apps/callhome-provider/src/main/java/org/opendaylight/netconf/callhome/mount/AuthorizedKeysDecoder.java

   1 /*
   2  * Copyright (c) 2016 Brocade Communication Systems 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.callhome.mount;
   9
  10 import com.google.common.collect.ImmutableMap;
  11 import java.io.ByteArrayOutputStream;
  12 import java.io.DataOutput;
  13 import java.io.DataOutputStream;
  14 import java.io.IOException;
  15 import java.math.BigInteger;
  16 import java.nio.charset.StandardCharsets;
  17 import java.security.GeneralSecurityException;
  18 import java.security.KeyFactory;
  19 import java.security.NoSuchAlgorithmException;
  20 import java.security.PublicKey;
  21 import java.security.interfaces.DSAPublicKey;
  22 import java.security.interfaces.RSAPublicKey;
  23 import java.security.spec.DSAPublicKeySpec;
  24 import java.security.spec.ECPoint;
  25 import java.security.spec.ECPublicKeySpec;
  26 import java.security.spec.RSAPublicKeySpec;
  27 import java.util.Arrays;
  28 import java.util.Base64;
  29 import org.bouncycastle.jce.ECNamedCurveTable;
  30 import org.bouncycastle.jce.ECPointUtil;
  31 import org.bouncycastle.jce.interfaces.ECPublicKey;
  32 import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec;
  33 import org.bouncycastle.jce.spec.ECNamedCurveSpec;
  34 import org.slf4j.Logger;
  35 import org.slf4j.LoggerFactory;
  36
  37 /**
  38  * FIXME: This should be probably located at AAA library.
  39  */
  40 public class AuthorizedKeysDecoder {
  41     private static final Logger LOG = LoggerFactory.getLogger(AuthorizedKeysDecoder.class);
  42
  43     private static final ImmutableMap<String, String> ECDSA_CURVES = ImmutableMap.<String, String>builder()
  44         .put("nistp256", "secp256r1")
  45         .put("nistp384", "secp384r1")
  46         .put("nistp512", "secp512r1")
  47         .build();
  48
  49     private static final String ECDSA_SUPPORTED_CURVE_NAME = "nistp256";
  50     private static final byte[] ECDSA_SUPPORTED_CURVE_NAME_BYTES =
  51         ECDSA_SUPPORTED_CURVE_NAME.getBytes(StandardCharsets.UTF_8);
  52     private static final String ECDSA_SUPPORTED_CURVE_NAME_SPEC = ECDSA_CURVES.get(ECDSA_SUPPORTED_CURVE_NAME);
  53
  54     private static final String KEY_TYPE_RSA = "ssh-rsa";
  55     private static final byte[] KEY_TYPE_RSA_BYTES = KEY_TYPE_RSA.getBytes(StandardCharsets.UTF_8);
  56
  57     private static final String KEY_TYPE_DSA = "ssh-dss";
  58     private static final byte[] KEY_TYPE_DSA_BYTES = KEY_TYPE_DSA.getBytes(StandardCharsets.UTF_8);
  59     private static final String KEY_TYPE_ECDSA = "ecdsa-sha2-" + ECDSA_SUPPORTED_CURVE_NAME;
  60     private static final byte[] KEY_TYPE_ECDSA_BYTES = KEY_TYPE_ECDSA.getBytes(StandardCharsets.UTF_8);
  61
  62     private static final KeyFactory RSA_FACTORY = loadOrWarn("RSA");
  63     private static final KeyFactory DSA_FACTORY = loadOrWarn("DSA");
  64     private static final KeyFactory EC_FACTORY = loadOrWarn("EC");
  65
  66     private static KeyFactory loadOrWarn(final String algorithm) {
  67         try {
  68             return KeyFactory.getInstance(algorithm);
  69         } catch (NoSuchAlgorithmException e) {
  70             LOG.warn("KeyFactory for {} not found", algorithm, e);
  71             return null;
  72         }
  73     }
  74
  75     private byte[] bytes = new byte[0];
  76     private int pos = 0;
  77
  78     public PublicKey decodePublicKey(final String keyLine) throws GeneralSecurityException {
  79
  80         // look for the Base64 encoded part of the line to decode
  81         // both ssh-rsa and ssh-dss begin with "AAAA" due to the length bytes
  82         bytes = Base64.getDecoder().decode(keyLine.getBytes(StandardCharsets.UTF_8));
  83         if (bytes.length == 0) {
  84             throw new IllegalArgumentException("No Base64 part to decode in " + keyLine);
  85         }
  86
  87         pos = 0;
  88
  89         final var type = decodeType();
  90         return switch (type) {
  91             case KEY_TYPE_RSA -> decodeAsRSA();
  92             case KEY_TYPE_DSA -> decodeAsDSA();
  93             case KEY_TYPE_ECDSA -> decodeAsEcDSA();
  94             default -> throw new IllegalArgumentException("Unknown decode key type " + type + " in " + keyLine);
  95         };
  96     }
  97
  98     private PublicKey decodeAsEcDSA() throws GeneralSecurityException {
  99         if (EC_FACTORY == null) {
 100             throw new NoSuchAlgorithmException("ECDSA keys are not supported");
 101         }
 102
 103         ECNamedCurveParameterSpec spec256r1 = ECNamedCurveTable.getParameterSpec(ECDSA_SUPPORTED_CURVE_NAME_SPEC);
 104         ECNamedCurveSpec params256r1 = new ECNamedCurveSpec(
 105             ECDSA_SUPPORTED_CURVE_NAME_SPEC, spec256r1.getCurve(), spec256r1.getG(), spec256r1.getN());
 106         // copy last 65 bytes from ssh key.
 107         ECPoint point = ECPointUtil.decodePoint(params256r1.getCurve(), Arrays.copyOfRange(bytes, 39, bytes.length));
 108         return EC_FACTORY.generatePublic(new ECPublicKeySpec(point, params256r1));
 109     }
 110
 111     private PublicKey decodeAsDSA() throws GeneralSecurityException {
 112         if (DSA_FACTORY == null) {
 113             throw new NoSuchAlgorithmException("RSA keys are not supported");
 114         }
 115
 116         final var p = decodeBigInt();
 117         final var q = decodeBigInt();
 118         final var g = decodeBigInt();
 119         final var y = decodeBigInt();
 120         return DSA_FACTORY.generatePublic(new DSAPublicKeySpec(y, p, q, g));
 121     }
 122
 123     private PublicKey decodeAsRSA() throws GeneralSecurityException {
 124         if (RSA_FACTORY == null) {
 125             throw new NoSuchAlgorithmException("RSA keys are not supported");
 126         }
 127
 128         final var exponent = decodeBigInt();
 129         final var modulus = decodeBigInt();
 130         return RSA_FACTORY.generatePublic(new RSAPublicKeySpec(modulus, exponent));
 131     }
 132
 133     private String decodeType() {
 134         int len = decodeInt();
 135         String type = new String(bytes, pos, len, StandardCharsets.UTF_8);
 136         pos += len;
 137         return type;
 138     }
 139
 140     private int decodeInt() {
 141         return (bytes[pos++] & 0xFF) << 24 | (bytes[pos++] & 0xFF) << 16
 142                 | (bytes[pos++] & 0xFF) << 8 | bytes[pos++] & 0xFF;
 143     }
 144
 145     private BigInteger decodeBigInt() {
 146         int len = decodeInt();
 147         byte[] bigIntBytes = new byte[len];
 148         System.arraycopy(bytes, pos, bigIntBytes, 0, len);
 149         pos += len;
 150         return new BigInteger(bigIntBytes);
 151     }
 152
 153     private static void encodeBigInt(final DataOutput out, final BigInteger value) throws IOException {
 154         final var bytes = value.toByteArray();
 155         out.writeInt(bytes.length);
 156         out.write(bytes);
 157     }
 158
 159     public static String encodePublicKey(final PublicKey publicKey) throws IOException {
 160         final var baos = new ByteArrayOutputStream();
 161
 162         try (var dout = new DataOutputStream(baos)) {
 163             if (publicKey instanceof RSAPublicKey rsa) {
 164                 dout.writeInt(KEY_TYPE_RSA_BYTES.length);
 165                 dout.write(KEY_TYPE_RSA_BYTES);
 166                 encodeBigInt(dout, rsa.getPublicExponent());
 167                 encodeBigInt(dout, rsa.getModulus());
 168             } else if (publicKey instanceof DSAPublicKey dsa) {
 169                 final var dsaParams = dsa.getParams();
 170                 dout.writeInt(KEY_TYPE_DSA_BYTES.length);
 171                 dout.write(KEY_TYPE_DSA_BYTES);
 172                 encodeBigInt(dout, dsaParams.getP());
 173                 encodeBigInt(dout, dsaParams.getQ());
 174                 encodeBigInt(dout, dsaParams.getG());
 175                 encodeBigInt(dout, dsa.getY());
 176             } else if (publicKey instanceof ECPublicKey ec) {
 177                 dout.writeInt(KEY_TYPE_ECDSA_BYTES.length);
 178                 dout.write(KEY_TYPE_ECDSA_BYTES);
 179                 dout.writeInt(ECDSA_SUPPORTED_CURVE_NAME_BYTES.length);
 180                 dout.write(ECDSA_SUPPORTED_CURVE_NAME_BYTES);
 181
 182                 final var q = ec.getQ();
 183                 final var coordX = q.getAffineXCoord().getEncoded();
 184                 final var coordY = q.getAffineYCoord().getEncoded();
 185                 dout.writeInt(coordX.length + coordY.length + 1);
 186                 dout.writeByte(0x04);
 187                 dout.write(coordX);
 188                 dout.write(coordY);
 189             } else {
 190                 throw new IllegalArgumentException("Unknown public key encoding: " + publicKey);
 191             }
 192         }
 193         return Base64.getEncoder().encodeToString(baos.toByteArray());
 194     }
 195 }