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fix(plc4j/opcua): correct unencrypted username token encoding #2828

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29 changes: 15 additions & 14 deletions plc4j/drivers/opcua/src/main/java/org/apache/plc4x/java/opcua/context/SecureChannel.java
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Original file line number Diff line number Diff line change
Expand Up @@ -848,25 +848,26 @@ private ExtensionObject getIdentityToken(UserTokenType tokenType, String securit

return new BinaryExtensionObjectWithMask(extExpandedNodeId, BINARY_ENCODING_MASK, anonymousIdentityToken);
case userTokenTypeUserName:
//Encrypt the password using the server nonce and server public key
byte[] remoteNonce = conversation.getRemoteNonce();
byte[] passwordBytes = this.password == null ? new byte[0] : this.password.getBytes(StandardCharsets.UTF_8);
ByteBuffer encodeableBuffer = ByteBuffer.allocate(4 + passwordBytes.length + remoteNonce.length);
encodeableBuffer.order(java.nio.ByteOrder.LITTLE_ENDIAN);
encodeableBuffer.putInt(passwordBytes.length + remoteNonce.length);
encodeableBuffer.put(passwordBytes);
encodeableBuffer.put(remoteNonce);
byte[] encodeablePassword = new byte[4 + passwordBytes.length + remoteNonce.length];
encodeableBuffer.position(0);
encodeableBuffer.get(encodeablePassword);

byte[] tokenPassword;
String encryptionAlgorithm;
if (tokenSecurityPolicy == SecurityPolicy.NONE) {
// No encryption: the password is sent as-is and no algorithm is declared.
tokenPassword = encodeablePassword;
encryptionAlgorithm = "";
// No encryption: send only the UTF-8 password, without a length prefix or nonce.
tokenPassword = passwordBytes;
// Part 4 allows null or empty; null also interoperates with servers such as asyncua.
encryptionAlgorithm = null;
} else {
// Encrypt the length, password and server nonce using the server public key.
byte[] remoteNonce = conversation.getRemoteNonce();
ByteBuffer encodeableBuffer = ByteBuffer.allocate(4 + passwordBytes.length + remoteNonce.length);
encodeableBuffer.order(java.nio.ByteOrder.LITTLE_ENDIAN);
encodeableBuffer.putInt(passwordBytes.length + remoteNonce.length);
encodeableBuffer.put(passwordBytes);
encodeableBuffer.put(remoteNonce);
byte[] encodeablePassword = new byte[4 + passwordBytes.length + remoteNonce.length];
encodeableBuffer.position(0);
encodeableBuffer.get(encodeablePassword);

tokenPassword = conversation.encryptPassword(encodeablePassword, tokenSecurityPolicy);
encryptionAlgorithm = tokenSecurityPolicy.getAsymmetricEncryptionAlgorithm().getUri();
}
Expand Down
267 changes: 267 additions & 0 deletions ...cua/src/test/java/org/apache/plc4x/java/opcua/context/SecureChannelUsernameTokenTest.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,267 @@
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.plc4x.java.opcua.context;

import org.apache.plc4x.java.api.authentication.PlcUsernamePasswordAuthentication;
import org.apache.plc4x.java.api.exceptions.PlcRuntimeException;
import org.apache.plc4x.java.opcua.TestCertificateGenerator;
import org.apache.plc4x.java.opcua.config.OpcuaConfiguration;
import org.apache.plc4x.java.opcua.readwrite.*;
import org.apache.plc4x.java.opcua.security.SecurityPolicy;
import org.apache.plc4x.java.spi.buffers.bytebased.WriteBufferByteBased;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.EnumSource;
import org.junit.jupiter.params.provider.MethodSource;
import org.junit.jupiter.params.provider.NullAndEmptySource;
import org.junit.jupiter.params.provider.ValueSource;

import javax.crypto.Cipher;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.StandardCharsets;
import java.security.KeyPair;
import java.security.PrivateKey;
import java.security.cert.X509Certificate;
import java.util.HexFormat;
import java.util.List;
import java.util.Map.Entry;
import java.util.stream.Stream;

import static java.util.Map.entry;
import static org.apache.plc4x.java.opcua.protocol.chunk.PayloadConverter.LITTLE_ENDIAN;
import static org.junit.jupiter.api.Assertions.*;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.Mockito.*;

/** Password and algorithm encoding for UserNameIdentityToken (GH-2791, OPC UA Part 4). */
class SecureChannelUsernameTokenTest {

private static final PascalString NULL_STRING = new PascalString(null);
private static final byte[] NONCE = HexFormat.of().parseHex(
"000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f");
private static Entry<PrivateKey, X509Certificate> server;

private Conversation conversation;
private OpcuaDriverContext driverContext;
private OpcuaConfiguration configuration;

@BeforeAll
static void generateServerCertificate() {
server = TestCertificateGenerator.generate(2048, "CN=server", 3600);
}

@BeforeEach
void setUp() {
conversation = mock(Conversation.class);
when(conversation.getSecurityPolicy()).thenReturn(SecurityPolicy.NONE);
when(conversation.getRemoteNonce()).thenReturn(NONCE);
when(conversation.getRemoteCertificate()).thenReturn(server.getValue());
when(conversation.createRequestHeader()).thenReturn(new RequestHeader(
new NodeId(new NodeIdTwoByte((short) 0)), 0L, 0L, 0L, NULL_STRING, 0L, null));
driverContext = mock(OpcuaDriverContext.class);
when(driverContext.getEndpoint()).thenReturn("opc.tcp://localhost:4840");
configuration = spy(new OpcuaConfiguration());
}

static Stream<Arguments> unencryptedPasswords() {
return Stream.of((String) null, "", SecurityPolicy.NONE.getSecurityPolicyUri())
.flatMap(uri -> Stream.of(
Arguments.of(uri, null, new byte[0]),
Arguments.of(uri, "", new byte[0]),
Arguments.of(uri, "secret", new byte[]{115, 101, 99, 114, 101, 116}),
Arguments.of(uri, "päss密碼🔒", HexFormat.of().parseHex("70c3a47373e5af86e7a2bcf09f9492")),
Arguments.of(uri, "a".repeat(256), "a".repeat(256).getBytes(StandardCharsets.UTF_8))));
}

@ParameterizedTest
@MethodSource("unencryptedPasswords")
void sendsOnlyUtf8PasswordAndNullAlgorithm(String tokenPolicyUri, String password, byte[] expected) throws Exception {
configuration.setAllowInsecureCredentials(true);
UserNameIdentityToken token = usernameToken(password, SecurityPolicy.NONE, tokenPolicyUri);

assertArrayEquals(expected, token.getPassword().getStringValue());
assertNull(token.getEncryptionAlgorithm().getStringValue());
ByteBuffer wire = serialize(token);
assertArrayEquals("user-policy".getBytes(StandardCharsets.UTF_8), readByteString(wire));
assertArrayEquals("user".getBytes(StandardCharsets.UTF_8), readByteString(wire));
assertArrayEquals(expected, readByteString(wire), "ByteString length must count only password bytes");
assertEquals(-1, wire.getInt(), "null algorithm must be encoded as a UA String length of -1");
assertFalse(wire.hasRemaining(), "no nonce, inner length or algorithm bytes may follow");
verify(conversation, never()).encryptPassword(any(), any());
verify(conversation, never()).getRemoteNonce();
}

@Test
void encodesTheUnencryptedAlgorithmAsANullUaString() throws Exception {
configuration.setAllowInsecureCredentials(true);
ByteBuffer wire = serialize(usernameToken("secret", SecurityPolicy.NONE, null));
readByteString(wire); // policyId
readByteString(wire); // userName
readByteString(wire); // password

assertEquals(-1, wire.getInt(), "use null rather than empty for compatibility with asyncua");
assertFalse(wire.hasRemaining());
}

@Test
void needsNeitherNonceNorCertificateForAnUnencryptedToken() {
configuration.setAllowInsecureCredentials(true);
when(conversation.getRemoteNonce()).thenReturn(null);
when(conversation.getRemoteCertificate()).thenReturn(null);

assertArrayEquals(new byte[]{112}, usernameToken("p", SecurityPolicy.NONE, null)
.getPassword().getStringValue());
}

@ParameterizedTest
@EnumSource(value = SecurityPolicy.class, names = "NONE", mode = EnumSource.Mode.EXCLUDE)
void encryptsLengthPasswordAndNonceWithTheTokenPolicy(SecurityPolicy tokenPolicy) throws Exception {
// Real RSA encryption and independent decryption, even though the channel policy is None.
when(conversation.encryptPassword(any(), any())).thenAnswer(invocation ->
new EncryptionHandler(conversation, server.getKey())
.encryptPassword(invocation.getArgument(0), invocation.getArgument(1)));

for (String password : new String[]{null, "", "secret", "päss密碼🔒", "a".repeat(64)}) {
UserNameIdentityToken token = usernameToken(password, SecurityPolicy.NONE, tokenPolicy.getSecurityPolicyUri());
byte[] expected = password == null ? new byte[0] : password.getBytes(StandardCharsets.UTF_8);
Cipher decrypt = tokenPolicy.getAsymmetricEncryptionAlgorithm().getCipher();
decrypt.init(Cipher.DECRYPT_MODE, server.getKey());
ByteBuffer plaintext = ByteBuffer.wrap(decrypt.doFinal(token.getPassword().getStringValue()))
.order(ByteOrder.LITTLE_ENDIAN);
assertEquals(expected.length + NONCE.length, plaintext.getInt());
byte[] actualPassword = new byte[expected.length];
plaintext.get(actualPassword);
assertArrayEquals(expected, actualPassword);
byte[] actualNonce = new byte[NONCE.length];
plaintext.get(actualNonce);
assertArrayEquals(NONCE, actualNonce);
assertFalse(plaintext.hasRemaining());

String algorithm = tokenPolicy.getAsymmetricEncryptionAlgorithm().getUri();
assertEquals(algorithm, token.getEncryptionAlgorithm().getStringValue());
ByteBuffer wire = serialize(token);
readByteString(wire); // policyId
readByteString(wire); // userName
assertArrayEquals(token.getPassword().getStringValue(), readByteString(wire));
assertArrayEquals(algorithm.getBytes(StandardCharsets.UTF_8), readByteString(wire));
assertFalse(wire.hasRemaining());
}
verify(conversation, times(5)).encryptPassword(any(), eq(tokenPolicy));
}

@ParameterizedTest
@NullAndEmptySource
void inheritsTheEndpointPolicyWhenTheTokenPolicyIsUnspecified(String tokenPolicyUri) {
when(conversation.encryptPassword(any(), any())).thenReturn(new byte[]{42});
UserNameIdentityToken token = usernameToken("secret", SecurityPolicy.Basic256Sha256, tokenPolicyUri);

assertArrayEquals(new byte[]{42}, token.getPassword().getStringValue());
verify(conversation).encryptPassword(any(), eq(SecurityPolicy.Basic256Sha256));
}

@Test
void doesNotFallBackToPlaintextWhenPasswordEncryptionFails() {
configuration.setAllowInsecureCredentials(true);
when(conversation.encryptPassword(any(), any())).thenThrow(new PlcRuntimeException("encryption failed"));

PlcRuntimeException exception = assertThrows(PlcRuntimeException.class,
() -> usernameToken("secret", SecurityPolicy.NONE, SecurityPolicy.Basic256Sha256.getSecurityPolicyUri()));

assertEquals("encryption failed", exception.getMessage());
verify(conversation).encryptPassword(any(), eq(SecurityPolicy.Basic256Sha256));
}

@Test
void honorsExplicitNoneTokenPolicyOnAnEncryptedChannel() throws Exception {
when(conversation.getSecurityPolicy()).thenReturn(SecurityPolicy.Basic256Sha256);
when(driverContext.getCertificateKeyPair()).thenReturn(new CertificateKeyPair(
new KeyPair(server.getValue().getPublicKey(), server.getKey()), server.getValue()));
when(driverContext.getThumbprint()).thenReturn(new PascalByteString(0, new byte[0]));
when(conversation.createClientSignature()).thenReturn(new SignatureData(NULL_STRING, new PascalByteString(0, new byte[0])));
configuration.setAllowInsecureCredentials(true);

UserNameIdentityToken token = usernameToken("p", SecurityPolicy.Basic256Sha256,
SecurityPolicy.NONE.getSecurityPolicyUri());

assertArrayEquals(new byte[]{112}, token.getPassword().getStringValue());
assertNull(token.getEncryptionAlgorithm().getStringValue());
verify(conversation, never()).encryptPassword(any(), any());
}

@ParameterizedTest
@NullAndEmptySource
@ValueSource(strings = "http://opcfoundation.org/UA/SecurityPolicy#None")
void refusesUnencryptedCredentialsUnlessExplicitlyAllowed(String tokenPolicyUri) {
PlcRuntimeException exception = assertThrows(PlcRuntimeException.class,
() -> usernameToken("secret", SecurityPolicy.NONE, tokenPolicyUri));

assertTrue(exception.getMessage().contains("allow-insecure-credentials"));
verify(conversation, never()).encryptPassword(any(), any());
}

@Test
void keepsAnonymousAuthenticationIndependentOfCredentialsOptIn() {
SecureChannel channel = new SecureChannel(conversation, driverContext, configuration, null);
UserTokenPolicy policy = new UserTokenPolicy(new PascalString("anonymous-policy"),
UserTokenType.userTokenTypeAnonymous, NULL_STRING, NULL_STRING, NULL_STRING);
BinaryExtensionObjectWithMask identity = assertInstanceOf(BinaryExtensionObjectWithMask.class,
channel.createActivateSessionRequest(endpoint(SecurityPolicy.NONE, policy)).getUserIdentityToken());

assertEquals("anonymous-policy", assertInstanceOf(AnonymousIdentityToken.class, identity.getBody())
.getPolicyId().getStringValue());
verify(conversation, never()).encryptPassword(any(), any());
}

private UserNameIdentityToken usernameToken(String password, SecurityPolicy endpointPolicy, String tokenPolicyUri) {
// The authentication object rejects null passwords; an omitted configuration password is allowed.
when(configuration.getUsername()).thenReturn("user");
when(configuration.getPassword()).thenReturn(password);
SecureChannel channel = new SecureChannel(conversation, driverContext, configuration,
password == null ? null : new PlcUsernamePasswordAuthentication("user", password));
UserTokenPolicy policy = new UserTokenPolicy(new PascalString("user-policy"),
UserTokenType.userTokenTypeUserName, NULL_STRING, NULL_STRING, new PascalString(tokenPolicyUri));
BinaryExtensionObjectWithMask identity = assertInstanceOf(BinaryExtensionObjectWithMask.class,
channel.createActivateSessionRequest(endpoint(endpointPolicy, policy)).getUserIdentityToken());
return assertInstanceOf(UserNameIdentityToken.class, identity.getBody());
}

private Entry<EndpointDescription, UserTokenPolicy> endpoint(SecurityPolicy policy, UserTokenPolicy tokenPolicy) {
return entry(new EndpointDescription(new PascalString("opc.tcp://localhost:4840"),
mock(ApplicationDescription.class), new PascalByteString(0, new byte[0]),
policy == SecurityPolicy.NONE ? MessageSecurityMode.messageSecurityModeNone
: MessageSecurityMode.messageSecurityModeSignAndEncrypt,
new PascalString(policy.getSecurityPolicyUri()), List.of(tokenPolicy), NULL_STRING, (short) 0), tokenPolicy);
}

private static ByteBuffer serialize(UserNameIdentityToken token) throws Exception {
byte[] bytes = new byte[token.getLengthInBytes()];
token.serialize(new WriteBufferByteBased(bytes, LITTLE_ENDIAN));
return ByteBuffer.wrap(bytes).order(ByteOrder.LITTLE_ENDIAN);
}

private static byte[] readByteString(ByteBuffer wire) {
byte[] bytes = new byte[wire.getInt()];
wire.get(bytes);
return bytes;
}
}