JGitClientSession.java
- /*
- * Copyright (C) 2018, 2021 Thomas Wolf <thomas.wolf@paranor.ch> and others
- *
- * This program and the accompanying materials are made available under the
- * terms of the Eclipse Distribution License v. 1.0 which is available at
- * https://www.eclipse.org/org/documents/edl-v10.php.
- *
- * SPDX-License-Identifier: BSD-3-Clause
- */
- package org.eclipse.jgit.internal.transport.sshd;
- import static java.text.MessageFormat.format;
- import static org.apache.sshd.core.CoreModuleProperties.MAX_IDENTIFICATION_SIZE;
- import java.io.IOException;
- import java.io.StreamCorruptedException;
- import java.net.SocketAddress;
- import java.nio.charset.StandardCharsets;
- import java.security.PublicKey;
- import java.util.ArrayList;
- import java.util.Collection;
- import java.util.Collections;
- import java.util.HashSet;
- import java.util.Iterator;
- import java.util.LinkedHashSet;
- import java.util.List;
- import java.util.Map;
- import java.util.Objects;
- import java.util.Set;
- import org.apache.sshd.client.ClientBuilder;
- import org.apache.sshd.client.ClientFactoryManager;
- import org.apache.sshd.client.config.hosts.HostConfigEntry;
- import org.apache.sshd.client.keyverifier.ServerKeyVerifier;
- import org.apache.sshd.client.session.ClientSessionImpl;
- import org.apache.sshd.common.AttributeRepository;
- import org.apache.sshd.common.FactoryManager;
- import org.apache.sshd.common.NamedResource;
- import org.apache.sshd.common.PropertyResolver;
- import org.apache.sshd.common.config.keys.KeyUtils;
- import org.apache.sshd.common.io.IoSession;
- import org.apache.sshd.common.io.IoWriteFuture;
- import org.apache.sshd.common.kex.BuiltinDHFactories;
- import org.apache.sshd.common.kex.DHFactory;
- import org.apache.sshd.common.kex.KeyExchangeFactory;
- import org.apache.sshd.common.kex.extension.KexExtensionHandler;
- import org.apache.sshd.common.kex.extension.KexExtensionHandler.AvailabilityPhase;
- import org.apache.sshd.common.kex.extension.KexExtensions;
- import org.apache.sshd.common.keyprovider.KeyPairProvider;
- import org.apache.sshd.common.signature.BuiltinSignatures;
- import org.apache.sshd.common.util.Readable;
- import org.apache.sshd.common.util.buffer.Buffer;
- import org.eclipse.jgit.errors.InvalidPatternException;
- import org.eclipse.jgit.fnmatch.FileNameMatcher;
- import org.eclipse.jgit.internal.transport.sshd.proxy.StatefulProxyConnector;
- import org.eclipse.jgit.transport.CredentialsProvider;
- import org.eclipse.jgit.transport.SshConstants;
- import org.eclipse.jgit.util.StringUtils;
- /**
- * A {@link org.apache.sshd.client.session.ClientSession ClientSession} that can
- * be associated with the {@link HostConfigEntry} the session was created for.
- * The {@link JGitSshClient} creates such sessions and sets this association.
- * <p>
- * Also provides for associating a JGit {@link CredentialsProvider} with a
- * session.
- * </p>
- */
- public class JGitClientSession extends ClientSessionImpl {
- /**
- * Default setting for the maximum number of bytes to read in the initial
- * protocol version exchange. 64kb is what OpenSSH < 8.0 read; OpenSSH
- * 8.0 changed it to 8Mb, but that seems excessive for the purpose stated in
- * RFC 4253. The Apache MINA sshd default in
- * {@link org.apache.sshd.core.CoreModuleProperties#MAX_IDENTIFICATION_SIZE}
- * is 16kb.
- */
- private static final int DEFAULT_MAX_IDENTIFICATION_SIZE = 64 * 1024;
- private static final AttributeKey<Boolean> INITIAL_KEX_DONE = new AttributeKey<>();
- private HostConfigEntry hostConfig;
- private CredentialsProvider credentialsProvider;
- private volatile StatefulProxyConnector proxyHandler;
- /**
- * @param manager
- * @param session
- * @throws Exception
- */
- public JGitClientSession(ClientFactoryManager manager, IoSession session)
- throws Exception {
- super(manager, session);
- }
- /**
- * Retrieves the {@link HostConfigEntry} this session was created for.
- *
- * @return the {@link HostConfigEntry}, or {@code null} if none set
- */
- public HostConfigEntry getHostConfigEntry() {
- return hostConfig;
- }
- /**
- * Sets the {@link HostConfigEntry} this session was created for.
- *
- * @param hostConfig
- * the {@link HostConfigEntry}
- */
- public void setHostConfigEntry(HostConfigEntry hostConfig) {
- this.hostConfig = hostConfig;
- }
- /**
- * Sets the {@link CredentialsProvider} for this session.
- *
- * @param provider
- * to set
- */
- public void setCredentialsProvider(CredentialsProvider provider) {
- credentialsProvider = provider;
- }
- /**
- * Retrieves the {@link CredentialsProvider} set for this session.
- *
- * @return the provider, or {@code null} if none is set.
- */
- public CredentialsProvider getCredentialsProvider() {
- return credentialsProvider;
- }
- /**
- * Sets a {@link StatefulProxyConnector} to handle proxy connection
- * protocols.
- *
- * @param handler
- * to set
- */
- public void setProxyHandler(StatefulProxyConnector handler) {
- proxyHandler = handler;
- }
- @Override
- protected IoWriteFuture sendIdentification(String ident,
- List<String> extraLines) throws Exception {
- StatefulProxyConnector proxy = proxyHandler;
- if (proxy != null) {
- // We must not block here; the framework starts reading messages
- // from the peer only once the initial sendKexInit() following
- // this call to sendIdentification() has returned!
- proxy.runWhenDone(() -> {
- JGitClientSession.super.sendIdentification(ident, extraLines);
- return null;
- });
- // Called only from the ClientSessionImpl constructor, where the
- // return value is ignored.
- return null;
- }
- return super.sendIdentification(ident, extraLines);
- }
- @Override
- protected byte[] sendKexInit() throws Exception {
- StatefulProxyConnector proxy = proxyHandler;
- if (proxy != null) {
- // We must not block here; the framework starts reading messages
- // from the peer only once the initial sendKexInit() has
- // returned!
- proxy.runWhenDone(() -> {
- JGitClientSession.super.sendKexInit();
- return null;
- });
- // This is called only from the ClientSessionImpl
- // constructor, where the return value is ignored.
- return null;
- }
- return super.sendKexInit();
- }
- /**
- * {@inheritDoc}
- *
- * As long as we're still setting up the proxy connection, diverts messages
- * to the {@link StatefulProxyConnector}.
- */
- @Override
- public void messageReceived(Readable buffer) throws Exception {
- StatefulProxyConnector proxy = proxyHandler;
- if (proxy != null) {
- proxy.messageReceived(getIoSession(), buffer);
- } else {
- super.messageReceived(buffer);
- }
- }
- Set<String> getAllAvailableSignatureAlgorithms() {
- Set<String> allAvailable = new HashSet<>();
- BuiltinSignatures.VALUES.forEach(s -> allAvailable.add(s.getName()));
- BuiltinSignatures.getRegisteredExtensions()
- .forEach(s -> allAvailable.add(s.getName()));
- return allAvailable;
- }
- private void setNewFactories(Collection<String> defaultFactories,
- Collection<String> finalFactories) {
- // If new factory names were added make sure we actually have factories
- // for them all.
- //
- // But add new ones at the end: we don't want to change the order for
- // pubkey auth, and any new ones added here were not included in the
- // default set for some reason, such as being deprecated or weak.
- //
- // The order for KEX is determined by the order in the proposal string,
- // but the order in pubkey auth is determined by the order in the
- // factory list (possibly overridden via ssh config
- // PubkeyAcceptedAlgorithms; see JGitPublicKeyAuthentication).
- Set<String> resultSet = new LinkedHashSet<>(defaultFactories);
- resultSet.addAll(finalFactories);
- setSignatureFactoriesNames(resultSet);
- }
- @Override
- protected String resolveAvailableSignaturesProposal(
- FactoryManager manager) {
- List<String> defaultSignatures = getSignatureFactoriesNames();
- HostConfigEntry config = resolveAttribute(
- JGitSshClient.HOST_CONFIG_ENTRY);
- String algorithms = config
- .getProperty(SshConstants.HOST_KEY_ALGORITHMS);
- if (!StringUtils.isEmptyOrNull(algorithms)) {
- List<String> result = modifyAlgorithmList(defaultSignatures,
- getAllAvailableSignatureAlgorithms(), algorithms,
- SshConstants.HOST_KEY_ALGORITHMS);
- if (!result.isEmpty()) {
- if (log.isDebugEnabled()) {
- log.debug(SshConstants.HOST_KEY_ALGORITHMS + ' ' + result);
- }
- setNewFactories(defaultSignatures, result);
- return String.join(",", result); //$NON-NLS-1$
- }
- log.warn(format(SshdText.get().configNoKnownAlgorithms,
- SshConstants.HOST_KEY_ALGORITHMS, algorithms));
- }
- // No HostKeyAlgorithms; using default -- change order to put existing
- // keys first.
- ServerKeyVerifier verifier = getServerKeyVerifier();
- if (verifier instanceof ServerKeyLookup) {
- SocketAddress remoteAddress = resolvePeerAddress(
- resolveAttribute(JGitSshClient.ORIGINAL_REMOTE_ADDRESS));
- List<PublicKey> allKnownKeys = ((ServerKeyLookup) verifier)
- .lookup(this, remoteAddress);
- Set<String> reordered = new LinkedHashSet<>();
- for (PublicKey key : allKnownKeys) {
- if (key != null) {
- String keyType = KeyUtils.getKeyType(key);
- if (keyType != null) {
- if (KeyPairProvider.SSH_RSA.equals(keyType)) {
- // Add all available signatures for ssh-rsa.
- reordered.add(KeyUtils.RSA_SHA512_KEY_TYPE_ALIAS);
- reordered.add(KeyUtils.RSA_SHA256_KEY_TYPE_ALIAS);
- }
- reordered.add(keyType);
- }
- }
- }
- reordered.addAll(defaultSignatures);
- if (log.isDebugEnabled()) {
- log.debug(SshConstants.HOST_KEY_ALGORITHMS + ' ' + reordered);
- }
- // Make sure we actually have factories for them all.
- if (reordered.size() > defaultSignatures.size()) {
- setNewFactories(defaultSignatures, reordered);
- }
- return String.join(",", reordered); //$NON-NLS-1$
- }
- if (log.isDebugEnabled()) {
- log.debug(
- SshConstants.HOST_KEY_ALGORITHMS + ' ' + defaultSignatures);
- }
- return String.join(",", defaultSignatures); //$NON-NLS-1$
- }
- private List<String> determineKexProposal() {
- List<KeyExchangeFactory> kexFactories = getKeyExchangeFactories();
- List<String> defaultKexMethods = NamedResource
- .getNameList(kexFactories);
- HostConfigEntry config = resolveAttribute(
- JGitSshClient.HOST_CONFIG_ENTRY);
- String algorithms = config.getProperty(SshConstants.KEX_ALGORITHMS);
- if (!StringUtils.isEmptyOrNull(algorithms)) {
- Set<String> allAvailable = new HashSet<>();
- BuiltinDHFactories.VALUES
- .forEach(s -> allAvailable.add(s.getName()));
- BuiltinDHFactories.getRegisteredExtensions()
- .forEach(s -> allAvailable.add(s.getName()));
- List<String> result = modifyAlgorithmList(defaultKexMethods,
- allAvailable, algorithms, SshConstants.KEX_ALGORITHMS);
- if (!result.isEmpty()) {
- // If new ones were added, update the installed factories
- Set<String> configuredKexMethods = new HashSet<>(
- defaultKexMethods);
- List<KeyExchangeFactory> newKexFactories = new ArrayList<>();
- result.forEach(name -> {
- if (!configuredKexMethods.contains(name)) {
- DHFactory factory = BuiltinDHFactories
- .resolveFactory(name);
- if (factory == null) {
- // Should not occur here
- if (log.isDebugEnabled()) {
- log.debug(
- "determineKexProposal({}) unknown KEX algorithm {} ignored", //$NON-NLS-1$
- this, name);
- }
- } else {
- newKexFactories
- .add(ClientBuilder.DH2KEX.apply(factory));
- }
- }
- });
- if (!newKexFactories.isEmpty()) {
- newKexFactories.addAll(kexFactories);
- setKeyExchangeFactories(newKexFactories);
- }
- return result;
- }
- log.warn(format(SshdText.get().configNoKnownAlgorithms,
- SshConstants.KEX_ALGORITHMS, algorithms));
- }
- return defaultKexMethods;
- }
- @Override
- protected String resolveSessionKexProposal(String hostKeyTypes)
- throws IOException {
- String kexMethods = String.join(",", determineKexProposal()); //$NON-NLS-1$
- Boolean isRekey = getAttribute(INITIAL_KEX_DONE);
- if (isRekey == null || !isRekey.booleanValue()) {
- // First time
- KexExtensionHandler extHandler = getKexExtensionHandler();
- if (extHandler != null && extHandler.isKexExtensionsAvailable(this,
- AvailabilityPhase.PROPOSAL)) {
- if (kexMethods.isEmpty()) {
- kexMethods = KexExtensions.CLIENT_KEX_EXTENSION;
- } else {
- kexMethods += ',' + KexExtensions.CLIENT_KEX_EXTENSION;
- }
- }
- setAttribute(INITIAL_KEX_DONE, Boolean.TRUE);
- }
- if (log.isDebugEnabled()) {
- log.debug(SshConstants.KEX_ALGORITHMS + ' ' + kexMethods);
- }
- return kexMethods;
- }
- /**
- * Modifies a given algorithm list according to a list from the ssh config,
- * including add ('+'), remove ('-') and reordering ('^') operators.
- *
- * @param defaultList
- * to modify
- * @param allAvailable
- * all available values
- * @param fromConfig
- * telling how to modify the {@code defaultList}, must not be
- * {@code null} or empty
- * @param overrideKey
- * ssh config key; used for logging
- * @return the modified list or {@code null} if {@code overrideKey} is not
- * set
- */
- public List<String> modifyAlgorithmList(List<String> defaultList,
- Set<String> allAvailable, String fromConfig, String overrideKey) {
- Set<String> defaults = new LinkedHashSet<>();
- defaults.addAll(defaultList);
- switch (fromConfig.charAt(0)) {
- case '+':
- List<String> newSignatures = filteredList(allAvailable, overrideKey,
- fromConfig.substring(1));
- defaults.addAll(newSignatures);
- return new ArrayList<>(defaults);
- case '-':
- // This takes wildcard patterns!
- removeFromList(defaults, overrideKey, fromConfig.substring(1));
- return new ArrayList<>(defaults);
- case '^':
- // Specified entries go to the front of the default list
- List<String> allSignatures = filteredList(allAvailable, overrideKey,
- fromConfig.substring(1));
- Set<String> atFront = new HashSet<>(allSignatures);
- for (String sig : defaults) {
- if (!atFront.contains(sig)) {
- allSignatures.add(sig);
- }
- }
- return allSignatures;
- default:
- // Default is overridden -- only accept the ones for which we do
- // have an implementation.
- return filteredList(allAvailable, overrideKey, fromConfig);
- }
- }
- private void removeFromList(Set<String> current, String key,
- String patterns) {
- for (String toRemove : patterns.split("\\s*,\\s*")) { //$NON-NLS-1$
- if (toRemove.indexOf('*') < 0 && toRemove.indexOf('?') < 0) {
- current.remove(toRemove);
- continue;
- }
- try {
- FileNameMatcher matcher = new FileNameMatcher(toRemove, null);
- for (Iterator<String> i = current.iterator(); i.hasNext();) {
- matcher.reset();
- matcher.append(i.next());
- if (matcher.isMatch()) {
- i.remove();
- }
- }
- } catch (InvalidPatternException e) {
- log.warn(format(SshdText.get().configInvalidPattern, key,
- toRemove));
- }
- }
- }
- private List<String> filteredList(Set<String> known, String key,
- String values) {
- List<String> newNames = new ArrayList<>();
- for (String newValue : values.split("\\s*,\\s*")) { //$NON-NLS-1$
- if (known.contains(newValue)) {
- newNames.add(newValue);
- } else {
- log.warn(format(SshdText.get().configUnknownAlgorithm, this,
- newValue, key, values));
- }
- }
- return newNames;
- }
- /**
- * Reads the RFC 4253, section 4.2 protocol version identification. The
- * Apache MINA sshd default implementation checks for NUL bytes also in any
- * preceding lines, whereas RFC 4253 requires such a check only for the
- * actual identification string starting with "SSH-". Likewise, the 255
- * character limit exists only for the identification string, not for the
- * preceding lines. CR-LF handling is also relaxed.
- *
- * @param buffer
- * to read from
- * @param server
- * whether we're an SSH server (should always be {@code false})
- * @return the lines read, with the server identification line last, or
- * {@code null} if no identification line was found and more bytes
- * are needed
- * @throws StreamCorruptedException
- * if the identification is malformed
- * @see <a href="https://tools.ietf.org/html/rfc4253#section-4.2">RFC 4253,
- * section 4.2</a>
- */
- @Override
- protected List<String> doReadIdentification(Buffer buffer, boolean server)
- throws StreamCorruptedException {
- if (server) {
- // Should never happen. No translation; internal bug.
- throw new IllegalStateException(
- "doReadIdentification of client called with server=true"); //$NON-NLS-1$
- }
- Integer maxIdentLength = MAX_IDENTIFICATION_SIZE.get(this).orElse(null);
- int maxIdentSize;
- if (maxIdentLength == null || maxIdentLength
- .intValue() < DEFAULT_MAX_IDENTIFICATION_SIZE) {
- maxIdentSize = DEFAULT_MAX_IDENTIFICATION_SIZE;
- MAX_IDENTIFICATION_SIZE.set(this, Integer.valueOf(maxIdentSize));
- } else {
- maxIdentSize = maxIdentLength.intValue();
- }
- int current = buffer.rpos();
- int end = current + buffer.available();
- if (current >= end) {
- return null;
- }
- byte[] raw = buffer.array();
- List<String> ident = new ArrayList<>();
- int start = current;
- boolean hasNul = false;
- for (int i = current; i < end; i++) {
- switch (raw[i]) {
- case 0:
- hasNul = true;
- break;
- case '\n':
- int eol = 1;
- if (i > start && raw[i - 1] == '\r') {
- eol++;
- }
- String line = new String(raw, start, i + 1 - eol - start,
- StandardCharsets.UTF_8);
- start = i + 1;
- if (log.isDebugEnabled()) {
- log.debug(format("doReadIdentification({0}) line: ", this) + //$NON-NLS-1$
- escapeControls(line));
- }
- ident.add(line);
- if (line.startsWith("SSH-")) { //$NON-NLS-1$
- if (hasNul) {
- throw new StreamCorruptedException(
- format(SshdText.get().serverIdWithNul,
- escapeControls(line)));
- }
- if (line.length() + eol > 255) {
- throw new StreamCorruptedException(
- format(SshdText.get().serverIdTooLong,
- escapeControls(line)));
- }
- buffer.rpos(start);
- return ident;
- }
- // If this were a server, we could throw an exception here: a
- // client is not supposed to send any extra lines before its
- // identification string.
- hasNul = false;
- break;
- default:
- break;
- }
- if (i - current + 1 >= maxIdentSize) {
- String msg = format(SshdText.get().serverIdNotReceived,
- Integer.toString(maxIdentSize));
- if (log.isDebugEnabled()) {
- log.debug(msg);
- log.debug(buffer.toHex());
- }
- throw new StreamCorruptedException(msg);
- }
- }
- // Need more data
- return null;
- }
- private static String escapeControls(String s) {
- StringBuilder b = new StringBuilder();
- int l = s.length();
- for (int i = 0; i < l; i++) {
- char ch = s.charAt(i);
- if (Character.isISOControl(ch)) {
- b.append(ch <= 0xF ? "\\u000" : "\\u00") //$NON-NLS-1$ //$NON-NLS-2$
- .append(Integer.toHexString(ch));
- } else {
- b.append(ch);
- }
- }
- return b.toString();
- }
- @Override
- public <T> T getAttribute(AttributeKey<T> key) {
- T value = super.getAttribute(key);
- if (value == null) {
- IoSession ioSession = getIoSession();
- if (ioSession != null) {
- Object obj = ioSession.getAttribute(AttributeRepository.class);
- if (obj instanceof AttributeRepository) {
- AttributeRepository sessionAttributes = (AttributeRepository) obj;
- value = sessionAttributes.resolveAttribute(key);
- }
- }
- }
- return value;
- }
- @Override
- public PropertyResolver getParentPropertyResolver() {
- IoSession ioSession = getIoSession();
- if (ioSession != null) {
- Object obj = ioSession.getAttribute(AttributeRepository.class);
- if (obj instanceof PropertyResolver) {
- return (PropertyResolver) obj;
- }
- }
- return super.getParentPropertyResolver();
- }
- /**
- * An {@link AttributeRepository} that chains together two other attribute
- * sources in a hierarchy.
- */
- public static class ChainingAttributes implements AttributeRepository {
- private final AttributeRepository delegate;
- private final AttributeRepository parent;
- /**
- * Create a new {@link ChainingAttributes} attribute source.
- *
- * @param self
- * to search for attributes first
- * @param parent
- * to search for attributes if not found in {@code self}
- */
- public ChainingAttributes(AttributeRepository self,
- AttributeRepository parent) {
- this.delegate = self;
- this.parent = parent;
- }
- @Override
- public int getAttributesCount() {
- return delegate.getAttributesCount();
- }
- @Override
- public <T> T getAttribute(AttributeKey<T> key) {
- return delegate.getAttribute(Objects.requireNonNull(key));
- }
- @Override
- public Collection<AttributeKey<?>> attributeKeys() {
- return delegate.attributeKeys();
- }
- @Override
- public <T> T resolveAttribute(AttributeKey<T> key) {
- T value = getAttribute(Objects.requireNonNull(key));
- if (value == null) {
- return parent.getAttribute(key);
- }
- return value;
- }
- }
- /**
- * A {@link ChainingAttributes} repository that doubles as a
- * {@link PropertyResolver}. The property map can be set via the attribute
- * key {@link SessionAttributes#PROPERTIES}.
- */
- public static class SessionAttributes extends ChainingAttributes
- implements PropertyResolver {
- /** Key for storing a map of properties in the attributes. */
- public static final AttributeKey<Map<String, Object>> PROPERTIES = new AttributeKey<>();
- private final PropertyResolver parentProperties;
- /**
- * Creates a new {@link SessionAttributes} attribute and property
- * source.
- *
- * @param self
- * to search for attributes first
- * @param parent
- * to search for attributes if not found in {@code self}
- * @param parentProperties
- * to search for properties if not found in {@code self}
- */
- public SessionAttributes(AttributeRepository self,
- AttributeRepository parent, PropertyResolver parentProperties) {
- super(self, parent);
- this.parentProperties = parentProperties;
- }
- @Override
- public PropertyResolver getParentPropertyResolver() {
- return parentProperties;
- }
- @Override
- public Map<String, Object> getProperties() {
- Map<String, Object> props = getAttribute(PROPERTIES);
- return props == null ? Collections.emptyMap() : props;
- }
- }
- }