netconf/netconf-netty-util/src/main/java/org/opendaylight/netconf/nettyutil/handler/ssh/client/NetconfClientBuilder.java

   1 /*
   2  * Copyright (c) 2019 PANTHEON.tech, s.r.o. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.netconf.nettyutil.handler.ssh.client;
   9
  10 import static com.google.common.base.Verify.verify;
  11
  12 import com.google.common.annotations.Beta;
  13 import com.google.common.collect.ImmutableList;
  14 import java.util.List;
  15 import java.util.stream.Stream;
  16 import org.opendaylight.netconf.shaded.sshd.client.ClientBuilder;
  17 import org.opendaylight.netconf.shaded.sshd.client.SshClient;
  18 import org.opendaylight.netconf.shaded.sshd.common.NamedFactory;
  19 import org.opendaylight.netconf.shaded.sshd.common.kex.BuiltinDHFactories;
  20 import org.opendaylight.netconf.shaded.sshd.common.kex.KeyExchangeFactory;
  21 import org.opendaylight.netconf.shaded.sshd.common.signature.BuiltinSignatures;
  22 import org.opendaylight.netconf.shaded.sshd.common.signature.Signature;
  23
  24 /**
  25  * A {@link ClientBuilder} which builds {@link NetconfSshClient} instances.
  26  */
  27 @Beta
  28 public class NetconfClientBuilder extends ClientBuilder {
  29     // RFC8332 rsa-sha2-256/rsa-sha2-512 are not a part of Mina's default set of signatures for clients as of 2.5.1.
  30     // Add them to ensure interop with modern highly-secured devices.
  31     private static final ImmutableList<NamedFactory<Signature>> FULL_SIGNATURE_PREFERENCE =
  32             Stream.concat(DEFAULT_SIGNATURE_PREFERENCE.stream(), Stream.of(
  33                 BuiltinSignatures.rsaSHA512, BuiltinSignatures.rsaSHA256))
  34             .filter(BuiltinSignatures::isSupported)
  35             .distinct()
  36             .collect(ImmutableList.toImmutableList());
  37
  38     // The SHA1 algorithm is disabled by default in Mina SSHD since 2.6.0.
  39     // More details available here: https://issues.apache.org/jira/browse/SSHD-1004
  40     // This block adds diffie-hellman-group14-sha1 back to the list of supported algorithms.
  41     private static final ImmutableList<BuiltinDHFactories> FULL_DH_FACTORIES_LIST =
  42         Stream.concat(DEFAULT_KEX_PREFERENCE.stream(), Stream.of(BuiltinDHFactories.dhg14))
  43             .collect(ImmutableList.toImmutableList());
  44     private static final List<KeyExchangeFactory> FULL_KEX_PREFERENCE =
  45         NamedFactory.setUpTransformedFactories(true, FULL_DH_FACTORIES_LIST, DH2KEX);
  46
  47     @Override
  48     public NetconfSshClient build() {
  49         final SshClient client = super.build();
  50         verify(client instanceof NetconfSshClient, "Unexpected client %s", client);
  51         return (NetconfSshClient) client;
  52     }
  53
  54     @Override
  55     protected ClientBuilder fillWithDefaultValues() {
  56         if (factory == null) {
  57             factory = NetconfSshClient.DEFAULT_NETCONF_SSH_CLIENT_FACTORY;
  58         }
  59         if (signatureFactories == null) {
  60             signatureFactories = FULL_SIGNATURE_PREFERENCE;
  61         }
  62         if (keyExchangeFactories == null) {
  63             keyExchangeFactories = FULL_KEX_PREFERENCE;
  64         }
  65         return super.fillWithDefaultValues();
  66     }
  67 }