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Return encoded signature blob instead of a raw signature in

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SshAuthenticationService
This commit is contained in:
Christian Hagau
2017-11-26 00:00:00 +00:00
parent 0a72dda6fc
commit 6e5f5405a2
4 changed files with 226 additions and 38 deletions
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138
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ssh/signature/SshSignatureConverter.java Normal file
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/*
* Copyright (C) 2017 Christian Hagau <ach@hagau.se>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.sufficientlysecure.keychain.ssh.signature;
import org.bouncycastle.asn1.ASN1Integer;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.bcpg.PublicKeyAlgorithmTags;
import org.bouncycastle.util.BigIntegers;
import org.sufficientlysecure.keychain.ssh.key.SshEncodedData;
import org.sufficientlysecure.keychain.ssh.utils.SshUtils;
import java.io.IOException;
import java.math.BigInteger;
import java.security.NoSuchAlgorithmException;
public class SshSignatureConverter {
private static String getSignatureType(int algorithm) throws NoSuchAlgorithmException {
switch (algorithm) {
case PublicKeyAlgorithmTags.RSA_SIGN:
case PublicKeyAlgorithmTags.RSA_GENERAL:
return "ssh-rsa";
case PublicKeyAlgorithmTags.EDDSA:
return "ssh-ed25519";
case PublicKeyAlgorithmTags.DSA:
return "ssh-dss";
default:
throw new NoSuchAlgorithmException("Unknown algorithm");
}
}
private static byte[] getSignatureBlob(byte[] rawSignature, int algorithm) throws NoSuchAlgorithmException {
switch (algorithm) {
case PublicKeyAlgorithmTags.RSA_SIGN:
case PublicKeyAlgorithmTags.RSA_GENERAL:
return rawSignature;
case PublicKeyAlgorithmTags.EDDSA:
return rawSignature;
case PublicKeyAlgorithmTags.DSA:
return getDsaSignatureBlob(rawSignature);
default:
throw new NoSuchAlgorithmException("Unknown algorithm");
}
}
private static byte[] getEcDsaSignatureBlob(byte[] rawSignature) {
BigInteger r = getR(rawSignature);
BigInteger s = getS(rawSignature);
SshEncodedData rsBlob = new SshEncodedData();
rsBlob.putMPInt(r);
rsBlob.putMPInt(s);
return rsBlob.getBytes();
}
private static BigInteger getR(byte[] rawSignature) {
ASN1Sequence asn1Sequence = getASN1Sequence(rawSignature);
return ASN1Integer.getInstance(asn1Sequence.getObjectAt(0)).getValue();
}
private static BigInteger getS(byte[] rawSignature) {
ASN1Sequence asn1Sequence = getASN1Sequence(rawSignature);
return ASN1Integer.getInstance(asn1Sequence.getObjectAt(1)).getValue();
}
private static ASN1Sequence getASN1Sequence(byte[] rawSignature) {
try {
return (ASN1Sequence) ASN1Primitive.fromByteArray(rawSignature);
} catch (IOException e) {
throw new IllegalArgumentException("Could not read ASN.1 object", e);
}
}
private static byte[] getDsaSignatureBlob(byte[] rawSignature) {
BigInteger r = getR(rawSignature);
BigInteger s = getS(rawSignature);
byte[] rByte = BigIntegers.asUnsignedByteArray(r);
byte[] sByte = BigIntegers.asUnsignedByteArray(s);
int integerLength = getDsaSignatureLength(rByte.length > sByte.length ? rByte.length : sByte.length);
int rPaddingLength = integerLength - rByte.length;
int sPaddingLength = integerLength - sByte.length;
byte[] rsBlob = new byte[2 * integerLength];
System.arraycopy(rByte, 0, rsBlob, rPaddingLength, rByte.length);
System.arraycopy(sByte, 0, rsBlob, integerLength + sPaddingLength, sByte.length);
return rsBlob;
}
private static int getDsaSignatureLength(int inLength) {
if (inLength <= 20) {
return 20;
} else {
return 32;
}
}
public static byte[] getSshSignature(byte[] rawSignature, int algorithm) throws NoSuchAlgorithmException {
SshEncodedData signature = new SshEncodedData();
signature.putString(getSignatureType(algorithm));
signature.putString(getSignatureBlob(rawSignature, algorithm));
return signature.getBytes();
}
public static byte[] getSshSignatureEcDsa(byte[] rawSignature, String curveOid) {
SshEncodedData signature = new SshEncodedData();
signature.putString("ecdsa-sha2-" + SshUtils.getCurveName(curveOid));
signature.putString(getEcDsaSignatureBlob(rawSignature));
return signature.getBytes();
}
}

57
OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ssh/utils/SshUtils.java Normal file
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/*
* Copyright (C) 2017 Christian Hagau <ach@hagau.se>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.sufficientlysecure.keychain.ssh.utils;
public class SshUtils {
public static String getCurveName(String curveOid) {
// see RFC5656 section 10.{1,2}
switch (curveOid) {
// REQUIRED curves
case "1.2.840.10045.3.1.7":
return "nistp256";
case "1.3.132.0.34":
return "nistp384";
case "1.3.132.0.35":
return "nistp521";
// RECOMMENDED curves
case "1.3.132.0.1":
return "1.3.132.0.1";
case "1.2.840.10045.3.1.1":
return "1.2.840.10045.3.1.1";
case "1.3.132.0.33":
return "1.3.132.0.33";
case "1.3.132.0.26":
return "1.3.132.0.26";
case "1.3.132.0.27":
return "1.3.132.0.27";
case "1.3.132.0.16":
return "1.3.132.0.16";
case "1.3.132.0.36":
return "1.3.132.0.36";
case "1.3.132.0.37":
return "1.3.132.0.37";
case "1.3.132.0.38":
return "1.3.132.0.38";
default:
return null;
}
}
}