The Tor Browser: content/canvas/src/CanvasUtils.cpp@6474c204b198 (annotated)

content/canvas/src/CanvasUtils.cpp@6474c204b198 (annotated)

content/canvas/src/CanvasUtils.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /* 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 <stdlib.h>
 #include <stdarg.h>
 #include "prprf.h"
 #include "nsIServiceManager.h"
 #include "nsIConsoleService.h"
 #include "nsIDOMCanvasRenderingContext2D.h"
 #include "nsICanvasRenderingContextInternal.h"
 #include "nsIHTMLCollection.h"
 #include "mozilla/dom/HTMLCanvasElement.h"
 #include "nsIPrincipal.h"
 #include "nsGfxCIID.h"
 #include "nsTArray.h"
 #include "CanvasUtils.h"
 #include "mozilla/gfx/Matrix.h"
 using namespace mozilla::gfx;
 #include "nsIScriptObjectPrincipal.h"
 #include "nsIPermissionManager.h"
 #include "nsIObserverService.h"
 #include "mozilla/Services.h"
 #include "mozIThirdPartyUtil.h"
 #include "nsContentUtils.h"
 #include "nsUnicharUtils.h"
 #include "nsPrintfCString.h"
 #include "nsIConsoleService.h"
 #include "jsapi.h"
 #define TOPIC_CANVAS_PERMISSIONS_PROMPT "canvas-permissions-prompt"
 #define PERMISSION_CANVAS_EXTRACT_DATA "canvas/extractData"
 namespace mozilla {
 namespace CanvasUtils {
 // Check site-specific permission and display prompt if appropriate.
 bool IsImageExtractionAllowed(nsIDocument *aDocument, JSContext *aCx)
 {
   if (!aDocument || !aCx)
     return false;
   nsPIDOMWindow *win = aDocument->GetWindow();
   nsCOMPtr<nsIScriptObjectPrincipal> sop(do_QueryInterface(win));
   if (sop && nsContentUtils::IsSystemPrincipal(sop->GetPrincipal()))
     return true;
   // Don't show canvas prompt for chrome scripts (e.g. Page Inspector)
   if (nsContentUtils::IsCallerChrome())
     return true;
   JS::AutoFilename scriptFile;
   unsigned scriptLine = 0;
   bool isScriptKnown = false;
   if (JS::DescribeScriptedCaller(aCx, &scriptFile, &scriptLine)) {
     isScriptKnown = true;
     // Don't show canvas prompt for PDF.js
     if (scriptFile.get() &&
         strcmp(scriptFile.get(), "resource://pdf.js/build/pdf.js") == 0)
       return true;
   }
   bool isAllowed = false;
   nsCOMPtr<mozIThirdPartyUtil> thirdPartyUtil =
                                 do_GetService(THIRDPARTYUTIL_CONTRACTID);
   nsCOMPtr<nsIPermissionManager> permissionManager =
                           do_GetService(NS_PERMISSIONMANAGER_CONTRACTID);
   if (thirdPartyUtil && permissionManager) {
     nsCOMPtr<nsIURI> uri;
     nsresult rv = thirdPartyUtil->GetFirstPartyURI(NULL, aDocument,
                                                    getter_AddRefs(uri));
     uint32_t permission = nsIPermissionManager::UNKNOWN_ACTION;
     if (NS_SUCCEEDED(rv)) {
       // Allow local files to access canvas data; check content permissions
       // for remote pages.
       bool isFileURL = false;
       (void)uri->SchemeIs("file", &isFileURL);
       if (isFileURL)
         permission = nsIPermissionManager::ALLOW_ACTION;
       else {
         rv = permissionManager->TestPermission(uri,
                                 PERMISSION_CANVAS_EXTRACT_DATA, &permission);
       }
     }
     if (NS_SUCCEEDED(rv)) {
       isAllowed = (permission == nsIPermissionManager::ALLOW_ACTION);
       if (!isAllowed && (permission != nsIPermissionManager::DENY_ACTION)) {
         // 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 document %s, ",  // L10n
                             firstPartySpec.get(), docSpec.get());
         if (isScriptKnown && scriptFile.get()) {
           msg += nsPrintfCString("script from %s:%u",  // L10n
                                  scriptFile.get(), scriptLine);
         } else {
           msg += nsPrintfCString("unknown script");  // L10n
         }
         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);
         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());
         }
       }
     }
   }
   return isAllowed;
 }
 void
 DoDrawImageSecurityCheck(dom::HTMLCanvasElement *aCanvasElement,
                          nsIPrincipal *aPrincipal,
                          bool forceWriteOnly,
                          bool CORSUsed)
 {
     NS_PRECONDITION(aPrincipal, "Must have a principal here");
     // Callers should ensure that mCanvasElement is non-null before calling this
     if (!aCanvasElement) {
         NS_WARNING("DoDrawImageSecurityCheck called without canvas element!");
         return;
     }
     if (aCanvasElement->IsWriteOnly())
         return;
     // If we explicitly set WriteOnly just do it and get out
     if (forceWriteOnly) {
         aCanvasElement->SetWriteOnly();
         return;
     }
     // No need to do a security check if the image used CORS for the load
     if (CORSUsed)
         return;
     if (aCanvasElement->NodePrincipal()->Subsumes(aPrincipal)) {
         // This canvas has access to that image anyway
         return;
     }
     aCanvasElement->SetWriteOnly();
 }
 bool
 CoerceDouble(JS::Value v, double* d)
 {
     if (JSVAL_IS_DOUBLE(v)) {
         *d = JSVAL_TO_DOUBLE(v);
     } else if (JSVAL_IS_INT(v)) {
         *d = double(JSVAL_TO_INT(v));
     } else if (JSVAL_IS_VOID(v)) {
         *d = 0.0;
     } else {
         return false;
     }
     return true;
 }
 } // namespace CanvasUtils
 } // namespace mozilla

The Tor Browser / annotate

content/canvas/src/CanvasUtils.cpp@6474c204b198 (annotated)

content/canvas/src/CanvasUtils.cpp