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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/html/HTMLCanvasElement.h"
     30 #include "core/html/HTMLImageElement.h"
     31 #include "core/html/HTMLVideoElement.h"
     32 #include "core/html/canvas/CanvasPattern.h"
     33 #include "core/loader/cache/ImageResource.h"
     34 #include "weborigin/SecurityOrigin.h"
     35 
     36 namespace WebCore {
     37 
     38 CanvasRenderingContext::CanvasRenderingContext(HTMLCanvasElement* canvas)
     39     : m_canvas(canvas)
     40 {
     41     ScriptWrappable::init(this);
     42 }
     43 
     44 bool CanvasRenderingContext::wouldTaintOrigin(const CanvasPattern* pattern)
     45 {
     46     if (canvas()->originClean() && pattern && !pattern->originClean())
     47         return true;
     48     return false;
     49 }
     50 
     51 bool CanvasRenderingContext::wouldTaintOrigin(const HTMLCanvasElement* sourceCanvas)
     52 {
     53     if (canvas()->originClean() && sourceCanvas && !sourceCanvas->originClean())
     54         return true;
     55     return false;
     56 }
     57 
     58 bool CanvasRenderingContext::wouldTaintOrigin(const HTMLImageElement* image)
     59 {
     60     if (!image || !canvas()->originClean())
     61         return false;
     62 
     63     ImageResource* cachedImage = image->cachedImage();
     64     if (!cachedImage->image()->hasSingleSecurityOrigin())
     65         return true;
     66 
     67     return wouldTaintOrigin(cachedImage->response().url()) && !cachedImage->passesAccessControlCheck(canvas()->securityOrigin());
     68 }
     69 
     70 bool CanvasRenderingContext::wouldTaintOrigin(const HTMLVideoElement* video)
     71 {
     72     // FIXME: This check is likely wrong when a redirect is involved. We need
     73     // to test the finalURL. Please be careful when fixing this issue not to
     74     // make currentSrc be the final URL because then the
     75     // HTMLMediaElement.currentSrc DOM API would leak redirect destinations!
     76     if (!video || !canvas()->originClean())
     77         return false;
     78 
     79     if (!video->hasSingleSecurityOrigin())
     80         return true;
     81 
     82     if (!(video->player() && video->player()->didPassCORSAccessCheck()) && wouldTaintOrigin(video->currentSrc()))
     83         return true;
     84 
     85     return false;
     86 }
     87 
     88 bool CanvasRenderingContext::wouldTaintOrigin(const KURL& url)
     89 {
     90     if (!canvas()->originClean() || m_cleanURLs.contains(url.string()))
     91         return false;
     92 
     93     if (canvas()->securityOrigin()->taintsCanvas(url))
     94         return true;
     95 
     96     if (url.protocolIsData())
     97         return false;
     98 
     99     m_cleanURLs.add(url.string());
    100     return false;
    101 }
    102 
    103 void CanvasRenderingContext::checkOrigin(const KURL& url)
    104 {
    105     if (wouldTaintOrigin(url))
    106         canvas()->setOriginTainted();
    107 }
    108 
    109 } // namespace WebCore
    110