/*
* 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.
*/
package org.apache.sshd.common.signature;
import java.security.spec.ECParameterSpec;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.EnumSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeMap;
import org.apache.sshd.common.NamedFactory;
import org.apache.sshd.common.NamedResource;
import org.apache.sshd.common.cipher.ECCurves;
import org.apache.sshd.common.config.NamedFactoriesListParseResult;
import org.apache.sshd.common.keyprovider.KeyPairProvider;
import org.apache.sshd.common.util.GenericUtils;
import org.apache.sshd.common.util.ValidateUtils;
import org.apache.sshd.common.util.security.SecurityUtils;
/**
* Provides easy access to the currently implemented signatures
*
* @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
*/
public enum BuiltinSignatures implements SignatureFactory {
dsa(KeyPairProvider.SSH_DSS) {
@Override
public Signature create() {
return new SignatureDSA();
}
},
rsa(KeyPairProvider.SSH_RSA) {
@Override
public Signature create() {
return new SignatureRSA();
}
},
nistp256(KeyPairProvider.ECDSA_SHA2_NISTP256) {
@Override
public Signature create() {
return new SignatureECDSA.SignatureECDSA256();
}
@Override
public boolean isSupported() {
return SecurityUtils.isECCSupported();
}
},
nistp384(KeyPairProvider.ECDSA_SHA2_NISTP384) {
@Override
public Signature create() {
return new SignatureECDSA.SignatureECDSA384();
}
@Override
public boolean isSupported() {
return SecurityUtils.isECCSupported();
}
},
nistp521(KeyPairProvider.ECDSA_SHA2_NISTP521) {
@Override
public Signature create() {
return new SignatureECDSA.SignatureECDSA521();
}
@Override
public boolean isSupported() {
return SecurityUtils.isECCSupported();
}
},
ed25519(KeyPairProvider.SSH_ED25519) {
@Override
public Signature create() {
return SecurityUtils.getEDDSASigner();
}
@Override
public boolean isSupported() {
return SecurityUtils.isEDDSACurveSupported();
}
};
public static final Set<BuiltinSignatures> VALUES =
Collections.unmodifiableSet(EnumSet.allOf(BuiltinSignatures.class));
private static final Map<String, SignatureFactory> EXTENSIONS =
new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
private final String factoryName;
BuiltinSignatures(String facName) {
factoryName = facName;
}
public static Signature getByCurveSize(ECParameterSpec params) {
int curveSize = ECCurves.getCurveSize(params);
if (curveSize <= 256) {
return nistp256.create();
} else if (curveSize <= 384) {
return nistp384.create();
} else {
return nistp521.create();
}
}
@Override
public final String getName() {
return factoryName;
}
@Override
public final String toString() {
return getName();
}
@Override
public boolean isSupported() {
return true;
}
/**
* Registered a {@link NamedFactory} to be available besides the built-in
* ones when parsing configuration
*
* @param extension The factory to register
* @throws IllegalArgumentException if factory instance is {@code null},
* or overrides a built-in one or overrides another registered factory
* with the same name (case <U>insensitive</U>).
*/
public static void registerExtension(SignatureFactory extension) {
String name = Objects.requireNonNull(extension, "No extension provided").getName();
ValidateUtils.checkTrue(fromFactoryName(name) == null, "Extension overrides built-in: %s", name);
synchronized (EXTENSIONS) {
ValidateUtils.checkTrue(!EXTENSIONS.containsKey(name), "Extension overrides existing: %s", name);
EXTENSIONS.put(name, extension);
}
}
/**
* @return A {@link SortedSet} of the currently registered extensions, sorted
* according to the factory name (case <U>insensitive</U>)
*/
public static SortedSet<SignatureFactory> getRegisteredExtensions() {
synchronized (EXTENSIONS) {
return GenericUtils.asSortedSet(NamedResource.BY_NAME_COMPARATOR, EXTENSIONS.values());
}
}
/**
* Unregisters specified extension
*
* @param name The factory name - ignored if {@code null}/empty
* @return The registered extension - {@code null} if not found
*/
public static SignatureFactory unregisterExtension(String name) {
if (GenericUtils.isEmpty(name)) {
return null;
}
synchronized (EXTENSIONS) {
return EXTENSIONS.remove(name);
}
}
/**
* @param s The {@link Enum}'s name - ignored if {@code null}/empty
* @return The matching {@link org.apache.sshd.common.signature.BuiltinSignatures} whose {@link Enum#name()} matches
* (case <U>insensitive</U>) the provided argument - {@code null} if no match
*/
public static BuiltinSignatures fromString(String s) {
if (GenericUtils.isEmpty(s)) {
return null;
}
for (BuiltinSignatures c : VALUES) {
if (s.equalsIgnoreCase(c.name())) {
return c;
}
}
return null;
}
/**
* @param factory The {@link org.apache.sshd.common.NamedFactory} for the signature - ignored if {@code null}
* @return The matching {@link org.apache.sshd.common.signature.BuiltinSignatures} whose factory name matches
* (case <U>insensitive</U>) the digest factory name
* @see #fromFactoryName(String)
*/
public static BuiltinSignatures fromFactory(NamedFactory<Signature> factory) {
if (factory == null) {
return null;
} else {
return fromFactoryName(factory.getName());
}
}
/**
* @param name The factory name - ignored if {@code null}/empty
* @return The matching {@link BuiltinSignatures} whose factory name matches
* (case <U>insensitive</U>) the provided name - {@code null} if no match
*/
public static BuiltinSignatures fromFactoryName(String name) {
return NamedResource.findByName(name, String.CASE_INSENSITIVE_ORDER, VALUES);
}
/**
* @param sigs A comma-separated list of signatures' names - ignored
* if {@code null}/empty
* @return A {@link ParseResult} of all the {@link NamedFactory} whose
* name appears in the string and represent a built-in signature. Any
* unknown name is <U>ignored</U>. The order of the returned result
* is the same as the original order - bar the unknown signatures.
* <B>Note:</B> it is up to caller to ensure that the list does not
* contain duplicates
*/
public static ParseResult parseSignatureList(String sigs) {
return parseSignatureList(GenericUtils.split(sigs, ','));
}
public static ParseResult parseSignatureList(String... sigs) {
return parseSignatureList(GenericUtils.isEmpty((Object[]) sigs) ? Collections.emptyList() : Arrays.asList(sigs));
}
public static ParseResult parseSignatureList(Collection<String> sigs) {
if (GenericUtils.isEmpty(sigs)) {
return ParseResult.EMPTY;
}
List<SignatureFactory> factories = new ArrayList<>(sigs.size());
List<String> unknown = Collections.emptyList();
for (String name : sigs) {
SignatureFactory s = resolveFactory(name);
if (s != null) {
factories.add(s);
} else {
// replace the (unmodifiable) empty list with a real one
if (unknown.isEmpty()) {
unknown = new ArrayList<>();
}
unknown.add(name);
}
}
return new ParseResult(factories, unknown);
}
/**
* @param name The factory name
* @return The factory or {@code null} if it is neither a built-in one
* or a registered extension
*/
public static SignatureFactory resolveFactory(String name) {
if (GenericUtils.isEmpty(name)) {
return null;
}
SignatureFactory s = fromFactoryName(name);
if (s != null) {
return s;
}
synchronized (EXTENSIONS) {
return EXTENSIONS.get(name);
}
}
/**
* Holds the result of the {@link BuiltinSignatures#parseSignatureList(String)}
*
* @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
*/
public static final class ParseResult extends NamedFactoriesListParseResult<Signature, SignatureFactory> {
public static final ParseResult EMPTY = new ParseResult(Collections.emptyList(), Collections.emptyList());
public ParseResult(List<SignatureFactory> parsed, List<String> unsupported) {
super(parsed, unsupported);
}
}
}