gecko-dev/dom/canvas/CanvasUtils.cpp
Tom Schuster c25af90ac1 Bug 1453916 - Fix bustage. r=me on CLOSED TREE
--HG--
extra : rebase_source : 6c823c29c324ef297ff0f28bdde9b40d3a8d7a36
2018-05-22 20:46:01 +02:00

280 lines
8.7 KiB
C++

/* -*- 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 "nsIServiceManager.h"
#include "nsIConsoleService.h"
#include "nsICanvasRenderingContextInternal.h"
#include "nsIHTMLCollection.h"
#include "mozilla/dom/HTMLCanvasElement.h"
#include "mozilla/dom/TabChild.h"
#include "mozilla/EventStateManager.h"
#include "nsIPrincipal.h"
#include "nsGfxCIID.h"
#include "nsTArray.h"
#include "CanvasUtils.h"
#include "mozilla/gfx/Matrix.h"
#include "WebGL2Context.h"
#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"
using namespace mozilla::gfx;
namespace mozilla {
namespace CanvasUtils {
bool IsImageExtractionAllowed(nsIDocument *aDocument, JSContext *aCx, nsIPrincipal& aPrincipal)
{
// Do the rest of the checks only if privacy.resistFingerprinting is on.
if (!nsContentUtils::ShouldResistFingerprinting()) {
return true;
}
// Don't proceed if we don't have a document or JavaScript context.
if (!aDocument || !aCx) {
return false;
}
// The system principal can always extract canvas data.
if (nsContentUtils::IsSystemPrincipal(&aPrincipal)) {
return true;
}
// Allow extension principals.
auto principal = BasePrincipal::Cast(&aPrincipal);
if (principal->AddonPolicy() || principal->ContentScriptAddonPolicy()) {
return true;
}
// Get the document URI and its spec.
nsIURI *docURI = aDocument->GetDocumentURI();
nsCString docURISpec;
docURI->GetSpec(docURISpec);
// Allow local files to extract canvas data.
bool isFileURL;
if (NS_SUCCEEDED(docURI->SchemeIs("file", &isFileURL)) && isFileURL) {
return true;
}
// Get calling script file and line for logging.
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;
}
}
nsIDocument* topLevelDocument = aDocument->GetTopLevelContentDocument();
nsIURI *topLevelDocURI = topLevelDocument ? topLevelDocument->GetDocumentURI() : nullptr;
nsCString topLevelDocURISpec;
if (topLevelDocURI) {
topLevelDocURI->GetSpec(topLevelDocURISpec);
}
// Load Third Party Util service.
nsresult rv;
nsCOMPtr<mozIThirdPartyUtil> thirdPartyUtil =
do_GetService(THIRDPARTYUTIL_CONTRACTID, &rv);
NS_ENSURE_SUCCESS(rv, false);
// Block all third-party attempts to extract canvas.
bool isThirdParty = true;
rv = thirdPartyUtil->IsThirdPartyURI(topLevelDocURI, docURI, &isThirdParty);
NS_ENSURE_SUCCESS(rv, false);
if (isThirdParty) {
nsAutoCString message;
message.AppendPrintf("Blocked third party %s in page %s from extracting canvas data.",
docURISpec.get(), topLevelDocURISpec.get());
if (isScriptKnown) {
message.AppendPrintf(" %s:%u.", scriptFile.get(), scriptLine);
}
nsContentUtils::LogMessageToConsole(message.get());
return false;
}
// Load Permission Manager service.
nsCOMPtr<nsIPermissionManager> permissionManager =
do_GetService(NS_PERMISSIONMANAGER_CONTRACTID, &rv);
NS_ENSURE_SUCCESS(rv, false);
// Check if the site has permission to extract canvas data.
// Either permit or block extraction if a stored permission setting exists.
uint32_t permission;
rv = permissionManager->TestPermission(topLevelDocURI,
PERMISSION_CANVAS_EXTRACT_DATA,
&permission);
NS_ENSURE_SUCCESS(rv, false);
switch (permission) {
case nsIPermissionManager::ALLOW_ACTION:
return true;
case nsIPermissionManager::DENY_ACTION:
return false;
default:
break;
}
// At this point, permission is unknown (nsIPermissionManager::UNKNOWN_ACTION).
// Check if the request is in response to user input
if (DOMPrefs::EnableAutoDeclineCanvasPrompts() && !EventStateManager::IsHandlingUserInput()) {
nsAutoCString message;
message.AppendPrintf("Blocked %s in page %s from extracting canvas data because no user input was detected.",
docURISpec.get(), topLevelDocURISpec.get());
if (isScriptKnown) {
message.AppendPrintf(" %s:%u.", scriptFile.get(), scriptLine);
}
nsContentUtils::LogMessageToConsole(message.get());
return false;
}
// It was in response to user input, so log and display the prompt.
nsAutoCString message;
message.AppendPrintf("Blocked %s in page %s from extracting canvas data, but prompting the user.",
docURISpec.get(), topLevelDocURISpec.get());
if (isScriptKnown) {
message.AppendPrintf(" %s:%u.", scriptFile.get(), scriptLine);
}
nsContentUtils::LogMessageToConsole(message.get());
// Prompt the user (asynchronous).
nsPIDOMWindowOuter *win = aDocument->GetWindow();
if (XRE_IsContentProcess()) {
TabChild* tabChild = TabChild::GetFrom(win);
if (tabChild) {
tabChild->SendShowCanvasPermissionPrompt(topLevelDocURISpec);
}
} else {
nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
if (obs) {
obs->NotifyObservers(win, TOPIC_CANVAS_PERMISSIONS_PROMPT,
NS_ConvertUTF8toUTF16(topLevelDocURISpec).get());
}
}
// We don't extract the image for now -- user may override at prompt.
return false;
}
bool
GetCanvasContextType(const nsAString& str, dom::CanvasContextType* const out_type)
{
if (str.EqualsLiteral("2d")) {
*out_type = dom::CanvasContextType::Canvas2D;
return true;
}
if (str.EqualsLiteral("webgl") ||
str.EqualsLiteral("experimental-webgl"))
{
*out_type = dom::CanvasContextType::WebGL1;
return true;
}
if (WebGL2Context::IsSupported()) {
if (str.EqualsLiteral("webgl2")) {
*out_type = dom::CanvasContextType::WebGL2;
return true;
}
}
if (str.EqualsLiteral("bitmaprenderer")) {
*out_type = dom::CanvasContextType::ImageBitmap;
return true;
}
return false;
}
/**
* This security check utility might be called from an source that never taints
* others. For example, while painting a CanvasPattern, which is created from an
* ImageBitmap, onto a canvas. In this case, the caller could set the CORSUsed
* true in order to pass this check and leave the aPrincipal to be a nullptr
* since the aPrincipal is not going to be used.
*/
void
DoDrawImageSecurityCheck(dom::HTMLCanvasElement *aCanvasElement,
nsIPrincipal *aPrincipal,
bool forceWriteOnly,
bool CORSUsed)
{
// 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;
MOZ_ASSERT(aPrincipal, "Must have a principal here");
if (aCanvasElement->NodePrincipal()->Subsumes(aPrincipal)) {
// This canvas has access to that image anyway
return;
}
aCanvasElement->SetWriteOnly();
}
bool
CoerceDouble(const JS::Value& v, double* d)
{
if (v.isDouble()) {
*d = v.toDouble();
} else if (v.isInt32()) {
*d = double(v.toInt32());
} else if (v.isUndefined()) {
*d = 0.0;
} else {
return false;
}
return true;
}
bool
HasDrawWindowPrivilege(JSContext* aCx, JSObject* /* unused */)
{
return nsContentUtils::CallerHasPermission(aCx, nsGkAtoms::all_urlsPermission);
}
} // namespace CanvasUtils
} // namespace mozilla