1.\" $OpenBSD: ssh-keysign.8,v 1.17 2022/03/31 17:27:27 naddy Exp $ 2.\" 3.\" Copyright (c) 2002 Markus Friedl. All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24.\" 25.Dd $Mdocdate: March 31 2022 $ 26.Dt SSH-KEYSIGN 8 27.Os 28.Sh NAME 29.Nm ssh-keysign 30.Nd OpenSSH helper for host-based authentication 31.Sh SYNOPSIS 32.Nm 33.Sh DESCRIPTION 34.Nm 35is used by 36.Xr ssh 1 37to access the local host keys and generate the digital signature 38required during host-based authentication. 39.Pp 40.Nm 41is disabled by default and can only be enabled in the 42global client configuration file 43.Pa /etc/ssh/ssh_config 44by setting 45.Cm EnableSSHKeysign 46to 47.Dq yes . 48.Pp 49.Nm 50is not intended to be invoked by the user, but from 51.Xr ssh 1 . 52See 53.Xr ssh 1 54and 55.Xr sshd 8 56for more information about host-based authentication. 57.Sh FILES 58.Bl -tag -width Ds -compact 59.It Pa /etc/ssh/ssh_config 60Controls whether 61.Nm 62is enabled. 63.Pp 64.It Pa /etc/ssh/ssh_host_dsa_key 65.It Pa /etc/ssh/ssh_host_ecdsa_key 66.It Pa /etc/ssh/ssh_host_ed25519_key 67.It Pa /etc/ssh/ssh_host_rsa_key 68These files contain the private parts of the host keys used to 69generate the digital signature. 70They should be owned by root, readable only by root, and not 71accessible to others. 72Since they are readable only by root, 73.Nm 74must be set-uid root if host-based authentication is used. 75.Pp 76.It Pa /etc/ssh/ssh_host_dsa_key-cert.pub 77.It Pa /etc/ssh/ssh_host_ecdsa_key-cert.pub 78.It Pa /etc/ssh/ssh_host_ed25519_key-cert.pub 79.It Pa /etc/ssh/ssh_host_rsa_key-cert.pub 80If these files exist, they are assumed to contain public certificate 81information corresponding with the private keys above. 82.El 83.Sh SEE ALSO 84.Xr ssh 1 , 85.Xr ssh-keygen 1 , 86.Xr ssh_config 5 , 87.Xr sshd 8 88.Sh HISTORY 89.Nm 90first appeared in 91.Ox 3.2 . 92.Sh AUTHORS 93.An Markus Friedl Aq Mt markus@openbsd.org 94