Vendor import of OpenSSH 3.3.

1 files changed, 40 insertions, 631 deletions

diff --git a/crypto/openssh/sshd.8 b/crypto/openssh/sshd.8
index 9d579f1..22f8143 100644
--- a/crypto/openssh/sshd.8
+++ b/crypto/openssh/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 1.170 2002/02/28 20:46:10 stevesk Exp $
+.\" $OpenBSD: sshd.8,v 1.184 2002/06/20 19:56:07 stevesk Exp $
 .Dd September 25, 1999
 .Dt SSHD 8
 .Os
@@ -116,14 +116,14 @@ 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
-.Xr rshd 8 ,
-.Xr rlogind 8 ,
+.Nm rshd ,
+.Nm rlogind ,
 and
-.Xr rexecd 8
+.Xr rexecd
 are disabled (thus completely disabling
-.Xr rlogin 1
+.Xr rlogin
 and
-.Xr rsh 1
+.Xr rsh
 into the machine).
 .Pp
 .Ss SSH protocol version 2
@@ -320,617 +320,8 @@ reads configuration data from
 (or the file specified with
 .Fl f
 on the command line).
-The file contains keyword-argument pairs, one per line.
-Lines starting with
-.Ql #
-and empty lines are interpreted as comments.
-.Pp
-The possible
-keywords and their meanings are as follows (note that
-keywords are case-insensitive and arguments are case-sensitive):
-.Bl -tag -width Ds
-.It Cm AFSTokenPassing
-Specifies whether an AFS token may be forwarded to the server.
-Default is
-.Dq yes .
-.It Cm AllowGroups
-This keyword can be followed by a list of group name patterns, separated
-by spaces.
-If specified, login is allowed only for users whose primary
-group or supplementary group list matches one of the patterns.
-.Ql \&*
-and
-.Ql ?
-can be used as
-wildcards in the patterns.
-Only group names are valid; a numerical group ID is not recognized.
-By default, login is allowed for all groups.
-.Pp
-.It Cm AllowTcpForwarding
-Specifies whether TCP forwarding is permitted.
-The default is
-.Dq yes .
-Note that disabling TCP forwarding does not improve security unless
-users are also denied shell access, as they can always install their
-own forwarders.
-.Pp
-.It Cm AllowUsers
-This keyword can be followed by a list of user name patterns, separated
-by spaces.
-If specified, login is allowed only for users names that
-match one of the patterns.
-.Ql \&*
-and
-.Ql ?
-can be used as
-wildcards in the patterns.
-Only user names are valid; a numerical user ID is not recognized.
-By default, login is allowed for all users.
-If the pattern takes the form USER@HOST then USER and HOST
-are separately checked, restricting logins to particular
-users from particular hosts.
-.Pp
-.It Cm AuthorizedKeysFile
-Specifies the file that contains the public keys that can be used
-for user authentication.
-.Cm AuthorizedKeysFile
-may contain tokens of the form %T which are substituted during connection
-set-up. The following tokens are defined: %% is replaced by a literal '%',
-%h is replaced by the home directory of the user being authenticated and
-%u is replaced by the username of that user.
-After expansion,
-.Cm AuthorizedKeysFile
-is taken to be an absolute path or one relative to the user's home
-directory.
-The default is
-.Dq .ssh/authorized_keys .
-.It Cm Banner
-In some jurisdictions, sending a warning message before authentication
-may be relevant for getting legal protection.
-The contents of the specified file are sent to the remote user before
-authentication is allowed.
-This option is only available for protocol version 2.
-.Pp
-.It Cm ChallengeResponseAuthentication
-Specifies whether challenge response authentication is allowed.
-All authentication styles from
-.Xr login.conf 5
-are supported.
-The default is
-.Dq yes .
-.It Cm Ciphers
-Specifies the ciphers allowed for protocol version 2.
-Multiple ciphers must be comma-separated.
-The default is
-.Pp
-.Bd -literal
-  ``aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,
-    aes192-cbc,aes256-cbc''
-.Ed
-.It Cm ClientAliveInterval
-Sets a timeout interval in seconds after which if no data has been received
-from the client,
-.Nm
-will send a message through the encrypted
-channel to request a response from the client.
-The default
-is 0, indicating that these messages will not be sent to the client.
-This option applies to protocol version 2 only.
-.It Cm ClientAliveCountMax
-Sets the number of client alive messages (see above) which may be
-sent without
-.Nm
-receiving any messages back from the client. If this threshold is
-reached while client alive messages are being sent,
-.Nm
-will disconnect the client, terminating the session. It is important
-to note that the use of client alive messages is very different from
-.Cm KeepAlive
-(below). The client alive messages are sent through the
-encrypted channel and therefore will not be spoofable. The TCP keepalive
-option enabled by
-.Cm KeepAlive
-is spoofable. The client alive mechanism is valuable when the client or
-server depend on knowing when a connection has become inactive.
-.Pp
-The default value is 3. If
-.Cm ClientAliveInterval
-(above) is set to 15, and
-.Cm ClientAliveCountMax
-is left at the default, unresponsive ssh clients
-will be disconnected after approximately 45 seconds.
-.It Cm DenyGroups
-This keyword can be followed by a list of group name patterns, separated
-by spaces.
-Login is disallowed for users whose primary group or supplementary
-group list matches one of the patterns.
-.Ql \&*
-and
-.Ql ?
-can be used as
-wildcards in the patterns.
-Only group names are valid; a numerical group ID is not recognized.
-By default, login is allowed for all groups.
-.Pp
-.It Cm DenyUsers
-This keyword can be followed by a list of user name patterns, separated
-by spaces.
-Login is disallowed for user names that match one of the patterns.
-.Ql \&*
-and
-.Ql ?
-can be used as wildcards in the patterns.
-Only user names are valid; a numerical user ID is not recognized.
-By default, login is allowed for all users.
-If the pattern takes the form USER@HOST then USER and HOST
-are separately checked, restricting logins to particular
-users from particular hosts.
-.It Cm GatewayPorts
-Specifies whether remote hosts are allowed to connect to ports
-forwarded for the client.
-By default,
-.Nm
-binds remote port forwardings to the loopback addresss.  This
-prevents other remote hosts from connecting to forwarded ports.
-.Cm GatewayPorts
-can be used to specify that
-.Nm
-should bind remote port forwardings to the wildcard address,
-thus allowing remote hosts to connect to forwarded ports.
-The argument must be
-.Dq yes
-or
-.Dq no .
-The default is
-.Dq no .
-.It Cm HostbasedAuthentication
-Specifies whether rhosts or /etc/hosts.equiv authentication together
-with successful public key client host authentication is allowed
-(hostbased authentication).
-This option is similar to
-.Cm RhostsRSAAuthentication
-and applies to protocol version 2 only.
-The default is
-.Dq no .
-.It Cm HostKey
-Specifies a file containing a private host key
-used by SSH.
-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.
-Note that
-.Nm
-will refuse to use a file if it is group/world-accessible.
-It is possible to have multiple host key files.
-.Dq rsa1
-keys are used for version 1 and
-.Dq dsa
-or
-.Dq rsa
-are used for version 2 of the SSH protocol.
-.It Cm IgnoreRhosts
-Specifies that
-.Pa .rhosts
-and
-.Pa .shosts
-files will not be used in
-.Cm RhostsAuthentication ,
-.Cm RhostsRSAAuthentication
-or
-.Cm HostbasedAuthentication .
-.Pp
-.Pa /etc/hosts.equiv
-and
-.Pa /etc/shosts.equiv
-are still used.
-The default is
-.Dq yes .
-.It Cm IgnoreUserKnownHosts
-Specifies whether
-.Nm
-should ignore the user's
-.Pa $HOME/.ssh/known_hosts
-during
-.Cm RhostsRSAAuthentication
-or
-.Cm HostbasedAuthentication .
-The default is
-.Dq no .
-.It Cm KeepAlive
-Specifies whether the system should send TCP keepalive messages to the
-other side.
-If they are sent, death of the connection or crash of one
-of the machines will be properly noticed.
-However, this means that
-connections will die if the route is down temporarily, and some people
-find it annoying.
-On the other hand, if keepalives are not sent,
-sessions may hang indefinitely on the server, leaving
-.Dq ghost
-users and consuming server resources.
-.Pp
-The default is
-.Dq yes
-(to send keepalives), and the server will notice
-if the network goes down or the client host crashes.
-This avoids infinitely hanging sessions.
-.Pp
-To disable keepalives, the value should be set to
-.Dq no .
-.It Cm KerberosAuthentication
-Specifies whether Kerberos authentication is allowed.
-This can be in the form of a Kerberos ticket, or if
-.Cm PasswordAuthentication
-is yes, the password provided by the user will be validated through
-the Kerberos KDC.
-To use this option, the server needs a
-Kerberos servtab which allows the verification of the KDC's identity.
-Default is
-.Dq yes .
-.It Cm KerberosOrLocalPasswd
-If set then if password authentication through Kerberos fails then
-the password will be validated via any additional local mechanism
-such as
-.Pa /etc/passwd .
-Default is
-.Dq yes .
-.It Cm KerberosTgtPassing
-Specifies whether a Kerberos TGT may be forwarded to the server.
-Default is
-.Dq no ,
-as this only works when the Kerberos KDC is actually an AFS kaserver.
-.It Cm KerberosTicketCleanup
-Specifies whether to automatically destroy the user's ticket cache
-file on logout.
-Default is
-.Dq yes .
-.It Cm KeyRegenerationInterval
-In protocol version 1, the ephemeral server key is automatically regenerated
-after this many seconds (if it has been used).
-The purpose of regeneration is to prevent
-decrypting captured sessions by later breaking into the machine and
-stealing the keys.
-The key is never stored anywhere.
-If the value is 0, the key is never regenerated.
-The default is 3600 (seconds).
-.It Cm ListenAddress
-Specifies the local addresses
-.Nm
-should listen on.
-The following forms may be used:
-.Pp
-.Bl -item -offset indent -compact
-.It
-.Cm ListenAddress
-.Sm off
-.Ar host No | Ar IPv4_addr No | Ar IPv6_addr
-.Sm on
-.It
-.Cm ListenAddress
-.Sm off
-.Ar host No | Ar IPv4_addr No : Ar port
-.Sm on
-.It
-.Cm ListenAddress
-.Sm off
-.Oo
-.Ar host No | Ar IPv6_addr Oc : Ar port
-.Sm on
-.El
-.Pp
-If
-.Ar port
-is not specified,
-.Nm
-will listen on the address and all prior
-.Cm Port
-options specified. The default is to listen on all local
-addresses.  Multiple
-.Cm ListenAddress
-options are permitted. Additionally, any
-.Cm Port
-options must precede this option for non port qualified addresses.
-.It Cm LoginGraceTime
-The server disconnects after this time if the user has not
-successfully logged in.
-If the value is 0, there is no time limit.
-The default is 600 (seconds).
-.It Cm LogLevel
-Gives the verbosity level that is used when logging messages from
-.Nm sshd .
-The possible values are:
-QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2 and DEBUG3.
-The default is INFO.  DEBUG and DEBUG1 are equivalent.  DEBUG2
-and DEBUG3 each specify higher levels of debugging output.
-Logging with a DEBUG level violates the privacy of users
-and is not recommended.
-.It Cm MACs
-Specifies the available MAC (message authentication code) algorithms.
-The MAC algorithm is used in protocol version 2
-for data integrity protection.
-Multiple algorithms must be comma-separated.
-The default is
-.Dq hmac-md5,hmac-sha1,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 .
-.It Cm MaxStartups
-Specifies the maximum number of concurrent unauthenticated connections to the
-.Nm
-daemon.
-Additional connections will be dropped until authentication succeeds or the
-.Cm LoginGraceTime
-expires for a connection.
-The default is 10.
-.Pp
-Alternatively, random early drop can be enabled by specifying
-the three colon separated values
-.Dq start:rate:full
-(e.g., "10:30:60").
-.Nm
-will refuse connection attempts with a probability of
-.Dq rate/100
-(30%)
-if there are currently
-.Dq start
-(10)
-unauthenticated connections.
-The probability increases linearly and all connection attempts
-are refused if the number of unauthenticated connections reaches
-.Dq full
-(60).
-.It Cm PasswordAuthentication
-Specifies whether password authentication is allowed.
-The default is
-.Dq yes .
-.It Cm PermitEmptyPasswords
-When password authentication is allowed, it specifies whether the
-server allows login to accounts with empty password strings.
-The default is
-.Dq no .
-.It Cm PermitRootLogin
-Specifies whether root can login using
-.Xr ssh 1 .
-The argument must be
-.Dq yes ,
-.Dq without-password ,
-.Dq forced-commands-only
-or
-.Dq no .
-The default is
-.Dq yes .
-.Pp
-If this option is set to
-.Dq without-password
-password authentication is disabled for root.
-.Pp
-If this option is set to
-.Dq forced-commands-only
-root login with public key authentication will be allowed,
-but only if the
-.Ar command
-option has been specified
-(which may be useful for taking remote backups even if root login is
-normally not allowed). All other authentication methods are disabled
-for root.
-.Pp
-If this option is set to
-.Dq no
-root is not allowed to login.
-.It Cm PidFile
-Specifies the file that contains the process identifier of the
-.Nm
-daemon.
-The default is
-.Pa /var/run/sshd.pid .
-.It Cm Port
-Specifies the port number that
-.Nm
-listens on.
-The default is 22.
-Multiple options of this type are permitted.
-See also
-.Cm ListenAddress .
-.It Cm PrintLastLog
-Specifies whether
-.Nm
-should print the date and time when the user last logged in.
-The default is
-.Dq yes .
-.It Cm PrintMotd
-Specifies whether
-.Nm
-should print
-.Pa /etc/motd
-when a user logs in interactively.
-(On some systems it is also printed by the shell,
-.Pa /etc/profile ,
-or equivalent.)
-The default is
-.Dq yes .
-.It Cm Protocol
-Specifies the protocol versions
-.Nm
-should support.
-The possible values are
-.Dq 1
-and
-.Dq 2 .
-Multiple versions must be comma-separated.
-The default is
-.Dq 2,1 .
-.It Cm PubkeyAuthentication
-Specifies whether public key authentication is allowed.
-The default is
-.Dq yes .
-Note that this option applies to protocol version 2 only.
-.It Cm RhostsAuthentication
-Specifies whether authentication using rhosts or /etc/hosts.equiv
-files is sufficient.
-Normally, this method should not be permitted because it is insecure.
-.Cm RhostsRSAAuthentication
-should be used
-instead, because it performs RSA-based host authentication in addition
-to normal rhosts or /etc/hosts.equiv authentication.
-The default is
-.Dq no .
-This option applies to protocol version 1 only.
-.It Cm RhostsRSAAuthentication
-Specifies whether rhosts or /etc/hosts.equiv authentication together
-with successful RSA host authentication is allowed.
-The default is
-.Dq no .
-This option applies to protocol version 1 only.
-.It Cm RSAAuthentication
-Specifies whether pure RSA authentication is allowed.
-The default is
-.Dq yes .
-This option applies to protocol version 1 only.
-.It Cm ServerKeyBits
-Defines the number of bits in the ephemeral protocol version 1 server key.
-The minimum value is 512, and the default is 768.
-.It Cm StrictModes
-Specifies whether
-.Nm
-should check file modes and ownership of the
-user's files and home directory before accepting login.
-This is normally desirable because novices sometimes accidentally leave their
-directory or files world-writable.
-The default is
-.Dq yes .
-.It Cm Subsystem
-Configures an external subsystem (e.g., file transfer daemon).
-Arguments should be a subsystem name and a command to execute upon subsystem
-request.
-The command
-.Xr sftp-server 8
-implements the
-.Dq sftp
-file transfer subsystem.
-By default no subsystems are defined.
-Note that this option applies to protocol version 2 only.
-.It Cm SyslogFacility
-Gives the facility code that is used when logging messages from
-.Nm sshd .
-The possible values are: DAEMON, USER, AUTH, LOCAL0, LOCAL1, LOCAL2,
-LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7.
-The default is AUTH.
-.It Cm UseLogin
-Specifies whether
-.Xr login 1
-is used for interactive login sessions.
-The default is
-.Dq no .
-Note that
-.Xr login 1
-is never used for remote command execution.
-Note also, that if this is enabled,
-.Cm X11Forwarding
-will be disabled because
-.Xr login 1
-does not know how to handle
-.Xr xauth 1
-cookies.
-.It Cm VerifyReverseMapping
-Specifies whether
-.Nm
-should try to verify the remote host name and check that
-the resolved host name for the remote IP address maps back to the
-very same IP address.
-The default is
-.Dq no .
-.It Cm X11DisplayOffset
-Specifies the first display number available for
-.Nm sshd Ns 's
-X11 forwarding.
-This prevents
-.Nm
-from interfering with real X11 servers.
-The default is 10.
-.It Cm X11Forwarding
-Specifies whether X11 forwarding is permitted.
-The default is
-.Dq no .
-Note that disabling X11 forwarding does not improve security in any
-way, as users can always install their own forwarders.
-X11 forwarding is automatically disabled if
-.Cm UseLogin
-is enabled.
-.It Cm X11UseLocalhost
-Specifies whether
-.Nm
-should bind the X11 forwarding server to the loopback address or to
-the wildcard address.  By default,
-.Nm
-binds the forwarding server to the loopback address and sets the
-hostname part of the
-.Ev DISPLAY
-environment variable to
-.Dq localhost .
-This prevents remote hosts from connecting to the fake display.
-However, some older X11 clients may not function with this
-configuration.
-.Cm X11UseLocalhost
-may be set to
-.Dq no
-to specify that the forwarding server should be bound to the wildcard
-address.
-The argument must be
-.Dq yes
-or
-.Dq no .
-The default is
-.Dq yes .
-.It Cm XAuthLocation
-Specifies the location of the
-.Xr xauth 1
-program.
-The default is
-.Pa /usr/X11R6/bin/xauth .
-.El
-.Ss Time Formats
-.Pp
-.Nm
-command-line arguments and configuration file options that specify time
-may be expressed using a sequence of the form:
-.Sm off
-.Ar time Oo Ar qualifier Oc ,
-.Sm on
-where
-.Ar time
-is a positive integer value and
-.Ar qualifier
-is one of the following:
-.Pp
-.Bl -tag -width Ds -compact -offset indent
-.It Cm <none>
-seconds
-.It Cm s | Cm S
-seconds
-.It Cm m | Cm M
-minutes
-.It Cm h | Cm H
-hours
-.It Cm d | Cm D
-days
-.It Cm w | Cm W
-weeks
-.El
-.Pp
-Each member of the sequence is added together to calculate
-the total time value.
-.Pp
-Time format examples:
-.Pp
-.Bl -tag -width Ds -compact -offset indent
-.It 600
-600 seconds (10 minutes)
-.It 10m
-10 minutes
-.It 1h30m
-1 hour 30 minutes (90 minutes)
-.El
+The file format and configuration options are described in
+.Xr sshd_config 5 .
 .Sh LOGIN PROCESS
 When a user successfully logs in,
 .Nm
@@ -1015,6 +406,10 @@ or the
 .Pa id_rsa.pub
 file and edit it.
 .Pp
+.Nm
+enforces a minimum RSA key modulus size for protocol 1
+and protocol 2 keys of 768 bits.
+.Pp
 The options (if present) consist of comma-separated option
 specifications.
 No spaces are permitted, except within double quotes.
@@ -1162,8 +557,8 @@ cvs.openbsd.org,199.185.137.3 ssh-rsa AAAA1234.....=
 .It Pa /etc/ssh/sshd_config
 Contains configuration data for
 .Nm sshd .
-This file should be writable by root only, but it is recommended
-(though not necessary) that it be world-readable.
+The file format and configuration options are described in
+.Xr sshd_config 5 .
 .It Pa /etc/ssh/ssh_host_key, /etc/ssh/ssh_host_dsa_key, /etc/ssh/ssh_host_rsa_key
 These three files contain the private parts of the host keys.
 These files should only be owned by root, readable only by root, and not
@@ -1299,13 +694,17 @@ only by the user; it need not be readable by anyone else.
 .It Pa $HOME/.ssh/rc
 If this file exists, it is run with /bin/sh after reading the
 environment files but before starting the user's shell or command.
-If X11 spoofing is in use, this will receive the "proto cookie" pair in
-standard input (and
+It must not produce any output on stdout; stderr must be used
+instead.
+If X11 forwarding is in use, it will receive the "proto cookie" pair in
+its standard input (and
 .Ev DISPLAY
-in environment).
-This must call
+in its environment).
+The script must call
 .Xr xauth 1
-in that case.
+because
+.Nm
+will not run xauth automatically to add X11 cookies.
 .Pp
 The primary purpose of this file is to run any initialization routines
 which may be needed before the user's home directory becomes
@@ -1314,15 +713,22 @@ accessible; AFS is a particular example of such an environment.
 This file will probably contain some initialization code followed by
 something similar to:
 .Bd -literal
-	if read proto cookie; then
-		echo add $DISPLAY $proto $cookie | xauth -q -
+if read proto cookie && [ -n "$DISPLAY" ]; then
+	if [ `echo $DISPLAY | cut -c1-10` = 'localhost:' ]; then
+		# X11UseLocalhost=yes
+		xauth add unix:`echo $DISPLAY |
+		    cut -c11-` $proto $cookie
+	else
+		# X11UseLocalhost=no
+		xauth add $DISPLAY $proto $cookie
 	fi
+fi
 .Ed
 .Pp
 If this file does not exist,
 .Pa /etc/ssh/sshrc
 is run, and if that
-does not exist either, xauth is used to store the cookie.
+does not exist either, xauth is used to add the cookie.
 .Pp
 This file should be writable only by the user, and need not be
 readable by anyone else.
@@ -1342,6 +748,8 @@ removed many bugs, re-added newer features and
 created OpenSSH.
 Markus Friedl contributed the support for SSH
 protocol versions 1.5 and 2.0.
+Niels Provos and Markus Friedl contributed support
+for privilege separation.
 .Sh SEE ALSO
 .Xr scp 1 ,
 .Xr sftp 1 ,
@@ -1351,6 +759,7 @@ protocol versions 1.5 and 2.0.
 .Xr ssh-keygen 1 ,
 .Xr login.conf 5 ,
 .Xr moduli 5 ,
+.Xr sshd_config 5 ,
 .Xr sftp-server 8
 .Rs
 .%A T. Ylonen
@@ -1359,8 +768,8 @@ protocol versions 1.5 and 2.0.
 .%A T. Rinne
 .%A S. Lehtinen
 .%T "SSH Protocol Architecture"
-.%N draft-ietf-secsh-architecture-09.txt
-.%D July 2001
+.%N draft-ietf-secsh-architecture-12.txt
+.%D January 2002
 .%O work in progress material
 .Re
 .Rs
@@ -1368,7 +777,7 @@ protocol versions 1.5 and 2.0.
 .%A N. Provos
 .%A W. A. Simpson
 .%T "Diffie-Hellman Group Exchange for the SSH Transport Layer Protocol"
-.%N draft-ietf-secsh-dh-group-exchange-01.txt
-.%D April 2001
+.%N draft-ietf-secsh-dh-group-exchange-02.txt
+.%D January 2002
 .%O work in progress material
 .Re