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   nsContentPolicyType contentType = aLoadInfo->GetExternalContentPolicyType();
  20   MOZ_ASSERT(contentType == nsContentUtils::InternalContentPolicyTypeToExternal(
  21                                 contentType),
  22              "We should only see external content policy types here.");
  23
  24   *aShouldLoad = nsIContentPolicy::ACCEPT;
  25
  26   // we only want to check http, https, ftp
  27   // for chrome:// and resources and others, no need to check.
  28   nsAutoCString scheme;
  29   aContentLocation->GetScheme(scheme);
  30   if (!scheme.LowerCaseEqualsLiteral("ftp") &&
  31       !scheme.LowerCaseEqualsLiteral("http") &&
  32       !scheme.LowerCaseEqualsLiteral("https")) {
  33     return NS_OK;
  34   }
  35
  36   // Block loading images depending on the permissions.default.image pref.
  37   if ((contentType == nsIContentPolicy::TYPE_IMAGE ||
  38        contentType == nsIContentPolicy::TYPE_IMAGESET) &&
  39       StaticPrefs::permissions_default_image() ==
  40           nsIPermissionManager::DENY_ACTION) {
  41     NS_SetRequestBlockingReason(
  42         aLoadInfo, nsILoadInfo::BLOCKING_REASON_CONTENT_POLICY_CONTENT_BLOCKED);
  43     *aShouldLoad = nsIContentPolicy::REJECT_TYPE;
  44   }
  45
  46   return NS_OK;
  47 }
  48
  49 NS_IMETHODIMP
  50 ImageBlocker::ShouldProcess(nsIURI* aContentLocation, nsILoadInfo* aLoadInfo,
  51                             const nsACString& aMimeGuess,
  52                             int16_t* aShouldProcess) {
  53 #ifdef DEBUG
  54   nsContentPolicyType contentType = aLoadInfo->GetExternalContentPolicyType();
  55   MOZ_ASSERT(contentType == nsContentUtils::InternalContentPolicyTypeToExternal(
  56                                 contentType),
  57              "We should only see external content policy types here.");
  58 #endif
  59
  60   // We block images at load level already, so those should not end up here.
  61   *aShouldProcess = nsIContentPolicy::ACCEPT;
  62   return NS_OK;
  63 }