filter,sc: try to prevent potential SeekToEndOfRecord infinite loops

SeekToEndOfRecord() now doesn't seek to EOF if the offset is too large;
break out of loops in the obvious cases where this could be problematic.

But don't use SAL_WARN_UNUSED_RESULT because unfortunately GCC doesn't
allow to explicitly suppress that with a (void) cast.

Change-Id: Ie0211075bf0f4ef271bb26bdfead5fb070875a2b

2 files changed, 16 insertions, 15 deletions

diff --git a/sc/source/filter/excel/xiescher.cxx b/sc/source/filter/excel/xiescher.cxx
index fd13897d33d1..3642f86e3e93 100644
--- a/sc/source/filter/excel/xiescher.cxx
+++ b/sc/source/filter/excel/xiescher.cxx
@@ -3681,7 +3681,7 @@ OUString XclImpDffConverter::ReadHlinkProperty( SvStream& rDffStrm ) const
     return aString;
 }
 
-void XclImpDffConverter::ProcessDgContainer( SvStream& rDffStrm, const DffRecordHeader& rDgHeader )
+bool XclImpDffConverter::ProcessDgContainer( SvStream& rDffStrm, const DffRecordHeader& rDgHeader )
 {
     std::size_t nEndPos = rDgHeader.GetRecEndFilePos();
     bool isBreak(false);
@@ -3692,26 +3692,27 @@ void XclImpDffConverter::ProcessDgContainer( SvStream& rDffStrm, const DffRecord
         switch( aHeader.nRecType )
         {
             case DFF_msofbtSolverContainer:
-                ProcessSolverContainer( rDffStrm, aHeader );
+                isBreak = !ProcessSolverContainer( rDffStrm, aHeader );
             break;
             case DFF_msofbtSpgrContainer:
-                ProcessShGrContainer( rDffStrm, aHeader );
+                isBreak = !ProcessShGrContainer( rDffStrm, aHeader );
             break;
             default:
                 isBreak = !aHeader.SeekToEndOfRecord( rDffStrm );
         }
     }
     // seek to end of drawing page container
-    rDgHeader.SeekToEndOfRecord( rDffStrm );
+    isBreak = !rDgHeader.SeekToEndOfRecord( rDffStrm );
 
     // #i12638# #i37900# connector rules
     XclImpSolverContainer& rSolverCont = GetConvData().maSolverCont;
     rSolverCont.UpdateConnectorRules();
     SolveSolver( rSolverCont );
     rSolverCont.RemoveConnectorRules();
+    return !isBreak;
 }
 
-void XclImpDffConverter::ProcessShGrContainer( SvStream& rDffStrm, const DffRecordHeader& rShGrHeader )
+bool XclImpDffConverter::ProcessShGrContainer( SvStream& rDffStrm, const DffRecordHeader& rShGrHeader )
 {
     std::size_t nEndPos = rShGrHeader.GetRecEndFilePos();
     bool isBreak(false);
@@ -3723,27 +3724,27 @@ void XclImpDffConverter::ProcessShGrContainer( SvStream& rDffStrm, const DffReco
         {
             case DFF_msofbtSpgrContainer:
             case DFF_msofbtSpContainer:
-                ProcessShContainer( rDffStrm, aHeader );
+                isBreak = !ProcessShContainer( rDffStrm, aHeader );
             break;
             default:
                 isBreak = !aHeader.SeekToEndOfRecord( rDffStrm );
         }
     }
     // seek to end of shape group container
-    rShGrHeader.SeekToEndOfRecord( rDffStrm );
+    return rShGrHeader.SeekToEndOfRecord( rDffStrm ) && !isBreak;
 }
 
-void XclImpDffConverter::ProcessSolverContainer( SvStream& rDffStrm, const DffRecordHeader& rSolverHeader )
+bool XclImpDffConverter::ProcessSolverContainer( SvStream& rDffStrm, const DffRecordHeader& rSolverHeader )
 {
     // solver container wants to read the solver container header again
     rSolverHeader.SeekToBegOfRecord( rDffStrm );
     // read the entire solver container
     ReadSvxMSDffSolverContainer( rDffStrm, GetConvData().maSolverCont );
     // seek to end of solver container
-    rSolverHeader.SeekToEndOfRecord( rDffStrm );
+    return rSolverHeader.SeekToEndOfRecord( rDffStrm );
 }
 
-void XclImpDffConverter::ProcessShContainer( SvStream& rDffStrm, const DffRecordHeader& rShHeader )
+bool XclImpDffConverter::ProcessShContainer( SvStream& rDffStrm, const DffRecordHeader& rShHeader )
 {
     rShHeader.SeekToBegOfRecord( rDffStrm );
     tools::Rectangle aDummy;
@@ -3757,7 +3758,7 @@ void XclImpDffConverter::ProcessShContainer( SvStream& rDffStrm, const DffRecord
     SdrObjectPtr xSdrObj( ImportObj( rDffStrm, &pDrawObj, aDummy, aDummy ) );
     if( pDrawObj && xSdrObj )
         InsertSdrObject( GetConvData().mrSdrPage, *pDrawObj, xSdrObj.release() );
-    rShHeader.SeekToEndOfRecord( rDffStrm );
+    return rShHeader.SeekToEndOfRecord( rDffStrm );
 }
 
 void XclImpDffConverter::InsertSdrObject( SdrObjList& rObjList, const XclImpDrawObjBase& rDrawObj, SdrObject* pSdrObj )
diff --git a/sc/source/filter/inc/xiescher.hxx b/sc/source/filter/inc/xiescher.hxx
index a4ac864c585d..6d0e7b1d56ef 100644
--- a/sc/source/filter/inc/xiescher.hxx
+++ b/sc/source/filter/inc/xiescher.hxx
@@ -1023,13 +1023,13 @@ private:
     OUString            ReadHlinkProperty( SvStream& rDffStrm ) const;
 
     /** Processes a drawing container (all drawing data of a sheet). */
-    void                ProcessDgContainer( SvStream& rDffStrm, const DffRecordHeader& rDgHeader );
+    bool                ProcessDgContainer( SvStream& rDffStrm, const DffRecordHeader& rDgHeader );
     /** Processes the global shape group container (all shapes of a sheet). */
-    void                ProcessShGrContainer( SvStream& rDffStrm, const DffRecordHeader& rShGrHeader );
+    bool                ProcessShGrContainer( SvStream& rDffStrm, const DffRecordHeader& rShGrHeader );
     /** Processes the solver container (connectors of a sheet). */
-    void                ProcessSolverContainer( SvStream& rDffStrm, const DffRecordHeader& rSolverHeader );
+    bool                ProcessSolverContainer( SvStream& rDffStrm, const DffRecordHeader& rSolverHeader );
     /** Processes a shape or shape group container (one top-level shape). */
-    void                ProcessShContainer( SvStream& rDffStrm, const DffRecordHeader& rShHeader );
+    bool                ProcessShContainer( SvStream& rDffStrm, const DffRecordHeader& rShHeader );
 
     /** Inserts the passed SdrObject into the document. This function takes ownership of pSdrObj! */
     void                InsertSdrObject( SdrObjList& rObjList, const XclImpDrawObjBase& rDrawObj, SdrObject* pSdrObj );