org.apache.sshd.common.session.SessionContext Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* 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.common.session;
import java.util.Map;
import org.apache.sshd.common.AttributeStore;
import org.apache.sshd.common.Closeable;
import org.apache.sshd.common.SshConstants;
import org.apache.sshd.common.auth.UsernameHolder;
import org.apache.sshd.common.cipher.BuiltinCiphers;
import org.apache.sshd.common.cipher.CipherInformation;
import org.apache.sshd.common.compression.CompressionInformation;
import org.apache.sshd.common.kex.KexProposalOption;
import org.apache.sshd.common.kex.KexState;
import org.apache.sshd.common.mac.MacInformation;
import org.apache.sshd.common.util.GenericUtils;
import org.apache.sshd.common.util.ValidateUtils;
import org.apache.sshd.common.util.net.ConnectionEndpointsIndicator;
/**
* A "succinct" summary of the most important attributes of an SSH session
*
* @author Apache MINA SSHD Project
*/
public interface SessionContext
extends ConnectionEndpointsIndicator,
UsernameHolder,
SessionHeartbeatController,
AttributeStore,
Closeable {
/**
* Default prefix expected for the client / server identification string
*
* @see RFC 4253 - section 4.2
*/
String DEFAULT_SSH_VERSION_PREFIX = "SSH-2.0-";
/**
* Backward compatible special prefix
*
* @see RFC 4253 - section 5
*/
String FALLBACK_SSH_VERSION_PREFIX = "SSH-1.99-";
/**
* Maximum number of characters for any single line sent as part of the initial handshake - according to
* RFC 4253 - section 4.2:
*
*
*
* The maximum length of the string is 255 characters,
* including the Carriage Return and Line Feed.
*
*
*/
int MAX_VERSION_LINE_LENGTH = 256;
/**
* @return A clone of the established session identifier - {@code null} if not yet established
*/
byte[] getSessionId();
/**
* Quick indication if this is a server or client session (instead of having to ask {@code instanceof}).
*
* @return {@code true} if this is a server session
*/
boolean isServerSession();
/**
* Retrieve the client version for this session.
*
* @return the client version - may be {@code null}/empty if versions not yet exchanged
*/
String getClientVersion();
/**
* @return An un-modifiable map of the latest KEX client proposal options May be empty if KEX not yet
* completed or re-keying in progress
* @see #getKexState()
*/
Map getClientKexProposals();
/**
* Retrieve the server version for this session.
*
* @return the server version - may be {@code null}/empty if versions not yet exchanged
*/
String getServerVersion();
/**
* @return An un-modifiable map of the latest KEX client proposal options. May be empty if KEX not yet
* completed or re-keying in progress
* @see #getKexState()
*/
Map getServerKexProposals();
KexState getKexState();
Map getKexNegotiationResult();
/**
* Retrieve one of the negotiated values during the KEX stage
*
* @param paramType The request {@link KexProposalOption} value - ignored if {@code null}
* @return The negotiated parameter value - {@code null} if invalid parameter or no negotiated value.
* @see #getKexState()
*/
String getNegotiatedKexParameter(KexProposalOption paramType);
/**
* Retrieves current cipher information - Note: may change if key re-exchange executed
*
* @param incoming If {@code true} then the cipher for the incoming data, otherwise for the outgoing data
* @return The {@link CipherInformation} - or {@code null} if not negotiated yet.
*/
CipherInformation getCipherInformation(boolean incoming);
/**
* Retrieves current compression information - Note: may change if key re-exchange executed
*
* @param incoming If {@code true} then the compression for the incoming data, otherwise for the outgoing data
* @return The {@link CompressionInformation} - or {@code null} if not negotiated yet.
*/
CompressionInformation getCompressionInformation(boolean incoming);
/**
* Retrieves current MAC information - Note: may change if key re-exchange executed
*
* @param incoming If {@code true} then the MAC for the incoming data, otherwise for the outgoing data
* @return The {@link MacInformation} - or {@code null} if not negotiated yet.
*/
MacInformation getMacInformation(boolean incoming);
/**
* @return {@code true} if session has successfully completed the authentication phase
*/
boolean isAuthenticated();
/**
* @param version The reported client/server version
* @return {@code true} if version not empty and starts with either {@value #DEFAULT_SSH_VERSION_PREFIX} or
* {@value #FALLBACK_SSH_VERSION_PREFIX}
*/
static boolean isValidVersionPrefix(String version) {
return GenericUtils.isNotEmpty(version)
&& (version.startsWith(DEFAULT_SSH_VERSION_PREFIX) || version.startsWith(FALLBACK_SSH_VERSION_PREFIX));
}
/**
* @param session The {@link SessionContext} to be examined
* @return {@code true} if the context is not {@code null} and the ciphers have been established to anything
* other than "none".
* @see #getNegotiatedKexParameter(KexProposalOption) getNegotiatedKexParameter
* @see KexProposalOption#CIPHER_PROPOSALS CIPHER_PROPOSALS
*/
static boolean isSecureSessionTransport(SessionContext session) {
if (session == null) {
return false;
}
for (KexProposalOption opt : KexProposalOption.CIPHER_PROPOSALS) {
String value = session.getNegotiatedKexParameter(opt);
if (GenericUtils.isEmpty(value)
|| BuiltinCiphers.Constants.NONE.equalsIgnoreCase(value)) {
return false;
}
}
return true;
}
/**
* @param session The {@link SessionContext} to be examined
* @return {@code true} if the context is not {@code null} and the MAC(s) used to verify packet integrity
* have been established.
* @see #getNegotiatedKexParameter(KexProposalOption) getNegotiatedKexParameter
* @see KexProposalOption#MAC_PROPOSALS MAC_PROPOSALS
*/
static boolean isDataIntegrityTransport(SessionContext session) {
if (session == null) {
return false;
}
for (KexProposalOption opt : KexProposalOption.MAC_PROPOSALS) {
String value = session.getNegotiatedKexParameter(opt);
if (GenericUtils.isEmpty(value)) {
return false;
}
}
return true;
}
static boolean isValidSessionPayloadSize(long value) {
return (value >= 0L) && (value < (Integer.MAX_VALUE - SshConstants.SSH_PACKET_HEADER_LEN - 8 /* some padding */));
}
static long validateSessionPayloadSize(long value, String format) {
ValidateUtils.checkTrue(isValidSessionPayloadSize(value), format, value);
return value;
}
}