test/jdk/sun/security/util/DerInputBuffer/PaddedBitString.java

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/*
 * @test
 * @bug 4511556
 * @summary Verify BitString value containing padding bits is accepted.
 * @modules java.base/sun.security.util
 * @library /test/lib
 */
import java.io.*;
import java.math.BigInteger;
import java.util.Arrays;
import java.util.HexFormat;
import jdk.test.lib.Asserts;
import jdk.test.lib.Utils;

import sun.security.util.BitArray;
import sun.security.util.DerInputStream;

public class PaddedBitString {

    // Relaxed the BitString parsing routine to accept bit strings
    // with padding bits, ex. treat DER_BITSTRING_PAD6_b as the same
    // bit string as DER_BITSTRING_PAD6_0/DER_BITSTRING_NOPAD.
    // Note:
    // 1. the number of padding bits has to be in [0...7]
    // 2. value of the padding bits is ignored

    // With no padding bits
    private final static byte[] DER_BITSTRING_NOPAD = { 3, 3, 0,
                                                   (byte)0x5d, (byte)0xc0 };
    // With 6 zero padding bits (01011101 11000000)
    private final static byte[] DER_BITSTRING_PAD6_0 = { 3, 3, 6,
                                                   (byte)0x5d, (byte)0xc0 };

    // With 6 nonzero padding bits (01011101 11001011)
    private final static byte[] DER_BITSTRING_PAD6_b = { 3, 3, 6,
                                                   (byte)0x5d, (byte)0xcb };

    // With 8 padding bits
    private final static byte[] DER_BITSTRING_PAD8_0 = { 3, 3, 8,
                                                   (byte)0x5d, (byte)0xc0 };

    private final static byte[] BITS = { (byte)0x5d, (byte)0xc0 };

    static enum Type {
        BIT_STRING,
        UNALIGNED_BIT_STRING;
    }

    public static void main(String args[]) throws Exception {
        test(DER_BITSTRING_NOPAD, new BitArray(16, BITS));
        test(DER_BITSTRING_PAD6_0, new BitArray(10, BITS));
        test(DER_BITSTRING_PAD6_b, new BitArray(10, BITS));
        test(DER_BITSTRING_PAD8_0, null);
        System.out.println("Tests Passed");
    }

    private static void test(byte[] in, BitArray ans) throws IOException {
        System.out.println("Testing " +
                HexFormat.of().withUpperCase().formatHex(in));
        for (Type t : Type.values()) {
            DerInputStream derin = new DerInputStream(in);
            boolean shouldPass = (ans != null);
            switch (t) {
            case BIT_STRING:
                if (shouldPass) {
                    Asserts.assertTrue(Arrays.equals(ans.toByteArray(),
                            derin.getBitString()));
                } else {
                    Utils.runAndCheckException(() -> derin.getBitString(),
                            IOException.class);
                }
                break;
            case UNALIGNED_BIT_STRING:
                if (shouldPass) {
                    Asserts.assertEQ(ans, derin.getUnalignedBitString());
                } else {
                    Utils.runAndCheckException(() ->
                            derin.getUnalignedBitString(), IOException.class);
                }
                break;
            }
        }
    }
}