 #endif
 
     DownloadItemModel(item).SetDangerLevel(target_info->danger_level);
   }
+  if (ShouldBlockFile(target_info->danger_type)) {
+    target_info->result = content::DOWNLOAD_INTERRUPT_REASON_FILE_BLOCKED;
+    // A dangerous type would take precendence over the blocking of the file.
+    target_info->danger_type = content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS;
+  }
+
   callback.Run(target_info->target_path, target_info->target_disposition,
                target_info->danger_type, target_info->intermediate_path,
                target_info->result);
 }
 
 bool ChromeDownloadManagerDelegate::IsOpenInBrowserPreferreredForFile(
     const base::FilePath& path) {
 #if defined(OS_WIN) || defined(OS_LINUX) || defined(OS_MACOSX)
   if (path.MatchesExtension(FILE_PATH_LITERAL(".pdf"))) {
     return !download_prefs_->ShouldOpenPdfInSystemReader();
@@ skipping 14 matching lines @@
       path.MatchesExtension(FILE_PATH_LITERAL(".xht")) ||
       path.MatchesExtension(FILE_PATH_LITERAL(".xhtm")) ||
       path.MatchesExtension(FILE_PATH_LITERAL(".xhtml")) ||
       path.MatchesExtension(FILE_PATH_LITERAL(".xsl")) ||
       path.MatchesExtension(FILE_PATH_LITERAL(".xslt"))) {
     return true;
   }
 #endif
   return false;
 }
+
+bool ChromeDownloadManagerDelegate::ShouldBlockFile(
+    content::DownloadDangerType danger_type) const {
+  DownloadPrefs::DOWNLOAD_RESTRICTION download_restriction =
+      download_prefs_->download_restriction();
+
+  if (download_restriction == DownloadPrefs::DOWNLOAD_RESTRICTION_ALL_FILES)

[David Trainor- moved to gerrit, 2017/06/12 19:09:05]

Would this be cleaner as a switch statement?  Fine either way though.

[MAD, 2017/06/12 19:45:14]

I don't see a clean way of making it work well with the 
(download_restriction == DownloadPrefs::DOWNLOAD_RESTRICTION_NONE ||
 danger_type == content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS)
condition.

+    return true;
+
+  if (download_restriction == DownloadPrefs::DOWNLOAD_RESTRICTION_NONE ||
+      danger_type == content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS) {
+    return false;
+  }
+
+  return (download_restriction ==
+              DownloadPrefs::DOWNLOAD_RESTRICTION_DANGEROUS_FILES &&
+          (danger_type == content::DOWNLOAD_DANGER_TYPE_DANGEROUS_CONTENT ||
+           danger_type == content::DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE ||
+           danger_type == content::DOWNLOAD_DANGER_TYPE_DANGEROUS_URL)) ||
+         // DANGEROUS_HOST, UNKNOWN, POTENTIALLY & MAYBE_DANGEROUS types.
+         (download_restriction ==
+          DownloadPrefs::DOWNLOAD_RESTRICTION_POTENTIALLY_DANGEROUS_FILES);
+}