image/ImageBlocker.cpp

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include "ImageBlocker.h"
   6 #include "nsIPermissionManager.h"
   7 #include "nsContentUtils.h"
   8 #include "mozilla/StaticPrefs_permissions.h"
   9 #include "nsNetUtil.h"
  10
  11 using namespace mozilla;
  12 using namespace mozilla::image;
  13
  14 NS_IMPL_ISUPPORTS(ImageBlocker, nsIContentPolicy)
  15
  16 NS_IMETHODIMP
  17 ImageBlocker::ShouldLoad(nsIURI* aContentLocation, nsILoadInfo* aLoadInfo,
  18                          const nsACString& aMimeGuess, int16_t* aShouldLoad) {
  19   ExtContentPolicyType contentType = aLoadInfo->GetExternalContentPolicyType();
  20
  21   *aShouldLoad = nsIContentPolicy::ACCEPT;
  22
  23   if (!aContentLocation) {
  24     // Bug 1720280: Ideally we should block the load, but to avoid a potential
  25     // null pointer deref, we return early in this case. Please note that
  26     // the ImageBlocker only applies about http/https loads anyway.
  27     return NS_OK;
  28   }
  29
  30   // we only want to check http, https
  31   // for chrome:// and resources and others, no need to check.
  32   nsAutoCString scheme;
  33   aContentLocation->GetScheme(scheme);
  34   if (!scheme.LowerCaseEqualsLiteral("http") &&
  35       !scheme.LowerCaseEqualsLiteral("https")) {
  36     return NS_OK;
  37   }
  38
  39   // Block loading images depending on the permissions.default.image pref.
  40   if ((contentType == ExtContentPolicy::TYPE_IMAGE ||
  41        contentType == ExtContentPolicy::TYPE_IMAGESET) &&
  42       StaticPrefs::permissions_default_image() ==
  43           nsIPermissionManager::DENY_ACTION) {
  44     NS_SetRequestBlockingReason(
  45         aLoadInfo, nsILoadInfo::BLOCKING_REASON_CONTENT_POLICY_CONTENT_BLOCKED);
  46     *aShouldLoad = nsIContentPolicy::REJECT_TYPE;
  47   }
  48
  49   return NS_OK;
  50 }
  51
  52 NS_IMETHODIMP
  53 ImageBlocker::ShouldProcess(nsIURI* aContentLocation, nsILoadInfo* aLoadInfo,
  54                             const nsACString& aMimeGuess,
  55                             int16_t* aShouldProcess) {
  56   // We block images at load level already, so those should not end up here.
  57   *aShouldProcess = nsIContentPolicy::ACCEPT;
  58   return NS_OK;
  59 }