[jira] [Created] (PDFBOX-5175) Behaviour change in 2.0.20 due to use of IOUtils.populateBuffer in SecurityHandler.prepareAESInitializationVector leading to IOException for certain PDF

["Sebastian Fieber (Jira)" <ji...@apache.org>]

Sebastian Fieber created PDFBOX-5175:
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             Summary: Behaviour change in 2.0.20 due to use of IOUtils.populateBuffer in SecurityHandler.prepareAESInitializationVector leading to IOException for certain PDF 
                 Key: PDFBOX-5175
                 URL: https://issues.apache.org/jira/browse/PDFBOX-5175
             Project: PDFBox
          Issue Type: Bug
          Components: Parsing
    Affects Versions: 2.0.23, 2.0.21, 2.0.20
            Reporter: Sebastian Fieber


We have a PDF file which we cannot share which has a cerification signature from Adobe.

Prior version 2.0.20 this PDF could be loaded and analyzed. From version 2.0.20 and newer calling the load method from PDDocument results in a IOException.

We tracked down the problem why this was not happening in 2.0.19 and found out the populateBuffer method changes the behaviour of the prepareAESInitializationVector method.

Before the code looked like this:
{code:java}
        if (decrypt)
        {
            // read IV from stream
            int ivSize = data.read(iv);
            if (ivSize == -1)
            {
                return false;
            }
            if (ivSize != iv.length)
            {
                throw new IOException(
                        "AES initialization vector not fully read: only "
                                + ivSize + " bytes read instead of " + iv.length);
            }

{code}
if data was empty -1 was returned from the read call and the method returned false and everything went on okay. 2.0.20 introduced changes this line to:
{code:java}
            int ivSize = (int) IOUtils.populateBuffer(data, iv);
            if (ivSize == -1) { 
                return false; 
            }
{code}
Due to the if condition being still there we are not quite sure if this was intentional.

populateBuffer will never return -1 but anything >= 0.

So either this is unintentionally than this is a bug and the if clause should check for 0 bytes read. Or this is intentional and the if clause is obsolete as well as the boolean return value.

Here is a stacktrace (no line numbers, sorry):
{code:java}
Caused by: java.io.IOException: AES initialization vector not fully read: only 0 bytes read instead of 16
	at org.apache.pdfbox@2.0.23/org.apache.pdfbox.pdmodel.encryption.SecurityHandler.prepareAESInitializationVector(Unknown Source)
	at org.apache.pdfbox@2.0.23/org.apache.pdfbox.pdmodel.encryption.SecurityHandler.encryptDataAESother(Unknown Source)
	at org.apache.pdfbox@2.0.23/org.apache.pdfbox.pdmodel.encryption.SecurityHandler.encryptData(Unknown Source)
	at org.apache.pdfbox@2.0.23/org.apache.pdfbox.pdmodel.encryption.SecurityHandler.decryptStream(Unknown Source)
	at org.apache.pdfbox@2.0.23/org.apache.pdfbox.pdfparser.COSParser.parseFileObject(Unknown Source)
	at org.apache.pdfbox@2.0.23/org.apache.pdfbox.pdfparser.COSParser.parseObjectDynamically(Unknown Source)
	at org.apache.pdfbox@2.0.23/org.apache.pdfbox.pdfparser.COSParser.parseObjectDynamically(Unknown Source)
	at org.apache.pdfbox@2.0.23/org.apache.pdfbox.pdfparser.COSParser.parseDictObjects(Unknown Source)
	at org.apache.pdfbox@2.0.23/org.apache.pdfbox.pdfparser.PDFParser.initialParse(Unknown Source)
	at org.apache.pdfbox@2.0.23/org.apache.pdfbox.pdfparser.PDFParser.parse(Unknown Source)
	at org.apache.pdfbox@2.0.23/org.apache.pdfbox.pdmodel.PDDocument.load(Unknown Source)
{code}



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