This is an automated email from the ASF dual-hosted git repository.
lgoldstein pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/mina-sshd.git
commit 6e63c9d0d42a33fb98a82d4b5dac66da08398db3
Author: Lyor Goldstein <lgoldst...@apache.org>
AuthorDate: Mon Sep 23 09:12:49 2019 +0300
[SSHD-941] Lazy-load and cache internal moduli used in Diffie-Helman group
key exchange
---
CHANGES.md | 3 +
README.md | 1 +
.../org/apache/sshd/client/kex/DHGEXClient.java | 18 ++++-
.../org/apache/sshd/server/kex/DHGEXServer.java | 87 ++++++++++++++--------
.../java/org/apache/sshd/server/kex/Moduli.java | 51 ++++++++++++-
.../org/apache/sshd/server/kex/ModuliTest.java | 70 +++++++++++++++++
6 files changed, 192 insertions(+), 38 deletions(-)
diff --git a/CHANGES.md b/CHANGES.md
index 1de1064..70c4c90 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -40,6 +40,9 @@ peer version data is received.
by tracking the initialized channels identifiers and being lenient only if
command is received for a channel that was
initialized in the past.
+* The internal moduli used in Diffie-Hellman group exchange are **cached** -
lazy-loaded the 1st time such an exchange
+occurs. The cache can be invalidated (and thus force a re-load) by invoking
`Moduli#clearInternalModuliCache`.
+
## Behavioral changes and enhancements
* [SSHD-926](https://issues.apache.org/jira/browse/SSHD-930) - Add support for
OpenSSH 'lsets...@openssh.com' SFTP protocol extension.
diff --git a/README.md b/README.md
index 49b4e38..ac35e7b 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,7 @@ based applications requiring SSH support.
* [RFC 4335 - The Secure Shell (SSH) Session Channel Break
Extension](https://tools.ietf.org/html/rfc4335)
* [RFC 4344 - The Secure Shell (SSH) Transport Layer Encryption
Modes](https://tools.ietf.org/html/rfc4344)
* [RFC 4345 - Improved Arcfour Modes for the Secure Shell (SSH) Transport
Layer Protocol](https://tools.ietf.org/html/rfc4345)
+* [RFC 4419 - Diffie-Hellman Group Exchange for the Secure Shell (SSH)
Transport Layer Protocol](https://tools.ietf.org/html/rfc4419)
* [RFC 4716 - The Secure Shell (SSH) Public Key File
Format](https://tools.ietf.org/html/rfc4716)
* [RFC 5480 - Elliptic Curve Cryptography Subject Public Key
Information](https://tools.ietf.org/html/rfc5480)
* [RFC 6668 - SHA-2 Data Integrity Verification for the Secure Shell (SSH)
Transport Layer Protocol](https://tools.ietf.org/html/rfc6668)
diff --git
a/sshd-core/src/main/java/org/apache/sshd/client/kex/DHGEXClient.java
b/sshd-core/src/main/java/org/apache/sshd/client/kex/DHGEXClient.java
index 597079b..ced2125 100644
--- a/sshd-core/src/main/java/org/apache/sshd/client/kex/DHGEXClient.java
+++ b/sshd-core/src/main/java/org/apache/sshd/client/kex/DHGEXClient.java
@@ -87,8 +87,10 @@ public class DHGEXClient extends AbstractDHClientKeyExchange
{
public void init(Session s, byte[] v_s, byte[] v_c, byte[] i_s, byte[]
i_c) throws Exception {
super.init(s, v_s, v_c, i_s, i_c);
if (log.isDebugEnabled()) {
- log.debug("init({}) Send SSH_MSG_KEX_DH_GEX_REQUEST", s);
+ log.debug("init({})[{}] Send SSH_MSG_KEX_DH_GEX_REQUEST - min={},
prf={}, max={}",
+ this, s, min, prf, max);
}
+
Buffer buffer =
s.createBuffer(SshConstants.SSH_MSG_KEX_DH_GEX_REQUEST, Integer.SIZE);
buffer.putInt(min);
buffer.putInt(prf);
@@ -104,8 +106,9 @@ public class DHGEXClient extends
AbstractDHClientKeyExchange {
Session session = getSession();
boolean debugEnabled = log.isDebugEnabled();
if (debugEnabled) {
- log.debug("next({})[{}] process command={}",
- this, session, KeyExchange.getGroupKexOpcodeName(cmd));
+ log.debug("next({})[{}] process command={} (expected={})",
+ this, session, KeyExchange.getGroupKexOpcodeName(cmd),
+ KeyExchange.getGroupKexOpcodeName(expected));
}
if (cmd != expected) {
@@ -126,6 +129,7 @@ public class DHGEXClient extends
AbstractDHClientKeyExchange {
if (debugEnabled) {
log.debug("next({})[{}] Send SSH_MSG_KEX_DH_GEX_INIT", this,
session);
}
+
buffer = session.createBuffer(
SshConstants.SSH_MSG_KEX_DH_GEX_INIT, e.length + Byte.SIZE);
buffer.putMPInt(e);
@@ -135,6 +139,11 @@ public class DHGEXClient extends
AbstractDHClientKeyExchange {
}
if (cmd == SshConstants.SSH_MSG_KEX_DH_GEX_REPLY) {
+ if (debugEnabled) {
+ log.debug("next({})[{}] validate SSH_MSG_KEX_DH_GEX_REPLY -
min={}, prf={}, max={}",
+ this, session, min, prf, max);
+ }
+
byte[] k_s = buffer.getBytes();
f = buffer.getMPIntAsBytes();
byte[] sig = buffer.getBytes();
@@ -146,7 +155,8 @@ public class DHGEXClient extends
AbstractDHClientKeyExchange {
String keyAlg = KeyUtils.getKeyType(serverKey);
if (GenericUtils.isEmpty(keyAlg)) {
- throw new SshException("Unsupported server key type");
+ throw new SshException("Unsupported server key type: " +
serverKey.getAlgorithm()
+ + " [" + serverKey.getFormat() + "]");
}
buffer = new ByteArrayBuffer();
diff --git
a/sshd-core/src/main/java/org/apache/sshd/server/kex/DHGEXServer.java
b/sshd-core/src/main/java/org/apache/sshd/server/kex/DHGEXServer.java
index 914c5b0..55d791f 100644
--- a/sshd-core/src/main/java/org/apache/sshd/server/kex/DHGEXServer.java
+++ b/sshd-core/src/main/java/org/apache/sshd/server/kex/DHGEXServer.java
@@ -55,7 +55,6 @@ import org.apache.sshd.server.session.ServerSession;
* @author <a href="mailto:d...@mina.apache.org";>Apache MINA SSHD Project</a>
*/
public class DHGEXServer extends AbstractDHServerKeyExchange {
-
protected final DHFactory factory;
protected DHG dh;
protected int min;
@@ -73,7 +72,7 @@ public class DHGEXServer extends AbstractDHServerKeyExchange {
return factory.getName();
}
- public static KeyExchangeFactory newFactory(final DHFactory factory) {
+ public static KeyExchangeFactory newFactory(DHFactory factory) {
return new KeyExchangeFactory() {
@Override
public KeyExchange create() {
@@ -105,10 +104,13 @@ public class DHGEXServer extends
AbstractDHServerKeyExchange {
ServerSession session = getServerSession();
boolean debugEnabled = log.isDebugEnabled();
if (debugEnabled) {
- log.debug("next({})[{}] process command={}", this, session,
KeyExchange.getGroupKexOpcodeName(cmd));
+ log.debug("next({})[{}] process command={} (expected={})",
+ this, session, KeyExchange.getGroupKexOpcodeName(cmd),
+ KeyExchange.getGroupKexOpcodeName(expected));
}
- if (cmd == SshConstants.SSH_MSG_KEX_DH_GEX_REQUEST_OLD && expected ==
SshConstants.SSH_MSG_KEX_DH_GEX_REQUEST) {
+ if ((cmd == SshConstants.SSH_MSG_KEX_DH_GEX_REQUEST_OLD)
+ && (expected == SshConstants.SSH_MSG_KEX_DH_GEX_REQUEST)) {
oldRequest = true;
min = SecurityUtils.MIN_DHGEX_KEY_SIZE;
prf = buffer.getInt();
@@ -116,15 +118,17 @@ public class DHGEXServer extends
AbstractDHServerKeyExchange {
if ((max < min) || (prf < min) || (max < prf)) {
throw new
SshException(SshConstants.SSH2_DISCONNECT_KEY_EXCHANGE_FAILED,
- "Protocol error: bad parameters " + min + " !< " + prf
+ " !< " + max);
+ "Protocol error: bad parameters " + min + " !< " + prf + "
!< " + max);
}
+
dh = chooseDH(min, prf, max);
f = dh.getE();
hash = dh.getHash();
hash.init();
if (debugEnabled) {
- log.debug("next({})[{}] send SSH_MSG_KEX_DH_GEX_GROUP", this,
session);
+ log.debug("next({})[{}] send (old request)
SSH_MSG_KEX_DH_GEX_GROUP - min={}, prf={}, max={}",
+ this, session, min, prf, max);
}
buffer =
session.createBuffer(SshConstants.SSH_MSG_KEX_DH_GEX_GROUP);
@@ -136,21 +140,25 @@ public class DHGEXServer extends
AbstractDHServerKeyExchange {
return false;
}
- if (cmd == SshConstants.SSH_MSG_KEX_DH_GEX_REQUEST && expected ==
SshConstants.SSH_MSG_KEX_DH_GEX_REQUEST) {
+ if ((cmd == SshConstants.SSH_MSG_KEX_DH_GEX_REQUEST)
+ && (expected == SshConstants.SSH_MSG_KEX_DH_GEX_REQUEST)) {
min = buffer.getInt();
prf = buffer.getInt();
max = buffer.getInt();
+
if ((prf < min) || (max < prf)) {
throw new
SshException(SshConstants.SSH2_DISCONNECT_KEY_EXCHANGE_FAILED,
- "Protocol error: bad parameters " + min + " !< " + prf
+ " !< " + max);
+ "Protocol error: bad parameters " + min + " !< " + prf + "
!< " + max);
}
+
dh = chooseDH(min, prf, max);
f = dh.getE();
hash = dh.getHash();
hash.init();
if (debugEnabled) {
- log.debug("next({})[{}] Send SSH_MSG_KEX_DH_GEX_GROUP", this,
session);
+ log.debug("next({})[{}] Send SSH_MSG_KEX_DH_GEX_GROUP -
min={}, prf={}, max={}",
+ this, session, min, prf, max);
}
buffer =
session.createBuffer(SshConstants.SSH_MSG_KEX_DH_GEX_GROUP);
buffer.putMPInt(dh.getP());
@@ -163,8 +171,8 @@ public class DHGEXServer extends
AbstractDHServerKeyExchange {
if (cmd != expected) {
throw new
SshException(SshConstants.SSH2_DISCONNECT_KEY_EXCHANGE_FAILED,
- "Protocol error: expected packet " +
KeyExchange.getGroupKexOpcodeName(expected)
- + ", got " + KeyExchange.getGroupKexOpcodeName(cmd));
+ "Protocol error: expected packet " +
KeyExchange.getGroupKexOpcodeName(expected)
+ + ", got " + KeyExchange.getGroupKexOpcodeName(cmd));
}
if (cmd == SshConstants.SSH_MSG_KEX_DH_GEX_INIT) {
@@ -190,6 +198,7 @@ public class DHGEXServer extends
AbstractDHServerKeyExchange {
buffer.putBytes(i_c);
buffer.putBytes(i_s);
buffer.putBytes(k_s);
+
if (oldRequest) {
buffer.putInt(prf);
} else {
@@ -197,6 +206,7 @@ public class DHGEXServer extends
AbstractDHServerKeyExchange {
buffer.putInt(prf);
buffer.putInt(max);
}
+
buffer.putMPInt(dh.getP());
buffer.putMPInt(dh.getG());
buffer.putMPInt(e);
@@ -220,10 +230,12 @@ public class DHGEXServer extends
AbstractDHServerKeyExchange {
// Send response
if (debugEnabled) {
- log.debug("next({})[{}] Send SSH_MSG_KEX_DH_GEX_REPLY", this,
session);
+ log.debug("next({})[{}] Send SSH_MSG_KEX_DH_GEX_REPLY -
old={}, min={}, prf={}, max={}",
+ this, session, oldRequest, min, prf, max);
}
- buffer =
session.prepareBuffer(SshConstants.SSH_MSG_KEX_DH_GEX_REPLY,
BufferUtils.clear(buffer));
+ buffer = session.prepareBuffer(
+ SshConstants.SSH_MSG_KEX_DH_GEX_REPLY,
BufferUtils.clear(buffer));
buffer.putBytes(k_s);
buffer.putBytes(f);
buffer.putBytes(sigH);
@@ -235,20 +247,23 @@ public class DHGEXServer extends
AbstractDHServerKeyExchange {
}
protected DHG chooseDH(int min, int prf, int max) throws Exception {
- List<Moduli.DhGroup> groups = loadModuliGroups();
-
+ int maxDHGroupExchangeKeySize =
SecurityUtils.getMaxDHGroupExchangeKeySize();
min = Math.max(min, SecurityUtils.MIN_DHGEX_KEY_SIZE);
prf = Math.max(prf, SecurityUtils.MIN_DHGEX_KEY_SIZE);
- prf = Math.min(prf, SecurityUtils.getMaxDHGroupExchangeKeySize());
- max = Math.min(max, SecurityUtils.getMaxDHGroupExchangeKeySize());
- int bestSize = 0;
+ prf = Math.min(prf, maxDHGroupExchangeKeySize);
+ max = Math.min(max, maxDHGroupExchangeKeySize);
+
+ List<Moduli.DhGroup> groups = loadModuliGroups();
+ Session session = getServerSession();
List<Moduli.DhGroup> selected = new ArrayList<>();
+ int bestSize = 0;
boolean traceEnabled = log.isTraceEnabled();
for (Moduli.DhGroup group : groups) {
int size = group.getSize();
if ((size < min) || (size > max)) {
if (traceEnabled) {
- log.trace("chooseDH - skip group={} - size not in range
[{}-{}]", group, min, max);
+ log.trace("chooseDH({})[{}] - skip group={} - size not in
range [{}-{}]",
+ this, session, group, min, max);
}
continue;
}
@@ -256,22 +271,24 @@ public class DHGEXServer extends
AbstractDHServerKeyExchange {
if (((size > prf) && (size < bestSize)) || ((size > bestSize) &&
(bestSize < prf))) {
bestSize = size;
if (traceEnabled) {
- log.trace("chooseDH(prf={}, min={}, max={}) new best
size={} from group={}", prf, min, max, bestSize, group);
+ log.trace("chooseDH({})[{}][prf={}, min={}, max={}] new
best size={} from group={}",
+ this, session, prf, min, max, bestSize, group);
}
selected.clear();
}
if (size == bestSize) {
if (traceEnabled) {
- log.trace("chooseDH(prf={}, min={}, max={}) selected {}",
prf, min, max, group);
+ log.trace("chooseDH({})[{}][prf={}, min={}, max={}]
selected {}",
+ this, session, prf, min, max, group);
}
selected.add(group);
}
}
- ServerSession session = getServerSession();
if (selected.isEmpty()) {
- log.warn("chooseDH({})[{}] No suitable primes found, defaulting to
DHG1", this, session);
+ log.warn("chooseDH({})[{}][prf={}, min={}, max={}] No suitable
primes found, defaulting to DHG1",
+ this, session, prf, min, max);
return getDH(new BigInteger(DHGroupData.getP1()), new
BigInteger(DHGroupData.getG()));
}
@@ -280,42 +297,48 @@ public class DHGEXServer extends
AbstractDHServerKeyExchange {
Random random = Objects.requireNonNull(factory.create(), "No random
generator");
int which = random.random(selected.size());
Moduli.DhGroup group = selected.get(which);
+ if (traceEnabled) {
+ log.trace("chooseDH({})[{}][prf={}, min={}, max={}] selected {}",
+ this, session, prf, min, max, group);
+ }
return getDH(group.getP(), group.getG());
}
protected List<Moduli.DhGroup> loadModuliGroups() throws IOException {
- ServerSession session = getServerSession();
+ Session session = getServerSession();
String moduliStr = session.getString(ServerFactoryManager.MODULI_URL);
List<Moduli.DhGroup> groups = null;
- URL moduli;
if (!GenericUtils.isEmpty(moduliStr)) {
try {
- moduli = new URL(moduliStr);
+ URL moduli = new URL(moduliStr);
groups = Moduli.parseModuli(moduli);
} catch (IOException e) { // OK - use internal moduli
- log.warn("Error (" + e.getClass().getSimpleName() + ") loading
external moduli from " + moduliStr + ": " + e.getMessage());
+ log.warn("loadModuliGroups({})[{}] Error ({}) loading external
moduli from {}: {}",
+ this, session, e.getClass().getSimpleName(), moduliStr,
e.getMessage());
}
}
if (groups == null) {
- moduliStr = "/org/apache/sshd/moduli";
+ moduliStr = Moduli.INTERNAL_MODULI_RESPATH;
try {
- moduli = getClass().getResource(moduliStr);
+ URL moduli = getClass().getResource(moduliStr);
if (moduli == null) {
throw new FileNotFoundException("Missing internal moduli
file");
}
moduliStr = moduli.toExternalForm();
- groups = Moduli.parseModuli(moduli);
+ groups = Moduli.loadInternalModuli(moduli);
} catch (IOException e) {
- log.warn("Error (" + e.getClass().getSimpleName() + ") loading
internal moduli from " + moduliStr + ": " + e.getMessage());
+ log.warn("loadModuliGroups({})[{}] Error ({}) loading internal
moduli from {}: {}",
+ this, session, e.getClass().getSimpleName(), moduliStr,
e.getMessage());
throw e; // this time we MUST throw the exception
}
}
if (log.isDebugEnabled()) {
- log.debug("Loaded moduli groups from {}", moduliStr);
+ log.debug("loadModuliGroups({})[{}] Loaded moduli groups from {}",
+ this, session, moduliStr);
}
return groups;
}
diff --git a/sshd-core/src/main/java/org/apache/sshd/server/kex/Moduli.java
b/sshd-core/src/main/java/org/apache/sshd/server/kex/Moduli.java
index adb7098..481b697 100644
--- a/sshd-core/src/main/java/org/apache/sshd/server/kex/Moduli.java
+++ b/sshd-core/src/main/java/org/apache/sshd/server/kex/Moduli.java
@@ -19,14 +19,21 @@
package org.apache.sshd.server.kex;
import java.io.BufferedReader;
+import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.math.BigInteger;
import java.net.URL;
import java.nio.charset.StandardCharsets;
+import java.util.AbstractMap.SimpleImmutableEntry;
import java.util.ArrayList;
+import java.util.Collections;
import java.util.List;
+import java.util.Map;
import java.util.Objects;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.apache.sshd.common.util.GenericUtils;
/**
* Helper class to load DH group primes from a file.
@@ -34,6 +41,10 @@ import java.util.Objects;
* @author <a href="mailto:d...@mina.apache.org";>Apache MINA SSHD Project</a>
*/
public final class Moduli {
+ /**
+ * Resource path of internal moduli file
+ */
+ public static final String INTERNAL_MODULI_RESPATH =
"/org/apache/sshd/moduli";
public static final int MODULI_TYPE_SAFE = 2;
public static final int MODULI_TESTS_COMPOSITE = 0x01;
@@ -63,20 +74,53 @@ public final class Moduli {
@Override
public String toString() {
- return "[size=" + getSize() + ",G=" + getG() + ",P=" + getP() +
"]";
+ return "[size=" + getSize() + ", G=" + getG() + ", P=" + getP() +
"]";
}
}
+ private static final AtomicReference<Map.Entry<String, List<DhGroup>>>
INTERNAL_MODULI_HOLDER = new AtomicReference<>();
+
// Private constructor
private Moduli() {
throw new UnsupportedOperationException("No instance allowed");
}
+ public static Map.Entry<String, List<DhGroup>> clearInternalModuliCache() {
+ return INTERNAL_MODULI_HOLDER.getAndSet(null);
+ }
+
+ public static List<DhGroup> loadInternalModuli(URL url) throws IOException
{
+ if (url == null) {
+ throw new FileNotFoundException("No internal moduli resource
specified");
+ }
+
+ String moduliStr = url.toExternalForm();
+ Map.Entry<String, List<DhGroup>> lastModuli =
INTERNAL_MODULI_HOLDER.get();
+ String lastResource = (lastModuli == null) ? null :
lastModuli.getKey();
+ if (Objects.equals(lastResource, moduliStr)) {
+ return lastModuli.getValue();
+ }
+
+ List<DhGroup> groups = parseModuli(url);
+ if (GenericUtils.isEmpty(groups)) {
+ groups = Collections.emptyList();
+ } else {
+ groups = Collections.unmodifiableList(groups);
+ }
+
+ INTERNAL_MODULI_HOLDER.set(new SimpleImmutableEntry<>(moduliStr,
groups));
+ return groups;
+ }
+
public static List<DhGroup> parseModuli(URL url) throws IOException {
List<DhGroup> groups = new ArrayList<>();
try (BufferedReader r = new BufferedReader(new
InputStreamReader(url.openStream(), StandardCharsets.UTF_8))) {
for (String line = r.readLine(); line != null; line =
r.readLine()) {
line = line.trim();
+ if (line.isEmpty()) {
+ continue;
+ }
+
if (line.startsWith("#")) {
continue;
}
@@ -105,7 +149,10 @@ public final class Moduli {
continue;
}
- DhGroup group = new DhGroup(Integer.parseInt(parts[4]) + 1,
new BigInteger(parts[5], 16), new BigInteger(parts[6], 16));
+ DhGroup group = new DhGroup(
+ Integer.parseInt(parts[4]) + 1,
+ new BigInteger(parts[5], 16),
+ new BigInteger(parts[6], 16));
groups.add(group);
}
diff --git a/sshd-core/src/test/java/org/apache/sshd/server/kex/ModuliTest.java
b/sshd-core/src/test/java/org/apache/sshd/server/kex/ModuliTest.java
new file mode 100644
index 0000000..ef37662
--- /dev/null
+++ b/sshd-core/src/test/java/org/apache/sshd/server/kex/ModuliTest.java
@@ -0,0 +1,70 @@
+/*
+ * 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
+ *
+ * http://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.sshd.server.kex;
+
+import java.io.IOException;
+import java.net.URL;
+import java.util.List;
+
+import org.apache.sshd.common.util.GenericUtils;
+import org.apache.sshd.server.kex.Moduli.DhGroup;
+import org.apache.sshd.util.test.JUnitTestSupport;
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.FixMethodOrder;
+import org.junit.Test;
+import org.junit.runners.MethodSorters;
+
+/**
+ * @author <a href="mailto:d...@mina.apache.org";>Apache MINA SSHD Project</a>
+ */
+@FixMethodOrder(MethodSorters.NAME_ASCENDING)
+public class ModuliTest extends JUnitTestSupport {
+ public ModuliTest() {
+ super();
+ }
+
+ @BeforeClass
+ @AfterClass
+ public static void clearInternalModuliCache() {
+ Moduli.clearInternalModuliCache();
+ }
+
+ @Before
+ @After
+ public void clearCache() {
+ clearInternalModuliCache();
+ }
+
+ @Test
+ public void testLoadInternalModuli() throws IOException {
+ URL moduli = getClass().getResource(Moduli.INTERNAL_MODULI_RESPATH);
+ assertNotNull("Missing internal moduli resource", moduli);
+
+ List<DhGroup> expected = Moduli.loadInternalModuli(moduli);
+ assertTrue("No moduli groups parsed",
GenericUtils.isNotEmpty(expected));
+
+ for (int index = 1; index <= Byte.SIZE; index++) {
+ List<DhGroup> actual = Moduli.loadInternalModuli(moduli);
+ assertSame("Mismatched cached instance at retry #" + index,
expected, actual);
+ }
+ }
+}
