com.sshtools.j2ssh.transport

Class AbstractKnownHostsKeyVerification

Implemented Interfaces:
HostKeyVerification
Known Direct Subclasses:
ConsoleKnownHostsKeyVerification, DialogKnownHostsKeyVerification

public abstract class AbstractKnownHostsKeyVerification
extends java.lang.Object
implements HostKeyVerification

An abstract HostKeyVerification class providing validation against the known_hosts format.
Version:
$Revision: 1.18 $
Author:
Lee David Painter
Since:
0.2.0

Constructor Summary

AbstractKnownHostsKeyVerification(String knownhosts)
Constructs a host key verification instance reading the specified known_hosts file.

Method Summary

void
allowHost(String host, SshPublicKey pk, boolean always)
Allows a host key, optionally recording the key to the known_hosts file.
Map
allowedHosts()
Returns a Map of the allowed hosts.
boolean
isHostFileWriteable()
Determines whether the host file is writable.
abstract void
onHostKeyMismatch(String host, SshPublicKey allowedHostKey, SshPublicKey actualHostKey)
Called by the verifyHost method when the host key supplied by the host does not match the current key recording in the known hosts file.
abstract void
onUnknownHost(String host, SshPublicKey key)
Called by the verifyHost method when the host key supplied is not recorded in the known_hosts file.
void
removeAllowedHost(String host)
Removes an allowed host.
void
saveHostFile()
Save's the host key file to be saved.
String
toString()
Outputs the allowed hosts in the known_hosts file format.
boolean
verifyHost(String host, SshPublicKey pk)
Verifies a host key against the list of known_hosts.

Constructor Details

AbstractKnownHostsKeyVerification

public AbstractKnownHostsKeyVerification(String knownhosts)
            throws InvalidHostFileException
Constructs a host key verification instance reading the specified known_hosts file.
Parameters:
knownhosts - the path of the known_hosts file
Throws:
InvalidHostFileException - if the known_hosts file is invalid
Since:
0.2.0

Method Details

allowHost

public void allowHost(String host,
                      SshPublicKey pk,
                      boolean always)
            throws InvalidHostFileException
Allows a host key, optionally recording the key to the known_hosts file.
Parameters:
host - the name of the host
pk - the public key to allow
always - true if the key should be written to the known_hosts file
Throws:
InvalidHostFileException - if the host file cannot be written
Since:
0.2.0

allowedHosts

public Map allowedHosts()
Returns a Map of the allowed hosts.

The keys of the returned Map are comma separated strings of "hostname,ipaddress". The value objects are Maps containing a string key of the public key alogorithm name and the public key as the value.

Returns:
the allowed hosts
Since:
0.2.0

isHostFileWriteable

public boolean isHostFileWriteable()
Determines whether the host file is writable.
Returns:
true if the host file is writable, otherwise false
Since:
0.2.0

onHostKeyMismatch

public abstract void onHostKeyMismatch(String host,
                                       SshPublicKey allowedHostKey,
                                       SshPublicKey actualHostKey)
            throws TransportProtocolException
Called by the verifyHost method when the host key supplied by the host does not match the current key recording in the known hosts file.
Parameters:
host - the name of the host
allowedHostKey - the current key recorded in the known_hosts file.
actualHostKey - the actual key supplied by the user
Throws:
TransportProtocolException - if an error occurs
Since:
0.2.0

onUnknownHost

public abstract void onUnknownHost(String host,
                                   SshPublicKey key)
            throws TransportProtocolException
Called by the verifyHost method when the host key supplied is not recorded in the known_hosts file.

Parameters:
host - the name of the host
key - the public key supplied by the host
Throws:
TransportProtocolException - if an error occurs
Since:
0.2.0

removeAllowedHost

public void removeAllowedHost(String host)
Removes an allowed host.
Parameters:
host - the host to remove
Since:
0.2.0

saveHostFile

public void saveHostFile()
            throws InvalidHostFileException
Save's the host key file to be saved.
Throws:
InvalidHostFileException - if the host file is invalid
Since:
0.2.0

toString

public String toString()
Outputs the allowed hosts in the known_hosts file format.

The format consists of any number of lines each representing one key for a single host. titan,192.168.1.12 ssh-dss AAAAB3NzaC1kc3MAAACBAP1/U4Ed..... titan,192.168.1.12 ssh-rsa AAAAB3NzaC1kc3MAAACBAP1/U4Ed..... einstein,192.168.1.40 ssh-dss AAAAB3NzaC1kc3MAAACBAP1/U4Ed.....

Returns:
Since:
0.2.0

verifyHost

public boolean verifyHost(String host,
                          SshPublicKey pk)
            throws TransportProtocolException
Verifies a host key against the list of known_hosts.

If the host unknown or the key does not match the currently allowed host key the abstract onUnknownHost or onHostKeyMismatch methods are called so that the caller may identify and allow the host.

Specified by:
verifyHost in interface HostKeyVerification
Parameters:
host - the name of the host
pk - the host key supplied
Returns:
true if the host is accepted, otherwise false
Throws:
TransportProtocolException - if an error occurs
Since:
0.2.0

Copyright © 2002-2003 Lee David Painter & Contributors. All Rights Reserved.