bundles/org.eclipse.osgi/security/src/org/eclipse/osgi/internal/signedcontent/BERProcessor.java - equinox/rt.equinox.framework - Git at Google

 /*******************************************************************************
  * Copyright (c) 2006, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.osgi.internal.signedcontent;

 import java.math.BigInteger;
 import java.security.SignatureException;

 /**
  * This is a simple class that processes BER structures. This class
  * uses BER processing as outlined in X.690.
  */
 public class BERProcessor {
 	/**
 	 * This is the buffer that contains the BER structures that are being interrogated.
 	 */
 	byte buffer[];
 	/**
 	 * The offset into <code>buffer</code> to the start of the structure being interrogated.
 	 * If the offset is -1 that means that we have read the last structure.
 	 */
 	int offset;
 	/**
 	 * The last valid offset in <code>buffer</code>.
 	 */
 	int lastOffset;
 	/**
 	 * The offset into <code>buffer</code> to the start of the content of the structure
 	 * being interrogated.
 	 */
 	int contentOffset;
 	/**
 	 * The length of the content of the structure being interrogated.
 	 */
 	int contentLength;
 	/**
 	 * The offset into <code>buffer</code> of the end of the structure being interrogated.
 	 */
 	int endOffset;
 	/**
 	 * The class of the tag of the current structure.
 	 */
 	int classOfTag;
 	static final int UNIVERSAL_TAGCLASS = 0;
 	static final int APPLICATION_TAGCLASS = 1;
 	static final int CONTEXTSPECIFIC_TAGCLASS = 2;
 	static final int PRIVATE_TAGCLASS = 3;

 	static final byte BOOLTAG = 1;
 	static final byte INTTAG = 2;
 	static final byte OIDTAG = 6;
 	static final byte SEQTAG = 16;
 	static final byte SETTAG = 17;
 	static final byte NULLTAG = 5;

 	/**
 	 * Tagnames used in toString()
 	 */
 	static final String tagNames[] = {"<null>", "boolean", "int", "bitstring", "octetstring", "null", "objid", "objdesc", "external", "real", "enum", "pdv", "utf8", "relobjid", "resv", "resv", "sequence", "set", "char string"}; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$ //$NON-NLS-5$ //$NON-NLS-6$ //$NON-NLS-7$ //$NON-NLS-8$ //$NON-NLS-9$ //$NON-NLS-10$ //$NON-NLS-11$ //$NON-NLS-12$ //$NON-NLS-13$ //$NON-NLS-14$ //$NON-NLS-15$ //$NON-NLS-16$ //$NON-NLS-17$ //$NON-NLS-18$ //$NON-NLS-19$

 	/**
 	 * True if this is a structure for a constructed encoding.
 	 */
 	public boolean constructed;
 	/**
 	 * The tag type. Note that X.690 specifies encodings for tags with values greater than 31,
 	 * but currently this class does not handle these kinds of tags.
 	 */
 	public byte tag;

 	/**
 	 * Constructs a BERProcessor to operate on the passed buffer. The first structure in the
 	 * buffer will be processed before this method returns.
 	 *
 	 * @param buffer the buffer containing the BER structures.
 	 * @param offset the offset into <code>buffer</code> to the start of the first structure.
 	 * @param len the length of the BER structure.
 	 * @throws SignatureException
 	 */
 	public BERProcessor(byte buffer[], int offset, int len) throws SignatureException {
 		this.buffer = buffer;
 		this.offset = offset;
 		lastOffset = len + offset;
 		processStructure();
 	}

 	/**
 	 * Parse the structure found at the current <code>offset</code> into <code>buffer</code>.
 	 * Most methods, constructor, and stepinto, will call this method automatically. If
 	 * <code>offset</code> is modified outside of those methods, this method will need to
 	 * be invoked.
 	 */
 	public void processStructure() throws SignatureException {
 		// Don't process if we are at the end
 		if (offset == -1)
 			return;
 		endOffset = offset;
 		// section 8.1.2.2
 		classOfTag = (buffer[offset] & 0xff) >> 6;
 		// section 8.1.2.5
 		constructed = (buffer[offset] & 0x20) != 0;
 		// section 8.1.2.3
 		byte tagNumber = (byte) (buffer[offset] & 0x1f);
 		if (tagNumber < 32) {
 			tag = tagNumber;
 			endOffset = offset + 1;
 		} else {
 			throw new SignatureException("Can't handle tags > 32"); //$NON-NLS-1$
 		}
 		if ((buffer[endOffset] & 0x80) == 0) {
 			// section 8.1.3.4 (doing the short form of the length)
 			contentLength = buffer[endOffset];
 			endOffset++;
 		} else {
 			// section 8.1.3.5 (doing the long form of the length)
 			int octetCount = buffer[endOffset] & 0x7f;
 			if (octetCount > 3)
 				throw new SignatureException("ContentLength octet count too large: " + octetCount); //$NON-NLS-1$
 			contentLength = 0;
 			endOffset++;
 			for (int i = 0; i < octetCount; i++) {
 				contentLength <<= 8;
 				contentLength |= buffer[endOffset] & 0xff;
 				endOffset++;
 			}
 			// section 8.1.3.6 (doing the indefinite form
 			if (octetCount == 0)
 				contentLength = -1;
 		}
 		contentOffset = endOffset;
 		if (contentLength != -1)
 			endOffset += contentLength;
 		if (endOffset > lastOffset)
 			throw new SignatureException("Content length too large: " + endOffset + " > " + lastOffset); //$NON-NLS-1$ //$NON-NLS-2$
 	}

 	/**
 	 * Returns a String representation of the current BER structure.
 	 * @return a String representation of the current BER structure.
 	 * @see java.lang.Object#toString()
 	 */
 	public String toString() {
 		StringBuffer sb = new StringBuffer();
 		switch (classOfTag) {
 			case UNIVERSAL_TAGCLASS :
 				sb.append('U');
 				break;
 			case APPLICATION_TAGCLASS :
 				sb.append('A');
 				break;
 			case CONTEXTSPECIFIC_TAGCLASS :
 				sb.append('C');
 				break;
 			case PRIVATE_TAGCLASS :
 				sb.append('P');
 				break;
 		}
 		sb.append(constructed ? 'C' : 'P');
 		sb.append(" tag=" + tag); //$NON-NLS-1$
 		if (tag < tagNames.length) {
 			sb.append("(" + tagNames[tag] + ")"); //$NON-NLS-1$ //$NON-NLS-2$
 		}
 		sb.append(" len="); //$NON-NLS-1$
 		sb.append(contentLength);
 		switch (tag) {
 			case INTTAG :
 				sb.append(" value=" + getIntValue()); //$NON-NLS-1$
 				break;
 			case OIDTAG :
 				sb.append(" value="); //$NON-NLS-1$
 				int oid[] = getObjId();
 				for (int i = 0; i < oid.length; i++) {
 					if (i > 0)
 						sb.append('.');
 					sb.append(oid[i]);
 				}
 		}
 		if (tag == 12 || (tag >= 18 && tag <= 22) || (tag >= 25 && tag <= 30)) {
 			sb.append(" value="); //$NON-NLS-1$
 			sb.append(getString());
 		}
 		return sb.toString();
 	}

 	/**
 	 * Returns a BERProcessor for the content of the current structure.
 	 * @throws SignatureException
 	 */
 	public BERProcessor stepInto() throws SignatureException {
 		return new BERProcessor(buffer, contentOffset, contentLength);
 	}

 	public void stepOver() throws SignatureException {
 		offset = endOffset;
 		if (endOffset >= lastOffset) {
 			offset = -1;
 			return;
 		}
 		processStructure();
 	}

 	public boolean endOfSequence() {
 		return offset == -1;
 	}

 	/**
 	 * Gets the content from the current structure as a String.
 	 * @return the content from the current structure as a String.
 	 */
 	public String getString() {
 		return new String(buffer, contentOffset, contentLength);
 	}

 	/**
 	 * Gets the content from the current structure as an int.
 	 * @return the content from the current structure as an int.
 	 */
 	public BigInteger getIntValue() {
 		return new BigInteger(getBytes());
 	}

 	/**
 	 * Gets the content from the current structure as an object id (int[]).
 	 * @return the content from the current structure as an object id (int[]).
 	 */
 	public int[] getObjId() {
 		// First count the ids
 		int count = 0;
 		for (int i = 0; i < contentLength; i++) {
 			// section 8.19.2
 			if ((buffer[contentOffset + i] & 0x80) == 0)
 				count++;
 		}
 		count++; // section 8.19.3
 		int oid[] = new int[count];
 		int index = 0;
 		int currentValue = 0;
 		for (int i = 0; i < contentLength; i++) {
 			currentValue <<= 7;
 			currentValue |= buffer[contentOffset + i] & 0x7f;
 			// section 8.19.2
 			if ((buffer[contentOffset + i] & 0x80) == 0) {
 				if (index == 0) {
 					// section 8.19.4 special processing
 					oid[index++] = currentValue / 40;
 					oid[index++] = currentValue % 40;
 				} else {
 					oid[index++] = currentValue;
 				}
 				currentValue = 0;
 			}
 		}
 		return oid;
 	}

 	/**
 	 * Get a copy of the bytes in the content of the current structure.
 	 * @return a copy of the bytes in the content of the current structure.
 	 */
 	public byte[] getBytes() {
 		byte v[] = new byte[contentLength];
 		System.arraycopy(buffer, contentOffset, v, 0, contentLength);
 		return v;
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2006, 2007 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/

	package org.eclipse.osgi.internal.signedcontent;

	import java.math.BigInteger;
	import java.security.SignatureException;

	/**
	* This is a simple class that processes BER structures. This class
	* uses BER processing as outlined in X.690.
	*/
	public class BERProcessor {
	/**
	* This is the buffer that contains the BER structures that are being interrogated.
	*/
	byte buffer[];
	/**
	* The offset into <code>buffer</code> to the start of the structure being interrogated.
	* If the offset is -1 that means that we have read the last structure.
	*/
	int offset;
	/**
	* The last valid offset in <code>buffer</code>.
	*/
	int lastOffset;
	/**
	* The offset into <code>buffer</code> to the start of the content of the structure
	* being interrogated.
	*/
	int contentOffset;
	/**
	* The length of the content of the structure being interrogated.
	*/
	int contentLength;
	/**
	* The offset into <code>buffer</code> of the end of the structure being interrogated.
	*/
	int endOffset;
	/**
	* The class of the tag of the current structure.
	*/
	int classOfTag;
	static final int UNIVERSAL_TAGCLASS = 0;
	static final int APPLICATION_TAGCLASS = 1;
	static final int CONTEXTSPECIFIC_TAGCLASS = 2;
	static final int PRIVATE_TAGCLASS = 3;

	static final byte BOOLTAG = 1;
	static final byte INTTAG = 2;
	static final byte OIDTAG = 6;
	static final byte SEQTAG = 16;
	static final byte SETTAG = 17;
	static final byte NULLTAG = 5;

	/**
	* Tagnames used in toString()
	*/
	static final String tagNames[] = {"<null>", "boolean", "int", "bitstring", "octetstring", "null", "objid", "objdesc", "external", "real", "enum", "pdv", "utf8", "relobjid", "resv", "resv", "sequence", "set", "char string"}; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$ //$NON-NLS-5$ //$NON-NLS-6$ //$NON-NLS-7$ //$NON-NLS-8$ //$NON-NLS-9$ //$NON-NLS-10$ //$NON-NLS-11$ //$NON-NLS-12$ //$NON-NLS-13$ //$NON-NLS-14$ //$NON-NLS-15$ //$NON-NLS-16$ //$NON-NLS-17$ //$NON-NLS-18$ //$NON-NLS-19$

	/**
	* True if this is a structure for a constructed encoding.
	*/
	public boolean constructed;
	/**
	* The tag type. Note that X.690 specifies encodings for tags with values greater than 31,
	* but currently this class does not handle these kinds of tags.
	*/
	public byte tag;

	/**
	* Constructs a BERProcessor to operate on the passed buffer. The first structure in the
	* buffer will be processed before this method returns.
	*
	* @param buffer the buffer containing the BER structures.
	* @param offset the offset into <code>buffer</code> to the start of the first structure.
	* @param len the length of the BER structure.
	* @throws SignatureException
	*/
	public BERProcessor(byte buffer[], int offset, int len) throws SignatureException {
	this.buffer = buffer;
	this.offset = offset;
	lastOffset = len + offset;
	processStructure();
	}

	/**
	* Parse the structure found at the current <code>offset</code> into <code>buffer</code>.
	* Most methods, constructor, and stepinto, will call this method automatically. If
	* <code>offset</code> is modified outside of those methods, this method will need to
	* be invoked.
	*/
	public void processStructure() throws SignatureException {
	// Don't process if we are at the end
	if (offset == -1)
	return;
	endOffset = offset;
	// section 8.1.2.2
	classOfTag = (buffer[offset] & 0xff) >> 6;
	// section 8.1.2.5
	constructed = (buffer[offset] & 0x20) != 0;
	// section 8.1.2.3
	byte tagNumber = (byte) (buffer[offset] & 0x1f);
	if (tagNumber < 32) {
	tag = tagNumber;
	endOffset = offset + 1;
	} else {
	throw new SignatureException("Can't handle tags > 32"); //$NON-NLS-1$
	}
	if ((buffer[endOffset] & 0x80) == 0) {
	// section 8.1.3.4 (doing the short form of the length)
	contentLength = buffer[endOffset];
	endOffset++;
	} else {
	// section 8.1.3.5 (doing the long form of the length)
	int octetCount = buffer[endOffset] & 0x7f;
	if (octetCount > 3)
	throw new SignatureException("ContentLength octet count too large: " + octetCount); //$NON-NLS-1$
	contentLength = 0;
	endOffset++;
	for (int i = 0; i < octetCount; i++) {
	contentLength <<= 8;
	contentLength \|= buffer[endOffset] & 0xff;
	endOffset++;
	}
	// section 8.1.3.6 (doing the indefinite form
	if (octetCount == 0)
	contentLength = -1;
	}
	contentOffset = endOffset;
	if (contentLength != -1)
	endOffset += contentLength;
	if (endOffset > lastOffset)
	throw new SignatureException("Content length too large: " + endOffset + " > " + lastOffset); //$NON-NLS-1$ //$NON-NLS-2$
	}

	/**
	* Returns a String representation of the current BER structure.
	* @return a String representation of the current BER structure.
	* @see java.lang.Object#toString()
	*/
	public String toString() {
	StringBuffer sb = new StringBuffer();
	switch (classOfTag) {
	case UNIVERSAL_TAGCLASS :
	sb.append('U');
	break;
	case APPLICATION_TAGCLASS :
	sb.append('A');
	break;
	case CONTEXTSPECIFIC_TAGCLASS :
	sb.append('C');
	break;
	case PRIVATE_TAGCLASS :
	sb.append('P');
	break;
	}
	sb.append(constructed ? 'C' : 'P');
	sb.append(" tag=" + tag); //$NON-NLS-1$
	if (tag < tagNames.length) {
	sb.append("(" + tagNames[tag] + ")"); //$NON-NLS-1$ //$NON-NLS-2$
	}
	sb.append(" len="); //$NON-NLS-1$
	sb.append(contentLength);
	switch (tag) {
	case INTTAG :
	sb.append(" value=" + getIntValue()); //$NON-NLS-1$
	break;
	case OIDTAG :
	sb.append(" value="); //$NON-NLS-1$
	int oid[] = getObjId();
	for (int i = 0; i < oid.length; i++) {
	if (i > 0)
	sb.append('.');
	sb.append(oid[i]);
	}
	}
	if (tag == 12 \|\| (tag >= 18 && tag <= 22) \|\| (tag >= 25 && tag <= 30)) {
	sb.append(" value="); //$NON-NLS-1$
	sb.append(getString());
	}
	return sb.toString();
	}

	/**
	* Returns a BERProcessor for the content of the current structure.
	* @throws SignatureException
	*/
	public BERProcessor stepInto() throws SignatureException {
	return new BERProcessor(buffer, contentOffset, contentLength);
	}

	public void stepOver() throws SignatureException {
	offset = endOffset;
	if (endOffset >= lastOffset) {
	offset = -1;
	return;
	}
	processStructure();
	}

	public boolean endOfSequence() {
	return offset == -1;
	}

	/**
	* Gets the content from the current structure as a String.
	* @return the content from the current structure as a String.
	*/
	public String getString() {
	return new String(buffer, contentOffset, contentLength);
	}

	/**
	* Gets the content from the current structure as an int.
	* @return the content from the current structure as an int.
	*/
	public BigInteger getIntValue() {
	return new BigInteger(getBytes());
	}

	/**
	* Gets the content from the current structure as an object id (int[]).
	* @return the content from the current structure as an object id (int[]).
	*/
	public int[] getObjId() {
	// First count the ids
	int count = 0;
	for (int i = 0; i < contentLength; i++) {
	// section 8.19.2
	if ((buffer[contentOffset + i] & 0x80) == 0)
	count++;
	}
	count++; // section 8.19.3
	int oid[] = new int[count];
	int index = 0;
	int currentValue = 0;
	for (int i = 0; i < contentLength; i++) {
	currentValue <<= 7;
	currentValue \|= buffer[contentOffset + i] & 0x7f;
	// section 8.19.2
	if ((buffer[contentOffset + i] & 0x80) == 0) {
	if (index == 0) {
	// section 8.19.4 special processing
	oid[index++] = currentValue / 40;
	oid[index++] = currentValue % 40;
	} else {
	oid[index++] = currentValue;
	}
	currentValue = 0;
	}
	}
	return oid;
	}

	/**
	* Get a copy of the bytes in the content of the current structure.
	* @return a copy of the bytes in the content of the current structure.
	*/
	public byte[] getBytes() {
	byte v[] = new byte[contentLength];
	System.arraycopy(buffer, contentOffset, v, 0, contentLength);
	return v;
	}

	}