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authordes <des@FreeBSD.org>2008-08-01 02:48:36 +0000
committerdes <des@FreeBSD.org>2008-08-01 02:48:36 +0000
commitb7aa600c416b507a21191efa2689c0a03031d58e (patch)
treeed813bdf7d8dbee35f19092d185e1a2793885204 /crypto/openssh/sshd.8
parenta2326b0bec3be2ec01f66d386cfe43139cbc579c (diff)
parent8f6f5baf400f08937451cf9c8ecc220e9efd2f63 (diff)
downloadFreeBSD-src-b7aa600c416b507a21191efa2689c0a03031d58e.zip
FreeBSD-src-b7aa600c416b507a21191efa2689c0a03031d58e.tar.gz
Upgrade to OpenSSH 5.1p1.
I have worked hard to reduce diffs against the vendor branch. One notable change in that respect is that we no longer prefer DSA over RSA - the reasons for doing so went away years ago. This may cause some surprises, as ssh will warn about unknown host keys even for hosts whose keys haven't changed. MFC after: 6 weeks
Diffstat (limited to 'crypto/openssh/sshd.8')
-rw-r--r--crypto/openssh/sshd.8111
1 files changed, 80 insertions, 31 deletions
diff --git a/crypto/openssh/sshd.8 b/crypto/openssh/sshd.8
index 6e283b0..117c970 100644
--- a/crypto/openssh/sshd.8
+++ b/crypto/openssh/sshd.8
@@ -34,9 +34,9 @@
.\" (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 1.234 2006/08/21 08:15:57 dtucker Exp $
+.\" $OpenBSD: sshd.8,v 1.246 2008/07/02 02:24:18 djm Exp $
.\" $FreeBSD$
-.Dd September 25, 1999
+.Dd $Mdocdate: July 2 2008 $
.Dt SSHD 8
.Os
.Sh NAME
@@ -45,8 +45,9 @@
.Sh SYNOPSIS
.Nm sshd
.Bk -words
-.Op Fl 46Ddeiqt
+.Op Fl 46DdeiqTt
.Op Fl b Ar bits
+.Op Fl C Ar connection_spec
.Op Fl f Ar config_file
.Op Fl g Ar login_grace_time
.Op Fl h Ar host_key_file
@@ -59,8 +60,11 @@
.Nm
(OpenSSH Daemon) is the daemon program for
.Xr ssh 1 .
-Together these programs replace rlogin and rsh, and
-provide secure encrypted communications between two untrusted hosts
+Together these programs replace
+.Xr rlogin 1
+and
+.Xr rsh 1 ,
+and provide secure encrypted communications between two untrusted hosts
over an insecure network.
.Pp
.Nm
@@ -97,7 +101,25 @@ Forces
to use IPv6 addresses only.
.It Fl b Ar bits
Specifies the number of bits in the ephemeral protocol version 1
-server key (default 768).
+server key (default 1024).
+.It Fl C Ar connection_spec
+Specify the connection parameters to use for the
+.Fl T
+extended test mode.
+If provided, any
+.Cm Match
+directives in the configuration file
+that would apply to the specified user, host, and address will be set before
+the configuration is written to standard output.
+The connection parameters are supplied as keyword=value pairs.
+The keywords are
+.Dq user ,
+.Dq host ,
+and
+.Dq addr .
+All are required and may be supplied in any order, either with multiple
+.Fl C
+options or as a comma-separated list.
.It Fl D
When this option is specified,
.Nm
@@ -118,7 +140,7 @@ Maximum is 3.
When this option is specified,
.Nm
will send the output to the standard error instead of the system log.
-.It Fl f Ar configuration_file
+.It Fl f Ar config_file
Specifies the name of the configuration file.
The default is
.Pa /etc/ssh/sshd_config .
@@ -139,6 +161,8 @@ host key files are normally not readable by anyone but root).
The default is
.Pa /etc/ssh/ssh_host_key
for protocol version 1, and
+.Pa /etc/ssh/ssh_host_rsa_key
+and
.Pa /etc/ssh/ssh_host_dsa_key
for protocol version 2.
It is possible to have multiple host key files for
@@ -187,6 +211,15 @@ Quiet mode.
Nothing is sent to the system log.
Normally the beginning,
authentication, and termination of each connection is logged.
+.It Fl T
+Extended test mode.
+Check the validity of the configuration file, output the effective configuration
+to stdout and then exit.
+Optionally,
+.Cm Match
+rules may be applied by specifying the connection parameters using one or more
+.Fl C
+options.
.It Fl t
Test mode.
Only check the validity of the configuration file and sanity of the keys.
@@ -272,7 +305,7 @@ The client selects the encryption algorithm
to use from those offered by the server.
Additionally, session integrity is provided
through a cryptographic message authentication code
-(hmac-sha1 or hmac-md5).
+(hmac-md5, hmac-sha1, umac-64 or hmac-ripemd160).
.Pp
Finally, the server and the client enter an authentication dialog.
The client tries to authenticate itself using
@@ -298,8 +331,9 @@ on Tru64,
a leading
.Ql \&*LOCKED\&*
on FreeBSD and a leading
-.Ql \&!!
-on Linux). If there is a requirement to disable password authentication
+.Ql \&!
+on most Linuxes).
+If there is a requirement to disable password authentication
for the account while allowing still public-key, then the passwd field
should be set to something other than these values (eg
.Ql NP
@@ -500,23 +534,27 @@ This option is automatically disabled if
.Cm UseLogin
is enabled.
.It Cm from="pattern-list"
-Specifies that in addition to public key authentication, the canonical name
-of the remote host must be present in the comma-separated list of
-patterns.
-The purpose
-of this option is to optionally increase security: public key authentication
-by itself does not trust the network or name servers or anything (but
-the key); however, if somebody somehow steals the key, the key
-permits an intruder to log in from anywhere in the world.
-This additional option makes using a stolen key more difficult (name
-servers and/or routers would have to be compromised in addition to
-just the key).
-.Pp
+Specifies that in addition to public key authentication, either the canonical
+name of the remote host or its IP address must be present in the
+comma-separated list of patterns.
See
.Sx PATTERNS
in
.Xr ssh_config 5
for more information on patterns.
+.Pp
+In addition to the wildcard matching that may be applied to hostnames or
+addresses, a
+.Cm from
+stanza may match IP addressess using CIDR address/masklen notation.
+.Pp
+The purpose of this option is to optionally increase security: public key
+authentication by itself does not trust the network or name servers or
+anything (but the key); however, if somebody somehow steals the key, the key
+permits an intruder to log in from anywhere in the world.
+This additional option makes using a stolen key more difficult (name
+servers and/or routers would have to be compromised in addition to
+just the key).
.It Cm no-agent-forwarding
Forbids authentication agent forwarding when this key is used for
authentication.
@@ -528,6 +566,9 @@ This might be used, e.g. in connection with the
option.
.It Cm no-pty
Prevents tty allocation (a request to allocate a pty will fail).
+.It Cm no-user-rc
+Disables execution of
+.Pa ~/.ssh/rc .
.It Cm no-X11-forwarding
Forbids X11 forwarding when this key is used for authentication.
Any X11 forward requests by the client will return an error.
@@ -679,6 +720,13 @@ This file is used in exactly the same way as
but allows host-based authentication without permitting login with
rlogin/rsh.
.Pp
+.It ~/.ssh/
+This directory is the default location for all user-specific configuration
+and authentication information.
+There is no general requirement to keep the entire contents of this directory
+secret, but the recommended permissions are read/write/execute for the user,
+and not accessible by others.
+.Pp
.It ~/.ssh/authorized_keys
Lists the public keys (RSA/DSA) that can be used for logging in as this user.
The format of this file is described above.
@@ -759,15 +807,6 @@ This file is used in exactly the same way as
but allows host-based authentication without permitting login with
rlogin/rsh.
.Pp
-.It /etc/ssh/ssh_known_hosts
-Systemwide list of known host keys.
-This file should be prepared by the
-system administrator to contain the public host keys of all machines in the
-organization.
-The format of this file is described above.
-This file should be writable only by root/the owner and
-should be world-readable.
-.Pp
.It /etc/ssh/ssh_host_key
.It /etc/ssh/ssh_host_dsa_key
.It /etc/ssh/ssh_host_rsa_key
@@ -791,6 +830,15 @@ the user so their contents can be copied to known hosts files.
These files are created using
.Xr ssh-keygen 1 .
.Pp
+.It /etc/ssh/ssh_known_hosts
+Systemwide list of known host keys.
+This file should be prepared by the
+system administrator to contain the public host keys of all machines in the
+organization.
+The format of this file is described above.
+This file should be writable only by root/the owner and
+should be world-readable.
+.Pp
.It /etc/ssh/sshd_config
Contains configuration data for
.Nm sshd .
@@ -827,6 +875,7 @@ The content of this file is not sensitive; it can be world-readable.
.Xr ssh-add 1 ,
.Xr ssh-agent 1 ,
.Xr ssh-keygen 1 ,
+.Xr ssh-keyscan 1 ,
.Xr chroot 2 ,
.Xr hosts_access 5 ,
.Xr login.conf 5 ,
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