[ssh.1 sshd.8]
     get rid of references to rhosts authentication; with jmc@
This commit is contained in:
Darren Tucker 2004-08-29 16:37:24 +10:00
parent 34620d6f71
commit db69390817
3 changed files with 45 additions and 53 deletions

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@ -16,6 +16,9 @@
- dtucker@cvs.openbsd.org 2004/08/23 14:29:23 - dtucker@cvs.openbsd.org 2004/08/23 14:29:23
[ssh-keysign.c] [ssh-keysign.c]
Remove duplicate getuid(), suggested by & ok markus@ Remove duplicate getuid(), suggested by & ok markus@
- markus@cvs.openbsd.org 2004/08/26 16:00:55
[ssh.1 sshd.8]
get rid of references to rhosts authentication; with jmc@
20040828 20040828
- (dtucker) [openbsd-compat/mktemp.c] Remove superfluous Cygwin #ifdef; from - (dtucker) [openbsd-compat/mktemp.c] Remove superfluous Cygwin #ifdef; from
@ -1683,4 +1686,4 @@
- (djm) Trim deprecated options from INSTALL. Mention UsePAM - (djm) Trim deprecated options from INSTALL. Mention UsePAM
- (djm) Fix quote handling in sftp; Patch from admorten AT umich.edu - (djm) Fix quote handling in sftp; Patch from admorten AT umich.edu
$Id: ChangeLog,v 1.3526 2004/08/29 06:32:59 dtucker Exp $ $Id: ChangeLog,v 1.3527 2004/08/29 06:37:24 dtucker Exp $

72
ssh.1
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@ -34,7 +34,7 @@
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\" .\"
.\" $OpenBSD: ssh.1,v 1.194 2004/08/12 21:41:13 jakob Exp $ .\" $OpenBSD: ssh.1,v 1.195 2004/08/26 16:00:55 markus Exp $
.Dd September 25, 1999 .Dd September 25, 1999
.Dt SSH 1 .Dt SSH 1
.Os .Os
@ -103,35 +103,25 @@ is specified,
.Ar command .Ar command
is executed on the remote host instead of a login shell. is executed on the remote host instead of a login shell.
.Ss SSH protocol version 1 .Ss SSH protocol version 1
First, if the machine the user logs in from is listed in The first authentication method is the
.Pa /etc/hosts.equiv
or
.Pa /etc/shosts.equiv
on the remote machine, and the user names are
the same on both sides, the user is immediately permitted to log in.
Second, if
.Pa .rhosts
or
.Pa .shosts
exists in the user's home directory on the
remote machine and contains a line containing the name of the client
machine and the name of the user on that machine, the user is
permitted to log in.
This form of authentication alone is normally not
allowed by the server because it is not secure.
.Pp
The second authentication method is the
.Em rhosts .Em rhosts
or or
.Em hosts.equiv .Em hosts.equiv
method combined with RSA-based host authentication. method combined with RSA-based host authentication.
It means that if the login would be permitted by If the machine the user logs in from is listed in
.Pa $HOME/.rhosts , .Pa /etc/hosts.equiv
.Pa $HOME/.shosts ,
.Pa /etc/hosts.equiv ,
or or
.Pa /etc/shosts.equiv , .Pa /etc/shosts.equiv
and if additionally the server can verify the client's on the remote machine, and the user names are
the same on both sides, or if the files
.Pa $HOME/.rhosts
or
.Pa $HOME/.shosts
exist in the user's home directory on the
remote machine and contain a line containing the name of the client
machine and the name of the user on that machine, the user is
considered for log in.
Additionally, if the server can verify the client's
host key (see host key (see
.Pa /etc/ssh/ssh_known_hosts .Pa /etc/ssh/ssh_known_hosts
and and
@ -147,7 +137,7 @@ spoofing, DNS spoofing and routing spoofing.
and the rlogin/rsh protocol in general, are inherently insecure and should be and the rlogin/rsh protocol in general, are inherently insecure and should be
disabled if security is desired.] disabled if security is desired.]
.Pp .Pp
As a third authentication method, As a second authentication method,
.Nm .Nm
supports RSA based authentication. supports RSA based authentication.
The scheme is based on public-key cryptography: there are cryptosystems The scheme is based on public-key cryptography: there are cryptosystems
@ -195,9 +185,6 @@ file corresponds to the conventional
file, and has one key file, and has one key
per line, though the lines can be very long). per line, though the lines can be very long).
After this, the user can log in without giving the password. After this, the user can log in without giving the password.
RSA authentication is much more secure than
.Em rhosts
authentication.
.Pp .Pp
The most convenient way to use RSA authentication may be with an The most convenient way to use RSA authentication may be with an
authentication agent. authentication agent.
@ -1012,7 +999,9 @@ By default
is not setuid root. is not setuid root.
.It Pa $HOME/.rhosts .It Pa $HOME/.rhosts
This file is used in This file is used in
.Em rhosts .Cm RhostsRSAAuthentication
and
.Cm HostbasedAuthentication
authentication to list the authentication to list the
host/user pairs that are permitted to log in. host/user pairs that are permitted to log in.
(Note that this file is (Note that this file is
@ -1031,12 +1020,10 @@ The recommended
permission for most machines is read/write for the user, and not permission for most machines is read/write for the user, and not
accessible by others. accessible by others.
.Pp .Pp
Note that by default Note that
.Xr sshd 8 .Xr sshd 8
will be installed so that it requires successful RSA host allows authentication only in combination with client host key
authentication before permitting authentication before permitting log in.
.Em rhosts
authentication.
If the server machine does not have the client's host key in If the server machine does not have the client's host key in
.Pa /etc/ssh/ssh_known_hosts , .Pa /etc/ssh/ssh_known_hosts ,
it can be stored in it can be stored in
@ -1049,15 +1036,19 @@ will automatically add the host key to
This file is used exactly the same way as This file is used exactly the same way as
.Pa .rhosts . .Pa .rhosts .
The purpose for The purpose for
having this file is to be able to use rhosts authentication with having this file is to be able to use
.Nm .Cm RhostsRSAAuthentication
without permitting login with and
.Cm HostbasedAuthentication
authentication without permitting login with
.Xr rlogin .Xr rlogin
or or
.Xr rsh 1 . .Xr rsh 1 .
.It Pa /etc/hosts.equiv .It Pa /etc/hosts.equiv
This file is used during This file is used during
.Em rhosts .Cm RhostsRSAAuthentication
and
.Cm HostbasedAuthentication
authentication. authentication.
It contains It contains
canonical hosts names, one per line (the full format is described in the canonical hosts names, one per line (the full format is described in the
@ -1066,8 +1057,7 @@ manual page).
If the client host is found in this file, login is If the client host is found in this file, login is
automatically permitted provided client and server user names are the automatically permitted provided client and server user names are the
same. same.
Additionally, successful RSA host authentication is normally Additionally, successful client host key authentication is required.
required.
This file should only be writable by root. This file should only be writable by root.
.It Pa /etc/shosts.equiv .It Pa /etc/shosts.equiv
This file is processed exactly as This file is processed exactly as

21
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@ -34,7 +34,7 @@
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\" .\"
.\" $OpenBSD: sshd.8,v 1.201 2004/05/02 11:54:31 dtucker Exp $ .\" $OpenBSD: sshd.8,v 1.202 2004/08/26 16:00:55 markus Exp $
.Dd September 25, 1999 .Dd September 25, 1999
.Dt SSHD 8 .Dt SSHD 8
.Os .Os
@ -106,8 +106,6 @@ to use from those offered by the server.
Next, the server and the client enter an authentication dialog. Next, the server and the client enter an authentication dialog.
The client tries to authenticate itself using The client tries to authenticate itself using
.Em .rhosts .Em .rhosts
authentication,
.Em .rhosts
authentication combined with RSA host authentication combined with RSA host
authentication, RSA challenge-response authentication, or password authentication, RSA challenge-response authentication, or password
based authentication. based authentication.
@ -135,11 +133,6 @@ or
.Ql \&*NP\&* .Ql \&*NP\&*
). ).
.Pp .Pp
.Em rhosts
authentication is normally disabled
because it is fundamentally insecure, but can be enabled in the server
configuration file if desired.
System security is not improved unless
.Nm rshd , .Nm rshd ,
.Nm rlogind , .Nm rlogind ,
and and
@ -670,7 +663,11 @@ Access controls that should be enforced by tcp-wrappers are defined here.
Further details are described in Further details are described in
.Xr hosts_access 5 . .Xr hosts_access 5 .
.It Pa $HOME/.rhosts .It Pa $HOME/.rhosts
This file contains host-username pairs, separated by a space, one per This file is used during
.Cm RhostsRSAAuthentication
and
.Cm HostbasedAuthentication
and contains host-username pairs, separated by a space, one per
line. line.
The given user on the corresponding host is permitted to log in The given user on the corresponding host is permitted to log in
without a password. without a password.
@ -691,7 +688,9 @@ However, this file is
not used by rlogin and rshd, so using this permits access using SSH only. not used by rlogin and rshd, so using this permits access using SSH only.
.It Pa /etc/hosts.equiv .It Pa /etc/hosts.equiv
This file is used during This file is used during
.Em rhosts .Cm RhostsRSAAuthentication
and
.Cm HostbasedAuthentication
authentication. authentication.
In the simplest form, this file contains host names, one per line. In the simplest form, this file contains host names, one per line.
Users on Users on
@ -710,7 +709,7 @@ Negated entries start with
If the client host/user is successfully matched in this file, login is If the client host/user is successfully matched in this file, login is
automatically permitted provided the client and server user names are the automatically permitted provided the client and server user names are the
same. same.
Additionally, successful RSA host authentication is normally required. Additionally, successful client host key authentication is required.
This file must be writable only by root; it is recommended This file must be writable only by root; it is recommended
that it be world-readable. that it be world-readable.
.Pp .Pp