Diego Rodrigues Azevedo created PDFBOX-3230:
-----------------------------------------------
Summary: Can't cast CosObject to CosStream when it is a Stream
Key: PDFBOX-3230
URL: https://issues.apache.org/jira/browse/PDFBOX-3230
Project: PDFBox
Issue Type: Bug
Affects Versions: 2.0.0
Environment: Windows 8.1, Java 8 u60, maven 3.2.2, PDFBOX 2.0.0-RC3
Reporter: Diego Rodrigues Azevedo
Problem:
When using digital signatures, one can add a DSS dictionary, referencing
Certificates, CRLs, OCSPs... saved as Streams (CosStream) in the PDF.
So, I signed my PDF with a DSS dictionary, and I want to re-sign it, checking
if any one of the streams is already there (same certificate chain, maybe same
CRLs (if the first signature wasn't made long ago)...)
How do I do this? I get the latest DSS dictionary and iterate over the
COSArray, knowing the elements must be CosStreams. But then I get a
ClassCastException, saying CosObject cannot be cast to CosStream. When I check
that CosObject in notepad, I can check it is a CosStream
Code (proof of concept):
<code>
private COSStream createStramIfNotExists(byte[] stream, String dssEntry)
throws IOException {
COSArray things = (COSArray) this.dictionary
.getDictionaryObject(dssEntry);
ByteArrayOutputStream out = null;
for (COSBase thing : things) {
InputStream input = null;
byte[] aux = null;
try {
System.out.println(thing);
out = new ByteArrayOutputStream();
input = ((COSStream)
thing.getCOSObject()).createInputStream();
IOUtils.copy(input, out);
aux = out.toByteArray();
} catch (IOException e) {
e.printStackTrace();
} finally {
IOUtils.closeQuietly(input);
IOUtils.closeQuietly(out);
}
if (Arrays.areEqual(stream, aux)) {
return (COSStream) thing;
}
}
COSStream cosStream = new COSStream();
OutputStream out1 = cosStream.createOutputStream();
out1.write(stream);
out1.close();
return cosStream;
}
</code>
That sysout prints "COSObject{170, 0}" in the PDF attached when my DSS entry is
"Certs", and throws the exception on line "input = ((COSStream)
thing.getCOSObject()).createInputStream();"
But if you open the PDF on notepad++ or similar, you'll see that object 170
(170 0 obj) is a stream.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
