/*

 * Copyright (c) 2015, 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.ssl;

import java.security.*;

import java.security.spec.AlgorithmParameterSpec;

import java.security.spec.PSSParameterSpec;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collection;

import java.util.Collections;

import java.util.EnumSet;

import java.util.LinkedList;

import java.util.List;

import java.util.Set;

import sun.security.util.KeyUtil;

enum SignatureScheme {

    // EdDSA algorithms

    ED25519                 (0x0807, "ed25519", "ed25519",

                                    "ed25519",

                                    ProtocolVersion.PROTOCOLS_OF_13),

    ED448                   (0x0808, "ed448", "ed448",

                                    "ed448",

                                    ProtocolVersion.PROTOCOLS_OF_13),

    // ECDSA algorithms

    ECDSA_SECP256R1_SHA256  (0x0403, "ecdsa_secp256r1_sha256",

                                    "SHA256withECDSA",

                                    "EC",

                                    ProtocolVersion.PROTOCOLS_TO_13),

    ECDSA_SECP384R1_SHA384  (0x0503, "ecdsa_secp384r1_sha384",

                                    "SHA384withECDSA",

                                    "EC",

                                    ProtocolVersion.PROTOCOLS_TO_13),

    ECDSA_SECP512R1_SHA512  (0x0603, "ecdsa_secp512r1_sha512",

                                    "SHA512withECDSA",

                                    "EC",

                                    ProtocolVersion.PROTOCOLS_TO_13),

    // RSASSA-PSS algorithms with public key OID rsaEncryption

    RSA_PSS_RSAE_SHA256     (0x0804, "rsa_pss_rsae_sha256",

                                    "RSASSA-PSS", "RSA",

                                    SigAlgParamSpec.RSA_PSS_SHA256, 512,

                                    ProtocolVersion.PROTOCOLS_OF_13),

    RSA_PSS_RSAE_SHA384     (0x0805, "rsa_pss_rsae_sha384",

                                    "RSASSA-PSS", "RSA",

                                    SigAlgParamSpec.RSA_PSS_SHA384, 768,

                                    ProtocolVersion.PROTOCOLS_OF_13),

    RSA_PSS_RSAE_SHA512     (0x0806, "rsa_pss_rsae_sha512",

                                    "RSASSA-PSS", "RSA",

                                    SigAlgParamSpec.RSA_PSS_SHA512, 768,

                                    ProtocolVersion.PROTOCOLS_OF_13),

    // RSASSA-PSS algorithms with public key OID RSASSA-PSS

    RSA_PSS_PSS_SHA256      (0x0809, "rsa_pss_pss_sha256",

                                    "RSASSA-PSS", "RSASSA-PSS",

                                    SigAlgParamSpec.RSA_PSS_SHA256, 512,

                                    ProtocolVersion.PROTOCOLS_OF_13),

    RSA_PSS_PSS_SHA384      (0x080A, "rsa_pss_pss_sha384",

                                    "RSASSA-PSS", "RSASSA-PSS",

                                    SigAlgParamSpec.RSA_PSS_SHA384, 768,

                                    ProtocolVersion.PROTOCOLS_OF_13),

    RSA_PSS_PSS_SHA512      (0x080B, "rsa_pss_pss_sha512",

                                    "RSASSA-PSS", "RSASSA-PSS",

                                    SigAlgParamSpec.RSA_PSS_SHA512, 768,

                                    ProtocolVersion.PROTOCOLS_OF_13),

    // RSASSA-PKCS1-v1_5 algorithms

    RSA_PKCS1_SHA256        (0x0401, "rsa_pkcs1_sha256", "SHA256withRSA",

                                    "RSA", null, 512,

                                    ProtocolVersion.PROTOCOLS_TO_13,

                                    ProtocolVersion.PROTOCOLS_TO_12),

    RSA_PKCS1_SHA384        (0x0501, "rsa_pkcs1_sha384", "SHA384withRSA",

                                    "RSA", null, 768,

                                    ProtocolVersion.PROTOCOLS_TO_13,

                                    ProtocolVersion.PROTOCOLS_TO_12),

    RSA_PKCS1_SHA512        (0x0601, "rsa_pkcs1_sha512", "SHA512withRSA",

                                    "RSA", null, 768,

                                    ProtocolVersion.PROTOCOLS_TO_13,

                                    ProtocolVersion.PROTOCOLS_TO_12),

    // Legacy algorithms

    DSA_SHA256              (0x0402, "dsa_sha256", "SHA256withDSA",

                                    "dsa",

                                    ProtocolVersion.PROTOCOLS_TO_12),

    ECDSA_SHA224            (0x0303, "ecdsa_sha224", "SHA224withECDSA",

                                    "EC",

                                    ProtocolVersion.PROTOCOLS_TO_12),

    RSA_SHA224              (0x0301, "rsa_sha224", "SHA224withRSA",

                                    "rsa", 768,

                                    ProtocolVersion.PROTOCOLS_TO_12),

    DSA_SHA224              (0x0302, "dsa_sha224", "SHA224withDSA",

                                    "dsa",

                                    ProtocolVersion.PROTOCOLS_TO_12),

    ECDSA_SHA1              (0x0203, "ecdsa_sha1", "SHA1withECDSA",

                                    "EC",

                                    ProtocolVersion.PROTOCOLS_TO_13),

    RSA_PKCS1_SHA1          (0x0201, "rsa_pkcs1_sha1", "SHA1withRSA",

                                    "rsa", null, 512,

                                    ProtocolVersion.PROTOCOLS_TO_13,

                                    ProtocolVersion.PROTOCOLS_TO_12),

    DSA_SHA1                (0x0202, "dsa_sha1", "SHA1withDSA",

                                    "dsa",

                                    ProtocolVersion.PROTOCOLS_TO_12),

    RSA_MD5                 (0x0101, "rsa_md5", "MD5withRSA",

                                    "rsa", 512,

                                    ProtocolVersion.PROTOCOLS_TO_12);

    final int id;                       // hash + signature

    final String name;                  // literal name

    private final String algorithm;     // signature algorithm

    final String keyAlgorithm;          // signature key algorithm

    private final AlgorithmParameterSpec signAlgParameter;

    // The minial required key size in bits.

    //

    // Only need to check RSA algorithm at present. RSA keys of 512 bits

    // have been shown to be practically breakable, it does not make much

    // sense to use the strong hash algorithm for keys whose key size less

    // than 512 bits.  So it is not necessary to caculate the minial

    // required key size exactly for a hash algorithm.

    final int minimalKeySize;

    final List<ProtocolVersion> supportedProtocols;

    // Some signature schemes are supported in different versions for handshake

    // messages and certificates. This field holds the supported protocols

    // for handshake messages.

    final List<ProtocolVersion> handshakeSupportedProtocols;

    final boolean isAvailable;

    private static final String[] hashAlgorithms = new String[] {

            "none",         "md5",      "sha1",     "sha224",

            "sha256",       "sha384",   "sha512"

        };

    private static final String[] signatureAlgorithms = new String[] {

            "anonymous",    "rsa",      "dsa",      "ecdsa",

        };

    static enum SigAlgParamSpec {   // support RSASSA-PSS only now

        RSA_PSS_SHA256 ("SHA-256", 32),

        RSA_PSS_SHA384 ("SHA-384", 48),

        RSA_PSS_SHA512 ("SHA-512", 64);

        final private AlgorithmParameterSpec parameterSpec;

        final boolean isAvailable;

        SigAlgParamSpec(String hash, int saltLength) {

            // See RFC 8017

            PSSParameterSpec pssParamSpec =

                    new PSSParameterSpec(hash, "MGF1", null, saltLength, 1);

            boolean mediator = true;

            try {

                Signature signer = JsseJce.getSignature("RSASSA-PSS");

                signer.setParameter(pssParamSpec);

            } catch (InvalidAlgorithmParameterException |

                    NoSuchAlgorithmException exp) {

                mediator = false;

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.warning(

                        "RSASSA-PSS signature with " + hash +

                        " is not supported by the underlying providers", exp);

                }

            }

            this.isAvailable = mediator;

            this.parameterSpec = mediator ? pssParamSpec : null;

        }

        AlgorithmParameterSpec getParameterSpec() {

            return parameterSpec;

        }

    }

    // performance optimization

    private static final Set<CryptoPrimitive> SIGNATURE_PRIMITIVE_SET =

        Collections.unmodifiableSet(EnumSet.of(CryptoPrimitive.SIGNATURE));

    private SignatureScheme(int id, String name,

            String algorithm, String keyAlgorithm,

            ProtocolVersion[] supportedProtocols) {

        this(id, name, algorithm, keyAlgorithm, -1, supportedProtocols);

    }

    private SignatureScheme(int id, String name,

            String algorithm, String keyAlgorithm,

            int minimalKeySize,

            ProtocolVersion[] supportedProtocols) {

        this(id, name, algorithm, keyAlgorithm, null,

                minimalKeySize, supportedProtocols);

    }

    private SignatureScheme(int id, String name,

                            String algorithm, String keyAlgorithm,

                            SigAlgParamSpec signAlgParamSpec, int minimalKeySize,

                            ProtocolVersion[] supportedProtocols) {

        this(id, name, algorithm, keyAlgorithm, signAlgParamSpec, minimalKeySize,

            supportedProtocols, supportedProtocols);

    }

    private SignatureScheme(int id, String name,

            String algorithm, String keyAlgorithm,

            SigAlgParamSpec signAlgParamSpec, int minimalKeySize,

            ProtocolVersion[] supportedProtocols,

            ProtocolVersion[] handshakeSupportedProtocols) {

        this.id = id;

        this.name = name;

        this.algorithm = algorithm;

        this.keyAlgorithm = keyAlgorithm;

        this.signAlgParameter =

            signAlgParamSpec != null ? signAlgParamSpec.parameterSpec : null;

        this.minimalKeySize = minimalKeySize;

        this.supportedProtocols = Arrays.asList(supportedProtocols);

        this.handshakeSupportedProtocols = Arrays.asList(handshakeSupportedProtocols);

        boolean mediator = true;

        if (signAlgParamSpec != null) {

            mediator = signAlgParamSpec.isAvailable;

        } else {

            try {

                JsseJce.getSignature(algorithm);

            } catch (Exception e) {

                mediator = false;

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.warning(

                        "Signature algorithm, " + algorithm +

                        ", is not supported by the underlying providers");

                }

            }

        }

        if (mediator && ((id >> 8) & 0xFF) == 0x03) {   // SHA224

            // There are some problems to use SHA224 on Windows.

            if (Security.getProvider("SunMSCAPI") != null) {

                mediator = false;

            }

        }

        this.isAvailable = mediator;

    }

    static SignatureScheme valueOf(int id) {

        for (SignatureScheme ss: SignatureScheme.values()) {

            if (ss.id == id) {

                return ss;

            }

        }

        return null;

    }

    static String nameOf(int id) {

        for (SignatureScheme ss: SignatureScheme.values()) {

            if (ss.id == id) {

                return ss.name;

            }

        }

        // Use TLS 1.2 style name for unknown signature scheme.

        int hashId = ((id >> 8) & 0xFF);

        int signId = (id & 0xFF);

        String hashName = (hashId >= hashAlgorithms.length) ?

            "UNDEFINED-HASH(" + hashId + ")" : hashAlgorithms[hashId];

        String signName = (signId >= signatureAlgorithms.length) ?

            "UNDEFINED-SIGNATURE(" + signId + ")" :

            signatureAlgorithms[signId];

        return signName + "_" + hashName;

    }

    // Return the size of a SignatureScheme structure in TLS record

    static int sizeInRecord() {

        return 2;

    }

    // Get local supported algorithm collection complying to algorithm

    // constraints.

    static List<SignatureScheme> getSupportedAlgorithms(

            AlgorithmConstraints constraints,

            List<ProtocolVersion> activeProtocols) {

        List<SignatureScheme> supported = new LinkedList<>();

        for (SignatureScheme ss: SignatureScheme.values()) {

            if (!ss.isAvailable) {

                continue;

            }

            boolean isMatch = false;

            for (ProtocolVersion pv : activeProtocols) {

                if (ss.supportedProtocols.contains(pv)) {

                    isMatch = true;

                    break;

                }

            }

            if (isMatch) {

                if (constraints.permits(

                        SIGNATURE_PRIMITIVE_SET, ss.algorithm, null)) {

                    supported.add(ss);

                } else if (SSLLogger.isOn &&

                        SSLLogger.isOn("ssl,handshake,verbose")) {

                    SSLLogger.finest(

                        "Ignore disabled signature sheme: " + ss.name);

                }

            } else if (SSLLogger.isOn &&

                    SSLLogger.isOn("ssl,handshake,verbose")) {

                SSLLogger.finest(

                    "Ignore inactive signature sheme: " + ss.name);

            }

        }

        return supported;

    }

    static List<SignatureScheme> getSupportedAlgorithms(

            AlgorithmConstraints constraints,

            ProtocolVersion protocolVersion, int[] algorithmIds) {

        List<SignatureScheme> supported = new LinkedList<>();

        for (int ssid : algorithmIds) {

            SignatureScheme ss = SignatureScheme.valueOf(ssid);

            if (ss == null) {

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.warning(

                            "Unsupported signature scheme: " +

                            SignatureScheme.nameOf(ssid));

                }

            } else if (ss.isAvailable &&

                    ss.supportedProtocols.contains(protocolVersion) &&

                    constraints.permits(SIGNATURE_PRIMITIVE_SET,

                           ss.algorithm, null)) {

                supported.add(ss);

            } else {

                if (SSLLogger.isOn && SSLLogger.isOn("ssl,handshake")) {

                    SSLLogger.warning(

                            "Unsupported signature scheme: " + ss.name);

                }

            }

        }

        return supported;

    }

    static SignatureScheme getPreferableAlgorithm(

            List<SignatureScheme> schemes,

            SignatureScheme certScheme,

            ProtocolVersion version) {

        for (SignatureScheme ss : schemes) {

            if (ss.isAvailable &&

            ss.handshakeSupportedProtocols.contains(version) &&

            certScheme.keyAlgorithm.equalsIgnoreCase(ss.keyAlgorithm)) {

                return ss;

            }

        }

        return null;

    }

    static SignatureScheme getPreferableAlgorithm(

            List<SignatureScheme> schemes,

            PrivateKey signingKey,

            ProtocolVersion version) {

        String keyAlgorithm = signingKey.getAlgorithm();

        int keySize;

        // Only need to check RSA algorithm at present.

        if (keyAlgorithm.equalsIgnoreCase("rsa")) {

            keySize = KeyUtil.getKeySize(signingKey);

        } else {

            keySize = Integer.MAX_VALUE;

        }

        for (SignatureScheme ss : schemes) {

            if (ss.isAvailable && (keySize >= ss.minimalKeySize) &&

                ss.handshakeSupportedProtocols.contains(version) &&

                keyAlgorithm.equalsIgnoreCase(ss.keyAlgorithm)) {

                return ss;

            }

        }

        return null;

    }

    static String[] getAlgorithmNames(Collection<SignatureScheme> schemes) {

        if (schemes != null) {

            ArrayList<String> names = new ArrayList<>(schemes.size());

            for (SignatureScheme scheme : schemes) {

                names.add(scheme.algorithm);

            }

            return names.toArray(new String[0]);

        }

        return new String[0];

    }

    Signature getSignature() throws NoSuchAlgorithmException,

            InvalidAlgorithmParameterException {

        if (!isAvailable) {

            return null;

        }

        Signature signer = JsseJce.getSignature(algorithm);

        if (signAlgParameter != null) {

            signer.setParameter(signAlgParameter);

        }

        return signer;

    }

}