Module org.eclipse.jgit.ssh.apache
Package 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:

  • Constructor Details

    • 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 Details

    • lookup

      public List<PublicKey> lookup(@NonNull String connectAddress, @NonNull InetSocketAddress remoteAddress, @NonNull ServerKeyDatabase.Configuration config)
      Description copied from interface: ServerKeyDatabase
      Retrieves all known and not revoked 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 and not revoked keys for the given addresses

    • accept

      public boolean accept(@NonNull String connectAddress, @NonNull InetSocketAddress remoteAddress, @NonNull PublicKey serverKey, @NonNull ServerKeyDatabase.Configuration config, org.eclipse.jgit.transport.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