diff options
author | des <des@FreeBSD.org> | 2002-06-23 21:42:47 +0000 |
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committer | des <des@FreeBSD.org> | 2002-06-23 21:42:47 +0000 |
commit | 2894284b2aba9c7c254dabe5434f2f4854d57635 (patch) | |
tree | 2b4d39ec7b952b21391c5fa71957a43f2fb0d8a7 | |
parent | af8d245e930bc98823814813db06b9bcbe8a737d (diff) | |
download | FreeBSD-src-2894284b2aba9c7c254dabe5434f2f4854d57635.zip FreeBSD-src-2894284b2aba9c7c254dabe5434f2f4854d57635.tar.gz |
Resolve conflicts and document local changes.
-rw-r--r-- | crypto/openssh/ssh.1 | 636 | ||||
-rw-r--r-- | crypto/openssh/ssh_config.5 | 4 | ||||
-rw-r--r-- | crypto/openssh/sshd.8 | 694 | ||||
-rw-r--r-- | crypto/openssh/sshd_config.5 | 33 |
4 files changed, 113 insertions, 1254 deletions
diff --git a/crypto/openssh/ssh.1 b/crypto/openssh/ssh.1 index 0b8a0cd..230e48e 100644 --- a/crypto/openssh/ssh.1 +++ b/crypto/openssh/ssh.1 @@ -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: ssh.1,v 1.148 2002/02/18 17:55:20 markus Exp $ +.\" $OpenBSD: ssh.1,v 1.158 2002/06/20 19:56:07 stevesk Exp $ .\" $FreeBSD$ -.Dd March 18, 2002 +.Dd September 25, 1999 .Dt SSH 1 .Os .Sh NAME @@ -298,6 +298,12 @@ Background ssh at logout when waiting for forwarded connection / X11 sessions to terminate .It Cm ~? Display a list of escape characters +.It Cm ~C +Open command line (only useful for adding port forwardings using the +.Fl L +and +.Fl R +options) .It Cm ~R Request rekeying of the connection (only useful for SSH protocol version 2 and if the peer supports it) @@ -380,7 +386,7 @@ this mechanism is to prevent man-in-the-middle attacks which could otherwise be used to circumvent the encryption. The .Cm StrictHostKeyChecking -option (see below) can be used to prevent logins to machines whose +option can be used to prevent logins to machines whose host key is not known or has changed. .Pp The options are as follows: @@ -564,13 +570,13 @@ and the .Dq level can be controlled by the .Cm CompressionLevel -option (see below). +option. Compression is desirable on modem lines and other slow connections, but will only slow down things on fast networks. The default value can be set on a host-by-host basis in the configuration files; see the .Cm Compression -option below. +option. .It Fl F Ar configfile Specifies an alternative per-user configuration file. If a configuration file is given on the command line, @@ -645,580 +651,10 @@ to use IPv6 addresses only. .El .Sh CONFIGURATION FILES .Nm -obtains configuration data from the following sources in -the following order: -command line options, user's configuration file -.Pq Pa $HOME/.ssh/config , -and system-wide configuration file -.Pq Pa /etc/ssh/ssh_config . -For each parameter, the first obtained value -will be used. -The configuration files contain sections bracketed by -.Dq Host -specifications, and that section is only applied for hosts that -match one of the patterns given in the specification. -The matched host name is the one given on the command line. -.Pp -Since the first obtained value for each parameter is used, more -host-specific declarations should be given near the beginning of the -file, and general defaults at the end. -.Pp -The configuration file has the following format: -.Pp -Empty lines and lines starting with -.Ql # -are comments. -.Pp -Otherwise a line is of the format -.Dq keyword arguments . -Configuration options may be separated by whitespace or -optional whitespace and exactly one -.Ql = ; -the latter format is useful to avoid the need to quote whitespace -when specifying configuration options using the -.Nm ssh , -.Nm scp -and -.Nm sftp -.Fl o -option. -.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 Host -Restricts the following declarations (up to the next -.Cm Host -keyword) to be only for those hosts that match one of the patterns -given after the keyword. -.Ql \&* -and -.Ql ? -can be used as wildcards in the -patterns. -A single -.Ql \&* -as a pattern can be used to provide global -defaults for all hosts. -The host is the -.Ar hostname -argument given on the command line (i.e., the name is not converted to -a canonicalized host name before matching). -.It Cm AFSTokenPassing -Specifies whether to pass AFS tokens to remote host. -The argument to this keyword must be -.Dq yes -or -.Dq no . -This option applies to protocol version 1 only. -.It Cm BatchMode -If set to -.Dq yes , -passphrase/password querying will be disabled. -This option is useful in scripts and other batch jobs where no user -is present to supply the password. -The argument must be -.Dq yes -or -.Dq no . -The default is -.Dq no . -.It Cm BindAddress -Specify the interface to transmit from on machines with multiple -interfaces or aliased addresses. -Note that this option does not work if -.Cm UsePrivilegedPort -is set to -.Dq yes . -.It Cm CheckHostIP -If this flag is set to -.Dq yes , -ssh will additionally check the host IP address in the -.Pa known_hosts -file. -This allows ssh to detect if a host key changed due to DNS spoofing. -If the option is set to -.Dq no , -the check will not be executed. -The default is -.Dq yes . -.It Cm Cipher -Specifies the cipher to use for encrypting the session -in protocol version 1. -Currently, -.Dq blowfish , -.Dq 3des , -and -.Dq des -are supported. -.Ar des -is only supported in the -.Nm -client for interoperability with legacy protocol 1 implementations -that do not support the -.Ar 3des -cipher. Its use is strongly discouraged due to cryptographic -weaknesses. -The default is -.Dq 3des . -.It Cm Ciphers -Specifies the ciphers allowed for protocol version 2 -in order of preference. -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 ClearAllForwardings -Specifies that all local, remote and dynamic port forwardings -specified in the configuration files or on the command line be -cleared. This option is primarily useful when used from the -.Nm -command line to clear port forwardings set in -configuration files, and is automatically set by -.Xr scp 1 -and -.Xr sftp 1 . -The argument must be -.Dq yes -or -.Dq no . -The default is -.Dq no . -.It Cm Compression -Specifies whether to use compression. -The argument must be -.Dq yes -or -.Dq no . -The default is -.Dq no . -.It Cm CompressionLevel -Specifies the compression level to use if compression is enabled. -The argument must be an integer from 1 (fast) to 9 (slow, best). -The default level is 6, which is good for most applications. -The meaning of the values is the same as in -.Xr gzip 1 . -Note that this option applies to protocol version 1 only. -.It Cm ConnectionAttempts -Specifies the number of tries (one per second) to make before falling -back to rsh or exiting. -The argument must be an integer. -This may be useful in scripts if the connection sometimes fails. -The default is 1. -.It Cm DynamicForward -Specifies that a TCP/IP port on the local machine be forwarded -over the secure channel, and the application -protocol is then used to determine where to connect to from the -remote machine. The argument must be a port number. -Currently the SOCKS4 protocol is supported, and -.Nm -will act as a SOCKS4 server. -Multiple forwardings may be specified, and -additional forwardings can be given on the command line. Only -the superuser can forward privileged ports. -.It Cm EscapeChar -Sets the escape character (default: -.Ql ~ ) . -The escape character can also -be set on the command line. -The argument should be a single character, -.Ql ^ -followed by a letter, or -.Dq none -to disable the escape -character entirely (making the connection transparent for binary -data). -.It Cm FallBackToRsh -Specifies that if connecting via -.Nm -fails due to a connection refused error (there is no -.Xr sshd 8 -listening on the remote host), -.Xr rsh 1 -should automatically be used instead (after a suitable warning about -the session being unencrypted). -The argument must be -.Dq yes -or -.Dq no . -The default is -.Dq no . -.It Cm ForwardAgent -Specifies whether the connection to the authentication agent (if any) -will be forwarded to the remote machine. -The argument must be -.Dq yes -or -.Dq no . -The default is -.Dq no . -.It Cm ForwardX11 -Specifies whether X11 connections will be automatically redirected -over the secure channel and -.Ev DISPLAY -set. -The argument must be -.Dq yes -or -.Dq no . -The default is -.Dq no . -.It Cm GatewayPorts -Specifies whether remote hosts are allowed to connect to local -forwarded ports. -By default, -.Nm -binds local 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 local 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 GlobalKnownHostsFile -Specifies a file to use for the global -host key database instead of -.Pa /etc/ssh/ssh_known_hosts . -.It Cm HostbasedAuthentication -Specifies whether to try rhosts based authentication with public key -authentication. -The argument must be -.Dq yes -or -.Dq no . -The default is -.Dq no . -This option applies to protocol version 2 only and -is similar to -.Cm RhostsRSAAuthentication . -.It Cm HostKeyAlgorithms -Specifies the protocol version 2 host key algorithms -that the client wants to use in order of preference. -The default for this option is: -.Dq ssh-rsa,ssh-dss . -.It Cm HostKeyAlias -Specifies an alias that should be used instead of the -real host name when looking up or saving the host key -in the host key database files. -This option is useful for tunneling ssh connections -or for multiple servers running on a single host. -.It Cm HostName -Specifies the real host name to log into. -This can be used to specify nicknames or abbreviations for hosts. -Default is the name given on the command line. -Numeric IP addresses are also permitted (both on the command line and in -.Cm HostName -specifications). -.It Cm IdentityFile -Specifies a file from which the user's RSA or DSA authentication identity -is read. The default is -.Pa $HOME/.ssh/identity -for protocol version 1, and -.Pa $HOME/.ssh/id_rsa -and -.Pa $HOME/.ssh/id_dsa -for protocol version 2. -Additionally, any identities represented by the authentication agent -will be used for authentication. -The file name may use the tilde -syntax to refer to a user's home directory. -It is possible to have -multiple identity files specified in configuration files; all these -identities will be tried in sequence. -.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. -.Pp -The default is -.Dq yes -(to send keepalives), and the client will notice -if the network goes down or the remote host dies. -This is important in scripts, and many users want it too. -.Pp -To disable keepalives, the value should be set to -.Dq no . -.It Cm KerberosAuthentication -Specifies whether Kerberos authentication will be used. -The argument to this keyword must be -.Dq yes -or -.Dq no . -.It Cm KerberosTgtPassing -Specifies whether a Kerberos TGT will be forwarded to the server. -This will only work if the Kerberos server is actually an AFS kaserver. -The argument to this keyword must be -.Dq yes -or -.Dq no . -.It Cm LocalForward -Specifies that a TCP/IP port on the local machine be forwarded over -the secure channel to the specified host and port from the remote machine. -The first argument must be a port number, and the second must be -.Ar host:port . -IPv6 addresses can be specified with an alternative syntax: -.Ar host/port . -Multiple forwardings may be specified, and additional -forwardings can be given on the command line. -Only the superuser can forward privileged ports. -.It Cm LogLevel -Gives the verbosity level that is used when logging messages from -.Nm ssh . -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 verbose output. -.It Cm MACs -Specifies the MAC (message authentication code) algorithms -in order of preference. -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 NoHostAuthenticationForLocalhost -This option can be used if the home directory is shared across machines. -In this case localhost will refer to a different machine on each of -the machines and the user will get many warnings about changed host keys. -However, this option disables host authentication for localhost. -The argument to this keyword must be -.Dq yes -or -.Dq no . -The default is to check the host key for localhost. -.It Cm NumberOfPasswordPrompts -Specifies the number of password prompts before giving up. -The argument to this keyword must be an integer. -Default is 3. -.It Cm PasswordAuthentication -Specifies whether to use password authentication. -The argument to this keyword must be -.Dq yes -or -.Dq no . -The default is -.Dq yes . -.It Cm Port -Specifies the port number to connect on the remote host. -Default is 22. -.It Cm PreferredAuthentications -Specifies the order in which the client should try protocol 2 -authentication methods. This allows a client to prefer one method (e.g. -.Cm keyboard-interactive ) -over another method (e.g. -.Cm password ) -The default for this option is: -.Dq hostbased,publickey,keyboard-interactive,password . -.It Cm Protocol -Specifies the protocol versions -.Nm -should support in order of preference. -The possible values are -.Dq 1 -and -.Dq 2 . -Multiple versions must be comma-separated. -The default is -.Dq 2,1 . -This means that -.Nm -tries version 2 and falls back to version 1 -if version 2 is not available. -.It Cm ProxyCommand -Specifies the command to use to connect to the server. -The command -string extends to the end of the line, and is executed with -.Pa /bin/sh . -In the command string, -.Ql %h -will be substituted by the host name to -connect and -.Ql %p -by the port. -The command can be basically anything, -and should read from its standard input and write to its standard output. -It should eventually connect an -.Xr sshd 8 -server running on some machine, or execute -.Ic sshd -i -somewhere. -Host key management will be done using the -HostName of the host being connected (defaulting to the name typed by -the user). -Note that -.Cm CheckHostIP -is not available for connects with a proxy command. -.Pp -.It Cm PubkeyAuthentication -Specifies whether to try public key authentication. -The argument to this keyword must be -.Dq yes -or -.Dq no . -The default is -.Dq yes . -This option applies to protocol version 2 only. -.It Cm RemoteForward -Specifies that a TCP/IP port on the remote machine be forwarded over -the secure channel to the specified host and port from the local machine. -The first argument must be a port number, and the second must be -.Ar host:port . -IPv6 addresses can be specified with an alternative syntax: -.Ar host/port . -Multiple forwardings may be specified, and additional -forwardings can be given on the command line. -Only the superuser can forward privileged ports. -.It Cm RhostsAuthentication -Specifies whether to try rhosts based authentication. -Note that this -declaration only affects the client side and has no effect whatsoever -on security. -Disabling rhosts authentication may reduce -authentication time on slow connections when rhosts authentication is -not used. -Most servers do not permit RhostsAuthentication because it -is not secure (see -.Cm RhostsRSAAuthentication ) . -The argument to this keyword must be -.Dq yes -or -.Dq no . -The default is -.Dq yes . -This option applies to protocol version 1 only. -.It Cm RhostsRSAAuthentication -Specifies whether to try rhosts based authentication with RSA host -authentication. -The argument must be -.Dq yes -or -.Dq no . -The default is -.Dq yes . -This option applies to protocol version 1 only. -.It Cm RSAAuthentication -Specifies whether to try RSA authentication. -The argument to this keyword must be -.Dq yes -or -.Dq no . -RSA authentication will only be -attempted if the identity file exists, or an authentication agent is -running. -The default is -.Dq yes . -Note that this option applies to protocol version 1 only. -.It Cm ChallengeResponseAuthentication -Specifies whether to use challenge response authentication. -The argument to this keyword must be -.Dq yes -or -.Dq no . -The default is -.Dq yes . -.It Cm SmartcardDevice -Specifies which smartcard device to use. The argument to this keyword is -the device -.Nm -should use to communicate with a smartcard used for storing the user's -private RSA key. By default, no device is specified and smartcard support -is not activated. -.It Cm StrictHostKeyChecking -If this flag is set to -.Dq yes , -.Nm -will never automatically add host keys to the -.Pa $HOME/.ssh/known_hosts -file, and refuses to connect to hosts whose host key has changed. -This provides maximum protection against trojan horse attacks, -however, can be annoying when the -.Pa /etc/ssh/ssh_known_hosts -file is poorly maintained, or connections to new hosts are -frequently made. -This option forces the user to manually -add all new hosts. -If this flag is set to -.Dq no , -.Nm -will automatically add new host keys to the -user known hosts files. -If this flag is set to -.Dq ask , -new host keys -will be added to the user known host files only after the user -has confirmed that is what they really want to do, and -.Nm -will refuse to connect to hosts whose host key has changed. -The host keys of -known hosts will be verified automatically in all cases. -The argument must be -.Dq yes , -.Dq no -or -.Dq ask . -The default is -.Dq ask . -.It Cm UsePrivilegedPort -Specifies whether to use a privileged port for outgoing connections. -The argument must be -.Dq yes -or -.Dq no . -The default is -.Dq no . -Note that this option must be set to -.Dq yes -if -.Cm RhostsAuthentication -and -.Cm RhostsRSAAuthentication -authentications are needed with older servers. -.It Cm User -Specifies the user to log in as. -This can be useful when a different user name is used on different machines. -This saves the trouble of -having to remember to give the user name on the command line. -.It Cm UserKnownHostsFile -Specifies a file to use for the user -host key database instead of -.Pa $HOME/.ssh/known_hosts . -.It Cm UseRsh -Specifies that rlogin/rsh should be used for this host. -It is possible that the host does not at all support the -.Nm -protocol. -This causes -.Nm -to immediately execute -.Xr rsh 1 . -All other options (except -.Cm HostName ) -are ignored if this has been specified. -The argument must be -.Dq yes -or -.Dq no . -.It Cm XAuthLocation -Specifies the location of the -.Xr xauth 1 -program. -The default is -.Pa /usr/X11R6/bin/xauth . -.El +may additionally obtain configuration data from +a per-user configuration file and a system-wide configuration file. +The file format and configuration options are described in +.Xr ssh_config 5 . .Sh ENVIRONMENT .Nm will normally set the following environment variables: @@ -1353,13 +789,8 @@ never used automatically and are not necessary; they are only provided for the convenience of the user. .It Pa $HOME/.ssh/config This is the per-user configuration file. -The format of this file is described above. -This file is used by the -.Nm -client. -This file does not usually contain any sensitive information, -but the recommended permissions are read/write for the user, and not -accessible by others. +The file format and configuration options are described in +.Xr ssh_config 5 . .It Pa $HOME/.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 in the @@ -1394,19 +825,31 @@ checking the key, because someone with access to the name servers would then be able to fool host authentication. .It Pa /etc/ssh/ssh_config Systemwide configuration file. -This file provides defaults for those -values that are not specified in the user's configuration file, and -for those users who do not have a configuration file. -This file must be world-readable. +The file format and configuration options are described in +.Xr ssh_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 and are used for .Cm RhostsRSAAuthentication and .Cm HostbasedAuthentication . -Since they are readable only by root +If the protocol version 1 +.Cm RhostsRSAAuthentication +method is used, +.Nm +must be setuid root, since the host key is readable only by root. +For protocol version 2, +.Nm +uses +.Xr ssh-keysign 8 +to access the host keys for +.Cm HostbasedAuthentication . +This eliminates the requirement that +.Nm +be setuid root when that authentication method is used. +By default .Nm -must be setuid root if these authentication methods are desired. +is not setuid root. .It Pa $HOME/.rhosts This file is used in .Pa \&.rhosts @@ -1447,7 +890,7 @@ The purpose for having this file is to be able to use rhosts authentication with .Nm without permitting login with -.Xr rlogin 1 +.Nm rlogin or .Xr rsh 1 . .It Pa /etc/hosts.equiv @@ -1505,7 +948,6 @@ created OpenSSH. Markus Friedl contributed the support for SSH protocol versions 1.5 and 2.0. .Sh SEE ALSO -.Xr rlogin 1 , .Xr rsh 1 , .Xr scp 1 , .Xr sftp 1 , @@ -1513,6 +955,8 @@ protocol versions 1.5 and 2.0. .Xr ssh-agent 1 , .Xr ssh-keygen 1 , .Xr telnet 1 , +.Xr ssh_config 4 , +.Xr ssh-keysign 8, .Xr sshd 8 .Rs .%A T. Ylonen @@ -1521,7 +965,7 @@ 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 diff --git a/crypto/openssh/ssh_config.5 b/crypto/openssh/ssh_config.5 index 53cb0fe..9ae6c78 100644 --- a/crypto/openssh/ssh_config.5 +++ b/crypto/openssh/ssh_config.5 @@ -35,6 +35,7 @@ .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" .\" $OpenBSD: ssh_config.5,v 1.1 2002/06/20 19:56:07 stevesk Exp $ +.\" $FreeBSD$ .Dd September 25, 1999 .Dt SSH_CONFIG 5 .Os @@ -583,6 +584,9 @@ having to remember to give the user name on the command line. Specifies a file to use for the user host key database instead of .Pa $HOME/.ssh/known_hosts . +.It Cm VersionAddendum +Specifies a string to append to the regular version string to identify +OS- or site-specific modifications. .It Cm XAuthLocation Specifies the location of the .Xr xauth 1 diff --git a/crypto/openssh/sshd.8 b/crypto/openssh/sshd.8 index 0f6c8ae..7bc85bd 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 1.170 2002/02/28 20:46:10 stevesk Exp $ +.\" $OpenBSD: sshd.8,v 1.184 2002/06/20 19:56:07 stevesk Exp $ .\" $FreeBSD$ -.Dd March 18, 2002 +.Dd September 25, 1999 .Dt SSHD 8 .Os .Sh NAME @@ -117,14 +117,14 @@ 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 @@ -321,634 +321,8 @@ 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 . -Note that OPIE authentication is enabled only if -.Cm PasswordAuthentication -is allowed, too. -.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 CheckMail -Specifies whether -.Nm -should notify the user of new mail for interactive logins. -The default is -.Dq yes . -.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/ssh/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 120 (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 no . -.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 -.Pa /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 -.Pa /etc/hosts.equiv -authentication. -The default is -.Dq no . -This option applies to protocol version 1 only. -.It Cm RhostsRSAAuthentication -Specifies whether rhosts or -.Pa /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 SkeyAuthentication -Backward-compatibility alias for -.Cm ChallengeResponseAuthentication . -.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 @@ -1035,6 +409,10 @@ 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. @@ -1182,8 +560,8 @@ 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 @@ -1321,13 +699,17 @@ If this file exists, it is run with .Pa /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 @@ -1335,18 +717,23 @@ accessible; AFS is a particular example of such an environment. .Pp This file will probably contain some initialization code followed by something similar to: -.Bd -literal -offset indent -if [ -n "$DISPLAY" ] && read proto cookie; then - echo add "$DISPLAY" "$proto" "$cookie" | xauth -q - +.Bd -literal +if read proto cookie && [ -n "$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, -.Xr xauth 1 -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. @@ -1366,6 +753,8 @@ 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 , @@ -1375,6 +764,7 @@ 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 @@ -1383,8 +773,8 @@ 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 @@ -1392,7 +782,7 @@ 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 diff --git a/crypto/openssh/sshd_config.5 b/crypto/openssh/sshd_config.5 index efa1305..826c34c 100644 --- a/crypto/openssh/sshd_config.5 +++ b/crypto/openssh/sshd_config.5 @@ -35,6 +35,7 @@ .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" .\" $OpenBSD: sshd_config.5,v 1.3 2002/06/20 23:37:12 markus Exp $ +.\" $FreeBSD$ .Dd September 25, 1999 .Dt SSHD_CONFIG 5 .Os @@ -131,6 +132,9 @@ All authentication styles from are supported. The default is .Dq yes . +Note that OPIE authentication is enabled only if +.Cm PasswordAuthentication +is allowed, too. .It Cm Ciphers Specifies the ciphers allowed for protocol version 2. Multiple ciphers must be comma-separated. @@ -140,6 +144,12 @@ The default is ``aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour, aes192-cbc,aes256-cbc'' .Ed +.It Cm CheckMail +Specifies whether +.Nm +should notify the user of new mail for interactive logins. +The default is +.Dq yes . .It Cm ClientAliveInterval Sets a timeout interval in seconds after which if no data has been received from the client, @@ -266,7 +276,7 @@ or .Pp .Pa /etc/hosts.equiv and -.Pa /etc/shosts.equiv +.Pa /etc/ssh/shosts.equiv are still used. The default is .Dq yes . @@ -379,7 +389,7 @@ options must precede this option for non port qualified addresses. 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). +The default is 120 (seconds). .It Cm LogLevel Gives the verbosity level that is used when logging messages from .Nm sshd . @@ -440,7 +450,7 @@ The argument must be or .Dq no . The default is -.Dq yes . +.Dq no . .Pp If this option is set to .Dq without-password @@ -507,18 +517,23 @@ 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 +Specifies whether authentication using rhosts or +.Pa /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. +to normal rhosts or +.Pa /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 +Specifies whether rhosts or +.Pa /etc/hosts.equiv +authentication together with successful RSA host authentication is allowed. The default is .Dq no . @@ -531,6 +546,9 @@ 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 SkeyAuthentication +Backward-compatibility alias for +.Cm ChallengeResponseAuthentication . .It Cm StrictModes Specifies whether .Nm sshd @@ -593,6 +611,9 @@ the resolved host name for the remote IP address maps back to the very same IP address. The default is .Dq no . +.It Cm VersionAddendum +Specifies a string to append to the regular version string to identify +OS- or site-specific modifications. .It Cm X11DisplayOffset Specifies the first display number available for .Nm sshd Ns 's |