Changeset 246647 in webkit

Timestamp:

Jun 20, 2019 1:03:58 PM (5 years ago)

Author:

wilander@apple.com

Message:

Storage Access API: Cap the number of times an iframe document can request access
​https://bugs.webkit.org/show_bug.cgi?id=199074
<rdar://problem/51857195>

Reviewed by Brent Fulgham.

Tested manually.

This change just adds a counter to the number of times the user explicitly
denies storage access and returns early if the counter has reached the limit
of 2.

We hoped that iframes that request storage access would count the number
of times the user has been asked and not repeat the request over and over.
However, we're seeing pretty aggressive use of the API and users are
complaining. Therefore, we need a cap on how many times an iframed
document can ask if it is explicitly denied access by the user.

This is a first measure. If we see continued aggressive use of the API,
we'll have to consider more drastic measures.

• dom/DocumentStorageAccess.cpp:

(WebCore::DocumentStorageAccess::requestStorageAccess):

• dom/DocumentStorageAccess.h:

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• dom/DocumentStorageAccess.cpp (modified) (2 diffs)
• dom/DocumentStorageAccess.h (modified) (3 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2019-06-20  John Wilander  <wilander@apple.com>
+
+        Storage Access API: Cap the number of times an iframe document can request access
+        https://bugs.webkit.org/show_bug.cgi?id=199074
+        <rdar://problem/51857195>
+
+        Reviewed by Brent Fulgham.
+
+        Tested manually.
+
+        This change just adds a counter to the number of times the user explicitly
+        denies storage access and returns early if the counter has reached the limit
+        of 2.
+
+        We hoped that iframes that request storage access would count the number
+        of times the user has been asked and not repeat the request over and over.
+        However, we're seeing pretty aggressive use of the API and users are
+        complaining. Therefore, we need a cap on how many times an iframed
+        document can ask if it is explicitly denied access by the user.
+
+        This is a first measure. If we see continued aggressive use of the API,
+        we'll have to consider more drastic measures.
+
+        * dom/DocumentStorageAccess.cpp:
+        (WebCore::DocumentStorageAccess::requestStorageAccess):
+        * dom/DocumentStorageAccess.h:
+
 2019-06-20  Youenn Fablet  <youenn@apple.com>
 

trunk/Source/WebCore/dom/DocumentStorageAccess.cpp

@@ -129 +129 @@
     }
     
-    if (!m_document.frame() || m_document.securityOrigin().isUnique()) {
+    if (!m_document.frame() || m_document.securityOrigin().isUnique() || !isAllowedToRequestFrameSpecificStorageAccess()) {
         promise->reject();
         return;
@@ -193 +193 @@
             document->setHasFrameSpecificStorageAccess(true);
             promise->resolve();
-        } else
+        } else {
+            if (promptWasShown == StorageAccessPromptWasShown::Yes)
+                document->setWasExplicitlyDeniedFrameSpecificStorageAccess();
             promise->reject();
+        }
 
         if (shouldPreserveUserGesture) {

trunk/Source/WebCore/dom/DocumentStorageAccess.h

@@ -47 +47 @@
 };
 
+const unsigned maxNumberOfTimesExplicitlyDeniedFrameSpecificStorageAccess = 2;
+
 class DocumentStorageAccess final : public Supplement<Document>, public CanMakeWeakPtr<DocumentStorageAccess> {
     WTF_MAKE_FAST_ALLOCATED;
@@ -65 +67 @@
     bool hasFrameSpecificStorageAccess() const;
     void setHasFrameSpecificStorageAccess(bool);
+    void setWasExplicitlyDeniedFrameSpecificStorageAccess() { ++m_numberOfTimesExplicitlyDeniedFrameSpecificStorageAccess; };
+    bool isAllowedToRequestFrameSpecificStorageAccess() { return m_numberOfTimesExplicitlyDeniedFrameSpecificStorageAccess < maxNumberOfTimesExplicitlyDeniedFrameSpecificStorageAccess; };
     void enableTemporaryTimeUserGesture();
     void consumeTemporaryTimeUserGesture();
@@ -71 +75 @@
     
     Document& m_document;
+
+    uint8_t m_numberOfTimesExplicitlyDeniedFrameSpecificStorageAccess = 0;
 };