diff options
Diffstat (limited to 'sshlib/src/main/java/com/trilead/ssh2/signature/DSASHA1Verify.java')
| -rw-r--r-- | sshlib/src/main/java/com/trilead/ssh2/signature/DSASHA1Verify.java | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/sshlib/src/main/java/com/trilead/ssh2/signature/DSASHA1Verify.java b/sshlib/src/main/java/com/trilead/ssh2/signature/DSASHA1Verify.java new file mode 100644 index 0000000..6fb6ddb --- /dev/null +++ b/sshlib/src/main/java/com/trilead/ssh2/signature/DSASHA1Verify.java @@ -0,0 +1,255 @@ + +package com.trilead.ssh2.signature; + +import java.io.IOException; +import java.math.BigInteger; +import java.security.InvalidKeyException; +import java.security.KeyFactory; +import java.security.NoSuchAlgorithmException; +import java.security.SecureRandom; +import java.security.Signature; +import java.security.SignatureException; +import java.security.interfaces.DSAParams; +import java.security.interfaces.DSAPrivateKey; +import java.security.interfaces.DSAPublicKey; +import java.security.spec.DSAPublicKeySpec; +import java.security.spec.InvalidKeySpecException; +import java.security.spec.KeySpec; + +import com.trilead.ssh2.log.Logger; +import com.trilead.ssh2.packets.TypesReader; +import com.trilead.ssh2.packets.TypesWriter; + + +/** + * DSASHA1Verify. + * + * @author Christian Plattner, plattner@trilead.com + * @version $Id: DSASHA1Verify.java,v 1.2 2008/04/01 12:38:09 cplattne Exp $ + */ +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!"); + + try { + KeyFactory kf = KeyFactory.getInstance("DSA"); + + KeySpec ks = new DSAPublicKeySpec(y, p, q, g); + return (DSAPublicKey) kf.generatePublic(ks); + } catch (NoSuchAlgorithmException e) { + IOException ex = new IOException(); + ex.initCause(e); + throw ex; + } catch (InvalidKeySpecException e) { + IOException ex = new IOException(); + ex.initCause(e); + throw ex; + } + } + + public static byte[] encodeSSHDSAPublicKey(DSAPublicKey pk) throws IOException + { + TypesWriter tw = new TypesWriter(); + + tw.writeString("ssh-dss"); + + DSAParams params = pk.getParams(); + tw.writeMPInt(params.getP()); + tw.writeMPInt(params.getQ()); + tw.writeMPInt(params.getG()); + tw.writeMPInt(pk.getY()); + + return tw.getBytes(); + } + + /** + * Convert from Java's signature ASN.1 encoding to the SSH spec. + * <p> + * Java ASN.1 encoding: + * <pre> + * SEQUENCE ::= { + * r INTEGER, + * s INTEGER + * } + * </pre> + */ + public static byte[] encodeSSHDSASignature(byte[] ds) + { + TypesWriter tw = new TypesWriter(); + + tw.writeString("ssh-dss"); + + int len, index; + + index = 3; + len = ds[index++] & 0xff; + byte[] r = new byte[len]; + System.arraycopy(ds, index, r, 0, r.length); + + index = index + len + 1; + len = ds[index++] & 0xff; + byte[] s = new byte[len]; + System.arraycopy(ds, index, s, 0, s.length); + + 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 byte[] decodeSSHDSASignature(byte[] sig) throws IOException + { + byte[] rsArray = null; + + if (sig.length == 40) + { + /* OK, another broken SSH server. */ + rsArray = sig; + } + else + { + /* Hopefully a server obeying the standard... */ + 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!"); + } + + int i = 0; + int j = 0; + byte[] tmp; + + if (rsArray[0] == 0 && rsArray[1] == 0 && rsArray[2] == 0) { + j = ((rsArray[i++] << 24) & 0xff000000) | ((rsArray[i++] << 16) & 0x00ff0000) + | ((rsArray[i++] << 8) & 0x0000ff00) | ((rsArray[i++]) & 0x000000ff); + i += j; + j = ((rsArray[i++] << 24) & 0xff000000) | ((rsArray[i++] << 16) & 0x00ff0000) + | ((rsArray[i++] << 8) & 0x0000ff00) | ((rsArray[i++]) & 0x000000ff); + tmp = new byte[j]; + System.arraycopy(rsArray, i, tmp, 0, j); + rsArray = tmp; + } + + /* ASN.1 */ + int frst = ((rsArray[0] & 0x80) != 0 ? 1 : 0); + int scnd = ((rsArray[20] & 0x80) != 0 ? 1 : 0); + + /* Calculate output length */ + int length = rsArray.length + 6 + frst + scnd; + tmp = new byte[length]; + + /* DER-encoding to match Java */ + tmp[0] = (byte) 0x30; + + if (rsArray.length != 40) + throw new IOException("Peer sent corrupt signature"); + /* Calculate length */ + tmp[1] = (byte) 0x2c; + tmp[1] += frst; + tmp[1] += scnd; + + /* First item */ + tmp[2] = (byte) 0x02; + + /* First item length */ + tmp[3] = (byte) 0x14; + tmp[3] += frst; + + /* Copy in the data for first item */ + System.arraycopy(rsArray, 0, tmp, 4 + frst, 20); + + /* Second item */ + tmp[4 + tmp[3]] = (byte) 0x02; + + /* Second item length */ + tmp[5 + tmp[3]] = (byte) 0x14; + tmp[5 + tmp[3]] += scnd; + + /* Copy in the data for the second item */ + System.arraycopy(rsArray, 20, tmp, 6 + tmp[3] + scnd, 20); + + /* Swap buffers */ + rsArray = tmp; + + return rsArray; + } + + public static boolean verifySignature(byte[] message, byte[] ds, DSAPublicKey dpk) throws IOException + { + try { + Signature s = Signature.getInstance("SHA1withDSA"); + s.initVerify(dpk); + s.update(message); + return s.verify(ds); + } catch (NoSuchAlgorithmException e) { + IOException ex = new IOException("No such algorithm"); + ex.initCause(e); + throw ex; + } catch (InvalidKeyException e) { + IOException ex = new IOException("No such algorithm"); + ex.initCause(e); + throw ex; + } catch (SignatureException e) { + IOException ex = new IOException(); + ex.initCause(e); + throw ex; + } + } + + public static byte[] generateSignature(byte[] message, DSAPrivateKey pk, SecureRandom rnd) throws IOException + { + try { + Signature s = Signature.getInstance("SHA1withDSA"); + s.initSign(pk); + s.update(message); + return s.sign(); + } catch (NoSuchAlgorithmException e) { + IOException ex = new IOException(); + ex.initCause(e); + throw ex; + } catch (InvalidKeyException e) { + IOException ex = new IOException(); + ex.initCause(e); + throw ex; + } catch (SignatureException e) { + IOException ex = new IOException(); + ex.initCause(e); + throw ex; + } + } +} |