mirror of
git://anongit.mindrot.org/openssh.git
synced 2024-12-30 06:02:07 +00:00
a9c9e91a82
This is prompted by: https://bugzilla.mindrot.org/show_bug.cgi?id=3201 Thanks go to Matthias Blümel for the idea, and the helpful patch, from which this patch grew. SSH-Copy-ID-Upstream: f7c76dc64427cd20287a6868f672423b62057614
199 lines
6.7 KiB
Groff
199 lines
6.7 KiB
Groff
.ig \" -*- nroff -*-
|
|
Copyright (c) 1999-2020 hands.com Ltd. <http://hands.com/>
|
|
|
|
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: June 17 2010 $
|
|
.Dt SSH-COPY-ID 1
|
|
.Os
|
|
.Sh NAME
|
|
.Nm ssh-copy-id
|
|
.Nd use locally available keys to authorise logins on a remote machine
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.Op Fl f
|
|
.Op Fl n
|
|
.Op Fl s
|
|
.Op Fl i Op Ar identity_file
|
|
.Op Fl p Ar port
|
|
.Op Fl o Ar ssh_option
|
|
.Op Ar user Ns @ Ns
|
|
.Ar hostname
|
|
.Nm
|
|
.Fl h | Fl ?
|
|
.br
|
|
.Sh DESCRIPTION
|
|
.Nm
|
|
is a script that uses
|
|
.Xr ssh 1
|
|
to log into a remote machine (presumably using a login password,
|
|
so password authentication should be enabled, unless you've done some
|
|
clever use of multiple identities). It assembles a list of one or more
|
|
fingerprints (as described below) and tries to log in with each key, to
|
|
see if any of them are already installed (of course, if you are not using
|
|
.Xr ssh-agent 1
|
|
this may result in you being repeatedly prompted for pass-phrases).
|
|
It then assembles a list of those that failed to log in, and using ssh,
|
|
enables logins with those keys on the remote server. By default it adds
|
|
the keys by appending them to the remote user's
|
|
.Pa ~/.ssh/authorized_keys
|
|
(creating the file, and directory, if necessary). It is also capable
|
|
of detecting if the remote system is a NetScreen, and using its
|
|
.Ql set ssh pka-dsa key ...
|
|
command instead.
|
|
.Pp
|
|
The options are as follows:
|
|
.Bl -tag -width Ds
|
|
.It Fl i Ar identity_file
|
|
Use only the key(s) contained in
|
|
.Ar identity_file
|
|
(rather than looking for identities via
|
|
.Xr ssh-add 1
|
|
or in the
|
|
.Ic default_ID_file ) .
|
|
If the filename does not end in
|
|
.Pa .pub
|
|
this is added. If the filename is omitted, the
|
|
.Ic default_ID_file
|
|
is used.
|
|
.Pp
|
|
Note that this can be used to ensure that the keys copied have the
|
|
comment one prefers and/or extra options applied, by ensuring that the
|
|
key file has these set as preferred before the copy is attempted.
|
|
.It Fl f
|
|
Forced mode: doesn't check if the keys are present on the remote server.
|
|
This means that it does not need the private key. Of course, this can result
|
|
in more than one copy of the key being installed on the remote system.
|
|
.It Fl n
|
|
do a dry-run. Instead of installing keys on the remote system simply
|
|
prints the key(s) that would have been installed.
|
|
.It Fl s
|
|
SFTP mode: usually the public keys are installed by executing commands on the remote side.
|
|
With this option the user's
|
|
.Pa ~/.ssh/authorized_keys
|
|
file will be downloaded, modified locally and uploaded with sftp.
|
|
This option is useful if the server has restrictions on commands which can be used on the remote side.
|
|
.It Fl h , Fl ?
|
|
Print Usage summary
|
|
.It Fl p Ar port , Fl o Ar ssh_option
|
|
These two options are simply passed through untouched, along with their
|
|
argument, to allow one to set the port or other
|
|
.Xr ssh 1
|
|
options, respectively.
|
|
.Pp
|
|
Rather than specifying these as command line options, it is often better to use (per-host) settings in
|
|
.Xr ssh 1 Ns 's
|
|
configuration file:
|
|
.Xr ssh_config 5 .
|
|
.El
|
|
.Pp
|
|
Default behaviour without
|
|
.Fl i ,
|
|
is to check if
|
|
.Ql ssh-add -L
|
|
provides any output, and if so those keys are used. Note that this results in
|
|
the comment on the key being the filename that was given to
|
|
.Xr ssh-add 1
|
|
when the key was loaded into your
|
|
.Xr ssh-agent 1
|
|
rather than the comment contained in that file, which is a bit of a shame.
|
|
Otherwise, if
|
|
.Xr ssh-add 1
|
|
provides no keys contents of the
|
|
.Ic default_ID_file
|
|
will be used.
|
|
.Pp
|
|
The
|
|
.Ic default_ID_file
|
|
is the most recent file that matches:
|
|
.Pa ~/.ssh/id*.pub ,
|
|
(excluding those that match
|
|
.Pa ~/.ssh/*-cert.pub )
|
|
so if you create a key that is not the one you want
|
|
.Nm
|
|
to use, just use
|
|
.Xr touch 1
|
|
on your preferred key's
|
|
.Pa .pub
|
|
file to reinstate it as the most recent.
|
|
.Pp
|
|
.Sh EXAMPLES
|
|
If you have already installed keys from one system on a lot of remote
|
|
hosts, and you then create a new key, on a new client machine, say,
|
|
it can be difficult to keep track of which systems on which you've
|
|
installed the new key. One way of dealing with this is to load both
|
|
the new key and old key(s) into your
|
|
.Xr ssh-agent 1 .
|
|
Load the new key first, without the
|
|
.Fl c
|
|
option, then load one or more old keys into the agent, possibly by
|
|
ssh-ing to the client machine that has that old key, using the
|
|
.Fl A
|
|
option to allow agent forwarding:
|
|
.Pp
|
|
.D1 user@newclient$ ssh-add
|
|
.D1 user@newclient$ ssh -A old.client
|
|
.D1 user@oldl$ ssh-add -c
|
|
.D1 No ... prompt for pass-phrase ...
|
|
.D1 user@old$ logoff
|
|
.D1 user@newclient$ ssh someserver
|
|
.Pp
|
|
now, if the new key is installed on the server, you'll be allowed in
|
|
unprompted, whereas if you only have the old key(s) enabled, you'll be
|
|
asked for confirmation, which is your cue to log back out and run
|
|
.Pp
|
|
.D1 user@newclient$ ssh-copy-id -i someserver
|
|
.Pp
|
|
The reason you might want to specify the -i option in this case is to
|
|
ensure that the comment on the installed key is the one from the
|
|
.Pa .pub
|
|
file, rather than just the filename that was loaded into your agent.
|
|
It also ensures that only the id you intended is installed, rather than
|
|
all the keys that you have in your
|
|
.Xr ssh-agent 1 .
|
|
Of course, you can specify another id, or use the contents of the
|
|
.Xr ssh-agent 1
|
|
as you prefer.
|
|
.Pp
|
|
Having mentioned
|
|
.Xr ssh-add 1 Ns 's
|
|
.Fl c
|
|
option, you might consider using this whenever using agent forwarding
|
|
to avoid your key being hijacked, but it is much better to instead use
|
|
.Xr ssh 1 Ns 's
|
|
.Ar ProxyCommand
|
|
and
|
|
.Fl W
|
|
option,
|
|
to bounce through remote servers while always doing direct end-to-end
|
|
authentication. This way the middle hop(s) don't get access to your
|
|
.Xr ssh-agent 1 .
|
|
A web search for
|
|
.Ql ssh proxycommand nc
|
|
should prove enlightening (N.B. the modern approach is to use the
|
|
.Fl W
|
|
option, rather than
|
|
.Xr nc 1 ) .
|
|
.Sh "SEE ALSO"
|
|
.Xr ssh 1 ,
|
|
.Xr ssh-agent 1 ,
|
|
.Xr sshd 8
|