Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 1 | .\" $OpenBSD: ssh-agent.1,v 1.16 2000/09/07 20:27:54 deraadt Exp $ |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 2 | .\" |
| 3 | .\" Author: Tatu Ylonen <ylo@cs.hut.fi> |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 4 | .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 5 | .\" All rights reserved |
| 6 | .\" |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 7 | .\" As far as I am concerned, the code I have written for this software |
| 8 | .\" can be used freely for any purpose. Any derived versions of this |
| 9 | .\" software must be clearly marked as such, and if the derived work is |
| 10 | .\" incompatible with the protocol description in the RFC file, it must be |
| 11 | .\" called by a name other than "ssh" or "Secure Shell". |
| 12 | .\" |
| 13 | .\" Copyright (c) 1999,2000 Markus Friedl. All rights reserved. |
| 14 | .\" Copyright (c) 1999 Aaron Campbell. All rights reserved. |
| 15 | .\" Copyright (c) 1999 Theo de Raadt. All rights reserved. |
| 16 | .\" |
| 17 | .\" Redistribution and use in source and binary forms, with or without |
| 18 | .\" modification, are permitted provided that the following conditions |
| 19 | .\" are met: |
| 20 | .\" 1. Redistributions of source code must retain the above copyright |
| 21 | .\" notice, this list of conditions and the following disclaimer. |
| 22 | .\" 2. Redistributions in binary form must reproduce the above copyright |
| 23 | .\" notice, this list of conditions and the following disclaimer in the |
| 24 | .\" documentation and/or other materials provided with the distribution. |
| 25 | .\" |
| 26 | .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 27 | .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 28 | .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 29 | .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 30 | .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 31 | .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 32 | .\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 33 | .\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 34 | .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 35 | .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 36 | .\" |
| 37 | .Dd September 25, 1999 |
| 38 | .Dt SSH-AGENT 1 |
| 39 | .Os |
| 40 | .Sh NAME |
| 41 | .Nm ssh-agent |
| 42 | .Nd authentication agent |
| 43 | .Sh SYNOPSIS |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 44 | .Nm ssh-agent |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 45 | .Op Fl c Li | Fl s |
| 46 | .Op Fl k |
| 47 | .Oo |
| 48 | .Ar command |
| 49 | .Op Ar args ... |
| 50 | .Oc |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 51 | .Sh DESCRIPTION |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 52 | .Nm |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 53 | is a program to hold private keys used for public key authentication |
| 54 | (RSA, DSA). |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 55 | The idea is that |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 56 | .Nm |
| 57 | is started in the beginning of an X-session or a login session, and |
| 58 | all other windows or programs are started as clients to the ssh-agent |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 59 | program. |
| 60 | Through use of environment variables the agent can be located |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 61 | and automatically used for authentication when logging in to other |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 62 | machines using |
| 63 | .Xr ssh 1 . |
| 64 | .Pp |
| 65 | The options are as follows: |
| 66 | .Bl -tag -width Ds |
| 67 | .It Fl c |
| 68 | Generate C-shell commands on |
| 69 | .Dv stdout . |
| 70 | This is the default if |
| 71 | .Ev SHELL |
| 72 | looks like it's a csh style of shell. |
| 73 | .It Fl s |
| 74 | Generate Bourne shell commands on |
| 75 | .Dv stdout . |
| 76 | This is the default if |
| 77 | .Ev SHELL |
| 78 | does not look like it's a csh style of shell. |
| 79 | .It Fl k |
| 80 | Kill the current agent (given by the |
| 81 | .Ev SSH_AGENT_PID |
| 82 | environment variable). |
| 83 | .El |
| 84 | .Pp |
| 85 | If a commandline is given, this is executed as a subprocess of the agent. |
| 86 | When the command dies, so does the agent. |
| 87 | .Pp |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 88 | The agent initially does not have any private keys. |
| 89 | Keys are added using |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 90 | .Xr ssh-add 1 . |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 91 | When executed without arguments, |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 92 | .Xr ssh-add 1 |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 93 | adds the |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 94 | .Pa $HOME/.ssh/identity |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 95 | file. |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 96 | If the identity has a passphrase, |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 97 | .Xr ssh-add 1 |
| 98 | asks for the passphrase (using a small X11 application if running |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 99 | under X11, or from the terminal if running without X). |
| 100 | It then sends the identity to the agent. |
| 101 | Several identities can be stored in the |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 102 | agent; the agent can automatically use any of these identities. |
| 103 | .Ic ssh-add -l |
| 104 | displays the identities currently held by the agent. |
| 105 | .Pp |
| 106 | The idea is that the agent is run in the user's local PC, laptop, or |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 107 | terminal. |
| 108 | Authentication data need not be stored on any other |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 109 | machine, and authentication passphrases never go over the network. |
| 110 | However, the connection to the agent is forwarded over SSH |
| 111 | remote logins, and the user can thus use the privileges given by the |
| 112 | identities anywhere in the network in a secure way. |
| 113 | .Pp |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 114 | There are two main ways to get an agent setup: |
| 115 | Either you let the agent |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 116 | start a new subcommand into which some environment variables are exported, or |
| 117 | you let the agent print the needed shell commands (either |
| 118 | .Xr sh 1 |
| 119 | or |
| 120 | .Xr csh 1 |
| 121 | syntax can be generated) which can be evalled in the calling shell. |
| 122 | Later |
| 123 | .Xr ssh 1 |
| 124 | look at these variables and use them to establish a connection to the agent. |
| 125 | .Pp |
| 126 | A unix-domain socket is created |
| 127 | .Pq Pa /tmp/ssh-XXXXXXXX/agent.<pid> , |
| 128 | and the name of this socket is stored in the |
| 129 | .Ev SSH_AUTH_SOCK |
| 130 | environment |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 131 | variable. |
| 132 | The socket is made accessible only to the current user. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 133 | This method is easily abused by root or another instance of the same |
| 134 | user. |
| 135 | .Pp |
| 136 | The |
| 137 | .Ev SSH_AGENT_PID |
| 138 | environment variable holds the agent's PID. |
| 139 | .Pp |
| 140 | The agent exits automatically when the command given on the command |
| 141 | line terminates. |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 142 | .Sh FILES |
| 143 | .Bl -tag -width Ds |
| 144 | .It Pa $HOME/.ssh/identity |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 145 | Contains the RSA authentication identity of the user. |
| 146 | This file should not be readable by anyone but the user. |
| 147 | It is possible to |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 148 | specify a passphrase when generating the key; that passphrase will be |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 149 | used to encrypt the private part of this file. |
| 150 | This file is not used by |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 151 | .Nm |
| 152 | but is normally added to the agent using |
| 153 | .Xr ssh-add 1 |
| 154 | at login time. |
Damien Miller | ad833b3 | 2000-08-23 10:46:23 +1000 | [diff] [blame] | 155 | .It Pa $HOME/.ssh/id_dsa |
| 156 | Contains the DSA authentication identity of the user. |
| 157 | .Pq Pa /tmp/ssh-XXXXXXXX/agent.<pid> , |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 158 | Unix-domain sockets used to contain the connection to the |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 159 | authentication agent. |
| 160 | These sockets should only be readable by the owner. |
| 161 | The sockets should get automatically removed when the agent exits. |
Damien Miller | 3702396 | 2000-07-11 17:31:38 +1000 | [diff] [blame] | 162 | .El |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 163 | .Sh AUTHOR |
| 164 | Tatu Ylonen <ylo@cs.hut.fi> |
| 165 | .Pp |
| 166 | OpenSSH |
| 167 | is a derivative of the original (free) ssh 1.2.12 release, but with bugs |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 168 | removed and newer features re-added. |
| 169 | Rapidly after the 1.2.12 release, |
| 170 | newer versions bore successively more restrictive licenses. |
| 171 | This version of OpenSSH |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 172 | .Bl -bullet |
| 173 | .It |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 174 | has all components of a restrictive nature (i.e., patents, see |
| 175 | .Xr crypto 3 ) |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 176 | directly removed from the source code; any licensed or patented components |
| 177 | are chosen from |
| 178 | external libraries. |
| 179 | .It |
| 180 | has been updated to support ssh protocol 1.5. |
| 181 | .It |
Damien Miller | 22c7726 | 2000-04-13 12:26:34 +1000 | [diff] [blame] | 182 | contains added support for |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 183 | .Xr kerberos 8 |
| 184 | authentication and ticket passing. |
| 185 | .It |
| 186 | supports one-time password authentication with |
| 187 | .Xr skey 1 . |
| 188 | .El |
Damien Miller | 32aa144 | 1999-10-29 09:15:49 +1000 | [diff] [blame] | 189 | .Sh SEE ALSO |
| 190 | .Xr ssh 1 , |
| 191 | .Xr ssh-add 1 , |
| 192 | .Xr ssh-keygen 1 , |
| 193 | .Xr sshd 8 , |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 194 | .Xr crypto 3 |