com.sshtools.publickey

Class AbstractKnownHostsKeyVerification

java.lang.Object

com.sshtools.publickey.AbstractKnownHostsKeyVerification

All Implemented Interfaces:

HostKeyVerification

Direct Known Subclasses:

ConsoleKnownHostsKeyVerification

public abstract class AbstractKnownHostsKeyVerification
extends Object
implements HostKeyVerification

An abstract HostKeyVerification class implementation providing validation against the known_hosts format.

Author:

Lee David Painter

Constructor Summary

Constructors

Constructor and Description
AbstractKnownHostsKeyVerification() Construct a known_hosts database based on the default path of ~/.ssh/known_hosts.
AbstractKnownHostsKeyVerification(String knownhosts) Constructs a known_hosts database based on the path provided.

Method Summary

Methods

Modifier and Type	Method and Description
Hashtable<String,Hashtable<String,SshPublicKey>>	allowedHosts() Returns a Map of the allowed hosts.
void	allowHost(String host, SshPublicKey pk, boolean always) Allows a host key, optionally recording the key to the known_hosts file.
File	getKnownHostsFile()
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.
protected void	onInvalidHostEntry(String entry)
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.
void	setHashHosts(boolean hashHosts)
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.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

AbstractKnownHostsKeyVerification

public AbstractKnownHostsKeyVerification()
                                  throws SshException

Construct a known_hosts database based on the default path of ~/.ssh/known_hosts.

Throws:

SshException

AbstractKnownHostsKeyVerification

public AbstractKnownHostsKeyVerification(String knownhosts)
                                  throws SshException

Constructs a known_hosts database based on the path provided.

Parameters:

knownhosts - the path of the known_hosts file

Throws:

InvalidHostFileException - if the known_hosts file is invalid

SshException

Since:

0.2.0

Method Detail

getKnownHostsFile

public File getKnownHostsFile()

setHashHosts

public void setHashHosts(boolean hashHosts)

onInvalidHostEntry

protected void onInvalidHostEntry(String entry)
                           throws SshException

Throws:

SshException

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 SshException

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:

SshException - if an error occurs

Since:

0.2.0

onUnknownHost

public abstract void onUnknownHost(String host,
                 SshPublicKey key)
                            throws SshException

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:

SshException - if an error occurs

Since:

0.2.0

allowHost

public void allowHost(String host,
             SshPublicKey pk,
             boolean always)
               throws SshException

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

SshException

Since:

0.2.0

allowedHosts

public Hashtable<String,Hashtable<String,SshPublicKey>> 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

removeAllowedHost

public void removeAllowedHost(String host)

Removes an allowed host.

Parameters:

host - the host to remove

Since:

0.2.0

verifyHost

public boolean verifyHost(String host,
                 SshPublicKey pk)
                   throws SshException

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:

SshException - if an error occurs

Since:

0.2.0

saveHostFile

public void saveHostFile()
                  throws IOException

Save's the host key file to be saved.

Throws:

InvalidHostFileException - if the host file is invalid

IOException

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.....

Overrides:

toString in class Object

Returns:

String

Since:

0.2.0