PDFXrefStreamParser iterates when no elements are available
-----------------------------------------------------------
Key: PDFBOX-590
URL: https://issues.apache.org/jira/browse/PDFBOX-590
Project: PDFBox
Issue Type: Bug
Reporter: Phil Varner
Exception:
org.apache.pdfbox.exceptions.WrappedIOException
at org.apache.pdfbox.pdfparser.PDFParser.parse(PDFParser.java:237)
at mycompany....
at java.lang.Thread.run(Thread.java:534)
Caused by: java.util.NoSuchElementException
at java.util.AbstractList$Itr.next(AbstractList.java:426)
at
org.apache.pdfbox.pdfparser.PDFXrefStreamParser.parse(PDFXrefStreamParser.java:115)
at
org.apache.pdfbox.cos.COSDocument.parseXrefStreams(COSDocument.java:538)
at org.apache.pdfbox.pdfparser.PDFParser.parse(PDFParser.java:203)
... 11 more
PDF file: www.oppenheim.pl/plpl/_download/09_05_11_Archiv.pdf
This is happening in the PDFXrefStreamParser.parse() method because there is no
objIter.hasNext() test to protect the objIter.next() call on line 115. This is
an outright bug.
Specifically, the current code looks like so:
public void parse() throws IOException {
...
Iterator objIter = objNums.iterator(); //<------- here we create
the Iterator
/*
* Calculating the size of the line in bytes
*/
int w0 = xrefFormat.getInt(0);
int w1 = xrefFormat.getInt(1);
int w2 = xrefFormat.getInt(2);
int lineSize = w0 + w1 + w2;
while(pdfSource.available() > 0)
{
byte[] currLine = new byte[lineSize];
pdfSource.read(currLine);
int type = 0;
/*
* Grabs the number of bytes specified for the first column in
* the W array and stores it.
*/
for(int i = 0; i < w0; i++)
{
type += (currLine[i] & 0x00ff) << ((w0 - i - 1)* 8);
}
//Need to remember the current objID
Integer objID = (Integer)objIter.next(); //<---- here we
attempt to pull objects out of it.
/*
* 3 different types of entries.
*/
switch(type)
{
// ... do stuff ...
}
}
...
}
The code seems to be written with the assumption that if pdfSource.available()
>0 that the object count will have another increment. That seems a bit
vulnerable to corrupt streams. Further it is a logic error because the stream
seems to contain lines of different types not processed as Xref objects. At
least that seems clear from my cursory step through.
I think it should be
while(pdfSource.available() > 0 && objIter.hasNext())
instead, so the call to next() returns the correct Integer when next() is
called later on.
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