/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @author Stepan M. Mishura
* @version $Revision$
*/
package org.apache.harmony.security.asn1;
import java.io.IOException;
import java.io.InputStream;
import org.apache.harmony.security.internal.nls.Messages;
/**
* Decodes ASN.1 types encoded with DER (X.690)
*
* @see <a href="http://asn1.elibel.tm.fr/en/standards/index.htm">ASN.1</a>
*/
public final class DerInputStream extends BerInputStream {
public DerInputStream(byte[] encoded) throws IOException {
super(encoded, 0, encoded.length);
}
public DerInputStream(byte[] encoded, int offset, int encodingLen)
throws IOException {
super(encoded, offset, encodingLen);
}
public DerInputStream(InputStream in) throws IOException {
super(in);
}
/**
* @see org.apache.harmony.security.asn1.BerInputStream#next()
*/
public final int next() throws IOException {
int tag = super.next();
if (length == INDEFINIT_LENGTH) {
throw new ASN1Exception(Messages.getString("security.105")); //$NON-NLS-1$
}
// FIXME add check: length encoding uses minimum number of octets
return tag;
}
// mask for verifying unused bits for ASN.1 bitstring
private static final byte[] UNUSED_BITS_MASK = new byte[] { 0x01, 0x03,
0x07, 0x0F, 0x1F, 0x3F, 0x7F };
/**
* @see org.apache.harmony.security.asn1.BerInputStream#readBitString()
*/
public void readBitString() throws IOException {
if (tag == ASN1Constants.TAG_C_BITSTRING) {
throw new ASN1Exception(Messages.getString("security.106", tagOffset)); //$NON-NLS-1$
}
super.readBitString();
//check: unused bits values - MUST be 0
if (length > 1
&& buffer[contentOffset] != 0
&& (buffer[offset - 1] & UNUSED_BITS_MASK[buffer[contentOffset] - 1]) != 0) {
throw new ASN1Exception(Messages.getString("security.107", contentOffset)); //$NON-NLS-1$
}
}
/**
* @see org.apache.harmony.security.asn1.BerInputStream#readBoolean()
*/
public void readBoolean() throws IOException {
super.readBoolean();
// check encoded content
if (buffer[contentOffset] != 0 && buffer[contentOffset] != (byte) 0xFF) {
throw new ASN1Exception(Messages.getString("security.108", contentOffset)); //$NON-NLS-1$
}
}
/**
* @see org.apache.harmony.security.asn1.BerInputStream#readOctetString()
*/
public void readOctetString() throws IOException {
if (tag == ASN1Constants.TAG_C_OCTETSTRING) {
throw new ASN1Exception(
Messages.getString("security.109", tagOffset)); //$NON-NLS-1$
}
super.readOctetString();
}
/**
* @see org.apache.harmony.security.asn1.BerInputStream#readSequence(org.apache.harmony.security.asn1.ASN1Sequence)
*/
public void readSequence(ASN1Sequence sequence) throws IOException {
//
// According to ASN.1 DER spec. sequence MUST not include
// any encoding which value is equal to its default value
//
// Verification of this assertion is not implemented
//
super.readSequence(sequence);
}
/**
* @see org.apache.harmony.security.asn1.BerInputStream#readSetOf(org.apache.harmony.security.asn1.ASN1SetOf)
*/
public void readSetOf(ASN1SetOf setOf) throws IOException {
//
// According to ASN.1 DER spec. set of MUST appear in
// ascending order (short component are padded for comparison)
//
// Verification of this assertion is not implemented
//
super.readSetOf(setOf);
}
/**
* @see org.apache.harmony.security.asn1.BerInputStream#readString(ASN1StringType)
*/
public void readString(ASN1StringType type) throws IOException {
if (tag == type.constrId) {
throw new ASN1Exception(Messages.getString("security.10A", tagOffset)); //$NON-NLS-1$
}
super.readString(type);
}
/**
* @see org.apache.harmony.security.asn1.BerInputStream#readUTCTime()
*/
public void readUTCTime() throws IOException {
if (tag == ASN1Constants.TAG_C_UTCTIME) {
// It is a string type and it can be encoded as primitive or constructed.
throw new ASN1Exception(Messages.getString("security.10B", tagOffset)); //$NON-NLS-1$
}
// check format: DER uses YYMMDDHHMMSS'Z' only
if (length != ASN1UTCTime.UTC_HMS) {
throw new ASN1Exception(Messages.getString("security.10C", tagOffset)); //$NON-NLS-1$
}
super.readUTCTime();
}
/**
* @see org.apache.harmony.security.asn1.BerInputStream#readGeneralizedTime()
*/
public void readGeneralizedTime() throws IOException {
if (tag == ASN1Constants.TAG_C_GENERALIZEDTIME) {
// It is a string type and it can be encoded as primitive or constructed.
throw new ASN1Exception(Messages.getString("security.10D", tagOffset)); //$NON-NLS-1$
}
super.readGeneralizedTime();
// FIXME makes sense only if we support all GeneralizedTime formats
// late check syntax: the last char MUST be Z
//if (buffer[offset - 1] != 'Z') {
// throw new ASN1Exception(
// "ASN.1 GeneralizedTime wrongly encoded at ["
// + contentOffset + ']');
//}
// the fractional-seconds elements, if present MUST
// omit all trailing zeros
// FIXME implement me
// if () {
// throw new IOException(
// "DER ASN.1 GeneralizedTime wrongly encoded at ["
// + contentOffset
// + "]. Trailing zeros MUST be omitted");
// }
}
}
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