Support ED25519 and ECDSA keys in the PuTTY format (#660)

* Support ED25519 PuTTY keys.

Fix #659

* PuTTYKeyFile: Use net.schmizz.sshj.common.Buffer instead of own KeyReader.

A tiny refactoring made in order to allow usage of other utility methods which require Buffer.

* Support ECDSA PuTTY keys.

* Some code cleanup

Co-authored-by: Jeroen van Erp <jeroen@hierynomus.com>

src/main/java/net/schmizz/sshj/userauth/keyprovider/PuTTYKeyFile.java

@@ -16,9 +16,20 @@
 package net.schmizz.sshj.userauth.keyprovider;
 
 import com.hierynomus.sshj.common.KeyAlgorithm;
+import net.i2p.crypto.eddsa.EdDSAPrivateKey;
+import net.i2p.crypto.eddsa.EdDSAPublicKey;
+import net.i2p.crypto.eddsa.spec.EdDSANamedCurveSpec;
+import net.i2p.crypto.eddsa.spec.EdDSANamedCurveTable;
+import net.i2p.crypto.eddsa.spec.EdDSAPrivateKeySpec;
+import net.i2p.crypto.eddsa.spec.EdDSAPublicKeySpec;
 import net.schmizz.sshj.common.Base64;
+import net.schmizz.sshj.common.Buffer;
 import net.schmizz.sshj.common.KeyType;
+import net.schmizz.sshj.common.SecurityUtils;
 import net.schmizz.sshj.userauth.password.PasswordUtils;
+import org.bouncycastle.asn1.nist.NISTNamedCurves;
+import org.bouncycastle.asn1.x9.X9ECParameters;
+import org.bouncycastle.jce.spec.ECNamedCurveSpec;
 import org.bouncycastle.util.encoders.Hex;
 
 import javax.crypto.Cipher;
@@ -101,17 +112,17 @@ public class PuTTYKeyFile extends BaseFileKeyProvider {
 
     protected KeyPair readKeyPair() throws IOException {
         this.parseKeyPair();
+        final Buffer.PlainBuffer publicKeyReader = new Buffer.PlainBuffer(publicKey);
+        final Buffer.PlainBuffer privateKeyReader = new Buffer.PlainBuffer(privateKey);
+        publicKeyReader.readBytes();  // The first part of the payload is a human-readable key format name.
         if (KeyType.RSA.equals(this.getType())) {
-            final KeyReader publicKeyReader = new KeyReader(publicKey);
-            publicKeyReader.skip();   // skip this
             // public key exponent
-            BigInteger e = publicKeyReader.readInt();
+            BigInteger e = publicKeyReader.readMPInt();
             // modulus
-            BigInteger n = publicKeyReader.readInt();
+            BigInteger n = publicKeyReader.readMPInt();
 
-            final KeyReader privateKeyReader = new KeyReader(privateKey);
             // private key exponent
-            BigInteger d = privateKeyReader.readInt();
+            BigInteger d = privateKeyReader.readMPInt();
 
             final KeyFactory factory;
             try {
@@ -129,16 +140,13 @@ public class PuTTYKeyFile extends BaseFileKeyProvider {
             }
         }
         if (KeyType.DSA.equals(this.getType())) {
-            final KeyReader publicKeyReader = new KeyReader(publicKey);
-            publicKeyReader.skip();   // skip this
-            BigInteger p = publicKeyReader.readInt();
-            BigInteger q = publicKeyReader.readInt();
-            BigInteger g = publicKeyReader.readInt();
-            BigInteger y = publicKeyReader.readInt();
+            BigInteger p = publicKeyReader.readMPInt();
+            BigInteger q = publicKeyReader.readMPInt();
+            BigInteger g = publicKeyReader.readMPInt();
+            BigInteger y = publicKeyReader.readMPInt();
 
-            final KeyReader privateKeyReader = new KeyReader(privateKey);
             // Private exponent from the private key
-            BigInteger x = privateKeyReader.readInt();
+            BigInteger x = privateKeyReader.readMPInt();
 
             final KeyFactory factory;
             try {
@@ -154,9 +162,42 @@ public class PuTTYKeyFile extends BaseFileKeyProvider {
             } catch (InvalidKeySpecException e) {
                 throw new IOException(e.getMessage(), e);
             }
-        } else {
-            throw new IOException(String.format("Unknown key type %s", this.getType()));
         }
+        if (KeyType.ED25519.equals(this.getType())) {
+            EdDSANamedCurveSpec ed25519 = EdDSANamedCurveTable.getByName("Ed25519");
+            EdDSAPublicKeySpec publicSpec = new EdDSAPublicKeySpec(publicKeyReader.readBytes(), ed25519);
+            EdDSAPrivateKeySpec privateSpec = new EdDSAPrivateKeySpec(privateKeyReader.readBytes(), ed25519);
+            return new KeyPair(new EdDSAPublicKey(publicSpec), new EdDSAPrivateKey(privateSpec));
+        }
+        final String ecdsaCurve;
+        switch (this.getType()) {
+            case ECDSA256:
+                ecdsaCurve = "P-256";
+                break;
+            case ECDSA384:
+                ecdsaCurve = "P-384";
+                break;
+            case ECDSA521:
+                ecdsaCurve = "P-521";
+                break;
+            default:
+                ecdsaCurve = null;
+                break;
+        }
+        if (ecdsaCurve != null) {
+            BigInteger s = new BigInteger(1, privateKeyReader.readBytes());
+            X9ECParameters ecParams = NISTNamedCurves.getByName(ecdsaCurve);
+            ECNamedCurveSpec ecCurveSpec =
+                    new ECNamedCurveSpec(ecdsaCurve, ecParams.getCurve(), ecParams.getG(), ecParams.getN());
+            ECPrivateKeySpec pks = new ECPrivateKeySpec(s, ecCurveSpec);
+            try {
+                PrivateKey privateKey = SecurityUtils.getKeyFactory(KeyAlgorithm.ECDSA).generatePrivate(pks);
+                return new KeyPair(getType().readPubKeyFromBuffer(publicKeyReader), privateKey);
+            } catch (GeneralSecurityException e) {
+                throw new IOException(e.getMessage(), e);
+            }
+        }
+        throw new IOException(String.format("Unknown key type %s", this.getType()));
     }
 
     protected void parseKeyPair() throws IOException {
@@ -297,40 +338,4 @@ public class PuTTYKeyFile extends BaseFileKeyProvider {
             throw new IOException(e.getMessage(), e);
         }
     }
-
-    /**
-     * Parses the putty key bit vector, which is an encoded sequence
-     * of {@link java.math.BigInteger}s.
-     */
-    private final static class KeyReader {
-        private final DataInput di;
-
-        public KeyReader(byte[] key) {
-            this.di = new DataInputStream(new ByteArrayInputStream(key));
-        }
-
-        /**
-         * Skips an integer without reading it.
-         */
-        public void skip() throws IOException {
-            final int read = di.readInt();
-            if (read != di.skipBytes(read)) {
-                throw new IOException(String.format("Failed to skip %d bytes", read));
-            }
-        }
-
-        private byte[] read() throws IOException {
-            int len = di.readInt();
-            byte[] r = new byte[len];
-            di.readFully(r);
-            return r;
-        }
-
-        /**
-         * Reads the next integer.
-         */
-        public BigInteger readInt() throws IOException {
-            return new BigInteger(read());
-        }
-    }
 }

src/test/java/net/schmizz/sshj/keyprovider/PuTTYKeyFileTest.java

@@ -15,14 +15,18 @@
  */
 package net.schmizz.sshj.keyprovider;
 
+import com.hierynomus.sshj.userauth.keyprovider.OpenSSHKeyV1KeyFile;
+import net.schmizz.sshj.userauth.keyprovider.PKCS8KeyFile;
 import net.schmizz.sshj.userauth.keyprovider.PuTTYKeyFile;
 import net.schmizz.sshj.userauth.password.PasswordFinder;
 import net.schmizz.sshj.userauth.password.Resource;
 import org.junit.Test;
 
+import java.io.File;
 import java.io.IOException;
 import java.io.StringReader;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 
@@ -246,6 +250,97 @@ public class PuTTYKeyFileTest {
         assertNotNull(key.getPublic());
     }
 
+    @Test
+    public void testEd25519() throws Exception {
+        // Generated with
+        //   puttygen src/test/resources/keytypes/test_ed25519 -O private \
+        //     -o src/test/resources/keytypes/test_ed25519_puttygen.ppk
+        PuTTYKeyFile key = new PuTTYKeyFile();
+        key.init(new File("src/test/resources/keytypes/test_ed25519_puttygen.ppk"));
+        assertNotNull(key.getPrivate());
+        assertNotNull(key.getPublic());
+
+        OpenSSHKeyV1KeyFile referenceKey = new OpenSSHKeyV1KeyFile();
+        referenceKey.init(new File("src/test/resources/keytypes/test_ed25519"));
+        assertEquals(key.getPrivate(), referenceKey.getPrivate());
+        assertEquals(key.getPublic(), referenceKey.getPublic());
+    }
+
+    @Test
+    public void testEd25519Encrypted() throws Exception {
+        // Generated with
+        //   puttygen src/test/resources/keytypes/test_ed25519 -O private \
+        //     -o src/test/resources/keytypes/test_ed25519_puttygen_protected.ppk \
+        //     --new-passphrase <(echo 123456)
+        PuTTYKeyFile key = new PuTTYKeyFile();
+        key.init(new File("src/test/resources/keytypes/test_ed25519_puttygen_protected.ppk"), new PasswordFinder() {
+            @Override
+            public char[] reqPassword(Resource<?> resource) {
+                return "123456".toCharArray();
+            }
+
+            @Override
+            public boolean shouldRetry(Resource<?> resource) {
+                return false;
+            }
+        });
+        assertNotNull(key.getPrivate());
+        assertNotNull(key.getPublic());
+
+        OpenSSHKeyV1KeyFile referenceKey = new OpenSSHKeyV1KeyFile();
+        referenceKey.init(new File("src/test/resources/keytypes/test_ed25519"));
+        assertEquals(key.getPrivate(), referenceKey.getPrivate());
+        assertEquals(key.getPublic(), referenceKey.getPublic());
+    }
+
+    @Test
+    public void testEcDsa256() throws Exception {
+        // Generated with
+        //   puttygen src/test/resources/keytypes/test_ecdsa_nistp256 -O private \
+        //     -o src/test/resources/keytypes/test_ecdsa_nistp256_puttygen.ppk
+        PuTTYKeyFile key = new PuTTYKeyFile();
+        key.init(new File("src/test/resources/keytypes/test_ecdsa_nistp256_puttygen.ppk"));
+        assertNotNull(key.getPrivate());
+        assertNotNull(key.getPublic());
+
+        PKCS8KeyFile referenceKey = new PKCS8KeyFile();
+        referenceKey.init(new File("src/test/resources/keytypes/test_ecdsa_nistp256"));
+        assertEquals(key.getPrivate(), referenceKey.getPrivate());
+        assertEquals(key.getPublic(), referenceKey.getPublic());
+    }
+
+    @Test
+    public void testEcDsa384() throws Exception {
+        // Generated with
+        //   puttygen src/test/resources/keytypes/test_ecdsa_nistp384_2 -O private \
+        //     -o src/test/resources/keytypes/test_ecdsa_nistp384_2_puttygen.ppk
+        PuTTYKeyFile key = new PuTTYKeyFile();
+        key.init(new File("src/test/resources/keytypes/test_ecdsa_nistp384_2_puttygen.ppk"));
+        assertNotNull(key.getPrivate());
+        assertNotNull(key.getPublic());
+
+        OpenSSHKeyV1KeyFile referenceKey = new OpenSSHKeyV1KeyFile();
+        referenceKey.init(new File("src/test/resources/keytypes/test_ecdsa_nistp384_2"));
+        assertEquals(key.getPrivate(), referenceKey.getPrivate());
+        assertEquals(key.getPublic(), referenceKey.getPublic());
+    }
+
+    @Test
+    public void testEcDsa521() throws Exception {
+        // Generated with
+        //   puttygen src/test/resources/keytypes/test_ecdsa_nistp521_2 -O private \
+        //     -o src/test/resources/keytypes/test_ecdsa_nistp521_2_puttygen.ppk
+        PuTTYKeyFile key = new PuTTYKeyFile();
+        key.init(new File("src/test/resources/keytypes/test_ecdsa_nistp521_2_puttygen.ppk"));
+        assertNotNull(key.getPrivate());
+        assertNotNull(key.getPublic());
+
+        OpenSSHKeyV1KeyFile referenceKey = new OpenSSHKeyV1KeyFile();
+        referenceKey.init(new File("src/test/resources/keytypes/test_ecdsa_nistp521_2"));
+        assertEquals(key.getPrivate(), referenceKey.getPrivate());
+        assertEquals(key.getPublic(), referenceKey.getPublic());
+    }
+
     @Test
     public void testCorrectPassphraseRsa() throws Exception {
         PuTTYKeyFile key = new PuTTYKeyFile();

src/test/resources/keytypes/test_ecdsa_nistp256_puttygen.ppk

@@ -0,0 +1,10 @@
+PuTTY-User-Key-File-2: ecdsa-sha2-nistp256
+Encryption: none
+Comment: imported-openssh-key
+Public-Lines: 3
+AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBOEQcvowiV3i
+gdRO7rKPrZrao1hCQrnC4tgsxqSJdQCbABI+vHrdbJRfWZNuSk48aAtARJzJVmkn
+/r63EPJgkh8=
+Private-Lines: 1
+AAAAIQCVDJbEpV6gmZgo5TeJFe4cz/qfabtH8CfK+JtapXufEg==
+Private-MAC: 48f3a17cf5f65f4f225e7a21f007d8270d7c8c8f

src/test/resources/keytypes/test_ecdsa_nistp384_2

@@ -0,0 +1,10 @@
+-----BEGIN OPENSSH PRIVATE KEY-----
+b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAiAAAABNlY2RzYS
+1zaGEyLW5pc3RwMzg0AAAACG5pc3RwMzg0AAAAYQTItEGNGyMGn9tCIM4oC3fpU7jVxDQP
+RRkB/Qv8lfM4mmSuYLPcakV6av0ATlM6mKD/TObWQNOJAYzp3MsUn1EMgVLe/sd9TY/hP6
+8Vn+zumMqjmtdX70Ty5ftEoH9zBlgAAADYhfSye4X0snsAAAATZWNkc2Etc2hhMi1uaXN0
+cDM4NAAAAAhuaXN0cDM4NAAAAGEEyLRBjRsjBp/bQiDOKAt36VO41cQ0D0UZAf0L/JXzOJ
+pkrmCz3GpFemr9AE5TOpig/0zm1kDTiQGM6dzLFJ9RDIFS3v7HfU2P4T+vFZ/s7pjKo5rX
+V+9E8uX7RKB/cwZYAAAAMGvH38HMnj6cELCBVQnAQYHlA/Vz1+RVZHj08cey/P3PALx7MR
+pV135UZNZAtWQm+wAAAAlyb290QHNzaGoBAgMEBQYH
+-----END OPENSSH PRIVATE KEY-----

src/test/resources/keytypes/test_ecdsa_nistp384_2.pub

@@ -0,0 +1 @@
+ecdsa-sha2-nistp384 AAAAE2VjZHNhLXNoYTItbmlzdHAzODQAAAAIbmlzdHAzODQAAABhBMi0QY0bIwaf20IgzigLd+lTuNXENA9FGQH9C/yV8ziaZK5gs9xqRXpq/QBOUzqYoP9M5tZA04kBjOncyxSfUQyBUt7+x31Nj+E/rxWf7O6YyqOa11fvRPLl+0Sgf3MGWA== root@sshj

src/test/resources/keytypes/test_ecdsa_nistp384_2_puttygen.ppk

@@ -0,0 +1,11 @@
+PuTTY-User-Key-File-2: ecdsa-sha2-nistp384
+Encryption: none
+Comment: root@sshj
+Public-Lines: 3
+AAAAE2VjZHNhLXNoYTItbmlzdHAzODQAAAAIbmlzdHAzODQAAABhBMi0QY0bIwaf
+20IgzigLd+lTuNXENA9FGQH9C/yV8ziaZK5gs9xqRXpq/QBOUzqYoP9M5tZA04kB
+jOncyxSfUQyBUt7+x31Nj+E/rxWf7O6YyqOa11fvRPLl+0Sgf3MGWA==
+Private-Lines: 2
+AAAAMGvH38HMnj6cELCBVQnAQYHlA/Vz1+RVZHj08cey/P3PALx7MRpV135UZNZA
+tWQm+w==
+Private-MAC: aa4d48441934e15491af0a30f75a02f4e324e652

src/test/resources/keytypes/test_ecdsa_nistp521_2

@@ -0,0 +1,12 @@
+-----BEGIN OPENSSH PRIVATE KEY-----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+-----END OPENSSH PRIVATE KEY-----

src/test/resources/keytypes/test_ecdsa_nistp521_2.pub

@@ -0,0 +1 @@
+ecdsa-sha2-nistp521 AAAAE2VjZHNhLXNoYTItbmlzdHA1MjEAAAAIbmlzdHA1MjEAAACFBADeKUPZeSGORK4SPwpwhdaOGMpI59BARkEVnKg9PhBXyhGIZPU1FVw3zo9rKarwzxaAA0VUQBmnt4OpOewonosSmgAz3cMlrURE5FbBJ4NMPLkYjEwNiCD4IplWEAwmZL+Jq+xJfIpR/WJtij1vlLzLyunO+aJGD91AaR+WglEEu7tzMA== root@sshj

src/test/resources/keytypes/test_ecdsa_nistp521_2_puttygen.ppk

@@ -0,0 +1,12 @@
+PuTTY-User-Key-File-2: ecdsa-sha2-nistp521
+Encryption: none
+Comment: root@sshj
+Public-Lines: 4
+AAAAE2VjZHNhLXNoYTItbmlzdHA1MjEAAAAIbmlzdHA1MjEAAACFBADeKUPZeSGO
+RK4SPwpwhdaOGMpI59BARkEVnKg9PhBXyhGIZPU1FVw3zo9rKarwzxaAA0VUQBmn
+t4OpOewonosSmgAz3cMlrURE5FbBJ4NMPLkYjEwNiCD4IplWEAwmZL+Jq+xJfIpR
+/WJtij1vlLzLyunO+aJGD91AaR+WglEEu7tzMA==
+Private-Lines: 2
+AAAAQSlrwjeSrVTc6OyiA3OTfac4+3nKcf/PRSjIhOLsGUIs2pVCxGYP8/ZfbVfk
+v7nHMn5Cc0fDZEs2cSWi2QhVKBSf
+Private-MAC: 052d1a2fe2c5837aec9dbe0bf10f2ccc376eda43

src/test/resources/keytypes/test_ed25519_puttygen.ppk

@@ -0,0 +1,9 @@
+PuTTY-User-Key-File-2: ssh-ed25519
+Encryption: none
+Comment: root@sshj
+Public-Lines: 2
+AAAAC3NzaC1lZDI1NTE5AAAAIDAdJiRkkBM8yC8seTEoAn2PfwbLKrkcahZ0xxPo
+WICJ
+Private-Lines: 1
+AAAAIKaxyRDJxad8ZArpe1ClowY4NsCQxA50k0rpclKKkHt0
+Private-MAC: 388f807649f181243015cad9650633ec28b25208

src/test/resources/keytypes/test_ed25519_puttygen_protected.ppk

@@ -0,0 +1,9 @@
+PuTTY-User-Key-File-2: ssh-ed25519
+Encryption: aes256-cbc
+Comment: root@sshj
+Public-Lines: 2
+AAAAC3NzaC1lZDI1NTE5AAAAIDAdJiRkkBM8yC8seTEoAn2PfwbLKrkcahZ0xxPo
+WICJ
+Private-Lines: 1
+XFJyRzRt5NjuCVhDEyb50sI+gRn8FB65hh0U8uhGvP3VBl4haChinQasOTBYa4pj
+Private-MAC: 80f50e1a7075567980742644460edffeb67ca829