Unable to read certain PKCS12 keystores from SequenceInputStream

FULL PRODUCT VERSION :


A DESCRIPTION OF THE PROBLEM :
When loading a PKCS12 file (that has a big undefined length DER value in it), i noticed that the loading succeeds when i load it from file directly, but fails when loaded though a servlet:

Exception in thread "main" java.io.IOException: not all indef len BER resolved
at sun.security.util.DerIndefLenConverter.convert(DerIndefLenConverter.java:340)
at sun.security.util.DerValue.init(DerValue.java:376)
at sun.security.util.DerValue.<init>(DerValue.java:320)
at sun.security.pkcs12.PKCS12KeyStore.engineLoad(PKCS12KeyStore.java:1914)
at java.security.KeyStore.load(KeyStore.java:1445)

When loading through a servlet, the container is using a SequenceInputStream (first x bytes are in memory, rest on disk).

Root cause analysis:

When loading a PKCS12 that has an 'indefinite length' value in it, the decoder assumes that stream.available represents the complete 'indefinite.length' section. However, this is not always the case. When using eg a SequenceInputStream, available will only return the available size of one element of the sequence, not the complete sequence.

Relevant code in sun.security.util.DerValue:

if(this.length == -1) {
            int bytes = ((InputStream)in).available();
            byte offset = 2;
            byte[] indefData = new byte[bytes + offset];
            indefData[0] = this.tag;
            indefData[1] = lenByte;
            DataInputStream dis = new DataInputStream((InputStream)in);
            dis.readFully(indefData, offset, bytes);
            dis.close();
            DerIndefLenConverter derIn = new DerIndefLenConverter();
            in = new ByteArrayInputStream(derIn.convert(indefData));
            if(this.tag != ((InputStream)in).read()) {
                throw new IOException("Indefinite length encoding not supported");
            }

            this.length = DerInputStream.getLength((InputStream)in);
        }


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
    public static void main(String[] args) throws KeyStoreException, IOException, CertificateException, NoSuchAlgorithmException
    {
        KeyStore p12 = KeyStore.getInstance("pkcs12");
        File file = new File("test.p12");
        ByteArrayOutputStream os = new ByteArrayOutputStream();
        java.nio.file.Files.copy(file.toPath(), os);
        os.flush();
        byte[] bytes = os.toByteArray();
        p12.load(new ByteArrayInputStream(bytes), "motive".toCharArray());
        int split = 10;
        p12.load(createSplitStream(bytes, split), "motive".toCharArray());

    }

    private static SequenceInputStream createSplitStream(byte[] bytes, int split) {
        return new SequenceInputStream(new ByteArrayInputStream(bytes, 0, split), new ByteArrayInputStream(bytes, split, bytes.length - split));
    }

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Workaround is to store the stream i get from our servlet to a bytearray first and then pass a bytearraystream to keystore.load