DO NOT REPLY [Bug 30783] New: - Protected Workbook Read Error

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http://issues.apache.org/bugzilla/show_bug.cgi?id=30783

Protected Workbook Read Error

           Summary: Protected Workbook Read Error
           Product: POI
           Version: 2.5
          Platform: PC
        OS/Version: Windows XP
            Status: NEW
          Severity: Major
          Priority: Other
         Component: HSSF
        AssignedTo: poi-dev@jakarta.apache.org
        ReportedBy: chang.zhao@c-reaction.com


Create a new Excel Document, select tools->protect workbook, and type in a 
password.
This will cause

POIFSFileSystem fs = new POIFSFileSystem(i);
HSSFWorkbook wb = new HSSFWorkbook(fs); <=

to fail.

Upon investigation of this bug, it seems that a protected workbook (but not a 
protected sheet) will cause the system to report length inaccurately:

i.e. in FontRecord 
fillFields(byte [] data, short size, int offset)
...
 field_10_font_name_len      = data[ 14 + offset ];
...

on an unprotected workbook would give a sane value like 5.  However, on a 
protected workbook it would report a wierd value like 49.  I believe the 
previous bugs with ArrayOutofBoundsException s might be related to this 
incorrect length reporting.  This is not limited to length, other fields are 
going insane as well.

Further, further investigation turns out that protected workbooks have an extra 
record of type 47, length 56 right between BOF and InterfaceHeader, and it 
looks like every record after that record (including the interfaceheader) got 
everything scambled.


On a related note,  as I was looking at FontRecord.java, in 
fillFields(byte [] data, short size, int offset)

if (data[ 15 ] == 0) {   // is compressed unicode
    field_11_font_name = StringUtil.getFromCompressedUnicode(data, 16,
        LittleEndian.ubyteToInt(field_10_font_name_len));
}

should perhaps be
if (data[ 15 + offset] == 0) {
    field_11_font_name = StringUtil.getFromCompressedUnicode(data, 16 + offset,
         LittleEndian.ubyteToInt(field_10_font_name_len));

}

?  Or is there any reason that offset shouldn't be added?

Thanks,


CZ

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