.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
-.\" $OpenBSD: sshd_config.5,v 1.73 2007/03/01 10:28:02 dtucker Exp $
-.Dd September 25, 1999
+.\" $OpenBSD: sshd_config.5,v 1.82 2008/02/10 09:55:37 djm Exp $
+.Dd $Mdocdate$
.Dt SSHD_CONFIG 5
.Os
.Sh NAME
The default is
.Dq .ssh/authorized_keys .
.It Cm Banner
-In some jurisdictions, sending a warning message before authentication
-may be relevant for getting legal protection.
The contents of the specified file are sent to the remote user before
authentication is allowed.
+If the argument is
+.Dq none
+then no banner is displayed.
This option is only available for protocol version 2.
By default, no banner is displayed.
.It Cm ChallengeResponseAuthentication
are supported.
The default is
.Dq yes .
+.It Cm ChrootDirectory
+Specifies a path to
+.Xr chroot 2
+to after authentication.
+This path, and all its components, must be root-owned directories that are
+not writable by any other user or group.
+.Pp
+The path may contain the following tokens that are expanded at runtime once
+the connecting user has been authenticated: %% is replaced by a literal '%',
+%h is replaced by the home directory of the user being authenticated, and
+%u is replaced by the username of that user.
+.Pp
+The
+.Cm ChrootDirectory
+must contain the necessary files and directories to support the
+users' session.
+For an interactive session this requires at least a shell, typically
+.Xr sh 1 ,
+and basic
+.Pa /dev
+nodes such as
+.Xr null 4 ,
+.Xr zero 4 ,
+.Xr stdin 4 ,
+.Xr stdout 4 ,
+.Xr stderr 4 ,
+.Xr arandom 4
+and
+.Xr tty 4
+devices.
+For file transfer sessions using
+.Dq sftp ,
+no additional configuration of the environment is necessary if the
+in-process sftp server is used (see
+.Cm Subsystem
+for details).
+.Pp
+The default is not to
+.Xr chroot 2 .
.It Cm Ciphers
Specifies the ciphers allowed for protocol version 2.
Multiple ciphers must be comma-separated.
The command originally supplied by the client is available in the
.Ev SSH_ORIGINAL_COMMAND
environment variable.
+Specifying a command of
+.Dq internal-sftp
+will force the use of an in-process sftp server that requires no support
+files when used with
+.Cm ChrootDirectory .
.It Cm GatewayPorts
Specifies whether remote hosts are allowed to connect to ports
forwarded for the client.
for data integrity protection.
Multiple algorithms must be comma-separated.
The default is:
-.Dq hmac-md5,hmac-sha1,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 .
+.Bd -literal -offset indent
+hmac-md5,hmac-sha1,umac-64@openssh.com,
+hmac-ripemd160,hmac-sha1-96,hmac-md5-96
+.Ed
.It Cm Match
Introduces a conditional block.
If all of the criteria on the
.Cm ForceCommand ,
.Cm GatewayPorts ,
.Cm GSSApiAuthentication ,
-.Cm KerberosAuthentication ,
.Cm KbdInteractiveAuthentication ,
+.Cm KerberosAuthentication ,
.Cm PasswordAuthentication ,
.Cm PermitOpen ,
+.Cm PermitRootLogin ,
.Cm RhostsRSAAuthentication ,
.Cm RSAAuthentication ,
.Cm X11DisplayOffset ,
Configures an external subsystem (e.g. file transfer daemon).
Arguments should be a subsystem name and a command (with optional arguments)
to execute upon subsystem request.
+.Pp
The command
.Xr sftp-server 8
implements the
.Dq sftp
file transfer subsystem.
+.Pp
+Alternately the name
+.Dq internal-sftp
+implements an in-process
+.Dq sftp
+server.
+This may simplify configurations using
+.Cm ChrootDirectory
+to force a different filesystem root on clients.
+.Pp
By default no subsystems are defined.
Note that this option applies to protocol version 2 only.
.It Cm SyslogFacility
andersk / openssh.git / blobdiff