From 48ded2421114c4c87ef3f8005c9f793a5d077cbd Mon Sep 17 00:00:00 2001 From: Mike Lockwood Date: Tue, 10 Jan 2012 14:24:22 -0800 Subject: ganymed-ssh2-build251beta1 Signed-off-by: Mike Lockwood --- .../java/ch/ethz/ssh2/signature/DSASHA1Verify.java | 210 +++++++++++++++++++++ 1 file changed, 210 insertions(+) create mode 100644 src/main/java/ch/ethz/ssh2/signature/DSASHA1Verify.java (limited to 'src/main/java/ch/ethz/ssh2/signature/DSASHA1Verify.java') diff --git a/src/main/java/ch/ethz/ssh2/signature/DSASHA1Verify.java b/src/main/java/ch/ethz/ssh2/signature/DSASHA1Verify.java new file mode 100644 index 0000000..81e0257 --- /dev/null +++ b/src/main/java/ch/ethz/ssh2/signature/DSASHA1Verify.java @@ -0,0 +1,210 @@ +/* + * Copyright (c) 2006-2011 Christian Plattner. All rights reserved. + * Please refer to the LICENSE.txt for licensing details. + */ +package ch.ethz.ssh2.signature; + +import java.io.IOException; +import java.math.BigInteger; +import java.security.SecureRandom; + +import ch.ethz.ssh2.crypto.digest.SHA1; +import ch.ethz.ssh2.log.Logger; +import ch.ethz.ssh2.packets.TypesReader; +import ch.ethz.ssh2.packets.TypesWriter; + +/** + * DSASHA1Verify. + * + * @author Christian Plattner + * @version $Id: DSASHA1Verify.java 41 2011-06-02 10:36:41Z dkocher@sudo.ch $ + */ +public class DSASHA1Verify +{ + private static final Logger log = Logger.getLogger(DSASHA1Verify.class); + + public static DSAPublicKey decodeSSHDSAPublicKey(byte[] key) throws IOException + { + TypesReader tr = new TypesReader(key); + + String key_format = tr.readString(); + + if (key_format.equals("ssh-dss") == false) + throw new IllegalArgumentException("This is not a ssh-dss public key!"); + + BigInteger p = tr.readMPINT(); + BigInteger q = tr.readMPINT(); + BigInteger g = tr.readMPINT(); + BigInteger y = tr.readMPINT(); + + if (tr.remain() != 0) + throw new IOException("Padding in DSA public key!"); + + return new DSAPublicKey(p, q, g, y); + } + + public static byte[] encodeSSHDSAPublicKey(DSAPublicKey pk) throws IOException + { + TypesWriter tw = new TypesWriter(); + + tw.writeString("ssh-dss"); + tw.writeMPInt(pk.getP()); + tw.writeMPInt(pk.getQ()); + tw.writeMPInt(pk.getG()); + tw.writeMPInt(pk.getY()); + + return tw.getBytes(); + } + + public static byte[] encodeSSHDSASignature(DSASignature ds) + { + TypesWriter tw = new TypesWriter(); + + tw.writeString("ssh-dss"); + + byte[] r = ds.getR().toByteArray(); + byte[] s = ds.getS().toByteArray(); + + byte[] a40 = new byte[40]; + + /* Patch (unsigned) r and s into the target array. */ + + int r_copylen = (r.length < 20) ? r.length : 20; + int s_copylen = (s.length < 20) ? s.length : 20; + + System.arraycopy(r, r.length - r_copylen, a40, 20 - r_copylen, r_copylen); + System.arraycopy(s, s.length - s_copylen, a40, 40 - s_copylen, s_copylen); + + tw.writeString(a40, 0, 40); + + return tw.getBytes(); + } + + public static DSASignature decodeSSHDSASignature(byte[] sig) throws IOException + { + byte[] rsArray; + + if (sig.length == 40) + { + rsArray = sig; + } + else + { + TypesReader tr = new TypesReader(sig); + + String sig_format = tr.readString(); + + if (sig_format.equals("ssh-dss") == false) + throw new IOException("Peer sent wrong signature format"); + + rsArray = tr.readByteString(); + + if (rsArray.length != 40) + throw new IOException("Peer sent corrupt signature"); + + if (tr.remain() != 0) + throw new IOException("Padding in DSA signature!"); + } + + /* Remember, s and r are unsigned ints. */ + + byte[] tmp = new byte[20]; + + System.arraycopy(rsArray, 0, tmp, 0, 20); + BigInteger r = new BigInteger(1, tmp); + + System.arraycopy(rsArray, 20, tmp, 0, 20); + BigInteger s = new BigInteger(1, tmp); + + if (log.isDebugEnabled()) + { + log.debug("decoded ssh-dss signature: first bytes r(" + ((rsArray[0]) & 0xff) + "), s(" + + ((rsArray[20]) & 0xff) + ")"); + } + + return new DSASignature(r, s); + } + + public static boolean verifySignature(byte[] message, DSASignature ds, DSAPublicKey dpk) throws IOException + { + /* Inspired by Bouncycastle's DSASigner class */ + + SHA1 md = new SHA1(); + md.update(message); + byte[] sha_message = new byte[md.getDigestLength()]; + md.digest(sha_message); + + BigInteger m = new BigInteger(1, sha_message); + + BigInteger r = ds.getR(); + BigInteger s = ds.getS(); + + BigInteger g = dpk.getG(); + BigInteger p = dpk.getP(); + BigInteger q = dpk.getQ(); + BigInteger y = dpk.getY(); + + BigInteger zero = BigInteger.ZERO; + + if (log.isDebugEnabled()) + { + log.debug("ssh-dss signature: m: " + m.toString(16)); + log.debug("ssh-dss signature: r: " + r.toString(16)); + log.debug("ssh-dss signature: s: " + s.toString(16)); + log.debug("ssh-dss signature: g: " + g.toString(16)); + log.debug("ssh-dss signature: p: " + p.toString(16)); + log.debug("ssh-dss signature: q: " + q.toString(16)); + log.debug("ssh-dss signature: y: " + y.toString(16)); + } + + if (zero.compareTo(r) >= 0 || q.compareTo(r) <= 0) + { + log.warning("ssh-dss signature: zero.compareTo(r) >= 0 || q.compareTo(r) <= 0"); + return false; + } + + if (zero.compareTo(s) >= 0 || q.compareTo(s) <= 0) + { + log.warning("ssh-dss signature: zero.compareTo(s) >= 0 || q.compareTo(s) <= 0"); + return false; + } + + BigInteger w = s.modInverse(q); + + BigInteger u1 = m.multiply(w).mod(q); + BigInteger u2 = r.multiply(w).mod(q); + + u1 = g.modPow(u1, p); + u2 = y.modPow(u2, p); + + BigInteger v = u1.multiply(u2).mod(p).mod(q); + + return v.equals(r); + } + + public static DSASignature generateSignature(byte[] message, DSAPrivateKey pk, SecureRandom rnd) + { + SHA1 md = new SHA1(); + md.update(message); + byte[] sha_message = new byte[md.getDigestLength()]; + md.digest(sha_message); + + BigInteger m = new BigInteger(1, sha_message); + BigInteger k; + int qBitLength = pk.getQ().bitLength(); + + do + { + k = new BigInteger(qBitLength, rnd); + } + while (k.compareTo(pk.getQ()) >= 0); + + BigInteger r = pk.getG().modPow(k, pk.getP()).mod(pk.getQ()); + + k = k.modInverse(pk.getQ()).multiply(m.add((pk).getX().multiply(r))); + + BigInteger s = k.mod(pk.getQ()); + + return new DSASignature(r, s); + } +} -- cgit v1.2.3