image/ImageCacheKey.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "ImageCacheKey.h"
   7
   8 #include <utility>
   9
  10 #include "mozilla/AntiTrackingUtils.h"
  11 #include "mozilla/ContentBlocking.h"
  12 #include "mozilla/HashFunctions.h"
  13 #include "mozilla/StorageAccess.h"
  14 #include "mozilla/StoragePrincipalHelper.h"
  15 #include "mozilla/Unused.h"
  16 #include "mozilla/dom/Document.h"
  17 #include "mozilla/dom/File.h"
  18 #include "mozilla/dom/ServiceWorkerManager.h"
  19 #include "mozilla/StaticPrefs_privacy.h"
  20 #include "nsContentUtils.h"
  21 #include "nsHashKeys.h"
  22 #include "nsLayoutUtils.h"
  23 #include "nsPrintfCString.h"
  24 #include "nsString.h"
  25
  26 namespace mozilla {
  27
  28 using namespace dom;
  29
  30 namespace image {
  31
  32 ImageCacheKey::ImageCacheKey(nsIURI* aURI, const OriginAttributes& aAttrs,
  33                              Document* aDocument)
  34     : mURI(aURI),
  35       mOriginAttributes(aAttrs),
  36       mControlledDocument(GetSpecialCaseDocumentToken(aDocument)),
  37       mIsolationKey(GetIsolationKey(aDocument, aURI)),
  38       mIsChrome(false) {
  39   if (mURI->SchemeIs("chrome")) {
  40     mIsChrome = true;
  41   }
  42 }
  43
  44 ImageCacheKey::ImageCacheKey(const ImageCacheKey& aOther)
  45     : mURI(aOther.mURI),
  46       mOriginAttributes(aOther.mOriginAttributes),
  47       mControlledDocument(aOther.mControlledDocument),
  48       mIsolationKey(aOther.mIsolationKey),
  49       mHash(aOther.mHash),
  50       mIsChrome(aOther.mIsChrome) {}
  51
  52 ImageCacheKey::ImageCacheKey(ImageCacheKey&& aOther)
  53     : mURI(std::move(aOther.mURI)),
  54       mOriginAttributes(aOther.mOriginAttributes),
  55       mControlledDocument(aOther.mControlledDocument),
  56       mIsolationKey(aOther.mIsolationKey),
  57       mHash(aOther.mHash),
  58       mIsChrome(aOther.mIsChrome) {}
  59
  60 bool ImageCacheKey::operator==(const ImageCacheKey& aOther) const {
  61   // Don't share the image cache between a controlled document and anything
  62   // else.
  63   if (mControlledDocument != aOther.mControlledDocument) {
  64     return false;
  65   }
  66   // Don't share the image cache between two top-level documents of different
  67   // base domains.
  68   if (!mIsolationKey.Equals(aOther.mIsolationKey,
  69                             nsCaseInsensitiveCStringComparator)) {
  70     return false;
  71   }
  72   // The origin attributes always have to match.
  73   if (mOriginAttributes != aOther.mOriginAttributes) {
  74     return false;
  75   }
  76
  77   // For non-blob URIs, compare the URIs.
  78   bool equals = false;
  79   nsresult rv = mURI->Equals(aOther.mURI, &equals);
  80   return NS_SUCCEEDED(rv) && equals;
  81 }
  82
  83 void ImageCacheKey::EnsureHash() const {
  84   MOZ_ASSERT(mHash.isNothing());
  85   PLDHashNumber hash = 0;
  86
  87   // Since we frequently call Hash() several times in a row on the same
  88   // ImageCacheKey, as an optimization we compute our hash once and store it.
  89
  90   nsPrintfCString ptr("%p", mControlledDocument);
  91   nsAutoCString suffix;
  92   mOriginAttributes.CreateSuffix(suffix);
  93
  94   nsAutoCString spec;
  95   Unused << mURI->GetSpec(spec);
  96   hash = HashString(spec);
  97
  98   hash = AddToHash(hash, HashString(suffix), HashString(mIsolationKey),
  99                    HashString(ptr));
 100   mHash.emplace(hash);
 101 }
 102
 103 /* static */
 104 void* ImageCacheKey::GetSpecialCaseDocumentToken(Document* aDocument) {
 105   // Cookie-averse documents can never have storage granted to them.  Since they
 106   // may not have inner windows, they would require special handling below, so
 107   // just bail out early here.
 108   if (!aDocument || aDocument->IsCookieAverse()) {
 109     return nullptr;
 110   }
 111
 112   // For controlled documents, we cast the pointer into a void* to avoid
 113   // dereferencing it (since we only use it for comparisons).
 114   RefPtr<ServiceWorkerManager> swm = ServiceWorkerManager::GetInstance();
 115   if (swm && aDocument->GetController().isSome()) {
 116     return aDocument;
 117   }
 118
 119   return nullptr;
 120 }
 121
 122 /* static */
 123 nsCString ImageCacheKey::GetIsolationKey(Document* aDocument, nsIURI* aURI) {
 124   if (!aDocument || !aDocument->GetInnerWindow()) {
 125     return ""_ns;
 126   }
 127
 128   // Network-state isolation
 129   if (StaticPrefs::privacy_partition_network_state()) {
 130     OriginAttributes oa;
 131     StoragePrincipalHelper::GetOriginAttributesForNetworkState(aDocument, oa);
 132
 133     nsAutoCString suffix;
 134     oa.CreateSuffix(suffix);
 135
 136     return std::move(suffix);
 137   }
 138
 139   // If the window is 3rd party resource, let's see if first-party storage
 140   // access is granted for this image.
 141   if (AntiTrackingUtils::IsThirdPartyWindow(aDocument->GetInnerWindow(),
 142                                             nullptr)) {
 143     uint32_t rejectedReason = 0;
 144     Unused << rejectedReason;
 145     return StorageDisabledByAntiTracking(aDocument, aURI, rejectedReason)
 146                ? aDocument->GetBaseDomain()
 147                : ""_ns;
 148   }
 149
 150   // Another scenario is if this image is a 3rd party resource loaded by a
 151   // first party context. In this case, we should check if the nsIChannel has
 152   // been marked as tracking resource, but we don't have the channel yet at
 153   // this point.  The best approach here is to be conservative: if we are sure
 154   // that the permission is granted, let's return 0. Otherwise, let's make a
 155   // unique image cache per the top-level document eTLD+1.
 156   if (!ContentBlocking::ApproximateAllowAccessForWithoutChannel(
 157           aDocument->GetInnerWindow(), aURI)) {
 158     // If we are here, the image is a 3rd-party resource loaded by a first-party
 159     // context. We can just use the document's base domain as the key because it
 160     // should be the same as the top-level document's base domain.
 161     return aDocument
 162         ->GetBaseDomain();  // because we don't have anything better!
 163   }
 164
 165   return ""_ns;
 166 }
 167
 168 }  // namespace image
 169 }  // namespace mozilla