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