- djm@cvs.openbsd.org 2010/01/30 02:54:53

[openssh.git] / ssh-agent.1

diff --git a/ssh-agent.1 b/ssh-agent.1
index b49d62b5a6e67711dc56fa43bb6c0ad0b955cb7e..8d1da46ef61fffa875d1ec514aa3655b87c3f54a 100644 (file)
--- a/ssh-agent.1
+++ b/ssh-agent.1
@@ -1,17 +1,40 @@
-.\" $OpenBSD: ssh-agent.1,v 1.11 2000/04/12 21:47:50 aaron Exp $
-.\"
-.\"  -*- nroff -*-
-.\"
-.\" ssh-agent.1
+.\" $OpenBSD: ssh-agent.1,v 1.50 2010/01/17 21:49:09 tedu Exp $

 .\"
 .\" Author: Tatu Ylonen <ylo@cs.hut.fi>
 .\"
 .\" Author: Tatu Ylonen <ylo@cs.hut.fi>

-.\"

 .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 .\"                    All rights reserved
 .\"
 .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 .\"                    All rights reserved
 .\"

-.\" Created: Sat Apr 23 20:10:43 1995 ylo
+.\" As far as I am concerned, the code I have written for this software
+.\" can be used freely for any purpose.  Any derived versions of this
+.\" software must be clearly marked as such, and if the derived work is
+.\" incompatible with the protocol description in the RFC file, it must be
+.\" called by a name other than "ssh" or "Secure Shell".
+.\"
+.\" Copyright (c) 1999,2000 Markus Friedl.  All rights reserved.
+.\" Copyright (c) 1999 Aaron Campbell.  All rights reserved.
+.\" Copyright (c) 1999 Theo de Raadt.  All rights reserved.

 .\"
 .\"

-.Dd September 25, 1999
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd $Mdocdate$

 .Dt SSH-AGENT 1
 .Os
 .Sh NAME
 .Dt SSH-AGENT 1
 .Os
 .Sh NAME


@@ -20,42 +43,65 @@
 .Sh SYNOPSIS
 .Nm ssh-agent
 .Op Fl c Li | Fl s
 .Sh SYNOPSIS
 .Nm ssh-agent
 .Op Fl c Li | Fl s

-.Op Fl k
-.Oo
-.Ar command
-.Op Ar args ...
-.Oc
+.Op Fl d
+.Op Fl a Ar bind_address
+.Op Fl t Ar life
+.Op Ar command Op Ar arg ...
+.Nm ssh-agent
+.Op Fl c Li | Fl s
+.Fl k

 .Sh DESCRIPTION
 .Nm
 .Sh DESCRIPTION
 .Nm

-is a program to hold authentication private keys.
+is a program to hold private keys used for public key authentication
+(RSA, DSA).

 The idea is that
 .Nm
 is started in the beginning of an X-session or a login session, and
 all other windows or programs are started as clients to the ssh-agent
 program.
 Through use of environment variables the agent can be located
 The idea is that
 .Nm
 is started in the beginning of an X-session or a login session, and
 all other windows or programs are started as clients to the ssh-agent
 program.
 Through use of environment variables the agent can be located

-and automatically used for RSA authentication when logging in to other
+and automatically used for authentication when logging in to other

 machines using
 .Xr ssh 1 .
 .Pp
 The options are as follows:
 .Bl -tag -width Ds
 machines using
 .Xr ssh 1 .
 .Pp
 The options are as follows:
 .Bl -tag -width Ds

+.It Fl a Ar bind_address
+Bind the agent to the
+.Ux Ns -domain
+socket
+.Ar bind_address .
+The default is
+.Pa /tmp/ssh-XXXXXXXXXX/agent.\*(Ltppid\*(Gt .

 .It Fl c
 Generate C-shell commands on
 .Dv stdout .
 This is the default if
 .Ev SHELL
 looks like it's a csh style of shell.
 .It Fl c
 Generate C-shell commands on
 .Dv stdout .
 This is the default if
 .Ev SHELL
 looks like it's a csh style of shell.

+.It Fl d
+Debug mode.
+When this option is specified
+.Nm
+will not fork.
+.It Fl k
+Kill the current agent (given by the
+.Ev SSH_AGENT_PID
+environment variable).

 .It Fl s
 Generate Bourne shell commands on
 .Dv stdout .
 This is the default if
 .Ev SHELL
 does not look like it's a csh style of shell.
 .It Fl s
 Generate Bourne shell commands on
 .Dv stdout .
 This is the default if
 .Ev SHELL
 does not look like it's a csh style of shell.

-.It Fl k
-Kill the current agent (given by the
-.Ev SSH_AGENT_PID
-environment variable).
+.It Fl t Ar life
+Set a default value for the maximum lifetime of identities added to the agent.
+The lifetime may be specified in seconds or in a time format specified in
+.Xr sshd_config 5 .
+A lifetime specified for an identity with
+.Xr ssh-add 1
+overrides this value.
+Without this option the default maximum lifetime is forever.

 .El
 .Pp
 If a commandline is given, this is executed as a subprocess of the agent.
 .El
 .Pp
 If a commandline is given, this is executed as a subprocess of the agent.


@@ -66,13 +112,16 @@ Keys are added using
 .Xr ssh-add 1 .
 When executed without arguments,
 .Xr ssh-add 1
 .Xr ssh-add 1 .
 When executed without arguments,
 .Xr ssh-add 1

-adds the
-.Pa $HOME/.ssh/identity
-file.
+adds the files
+.Pa ~/.ssh/id_rsa ,
+.Pa ~/.ssh/id_dsa
+and
+.Pa ~/.ssh/identity .

 If the identity has a passphrase,
 .Xr ssh-add 1
 If the identity has a passphrase,
 .Xr ssh-add 1

-asks for the passphrase (using a small X11 application if running
-under X11, or from the terminal if running without X).
+asks for the passphrase on the terminal if it has one or from a small X11
+program if running under X11.
+If neither of these is the case then the authentication will fail.

 It then sends the identity to the agent.
 Several identities can be stored in the
 agent; the agent can automatically use any of these identities.
 It then sends the identity to the agent.
 Several identities can be stored in the
 agent; the agent can automatically use any of these identities.


@@ -87,21 +136,38 @@ However, the connection to the agent is forwarded over SSH
 remote logins, and the user can thus use the privileges given by the
 identities anywhere in the network in a secure way.
 .Pp
 remote logins, and the user can thus use the privileges given by the
 identities anywhere in the network in a secure way.
 .Pp

-There are two main ways to get an agent setup:
-Either you let the agent
-start a new subcommand into which some environment variables are exported, or
-you let the agent print the needed shell commands (either
+There are two main ways to get an agent set up:
+The first is that the agent starts a new subcommand into which some environment
+variables are exported, eg
+.Cm ssh-agent xterm & .
+The second is that the agent prints the needed shell commands (either
+.Xr sh 1
+or
+.Xr csh 1
+syntax can be generated) which can be evaluated in the calling shell, eg
+.Cm eval `ssh-agent -s`
+for Bourne-type shells such as

 .Xr sh 1
 or
 .Xr sh 1
 or

+.Xr ksh 1
+and
+.Cm eval `ssh-agent -c`
+for

 .Xr csh 1
 .Xr csh 1

-syntax can be generated) which can be evalled in the calling shell.
+and derivatives.
+.Pp

 Later
 .Xr ssh 1
 Later
 .Xr ssh 1

-look at these variables and use them to establish a connection to the agent.
+looks at these variables and uses them to establish a connection to the agent.
+.Pp
+The agent will never send a private key over its request channel.
+Instead, operations that require a private key will be performed
+by the agent, and the result will be returned to the requester.
+This way, private keys are not exposed to clients using the agent.

 .Pp
 .Pp

-A unix-domain socket is created
-.Pq Pa /tmp/ssh-XXXXXXXX/agent.<pid> ,
-and the name of this socket is stored in the
+A
+.Ux Ns -domain
+socket is created and the name of this socket is stored in the

 .Ev SSH_AUTH_SOCK
 environment
 variable.
 .Ev SSH_AUTH_SOCK
 environment
 variable.


@@ -111,61 +177,35 @@ user.
 .Pp
 The
 .Ev SSH_AGENT_PID
 .Pp
 The
 .Ev SSH_AGENT_PID

-environment variable holds the agent's PID.
+environment variable holds the agent's process ID.

 .Pp
 The agent exits automatically when the command given on the command
 line terminates.
 .Sh FILES
 .Bl -tag -width Ds
 .Pp
 The agent exits automatically when the command given on the command
 line terminates.
 .Sh FILES
 .Bl -tag -width Ds

-.It Pa $HOME/.ssh/identity
-Contains the RSA authentication identity of the user.
-This file should not be readable by anyone but the user.
-It is possible to
-specify a passphrase when generating the key; that passphrase will be
-used to encrypt the private part of this file.
-This file is not used by
-.Nm
-but is normally added to the agent using
-.Xr ssh-add 1
-at login time.
-.It Pa /tmp/ssh-XXXX/agent.<pid> ,
-Unix-domain sockets used to contain the connection to the
-authentication agent.
+.It Pa ~/.ssh/identity
+Contains the protocol version 1 RSA authentication identity of the user.
+.It Pa ~/.ssh/id_dsa
+Contains the protocol version 2 DSA authentication identity of the user.
+.It Pa ~/.ssh/id_rsa
+Contains the protocol version 2 RSA authentication identity of the user.
+.It Pa /tmp/ssh-XXXXXXXXXX/agent.\*(Ltppid\*(Gt
+.Ux Ns -domain
+sockets used to contain the connection to the authentication agent.

 These sockets should only be readable by the owner.
 The sockets should get automatically removed when the agent exits.
 These sockets should only be readable by the owner.
 The sockets should get automatically removed when the agent exits.

-.Sh AUTHOR
-Tatu Ylonen <ylo@cs.hut.fi>
-.Pp
-OpenSSH
-is a derivative of the original (free) ssh 1.2.12 release, but with bugs
-removed and newer features re-added.
-Rapidly after the 1.2.12 release,
-newer versions bore successively more restrictive licenses.
-This version of OpenSSH
-.Bl -bullet
-.It
-has all components of a restrictive nature (i.e., patents, see
-.Xr ssl 8 )
-directly removed from the source code; any licensed or patented components
-are chosen from
-external libraries.
-.It
-has been updated to support ssh protocol 1.5.
-.It
-contains added support for
-.Xr kerberos 8
-authentication and ticket passing.
-.It
-supports one-time password authentication with
-.Xr skey 1 .

 .El
 .El

-.Pp
-The libraries described in
-.Xr ssl 8
-are required for proper operation.

 .Sh SEE ALSO
 .Xr ssh 1 ,
 .Xr ssh-add 1 ,
 .Xr ssh-keygen 1 ,
 .Sh SEE ALSO
 .Xr ssh 1 ,
 .Xr ssh-add 1 ,
 .Xr ssh-keygen 1 ,

-.Xr sshd 8 ,
-.Xr ssl 8
+.Xr sshd 8
+.Sh AUTHORS
+OpenSSH is a derivative of the original and free
+ssh 1.2.12 release by Tatu Ylonen.
+Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
+Theo de Raadt and Dug Song
+removed many bugs, re-added newer features and
+created OpenSSH.
+Markus Friedl contributed the support for SSH
+protocol versions 1.5 and 2.0.