[tbb-commits] [tor-browser/tor-browser-24.7.0esr-3.x-1] fixup! Add canvas image extraction prompt.

[mikeperry at torproject.org]

commit e3d04fb74ac49a2e3f4d074d0e3ea6edec77b8c3
Author: Isis Lovecruft <isis at torproject.org>
Date:   Sun Aug 17 01:31:03 2014 +0000

    fixup! Add canvas image extraction prompt.
    
    Modify Pearl Crescent's #7265 patch to log all HTML5 canvas access attempts.
---
 content/canvas/src/CanvasUtils.cpp |   42 ++++++++++++++++++++++++++++++------
 1 file changed, 35 insertions(+), 7 deletions(-)

diff --git a/content/canvas/src/CanvasUtils.cpp b/content/canvas/src/CanvasUtils.cpp
index 203dd92..f2f4536 100644
--- a/content/canvas/src/CanvasUtils.cpp
+++ b/content/canvas/src/CanvasUtils.cpp
@@ -33,6 +33,8 @@ using namespace mozilla::gfx;
 #include "mozIThirdPartyUtil.h"
 #include "nsContentUtils.h"
 #include "nsUnicharUtils.h"
+#include "nsPrintfCString.h"
+#include "nsIConsoleService.h"
 
 #define TOPIC_CANVAS_PERMISSIONS_PROMPT "canvas-permissions-prompt"
 #define PERMISSION_CANVAS_EXTRACT_DATA "canvas/extractData"
@@ -79,14 +81,40 @@ IsImageExtractionAllowed(nsIDocument *aDocument)
       isAllowed = (permission == nsIPermissionManager::ALLOW_ACTION);
 
       if (!isAllowed && (permission != nsIPermissionManager::DENY_ACTION)) {
-        // Send notification so that a prompt is displayed.
-        nsCString spec;
-        rv = uri->GetSpec(spec);
+        // Log all attempted canvas access and block access by third parties.
+        bool isThirdParty = true;
+        nsIURI *docURI = aDocument->GetDocumentURI();
+        rv = thirdPartyUtil->IsThirdPartyURI(uri, docURI, &isThirdParty);
+        NS_ENSURE_SUCCESS(rv, false);
+
+        nsCString firstPartySpec;
+        rv = uri->GetSpec(firstPartySpec);
+        nsCString docSpec;
+        docURI->GetSpec(docSpec);
+        nsPrintfCString msg("On %s: blocked access to canvas image data"
+                            " from %s ",  // L10n
+                            firstPartySpec.get(), docSpec.get());
+
+        nsCOMPtr<nsIConsoleService> console
+                              (do_GetService(NS_CONSOLESERVICE_CONTRACTID));
+        if (console)
+          console->LogStringMessage(NS_ConvertUTF8toUTF16(msg).get());
+
+        // Log every canvas access attempt to stdout if debugging:
+#ifdef DEBUG
+        printf("%s\n", msg.get());
+#endif
+        // Ensure URI is valid after logging, but before trying to notify the
+        // user:
         NS_ENSURE_SUCCESS(rv, false);
-        nsCOMPtr<nsIObserverService> obs =
-                                    mozilla::services::GetObserverService();
-        obs->NotifyObservers(win, TOPIC_CANVAS_PERMISSIONS_PROMPT,
-                             NS_ConvertUTF8toUTF16(spec).get());
+
+        if (!isThirdParty) {
+          // Send notification so that a prompt is displayed.
+          nsCOMPtr<nsIObserverService> obs =
+                                       mozilla::services::GetObserverService();
+          obs->NotifyObservers(win, TOPIC_CANVAS_PERMISSIONS_PROMPT,
+                               NS_ConvertUTF8toUTF16(firstPartySpec).get());
+        }
       }
     }
   }