lazy image loading shouldn't read the entire .xls file (tdf#124828)

b1118883 changed msfilter to use
GraphicFilter::ImportUnloadedGraphic() to lazy-load images
from the document. However, that function in some cases simply
reads the entire rest of the passed SvStream, which in this case
is the entire .xls file. And the document from tdf#124828 is ~50MiB
and contains ~4000 images => 100+ GiB memory required.

Change-Id: I74926383204ec642eabb28b62e2cf2e1ff8054a9
Reviewed-on: https://gerrit.libreoffice.org/71136
Tested-by: Jenkins
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
(cherry picked from commit af84fc9d)
Reviewed-on: https://gerrit.libreoffice.org/71221Reviewed-by: Xisco Faulí <xiscofauli@libreoffice.org>

filter/source/msfilter/msdffimp.cxx

@@ -6553,7 +6553,11 @@ bool SvxMSDffManager::GetBLIPDirect( SvStream& rBLIPStream, Graphic& rData, tool
         else
         {   // and unleash our filter
             GraphicFilter& rGF = GraphicFilter::GetGraphicFilter();
-            Graphic aGraphic = rGF.ImportUnloadedGraphic(*pGrStream);
+            // ImportUnloadedGraphic() may simply read the entire rest of the stream,
+            // which may be very large if the whole document is large. Limit the read
+            // size to the size of this record.
+            sal_uInt64 maxSize = pGrStream == &rBLIPStream ? nLength : 0;
+            Graphic aGraphic = rGF.ImportUnloadedGraphic(*pGrStream, maxSize);
             if (aGraphic)
             {
                 rData = aGraphic;

include/vcl/graphicfilter.hxx

@@ -294,7 +294,8 @@ public:
                                    css::uno::Sequence< css::beans::PropertyValue >* pFilterData,
                                    WmfExternal const *pExtHeader = nullptr );
 
-    Graphic ImportUnloadedGraphic(SvStream& rIStream);
+    // Setting sizeLimit limits how much will be read from the stream.
+    Graphic ImportUnloadedGraphic(SvStream& rIStream, sal_uInt64 sizeLimit = 0);
 
     const FilterErrorEx&    GetLastError() const { return *pErrorEx;}
     void                    ResetLastError();

vcl/source/filter/graphicfilter.cxx

@@ -1428,7 +1428,7 @@ void GraphicFilter::ImportGraphics(std::vector< std::shared_ptr<Graphic> >& rGra
     }
 }
 
-Graphic GraphicFilter::ImportUnloadedGraphic(SvStream& rIStream)
+Graphic GraphicFilter::ImportUnloadedGraphic(SvStream& rIStream, sal_uInt64 sizeLimit)
 {
     Graphic aGraphic;
     sal_uInt16 nFormat = GRFILTER_FORMAT_DONTKNOW;
@@ -1443,7 +1443,7 @@ Graphic GraphicFilter::ImportUnloadedGraphic(SvStream& rIStream)
     ErrCode nStatus = ImpTestOrFindFormat("", rIStream, nFormat);
 
     rIStream.Seek(nStreamBegin);
-    const sal_uInt32 nStreamLength(rIStream.remainingSize());
+    const sal_uInt32 nStreamLength( sizeLimit ? sizeLimit : rIStream.remainingSize());
 
     OUString aFilterName = pConfig->GetImportFilterName(nFormat);
     OUString aExternalFilterName = pConfig->GetExternalFilterName(nFormat, false);