diff options
Diffstat (limited to 'usr.bin')
-rw-r--r-- | usr.bin/ssh/ssh.1 | 70 | ||||
-rw-r--r-- | usr.bin/ssh/sshd.8 | 20 |
2 files changed, 40 insertions, 50 deletions
diff --git a/usr.bin/ssh/ssh.1 b/usr.bin/ssh/ssh.1 index 0ff77ea296f..b9ee4c62b94 100644 --- a/usr.bin/ssh/ssh.1 +++ b/usr.bin/ssh/ssh.1 @@ -34,7 +34,7 @@ .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" 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 .Dt SSH 1 .Os @@ -103,35 +103,25 @@ is specified, .Ar command is executed on the remote host instead of a login shell. .Ss SSH protocol version 1 -First, if the machine the user logs in from is listed in +The first authentication method is the +.Em rhosts +or +.Em hosts.equiv +method combined with RSA-based host authentication. +If the machine the user logs in from is listed in .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 +the same on both sides, or if the files +.Pa $HOME/.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 +.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 -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 -or -.Em hosts.equiv -method combined with RSA-based host authentication. -It means that if the login would be permitted by -.Pa $HOME/.rhosts , -.Pa $HOME/.shosts , -.Pa /etc/hosts.equiv , -or -.Pa /etc/shosts.equiv , -and if additionally the server can verify the client's +considered for log in. +Additionally, if the server can verify the client's host key (see .Pa /etc/ssh/ssh_known_hosts and @@ -147,7 +137,7 @@ spoofing, DNS spoofing and routing spoofing. and the rlogin/rsh protocol in general, are inherently insecure and should be disabled if security is desired.] .Pp -As a third authentication method, +As a second authentication method, .Nm supports RSA based authentication. 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 per line, though the lines can be very long). After this, the user can log in without giving the password. -RSA authentication is much more secure than -.Em rhosts -authentication. .Pp The most convenient way to use RSA authentication may be with an authentication agent. @@ -1012,7 +999,9 @@ By default is not setuid root. .It Pa $HOME/.rhosts This file is used in -.Em rhosts +.Cm RhostsRSAAuthentication +and +.Cm HostbasedAuthentication authentication to list the host/user pairs that are permitted to log in. (Note that this file is @@ -1031,12 +1020,10 @@ The recommended permission for most machines is read/write for the user, and not accessible by others. .Pp -Note that by default +Note that .Xr sshd 8 -will be installed so that it requires successful RSA host -authentication before permitting -.Em rhosts -authentication. +allows authentication only in combination with client host key +authentication before permitting log in. If the server machine does not have the client's host key in .Pa /etc/ssh/ssh_known_hosts , 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 .Pa .rhosts . The purpose for -having this file is to be able to use rhosts authentication with -.Nm -without permitting login with +having this file is to be able to use +.Cm RhostsRSAAuthentication +and +.Cm HostbasedAuthentication +authentication without permitting login with .Xr rlogin or .Xr rsh 1 . .It Pa /etc/hosts.equiv This file is used during -.Em rhosts +.Cm RhostsRSAAuthentication +and +.Cm HostbasedAuthentication authentication. It contains 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 automatically permitted provided client and server user names are the same. -Additionally, successful RSA host authentication is normally -required. +Additionally, successful client host key authentication is required. This file should only be writable by root. .It Pa /etc/shosts.equiv This file is processed exactly as diff --git a/usr.bin/ssh/sshd.8 b/usr.bin/ssh/sshd.8 index d019ccb5bb8..b2ec23741bd 100644 --- a/usr.bin/ssh/sshd.8 +++ b/usr.bin/ssh/sshd.8 @@ -34,7 +34,7 @@ .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" 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 .Dt SSHD 8 .Os @@ -106,16 +106,10 @@ to use from those offered by the server. Next, the server and the client enter an authentication dialog. The client tries to authenticate itself using .Em rhosts -authentication, -.Em rhosts authentication combined with RSA host authentication, RSA challenge-response authentication, or password based authentication. .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 rlogind , @@ -647,7 +641,11 @@ Access controls that should be enforced by tcp-wrappers are defined here. Further details are described in .Xr hosts_access 5 . .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. The given user on the corresponding host is permitted to log in without a password. @@ -668,7 +666,9 @@ However, this file is not used by rlogin and rshd, so using this permits access using SSH only. .It Pa /etc/hosts.equiv This file is used during -.Em rhosts +.Cm RhostsRSAAuthentication +and +.Cm HostbasedAuthentication authentication. In the simplest form, this file contains host names, one per line. Users on @@ -687,7 +687,7 @@ Negated entries start with If the client host/user is successfully matched in this file, login is automatically permitted provided the client and server user names are the 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 that it be world-readable. .Pp |