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      1 /*
      2  * Copyright (C) 2009 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #include "config.h"
     27 #include "core/html/canvas/CanvasRenderingContext.h"
     28 
     29 #include "core/fetch/ImageResource.h"
     30 #include "core/html/HTMLImageElement.h"
     31 #include "core/html/HTMLVideoElement.h"
     32 #include "core/html/canvas/CanvasPattern.h"
     33 #include "platform/weborigin/SecurityOrigin.h"
     34 
     35 namespace WebCore {
     36 
     37 CanvasRenderingContext::CanvasRenderingContext(HTMLCanvasElement* canvas)
     38     : m_canvas(canvas)
     39 {
     40     ScriptWrappable::init(this);
     41 }
     42 
     43 bool CanvasRenderingContext::wouldTaintOrigin(const CanvasPattern* pattern)
     44 {
     45     if (canvas()->originClean() && pattern && !pattern->originClean())
     46         return true;
     47     return false;
     48 }
     49 
     50 bool CanvasRenderingContext::wouldTaintOrigin(const HTMLCanvasElement* sourceCanvas)
     51 {
     52     if (canvas()->originClean() && sourceCanvas && !sourceCanvas->originClean())
     53         return true;
     54     return false;
     55 }
     56 
     57 bool CanvasRenderingContext::wouldTaintOrigin(const HTMLImageElement* image)
     58 {
     59     if (!image || !canvas()->originClean())
     60         return false;
     61 
     62     ImageResource* cachedImage = image->cachedImage();
     63     if (!cachedImage->image()->currentFrameHasSingleSecurityOrigin())
     64         return true;
     65 
     66     return wouldTaintOrigin(cachedImage->response().url()) && !cachedImage->passesAccessControlCheck(canvas()->securityOrigin());
     67 }
     68 
     69 bool CanvasRenderingContext::wouldTaintOrigin(const HTMLVideoElement* video)
     70 {
     71     // FIXME: This check is likely wrong when a redirect is involved. We need
     72     // to test the finalURL. Please be careful when fixing this issue not to
     73     // make currentSrc be the final URL because then the
     74     // HTMLMediaElement.currentSrc DOM API would leak redirect destinations!
     75     if (!video || !canvas()->originClean())
     76         return false;
     77 
     78     if (!video->hasSingleSecurityOrigin())
     79         return true;
     80 
     81     if (!(video->player() && video->player()->didPassCORSAccessCheck()) && wouldTaintOrigin(video->currentSrc()))
     82         return true;
     83 
     84     return false;
     85 }
     86 
     87 bool CanvasRenderingContext::wouldTaintOrigin(const KURL& url)
     88 {
     89     if (!canvas()->originClean() || m_cleanURLs.contains(url.string()))
     90         return false;
     91 
     92     if (canvas()->securityOrigin()->taintsCanvas(url))
     93         return true;
     94 
     95     if (url.protocolIsData())
     96         return false;
     97 
     98     m_cleanURLs.add(url.string());
     99     return false;
    100 }
    101 
    102 void CanvasRenderingContext::checkOrigin(const KURL& url)
    103 {
    104     if (wouldTaintOrigin(url))
    105         canvas()->setOriginTainted();
    106 }
    107 
    108 } // namespace WebCore
    109