Added support for RSA encrypted keys in PEM client credentials (#4230)

* Added support for RSA encrypted keys in PEM client credentials

* Refactoring

* Refactoring

@@ -27,21 +27,28 @@ import org.bouncycastle.openssl.PEMEncryptedKeyPair;
 import org.bouncycastle.openssl.PEMKeyPair;
 import org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter;
 import org.bouncycastle.openssl.jcajce.JcePEMDecryptorProviderBuilder;
+import org.bouncycastle.util.encoders.Hex;
 import org.springframework.util.StringUtils;
 
 import javax.crypto.Cipher;
 import javax.crypto.EncryptedPrivateKeyInfo;
+import javax.crypto.SecretKey;
 import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.IvParameterSpec;
 import javax.crypto.spec.PBEKeySpec;
+import javax.crypto.spec.SecretKeySpec;
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.TrustManagerFactory;
 import java.io.ByteArrayInputStream;
 import java.io.InputStream;
+import java.math.BigInteger;
+import java.nio.ByteBuffer;
 import java.security.AlgorithmParameters;
 import java.security.Key;
 import java.security.KeyFactory;
 import java.security.KeyPair;
 import java.security.KeyStore;
+import java.security.MessageDigest;
 import java.security.PrivateKey;
 import java.security.Security;
 import java.security.cert.Certificate;
@@ -49,6 +56,9 @@ import java.security.cert.CertificateFactory;
 import java.security.cert.X509Certificate;
 import java.security.spec.KeySpec;
 import java.security.spec.PKCS8EncodedKeySpec;
+import java.security.spec.RSAPrivateCrtKeySpec;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 @Data
 @Slf4j
@@ -61,6 +71,15 @@ public class CertPemCredentials implements ClientCredentials {
     private String privateKey;
     private String password;
 
+    static final String OPENSSL_ENCRYPTED_RSA_PRIVATEKEY_REGEX = "\\s*"
+            + "-----BEGIN RSA PRIVATE KEY-----" + "\\s*"
+            + "Proc-Type: 4,ENCRYPTED" + "\\s*"
+            + "DEK-Info:" + "\\s*([^\\s]+)" + "\\s+"
+            + "([\\s\\S]*)"
+            + "-----END RSA PRIVATE KEY-----" + "\\s*";
+
+    static final Pattern OPENSSL_ENCRYPTED_RSA_PRIVATEKEY_PATTERN = Pattern.compile(OPENSSL_ENCRYPTED_RSA_PRIVATEKEY_REGEX);
+
     @Override
     public CredentialsType getType() {
         return CredentialsType.CERT_PEM;
@@ -103,7 +122,7 @@ public class CertPemCredentials implements ClientCredentials {
             KeyPair key = keyConverter.getKeyPair((PEMKeyPair) keyObject);
             privateKey = key.getPrivate();
         } else if (keyObject instanceof PrivateKey) {
-            privateKey = (PrivateKey)keyObject;
+            privateKey = (PrivateKey) keyObject;
         } else {
             throw new RuntimeException("Unable to get private key from object: " + keyObject.getClass());
         }
@@ -152,34 +171,144 @@ public class CertPemCredentials implements ClientCredentials {
     private PrivateKey readPrivateKeyFile(String fileContent) throws Exception {
         PrivateKey privateKey = null;
         if (fileContent != null && !fileContent.isEmpty()) {
-            fileContent = fileContent.replaceAll(".*BEGIN.*PRIVATE KEY.*", "")
-                    .replaceAll(".*END.*PRIVATE KEY.*", "")
-                    .replaceAll("\\s", "");
-            byte[] decoded = Base64.decodeBase64(fileContent);
             KeyFactory keyFactory = KeyFactory.getInstance("RSA");
-            KeySpec keySpec = getKeySpec(decoded);
+            KeySpec keySpec = getKeySpec(fileContent);
             privateKey = keyFactory.generatePrivate(keySpec);
         }
         return privateKey;
     }
 
-    private KeySpec getKeySpec(byte[] encodedKey) throws Exception {
-        KeySpec keySpec;
-        if (password == null || password.isEmpty()) {
-            keySpec = new PKCS8EncodedKeySpec(encodedKey);
+    private KeySpec getKeySpec(String encodedKey) throws Exception {
+        KeySpec keySpec = null;
+        Matcher matcher = OPENSSL_ENCRYPTED_RSA_PRIVATEKEY_PATTERN.matcher(encodedKey);
+        if (matcher.matches()) {
+            String encryptionDetails = matcher.group(1).trim();
+            String encryptedKey = matcher.group(2).replaceAll("\\s", "");
+            byte[] encryptedBinaryKey = java.util.Base64.getDecoder().decode(encryptedKey);
+            String[] encryptionDetailsParts = encryptionDetails.split(",");
+            if (encryptionDetailsParts.length == 2) {
+                String encryptionAlgorithm = encryptionDetailsParts[0];
+                String encryptedAlgorithmParams = encryptionDetailsParts[1];
+                byte[] pw = password.getBytes();
+                byte[] iv = Hex.decode(encryptedAlgorithmParams);
+
+                MessageDigest digest = MessageDigest.getInstance("MD5");
+                digest.update(pw);
+                digest.update(iv, 0, 8);
+
+                byte[] round1Digest = digest.digest();
+                digest.update(round1Digest);
+                digest.update(pw);
+                digest.update(iv, 0, 8);
+
+                byte[] round2Digest = digest.digest();
+                Cipher cipher = null;
+                SecretKey secretKey = null;
+                byte[] key = null;
+
+                switch(encryptionAlgorithm) {
+                    case "AES-256-CBC":
+                        cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+                        key = new byte[32];
+                        System.arraycopy(round1Digest, 0, key, 0, 16);
+                        System.arraycopy(round2Digest, 0, key, 16, 16);
+                        secretKey = new SecretKeySpec(key, "AES");
+                        break;
+                    case "AES-192-CBC":
+                        cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+                        key = new byte[24];
+                        System.arraycopy(round1Digest, 0, key, 0, 16);
+                        System.arraycopy(round2Digest, 0, key, 16, 8);
+                        secretKey = new SecretKeySpec(key, "AES");
+                        break;
+                    case "AES-128-CBC":
+                        cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+                        key = new byte[16];
+                        System.arraycopy(round1Digest, 0, key, 0, 16);
+                        secretKey = new SecretKeySpec(key, "AES");
+                        break;
+                    case "DES-EDE3-CBC":
+                        cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
+                        key = new byte[24];
+                        System.arraycopy(round1Digest, 0, key, 0, 16);
+                        System.arraycopy(round2Digest, 0, key, 16, 8);
+                        secretKey = new SecretKeySpec(key, "DESede");
+                        break;
+                    case "DES-CBC":
+                        cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
+                        key = new byte[8];
+                        System.arraycopy(round1Digest, 0, key, 0, 8);
+                        secretKey = new SecretKeySpec(key, "DES");
+                        break;
+                    }
+                if (cipher != null) {
+                    cipher.init(Cipher.DECRYPT_MODE, secretKey, new IvParameterSpec(iv));
+                    byte[] pkcs1 = cipher.doFinal(encryptedBinaryKey);
+                    keySpec = decodeRSAPrivatePKCS1(pkcs1);
+                } else {
+                    throw new RuntimeException("Unknown Encryption algorithm!");
+                }
+            } else {
+                throw new RuntimeException("Wrong encryption details!");
+            }
         } else {
-            PBEKeySpec pbeKeySpec = new PBEKeySpec(password.toCharArray());
+            encodedKey = encodedKey.replaceAll(".*BEGIN.*PRIVATE KEY.*", "")
+                    .replaceAll(".*END.*PRIVATE KEY.*", "")
+                    .replaceAll("\\s", "");
+            byte[] decoded = Base64.decodeBase64(encodedKey);
+            if (password == null || password.isEmpty()) {
+                keySpec = new PKCS8EncodedKeySpec(decoded);
+            } else {
+                PBEKeySpec pbeKeySpec = new PBEKeySpec(password.toCharArray());
 
-            EncryptedPrivateKeyInfo privateKeyInfo = new EncryptedPrivateKeyInfo(encodedKey);
-            String algorithmName = privateKeyInfo.getAlgName();
-            Cipher cipher = Cipher.getInstance(algorithmName);
-            SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance(algorithmName);
+                EncryptedPrivateKeyInfo privateKeyInfo = new EncryptedPrivateKeyInfo(decoded);
+                String algorithmName = privateKeyInfo.getAlgName();
+                Cipher cipher = Cipher.getInstance(algorithmName);
+                SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance(algorithmName);
 
-            Key pbeKey = secretKeyFactory.generateSecret(pbeKeySpec);
-            AlgorithmParameters algParams = privateKeyInfo.getAlgParameters();
-            cipher.init(Cipher.DECRYPT_MODE, pbeKey, algParams);
-            keySpec = privateKeyInfo.getKeySpec(cipher);
+                Key pbeKey = secretKeyFactory.generateSecret(pbeKeySpec);
+                AlgorithmParameters algParams = privateKeyInfo.getAlgParameters();
+                cipher.init(Cipher.DECRYPT_MODE, pbeKey, algParams);
+                keySpec = privateKeyInfo.getKeySpec(cipher);
+            }
         }
         return keySpec;
     }
+
+    private static BigInteger derint(ByteBuffer input) {
+        int len = der(input, 0x02);
+        byte[] value = new byte[len];
+        input.get(value);
+        return new BigInteger(+1, value);
+    }
+
+    private static int der(ByteBuffer input, int exp) {
+        int tag = input.get() & 0xFF;
+        if (tag != exp) throw new IllegalArgumentException("Unexpected tag");
+        int n = input.get() & 0xFF;
+        if (n < 128) return n;
+        n &= 0x7F;
+        if ((n < 1) || (n > 2)) throw new IllegalArgumentException("Invalid length");
+        int len = 0;
+        while (n-- > 0) {
+            len <<= 8;
+            len |= input.get() & 0xFF;
+        }
+        return len;
+    }
+
+    static RSAPrivateCrtKeySpec decodeRSAPrivatePKCS1(byte[] encoded) {
+        ByteBuffer input = ByteBuffer.wrap(encoded);
+        if (der(input, 0x30) != input.remaining()) throw new IllegalArgumentException("Excess data");
+        if (!BigInteger.ZERO.equals(derint(input))) throw new IllegalArgumentException("Unsupported version");
+        BigInteger n = derint(input);
+        BigInteger e = derint(input);
+        BigInteger d = derint(input);
+        BigInteger p = derint(input);
+        BigInteger q = derint(input);
+        BigInteger ep = derint(input);
+        BigInteger eq = derint(input);
+        BigInteger c = derint(input);
+        return new RSAPrivateCrtKeySpec(n, e, d, p, q, ep, eq, c);
+    }
 }