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	/*
	* Copyright (c) 1996, 2018, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.security.pkcs;

	import java.io.OutputStream;
	import java.io.IOException;
	import java.math.BigInteger;
	import java.security.cert.CertPathValidatorException;
	import java.security.cert.CertificateException;
	import java.security.cert.CertificateFactory;
	import java.security.cert.CertPath;
	import java.security.cert.X509Certificate;
	import java.security.*;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Collections;
	import java.util.EnumSet;
	import java.util.Set;

	import sun.security.timestamp.TimestampToken;
	import sun.security.util.ConstraintsParameters;
	import sun.security.util.Debug;
	import sun.security.util.DerEncoder;
	import sun.security.util.DerInputStream;
	import sun.security.util.DerOutputStream;
	import sun.security.util.DerValue;
	import sun.security.util.DisabledAlgorithmConstraints;
	import sun.security.util.HexDumpEncoder;
	import sun.security.util.KeyUtil;
	import sun.security.util.ObjectIdentifier;
	import sun.security.x509.AlgorithmId;
	import sun.security.x509.X500Name;
	import sun.security.x509.KeyUsageExtension;
	import sun.security.util.SignatureUtil;

	/**
	* A SignerInfo, as defined in PKCS#7's signedData type.
	*
	* @author Benjamin Renaud
	*/
	public class SignerInfo implements DerEncoder {

	// Digest and Signature restrictions
	private static final Set<CryptoPrimitive> DIGEST_PRIMITIVE_SET =
	Collections.unmodifiableSet(EnumSet.of(CryptoPrimitive.MESSAGE_DIGEST));

	private static final Set<CryptoPrimitive> SIG_PRIMITIVE_SET =
	Collections.unmodifiableSet(EnumSet.of(CryptoPrimitive.SIGNATURE));

	private static final DisabledAlgorithmConstraints JAR_DISABLED_CHECK =
	new DisabledAlgorithmConstraints(
	DisabledAlgorithmConstraints.PROPERTY_JAR_DISABLED_ALGS);

	BigInteger version;
	X500Name issuerName;
	BigInteger certificateSerialNumber;
	AlgorithmId digestAlgorithmId;
	AlgorithmId digestEncryptionAlgorithmId;
	byte[] encryptedDigest;
	Timestamp timestamp;
	private boolean hasTimestamp = true;
	private static final Debug debug = Debug.getInstance("jar");

	PKCS9Attributes authenticatedAttributes;
	PKCS9Attributes unauthenticatedAttributes;

	public SignerInfo(X500Name issuerName,
	BigInteger serial,
	AlgorithmId digestAlgorithmId,
	AlgorithmId digestEncryptionAlgorithmId,
	byte[] encryptedDigest) {
	this.version = BigInteger.ONE;
	this.issuerName = issuerName;
	this.certificateSerialNumber = serial;
	this.digestAlgorithmId = digestAlgorithmId;
	this.digestEncryptionAlgorithmId = digestEncryptionAlgorithmId;
	this.encryptedDigest = encryptedDigest;
	}

	public SignerInfo(X500Name issuerName,
	BigInteger serial,
	AlgorithmId digestAlgorithmId,
	PKCS9Attributes authenticatedAttributes,
	AlgorithmId digestEncryptionAlgorithmId,
	byte[] encryptedDigest,
	PKCS9Attributes unauthenticatedAttributes) {
	this.version = BigInteger.ONE;
	this.issuerName = issuerName;
	this.certificateSerialNumber = serial;
	this.digestAlgorithmId = digestAlgorithmId;
	this.authenticatedAttributes = authenticatedAttributes;
	this.digestEncryptionAlgorithmId = digestEncryptionAlgorithmId;
	this.encryptedDigest = encryptedDigest;
	this.unauthenticatedAttributes = unauthenticatedAttributes;
	}

	/**
	* Parses a PKCS#7 signer info.
	*/
	public SignerInfo(DerInputStream derin)
	throws IOException, ParsingException
	{
	this(derin, false);
	}

	/**
	* Parses a PKCS#7 signer info.
	*
	* <p>This constructor is used only for backwards compatibility with
	* PKCS#7 blocks that were generated using JDK1.1.x.
	*
	* @param derin the ASN.1 encoding of the signer info.
	* @param oldStyle flag indicating whether or not the given signer info
	* is encoded according to JDK1.1.x.
	*/
	public SignerInfo(DerInputStream derin, boolean oldStyle)
	throws IOException, ParsingException
	{
	// version
	version = derin.getBigInteger();

	// issuerAndSerialNumber
	DerValue[] issuerAndSerialNumber = derin.getSequence(2);
	byte[] issuerBytes = issuerAndSerialNumber[0].toByteArray();
	issuerName = new X500Name(new DerValue(DerValue.tag_Sequence,
	issuerBytes));
	certificateSerialNumber = issuerAndSerialNumber[1].getBigInteger();

	// digestAlgorithmId
	DerValue tmp = derin.getDerValue();

	digestAlgorithmId = AlgorithmId.parse(tmp);

	// authenticatedAttributes
	if (oldStyle) {
	// In JDK1.1.x, the authenticatedAttributes are always present,
	// encoded as an empty Set (Set of length zero)
	derin.getSet(0);
	} else {
	// check if set of auth attributes (implicit tag) is provided
	// (auth attributes are OPTIONAL)
	if ((byte)(derin.peekByte()) == (byte)0xA0) {
	authenticatedAttributes = new PKCS9Attributes(derin);
	}
	}

	// digestEncryptionAlgorithmId - little RSA naming scheme -
	// signature == encryption...
	tmp = derin.getDerValue();

	digestEncryptionAlgorithmId = AlgorithmId.parse(tmp);

	// encryptedDigest
	encryptedDigest = derin.getOctetString();

	// unauthenticatedAttributes
	if (oldStyle) {
	// In JDK1.1.x, the unauthenticatedAttributes are always present,
	// encoded as an empty Set (Set of length zero)
	derin.getSet(0);
	} else {
	// check if set of unauth attributes (implicit tag) is provided
	// (unauth attributes are OPTIONAL)
	if (derin.available() != 0
	&& (byte)(derin.peekByte()) == (byte)0xA1) {
	unauthenticatedAttributes =
	new PKCS9Attributes(derin, true);// ignore unsupported attrs
	}
	}

	// all done
	if (derin.available() != 0) {
	throw new ParsingException("extra data at the end");
	}
	}

	public void encode(DerOutputStream out) throws IOException {

	derEncode(out);
	}

	/**
	* DER encode this object onto an output stream.
	* Implements the {@code DerEncoder} interface.
	*
	* @param out
	* the output stream on which to write the DER encoding.
	*
	* @exception IOException on encoding error.
	*/
	public void derEncode(OutputStream out) throws IOException {
	DerOutputStream seq = new DerOutputStream();
	seq.putInteger(version);
	DerOutputStream issuerAndSerialNumber = new DerOutputStream();
	issuerName.encode(issuerAndSerialNumber);
	issuerAndSerialNumber.putInteger(certificateSerialNumber);
	seq.write(DerValue.tag_Sequence, issuerAndSerialNumber);

	digestAlgorithmId.encode(seq);

	// encode authenticated attributes if there are any
	if (authenticatedAttributes != null)
	authenticatedAttributes.encode((byte)0xA0, seq);

	digestEncryptionAlgorithmId.encode(seq);

	seq.putOctetString(encryptedDigest);

	// encode unauthenticated attributes if there are any
	if (unauthenticatedAttributes != null)
	unauthenticatedAttributes.encode((byte)0xA1, seq);

	DerOutputStream tmp = new DerOutputStream();
	tmp.write(DerValue.tag_Sequence, seq);

	out.write(tmp.toByteArray());
	}



	/*
	* Returns the (user) certificate pertaining to this SignerInfo.
	*/
	public X509Certificate getCertificate(PKCS7 block)
	throws IOException
	{
	return block.getCertificate(certificateSerialNumber, issuerName);
	}

	/*
	* Returns the certificate chain pertaining to this SignerInfo.
	*/
	public ArrayList<X509Certificate> getCertificateChain(PKCS7 block)
	throws IOException
	{
	X509Certificate userCert;
	userCert = block.getCertificate(certificateSerialNumber, issuerName);
	if (userCert == null)
	return null;

	ArrayList<X509Certificate> certList = new ArrayList<>();
	certList.add(userCert);

	X509Certificate[] pkcsCerts = block.getCertificates();
	if (pkcsCerts == null
	\|\| userCert.getSubjectDN().equals(userCert.getIssuerDN())) {
	return certList;
	}

	Principal issuer = userCert.getIssuerDN();
	int start = 0;
	while (true) {
	boolean match = false;
	int i = start;
	while (i < pkcsCerts.length) {
	if (issuer.equals(pkcsCerts[i].getSubjectDN())) {
	// next cert in chain found
	certList.add(pkcsCerts[i]);
	// if selected cert is self-signed, we're done
	// constructing the chain
	if (pkcsCerts[i].getSubjectDN().equals(
	pkcsCerts[i].getIssuerDN())) {
	start = pkcsCerts.length;
	} else {
	issuer = pkcsCerts[i].getIssuerDN();
	X509Certificate tmpCert = pkcsCerts[start];
	pkcsCerts[start] = pkcsCerts[i];
	pkcsCerts[i] = tmpCert;
	start++;
	}
	match = true;
	break;
	} else {
	i++;
	}
	}
	if (!match)
	break;
	}

	return certList;
	}

	/* Returns null if verify fails, this signerInfo if
	verify succeeds. */
	SignerInfo verify(PKCS7 block, byte[] data)
	throws NoSuchAlgorithmException, SignatureException {

	try {

	ContentInfo content = block.getContentInfo();
	if (data == null) {
	data = content.getContentBytes();
	}

	Timestamp timestamp = null;
	try {
	timestamp = getTimestamp();
	} catch (Exception ignore) {
	}

	ConstraintsParameters cparams =
	new ConstraintsParameters(timestamp);
	String digestAlgname = getDigestAlgorithmId().getName();

	byte[] dataSigned;

	// if there are authenticate attributes, get the message
	// digest and compare it with the digest of data
	if (authenticatedAttributes == null) {
	dataSigned = data;
	} else {

	// first, check content type
	ObjectIdentifier contentType = (ObjectIdentifier)
	authenticatedAttributes.getAttributeValue(
	PKCS9Attribute.CONTENT_TYPE_OID);
	if (contentType == null \|\|
	!contentType.equals(content.contentType))
	return null; // contentType does not match, bad SignerInfo

	// now, check message digest
	byte[] messageDigest = (byte[])
	authenticatedAttributes.getAttributeValue(
	PKCS9Attribute.MESSAGE_DIGEST_OID);

	if (messageDigest == null) // fail if there is no message digest
	return null;

	// check that digest algorithm is not restricted
	try {
	JAR_DISABLED_CHECK.permits(digestAlgname, cparams);
	} catch (CertPathValidatorException e) {
	throw new SignatureException(e.getMessage(), e);
	}

	MessageDigest md = MessageDigest.getInstance(digestAlgname);
	byte[] computedMessageDigest = md.digest(data);

	if (messageDigest.length != computedMessageDigest.length)
	return null;
	for (int i = 0; i < messageDigest.length; i++) {
	if (messageDigest[i] != computedMessageDigest[i])
	return null;
	}

	// message digest attribute matched
	// digest of original data

	// the data actually signed is the DER encoding of
	// the authenticated attributes (tagged with
	// the "SET OF" tag, not 0xA0).
	dataSigned = authenticatedAttributes.getDerEncoding();
	}

	// put together digest algorithm and encryption algorithm
	// to form signing algorithm
	String encryptionAlgname =
	getDigestEncryptionAlgorithmId().getName();

	// Workaround: sometimes the encryptionAlgname is actually
	// a signature name
	String tmp = AlgorithmId.getEncAlgFromSigAlg(encryptionAlgname);
	if (tmp != null) encryptionAlgname = tmp;
	String algname = AlgorithmId.makeSigAlg(
	digestAlgname, encryptionAlgname);

	// check that jar signature algorithm is not restricted
	try {
	JAR_DISABLED_CHECK.permits(algname, cparams);
	} catch (CertPathValidatorException e) {
	throw new SignatureException(e.getMessage(), e);
	}

	X509Certificate cert = getCertificate(block);
	if (cert == null) {
	return null;
	}
	PublicKey key = cert.getPublicKey();

	// check if the public key is restricted
	if (!JAR_DISABLED_CHECK.permits(SIG_PRIMITIVE_SET, key)) {
	throw new SignatureException("Public key check failed. " +
	"Disabled key used: " +
	KeyUtil.getKeySize(key) + " bit " +
	key.getAlgorithm());
	}

	if (cert.hasUnsupportedCriticalExtension()) {
	throw new SignatureException("Certificate has unsupported "
	+ "critical extension(s)");
	}

	// Make sure that if the usage of the key in the certificate is
	// restricted, it can be used for digital signatures.
	// XXX We may want to check for additional extensions in the
	// future.
	boolean[] keyUsageBits = cert.getKeyUsage();
	if (keyUsageBits != null) {
	KeyUsageExtension keyUsage;
	try {
	// We don't care whether or not this extension was marked
	// critical in the certificate.
	// We're interested only in its value (i.e., the bits set)
	// and treat the extension as critical.
	keyUsage = new KeyUsageExtension(keyUsageBits);
	} catch (IOException ioe) {
	throw new SignatureException("Failed to parse keyUsage "
	+ "extension");
	}

	boolean digSigAllowed = keyUsage.get(
	KeyUsageExtension.DIGITAL_SIGNATURE).booleanValue();

	boolean nonRepuAllowed = keyUsage.get(
	KeyUsageExtension.NON_REPUDIATION).booleanValue();

	if (!digSigAllowed && !nonRepuAllowed) {
	throw new SignatureException("Key usage restricted: "
	+ "cannot be used for "
	+ "digital signatures");
	}
	}

	Signature sig = Signature.getInstance(algname);

	sig.initVerify(key);

	// set parameters after Signature.initSign/initVerify call,
	// so the deferred provider selections occur when key is set
	AlgorithmParameters ap =
	digestEncryptionAlgorithmId.getParameters();
	try {
	SignatureUtil.specialSetParameter(sig, ap);
	} catch (ProviderException \| InvalidAlgorithmParameterException e) {
	throw new SignatureException(e.getMessage(), e);
	}

	sig.update(dataSigned);
	if (sig.verify(encryptedDigest)) {
	return this;
	}
	} catch (IOException e) {
	throw new SignatureException("IO error verifying signature:\n" +
	e.getMessage());
	} catch (InvalidKeyException e) {
	throw new SignatureException("InvalidKey: " + e.getMessage());
	}
	return null;
	}

	/* Verify the content of the pkcs7 block. */
	SignerInfo verify(PKCS7 block)
	throws NoSuchAlgorithmException, SignatureException {
	return verify(block, null);
	}

	public BigInteger getVersion() {
	return version;
	}

	public X500Name getIssuerName() {
	return issuerName;
	}

	public BigInteger getCertificateSerialNumber() {
	return certificateSerialNumber;
	}

	public AlgorithmId getDigestAlgorithmId() {
	return digestAlgorithmId;
	}

	public PKCS9Attributes getAuthenticatedAttributes() {
	return authenticatedAttributes;
	}

	public AlgorithmId getDigestEncryptionAlgorithmId() {
	return digestEncryptionAlgorithmId;
	}

	public byte[] getEncryptedDigest() {
	return encryptedDigest;
	}

	public PKCS9Attributes getUnauthenticatedAttributes() {
	return unauthenticatedAttributes;
	}

	/**
	* Returns the timestamp PKCS7 data unverified.
	* @return a PKCS7 object
	*/
	public PKCS7 getTsToken() throws IOException {
	if (unauthenticatedAttributes == null) {
	return null;
	}
	PKCS9Attribute tsTokenAttr =
	unauthenticatedAttributes.getAttribute(
	PKCS9Attribute.SIGNATURE_TIMESTAMP_TOKEN_OID);
	if (tsTokenAttr == null) {
	return null;
	}
	return new PKCS7((byte[])tsTokenAttr.getValue());
	}

	/*
	* Extracts a timestamp from a PKCS7 SignerInfo.
	*
	* Examines the signer's unsigned attributes for a
	* {@code signatureTimestampToken} attribute. If present,
	* then it is parsed to extract the date and time at which the
	* timestamp was generated.
	*
	* @param info A signer information element of a PKCS 7 block.
	*
	* @return A timestamp token or null if none is present.
	* @throws IOException if an error is encountered while parsing the
	* PKCS7 data.
	* @throws NoSuchAlgorithmException if an error is encountered while
	* verifying the PKCS7 object.
	* @throws SignatureException if an error is encountered while
	* verifying the PKCS7 object.
	* @throws CertificateException if an error is encountered while generating
	* the TSA's certpath.
	*/
	public Timestamp getTimestamp()
	throws IOException, NoSuchAlgorithmException, SignatureException,
	CertificateException
	{
	if (timestamp != null \|\| !hasTimestamp)
	return timestamp;

	PKCS7 tsToken = getTsToken();
	if (tsToken == null) {
	hasTimestamp = false;
	return null;
	}

	// Extract the content (an encoded timestamp token info)
	byte[] encTsTokenInfo = tsToken.getContentInfo().getData();
	// Extract the signer (the Timestamping Authority)
	// while verifying the content
	SignerInfo[] tsa = tsToken.verify(encTsTokenInfo);
	// Expect only one signer
	ArrayList<X509Certificate> chain = tsa[0].getCertificateChain(tsToken);
	CertificateFactory cf = CertificateFactory.getInstance("X.509");
	CertPath tsaChain = cf.generateCertPath(chain);
	// Create a timestamp token info object
	TimestampToken tsTokenInfo = new TimestampToken(encTsTokenInfo);
	// Check that the signature timestamp applies to this signature
	verifyTimestamp(tsTokenInfo);
	// Create a timestamp object
	timestamp = new Timestamp(tsTokenInfo.getDate(), tsaChain);
	return timestamp;
	}

	/*
	* Check that the signature timestamp applies to this signature.
	* Match the hash present in the signature timestamp token against the hash
	* of this signature.
	*/
	private void verifyTimestamp(TimestampToken token)
	throws NoSuchAlgorithmException, SignatureException {
	String digestAlgname = token.getHashAlgorithm().getName();
	// check that algorithm is not restricted
	if (!JAR_DISABLED_CHECK.permits(DIGEST_PRIMITIVE_SET, digestAlgname,
	null)) {
	throw new SignatureException("Timestamp token digest check failed. " +
	"Disabled algorithm used: " + digestAlgname);
	}

	MessageDigest md =
	MessageDigest.getInstance(digestAlgname);

	if (!Arrays.equals(token.getHashedMessage(),
	md.digest(encryptedDigest))) {

	throw new SignatureException("Signature timestamp (#" +
	token.getSerialNumber() + ") generated on " + token.getDate() +
	" is inapplicable");
	}

	if (debug != null) {
	debug.println();
	debug.println("Detected signature timestamp (#" +
	token.getSerialNumber() + ") generated on " + token.getDate());
	debug.println();
	}
	}

	public String toString() {
	HexDumpEncoder hexDump = new HexDumpEncoder();

	String out = "";

	out += "Signer Info for (issuer): " + issuerName + "\n";
	out += "\tversion: " + Debug.toHexString(version) + "\n";
	out += "\tcertificateSerialNumber: " +
	Debug.toHexString(certificateSerialNumber) + "\n";
	out += "\tdigestAlgorithmId: " + digestAlgorithmId + "\n";
	if (authenticatedAttributes != null) {
	out += "\tauthenticatedAttributes: " + authenticatedAttributes +
	"\n";
	}
	out += "\tdigestEncryptionAlgorithmId: " + digestEncryptionAlgorithmId +
	"\n";

	out += "\tencryptedDigest: " + "\n" +
	hexDump.encodeBuffer(encryptedDigest) + "\n";
	if (unauthenticatedAttributes != null) {
	out += "\tunauthenticatedAttributes: " +
	unauthenticatedAttributes + "\n";
	}
	return out;
	}
	}

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