1 files changed, 168 insertions, 0 deletions
diff --git a/image/ImageCacheKey.cpp b/image/ImageCacheKey.cpp
new file mode 100644
index 0000000000..7ded0b771b
--- /dev/null
+++ b/image/ImageCacheKey.cpp
@@ -0,0 +1,168 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ImageCacheKey.h"
+
+#include <utility>
+
+#include "mozilla/ContentBlocking.h"
+#include "mozilla/HashFunctions.h"
+#include "mozilla/StorageAccess.h"
+#include "mozilla/StoragePrincipalHelper.h"
+#include "mozilla/Unused.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/File.h"
+#include "mozilla/dom/ServiceWorkerManager.h"
+#include "mozilla/StaticPrefs_privacy.h"
+#include "nsContentUtils.h"
+#include "nsHashKeys.h"
+#include "nsLayoutUtils.h"
+#include "nsPrintfCString.h"
+#include "nsString.h"
+
+namespace mozilla {
+
+using namespace dom;
+
+namespace image {
+
+ImageCacheKey::ImageCacheKey(nsIURI* aURI, const OriginAttributes& aAttrs,
+                             Document* aDocument)
+    : mURI(aURI),
+      mOriginAttributes(aAttrs),
+      mControlledDocument(GetSpecialCaseDocumentToken(aDocument)),
+      mIsolationKey(GetIsolationKey(aDocument, aURI)),
+      mIsChrome(false) {
+  if (mURI->SchemeIs("chrome")) {
+    mIsChrome = true;
+  }
+}
+
+ImageCacheKey::ImageCacheKey(const ImageCacheKey& aOther)
+    : mURI(aOther.mURI),
+      mOriginAttributes(aOther.mOriginAttributes),
+      mControlledDocument(aOther.mControlledDocument),
+      mIsolationKey(aOther.mIsolationKey),
+      mHash(aOther.mHash),
+      mIsChrome(aOther.mIsChrome) {}
+
+ImageCacheKey::ImageCacheKey(ImageCacheKey&& aOther)
+    : mURI(std::move(aOther.mURI)),
+      mOriginAttributes(aOther.mOriginAttributes),
+      mControlledDocument(aOther.mControlledDocument),
+      mIsolationKey(aOther.mIsolationKey),
+      mHash(aOther.mHash),
+      mIsChrome(aOther.mIsChrome) {}
+
+bool ImageCacheKey::operator==(const ImageCacheKey& aOther) const {
+  // Don't share the image cache between a controlled document and anything
+  // else.
+  if (mControlledDocument != aOther.mControlledDocument) {
+    return false;
+  }
+  // Don't share the image cache between two top-level documents of different
+  // base domains.
+  if (!mIsolationKey.Equals(aOther.mIsolationKey,
+                            nsCaseInsensitiveCStringComparator)) {
+    return false;
+  }
+  // The origin attributes always have to match.
+  if (mOriginAttributes != aOther.mOriginAttributes) {
+    return false;
+  }
+
+  // For non-blob URIs, compare the URIs.
+  bool equals = false;
+  nsresult rv = mURI->Equals(aOther.mURI, &equals);
+  return NS_SUCCEEDED(rv) && equals;
+}
+
+void ImageCacheKey::EnsureHash() const {
+  MOZ_ASSERT(mHash.isNothing());
+  PLDHashNumber hash = 0;
+
+  // Since we frequently call Hash() several times in a row on the same
+  // ImageCacheKey, as an optimization we compute our hash once and store it.
+
+  nsPrintfCString ptr("%p", mControlledDocument);
+  nsAutoCString suffix;
+  mOriginAttributes.CreateSuffix(suffix);
+
+  nsAutoCString spec;
+  Unused << mURI->GetSpec(spec);
+  hash = HashString(spec);
+
+  hash = AddToHash(hash, HashString(suffix), HashString(mIsolationKey),
+                   HashString(ptr));
+  mHash.emplace(hash);
+}
+
+/* static */
+void* ImageCacheKey::GetSpecialCaseDocumentToken(Document* aDocument) {
+  // Cookie-averse documents can never have storage granted to them.  Since they
+  // may not have inner windows, they would require special handling below, so
+  // just bail out early here.
+  if (!aDocument || aDocument->IsCookieAverse()) {
+    return nullptr;
+  }
+
+  // For controlled documents, we cast the pointer into a void* to avoid
+  // dereferencing it (since we only use it for comparisons).
+  RefPtr<ServiceWorkerManager> swm = ServiceWorkerManager::GetInstance();
+  if (swm && aDocument->GetController().isSome()) {
+    return aDocument;
+  }
+
+  return nullptr;
+}
+
+/* static */
+nsCString ImageCacheKey::GetIsolationKey(Document* aDocument, nsIURI* aURI) {
+  if (!aDocument || !aDocument->GetInnerWindow()) {
+    return ""_ns;
+  }
+
+  // Network-state isolation
+  if (StaticPrefs::privacy_partition_network_state()) {
+    OriginAttributes oa;
+    StoragePrincipalHelper::GetOriginAttributesForNetworkState(aDocument, oa);
+
+    nsAutoCString suffix;
+    oa.CreateSuffix(suffix);
+
+    return std::move(suffix);
+  }
+
+  // If the window is 3rd party resource, let's see if first-party storage
+  // access is granted for this image.
+  if (nsContentUtils::IsThirdPartyWindowOrChannel(aDocument->GetInnerWindow(),
+                                                  nullptr, nullptr)) {
+    uint32_t rejectedReason = 0;
+    Unused << rejectedReason;
+    return StorageDisabledByAntiTracking(aDocument, aURI, rejectedReason)
+               ? aDocument->GetBaseDomain()
+               : ""_ns;
+  }
+
+  // Another scenario is if this image is a 3rd party resource loaded by a
+  // first party context. In this case, we should check if the nsIChannel has
+  // been marked as tracking resource, but we don't have the channel yet at
+  // this point.  The best approach here is to be conservative: if we are sure
+  // that the permission is granted, let's return 0. Otherwise, let's make a
+  // unique image cache per the top-level document eTLD+1.
+  if (!ContentBlocking::ApproximateAllowAccessForWithoutChannel(
+          aDocument->GetInnerWindow(), aURI)) {
+    // If we are here, the image is a 3rd-party resource loaded by a first-party
+    // context. We can just use the document's base domain as the key because it
+    // should be the same as the top-level document's base domain.
+    return aDocument
+        ->GetBaseDomain();  // because we don't have anything better!
+  }
+
+  return ""_ns;
+}
+
+}  // namespace image
+}  // namespace mozilla