org.eclipse.jgit.internal.transport.sshd

Class OpenSshServerKeyDatabase

java.lang.Object

org.eclipse.jgit.internal.transport.sshd.OpenSshServerKeyDatabase

All Implemented Interfaces:

ServerKeyDatabase

public class OpenSshServerKeyDatabase
extends Object
implements ServerKeyDatabase

A sever host key verifier that honors the StrictHostKeyChecking and UserKnownHostsFile values from the ssh configuration.

The verifier can be given default known_hosts files in the constructor, which will be used if the ssh config does not specify a UserKnownHostsFile. If the ssh config does set UserKnownHostsFile, the verifier uses the given files in the order given. Non-existing or unreadable files are ignored.

StrictHostKeyChecking accepts the following values:

ask

Ask the user whether new or changed keys shall be accepted and be added to the known_hosts file.

yes/true

Accept only keys listed in the known_hosts file.

no/false

Silently accept all new or changed keys, add new keys to the known_hosts file.

accept-new

Silently accept keys for new hosts and add them to the known_hosts file.

If StrictHostKeyChecking is not set, or set to any other value, the default value ask is active.

This implementation relies on the ClientSession being a JGitClientSession. By default Apache MINA sshd does not forward the config file host entry to the session, so it would be unknown here which entry it was and what setting of StrictHostKeyChecking should be used. If used with some other session type, the implementation assumes "ask".

Asking the user is done via a CredentialsProvider obtained from the session. If none is set, the implementation falls back to strict host key checking ("yes").

Note that adding a key to the known hosts file may create the file. You can specify in the constructor whether the user shall be asked about that, too. If the user declines updating the file, but the key was otherwise accepted (user confirmed for "ask", or "no" or "accept-new" are active), the key is accepted for this session only.

If several known hosts files are specified, a new key is always added to the first file (even if it doesn't exist yet; see the note about file creation above).

See Also:

man ssh-config

Nested Class Summary

Nested classes/interfaces inherited from interface org.eclipse.jgit.transport.sshd.ServerKeyDatabase

ServerKeyDatabase.Configuration

Constructor Summary

Constructors

Constructor and Description
OpenSshServerKeyDatabase(boolean askAboutNewFile, List<Path> defaultFiles) Creates a new OpenSshServerKeyDatabase.

Method Summary

Modifier and Type	Method and Description
boolean	accept(String connectAddress, InetSocketAddress remoteAddress, PublicKey serverKey, ServerKeyDatabase.Configuration config, CredentialsProvider provider) Determines whether to accept a received server host key.
List<PublicKey>	lookup(String connectAddress, InetSocketAddress remoteAddress, ServerKeyDatabase.Configuration config) Retrieves all known host keys for the given addresses.

Methods inherited from class java.lang.Object

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

Constructor Detail

OpenSshServerKeyDatabase

public OpenSshServerKeyDatabase(boolean askAboutNewFile,
                                List<Path> defaultFiles)

Creates a new OpenSshServerKeyDatabase.

Parameters:

askAboutNewFile - whether to ask the user, if possible, about creating a new non-existing known_hosts file

defaultFiles - typically ~/.ssh/known_hosts and ~/.ssh/known_hosts2. May be empty or null, in which case no default files are installed. The files need not exist.

Method Detail

lookup

public List<PublicKey> lookup(@NonNull
                              String connectAddress,
                              @NonNull
                              InetSocketAddress remoteAddress,
                              @NonNull
                              ServerKeyDatabase.Configuration config)

Description copied from interface: ServerKeyDatabase

Retrieves all known host keys for the given addresses.

Specified by:

lookup in interface ServerKeyDatabase

Parameters:

connectAddress - IP address the session tried to connect to

remoteAddress - IP address as reported for the remote end point

config - giving access to potentially interesting configuration settings

Returns:

the list of known keys for the given addresses

accept

public boolean accept(@NonNull
                      String connectAddress,
                      @NonNull
                      InetSocketAddress remoteAddress,
                      @NonNull
                      PublicKey serverKey,
                      @NonNull
                      ServerKeyDatabase.Configuration config,
                      CredentialsProvider provider)

Description copied from interface: ServerKeyDatabase

Determines whether to accept a received server host key.

Specified by:

accept in interface ServerKeyDatabase

Parameters:

connectAddress - IP address the session tried to connect to

remoteAddress - IP address as reported for the remote end point

serverKey - received from the remote end

config - giving access to potentially interesting configuration settings

provider - for interacting with the user, if required; may be null

Returns:

true if the serverKey is accepted, false otherwise