[
https://issues.apache.org/jira/browse/PDFBOX-3230?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Diego Rodrigues Azevedo updated PDFBOX-3230:
--------------------------------------------
Description:
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:java}
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.
was:
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:java}
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.
> 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
> Attachments: TestFile-assinado.pdf
>
>
> 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:java}
> 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.
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