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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * 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

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package sun.security.rsa;

import java.io.*;

import sun.security.util.*;

import sun.security.x509.*;

import java.security.AlgorithmParametersSpi;

import java.security.NoSuchAlgorithmException;

import java.security.spec.AlgorithmParameterSpec;

import java.security.spec.InvalidParameterSpecException;

import java.security.spec.MGF1ParameterSpec;

import java.security.spec.PSSParameterSpec;

import static java.security.spec.PSSParameterSpec.DEFAULT;

/**

 * This class implements the PSS parameters used with the RSA

 * signatures in PSS padding. Here is its ASN.1 definition:

 * RSASSA-PSS-params ::= SEQUENCE {

 *   hashAlgorithm      [0] HashAlgorithm     DEFAULT sha1,

 *   maskGenAlgorithm   [1] MaskGenAlgorithm  DEFAULT mgf1SHA1,

 *   saltLength         [2] INTEGER           DEFAULT 20

 *   trailerField       [3] TrailerField      DEFAULT trailerFieldBC

 * }

 *

 * @author Valerie Peng

 *

 */

public final class PSSParameters extends AlgorithmParametersSpi {

    private String mdName;

    private MGF1ParameterSpec mgfSpec;

    private int saltLength;

    private int trailerField;

    private static final ObjectIdentifier OID_MGF1 =

           ObjectIdentifier.newInternal(new int[] {1,2,840,113549,1,1,8});

    public PSSParameters() {

    }

    @Override

    protected void engineInit(AlgorithmParameterSpec paramSpec)

            throws InvalidParameterSpecException {

        if (!(paramSpec instanceof PSSParameterSpec)) {

            throw new InvalidParameterSpecException

                ("Inappropriate parameter specification");

        }

        PSSParameterSpec spec = (PSSParameterSpec) paramSpec;

        this.mdName = spec.getDigestAlgorithm();

        String mgfName = spec.getMGFAlgorithm();

        if (!mgfName.equalsIgnoreCase("MGF1")) {

            throw new InvalidParameterSpecException("Unsupported mgf " +

                mgfName + "; MGF1 only");

        }

        AlgorithmParameterSpec mgfSpec = spec.getMGFParameters();

        if (!(mgfSpec instanceof MGF1ParameterSpec)) {

            throw new InvalidParameterSpecException("Inappropriate mgf " +

                "parameters; non-null MGF1ParameterSpec only");

        }

        this.mgfSpec = (MGF1ParameterSpec) mgfSpec;

        this.saltLength = spec.getSaltLength();

        this.trailerField = spec.getTrailerField();

    }

    @Override

    protected void engineInit(byte[] encoded) throws IOException {

        // first initialize with the DEFAULT values before

        // retrieving from the encoding bytes

        this.mdName = DEFAULT.getDigestAlgorithm();

        this.mgfSpec = (MGF1ParameterSpec) DEFAULT.getMGFParameters();

        this.saltLength = DEFAULT.getSaltLength();

        this.trailerField = DEFAULT.getTrailerField();

        DerInputStream der = new DerInputStream(encoded);

        DerValue[] datum = der.getSequence(4);

        for (DerValue d : datum) {

            if (d.isContextSpecific((byte) 0x00)) {

                // hash algid

                this.mdName = AlgorithmId.parse

                    (d.data.getDerValue()).getName();

            } else if (d.isContextSpecific((byte) 0x01)) {

                // mgf algid

                AlgorithmId val = AlgorithmId.parse(d.data.getDerValue());

                if (!val.getOID().equals(OID_MGF1)) {

                    throw new IOException("Only MGF1 mgf is supported");

                }

                AlgorithmId params = AlgorithmId.parse(

                    new DerValue(val.getEncodedParams()));

                String mgfDigestName = params.getName();

                switch (mgfDigestName) {

                case "SHA-1":

                    this.mgfSpec = MGF1ParameterSpec.SHA1;

                    break;

                case "SHA-224":

                    this.mgfSpec = MGF1ParameterSpec.SHA224;

                    break;

                case "SHA-256":

                    this.mgfSpec = MGF1ParameterSpec.SHA256;

                    break;

                case "SHA-384":

                    this.mgfSpec = MGF1ParameterSpec.SHA384;

                    break;

                case "SHA-512":

                    this.mgfSpec = MGF1ParameterSpec.SHA512;

                    break;

                case "SHA-512/224":

                    this.mgfSpec = MGF1ParameterSpec.SHA512_224;

                    break;

                case "SHA-512/256":

                    this.mgfSpec = MGF1ParameterSpec.SHA512_256;

                    break;

                default:

                    throw new IOException

                        ("Unrecognized message digest algorithm " +

                        mgfDigestName);

                }

            } else if (d.isContextSpecific((byte) 0x02)) {

                // salt length

                this.saltLength = d.data.getDerValue().getInteger();

                if (this.saltLength < 0) {

                    throw new IOException("Negative value for saltLength");

                }

            } else if (d.isContextSpecific((byte) 0x03)) {

                // trailer field

                this.trailerField = d.data.getDerValue().getInteger();

                if (this.trailerField != 1) {

                    throw new IOException("Unsupported trailerField value " +

                    this.trailerField);

                }

            } else {

                throw new IOException("Invalid encoded PSSParameters");

            }

        }

    }

    @Override

    protected void engineInit(byte[] encoded, String decodingMethod)

            throws IOException {

        if ((decodingMethod != null) &&

            (!decodingMethod.equalsIgnoreCase("ASN.1"))) {

            throw new IllegalArgumentException("Only support ASN.1 format");

        }

        engineInit(encoded);

    }

    @Override

    protected <T extends AlgorithmParameterSpec>

            T engineGetParameterSpec(Class<T> paramSpec)

            throws InvalidParameterSpecException {

        if (PSSParameterSpec.class.isAssignableFrom(paramSpec)) {

            return paramSpec.cast(

                new PSSParameterSpec(mdName, "MGF1", mgfSpec,

                                     saltLength, trailerField));

        } else {

            throw new InvalidParameterSpecException

                ("Inappropriate parameter specification");

        }

    }

    @Override

    protected byte[] engineGetEncoded() throws IOException {

        DerOutputStream tmp = new DerOutputStream();

        DerOutputStream tmp2, tmp3;

        // MD

        AlgorithmId mdAlgId;

        try {

            mdAlgId = AlgorithmId.get(mdName);

        } catch (NoSuchAlgorithmException nsae) {

            throw new IOException("AlgorithmId " + mdName +

                                  " impl not found");

        }

        tmp2 = new DerOutputStream();

        mdAlgId.derEncode(tmp2);

        tmp.write(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte)0),

                      tmp2);

        // MGF

        tmp2 = new DerOutputStream();

        tmp2.putOID(OID_MGF1);

        AlgorithmId mgfDigestId;

        try {

            mgfDigestId = AlgorithmId.get(mgfSpec.getDigestAlgorithm());

        } catch (NoSuchAlgorithmException nase) {

            throw new IOException("AlgorithmId " +

                    mgfSpec.getDigestAlgorithm() + " impl not found");

        }

        mgfDigestId.encode(tmp2);

        tmp3 = new DerOutputStream();

        tmp3.write(DerValue.tag_Sequence, tmp2);

        tmp.write(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte)1),

                  tmp3);

        // SaltLength

        tmp2 = new DerOutputStream();

        tmp2.putInteger(saltLength);

        tmp.write(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte)2),

                  tmp2);

        // TrailerField

        tmp2 = new DerOutputStream();

        tmp2.putInteger(trailerField);

        tmp.write(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte)3),

                  tmp2);

        // Put all together under a SEQUENCE tag

        DerOutputStream out = new DerOutputStream();

        out.write(DerValue.tag_Sequence, tmp);

        return out.toByteArray();

    }

    @Override

    protected byte[] engineGetEncoded(String encMethod) throws IOException {

        if ((encMethod != null) &&

            (!encMethod.equalsIgnoreCase("ASN.1"))) {

            throw new IllegalArgumentException("Only support ASN.1 format");

        }

        return engineGetEncoded();

    }

    @Override

    protected String engineToString() {

        StringBuilder sb = new StringBuilder();

        sb.append("MD: " + mdName + "\n")

            .append("MGF: MGF1" + mgfSpec.getDigestAlgorithm() + "\n")

            .append("SaltLength: " + saltLength + "\n")

            .append("TrailerField: " + trailerField + "\n");

        return sb.toString();

    }

}