277 lines
9.4 KiB
Plaintext
277 lines
9.4 KiB
Plaintext
1. Prerequisites
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----------------
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A C compiler. Any C89 or better compiler should work. Where supported,
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configure will attempt to enable the compiler's run-time integrity checking
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options. Some notes about specific compilers:
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- clang: -ftrapv and -sanitize=integer require the compiler-rt runtime
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(CC=clang LDFLAGS=--rtlib=compiler-rt ./configure)
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You will need working installations of Zlib and libcrypto (LibreSSL /
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OpenSSL)
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Zlib 1.1.4 or 1.2.1.2 or greater (earlier 1.2.x versions have problems):
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http://www.gzip.org/zlib/
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libcrypto (LibreSSL or OpenSSL >= 1.0.1 < 1.1.0)
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LibreSSL http://www.libressl.org/ ; or
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OpenSSL http://www.openssl.org/
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LibreSSL/OpenSSL should be compiled as a position-independent library
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(i.e. with -fPIC) otherwise OpenSSH will not be able to link with it.
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If you must use a non-position-independent libcrypto, then you may need
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to configure OpenSSH --without-pie. Note that because of API changes,
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OpenSSL 1.1.x is not currently supported.
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The remaining items are optional.
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NB. If you operating system supports /dev/random, you should configure
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libcrypto (LibreSSL/OpenSSL) to use it. OpenSSH relies on libcrypto's
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direct support of /dev/random, or failing that, either prngd or egd
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PRNGD:
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If your system lacks kernel-based random collection, the use of Lutz
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Jaenicke's PRNGd is recommended.
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http://prngd.sourceforge.net/
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EGD:
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If the kernel lacks /dev/random the Entropy Gathering Daemon (EGD) is
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supported only if libcrypto supports it.
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http://egd.sourceforge.net/
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PAM:
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OpenSSH can utilise Pluggable Authentication Modules (PAM) if your
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system supports it. PAM is standard most Linux distributions, Solaris,
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HP-UX 11, AIX >= 5.2, FreeBSD and NetBSD.
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Information about the various PAM implementations are available:
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Solaris PAM: http://www.sun.com/software/solaris/pam/
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Linux PAM: http://www.kernel.org/pub/linux/libs/pam/
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OpenPAM: http://www.openpam.org/
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If you wish to build the GNOME passphrase requester, you will need the GNOME
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libraries and headers.
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GNOME:
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http://www.gnome.org/
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Alternatively, Jim Knoble <jmknoble@pobox.com> has written an excellent X11
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passphrase requester. This is maintained separately at:
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http://www.jmknoble.net/software/x11-ssh-askpass/
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TCP Wrappers:
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If you wish to use the TCP wrappers functionality you will need at least
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tcpd.h and libwrap.a, either in the standard include and library paths,
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or in the directory specified by --with-tcp-wrappers. Version 7.6 is
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known to work.
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http://ftp.porcupine.org/pub/security/index.html
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LibEdit:
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sftp supports command-line editing via NetBSD's libedit. If your platform
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has it available natively you can use that, alternatively you might try
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these multi-platform ports:
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http://www.thrysoee.dk/editline/
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http://sourceforge.net/projects/libedit/
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LDNS:
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LDNS is a DNS BSD-licensed resolver library which supports DNSSEC.
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http://nlnetlabs.nl/projects/ldns/
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Autoconf:
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If you modify configure.ac or configure doesn't exist (eg if you checked
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the code out of git yourself) then you will need autoconf-2.69 to rebuild
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the automatically generated files by running "autoreconf". Earlier
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versions may also work but this is not guaranteed.
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http://www.gnu.org/software/autoconf/
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Basic Security Module (BSM):
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Native BSM support is known to exist in Solaris from at least 2.5.1,
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FreeBSD 6.1 and OS X. Alternatively, you may use the OpenBSM
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implementation (http://www.openbsm.org).
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makedepend:
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https://www.x.org/archive/individual/util/
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If you are making significant changes to the code you may need to rebuild
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the dependency (.depend) file using "make depend", which requires the
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"makedepend" tool from the X11 distribution.
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2. Building / Installation
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--------------------------
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To install OpenSSH with default options:
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./configure
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make
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make install
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This will install the OpenSSH binaries in /usr/local/bin, configuration files
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in /usr/local/etc, the server in /usr/local/sbin, etc. To specify a different
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installation prefix, use the --prefix option to configure:
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./configure --prefix=/opt
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make
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make install
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Will install OpenSSH in /opt/{bin,etc,lib,sbin}. You can also override
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specific paths, for example:
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./configure --prefix=/opt --sysconfdir=/etc/ssh
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make
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make install
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This will install the binaries in /opt/{bin,lib,sbin}, but will place the
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configuration files in /etc/ssh.
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If you are using Privilege Separation (which is enabled by default)
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then you will also need to create the user, group and directory used by
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sshd for privilege separation. See README.privsep for details.
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If you are using PAM, you may need to manually install a PAM control
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file as "/etc/pam.d/sshd" (or wherever your system prefers to keep
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them). Note that the service name used to start PAM is __progname,
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which is the basename of the path of your sshd (e.g., the service name
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for /usr/sbin/osshd will be osshd). If you have renamed your sshd
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executable, your PAM configuration may need to be modified.
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A generic PAM configuration is included as "contrib/sshd.pam.generic",
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you may need to edit it before using it on your system. If you are
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using a recent version of Red Hat Linux, the config file in
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contrib/redhat/sshd.pam should be more useful. Failure to install a
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valid PAM file may result in an inability to use password
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authentication. On HP-UX 11 and Solaris, the standard /etc/pam.conf
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configuration will work with sshd (sshd will match the other service
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name).
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There are a few other options to the configure script:
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--with-audit=[module] enable additional auditing via the specified module.
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Currently, drivers for "debug" (additional info via syslog) and "bsm"
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(Sun's Basic Security Module) are supported.
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--with-pam enables PAM support. If PAM support is compiled in, it must
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also be enabled in sshd_config (refer to the UsePAM directive).
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--with-prngd-socket=/some/file allows you to enable EGD or PRNGD
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support and to specify a PRNGd socket. Use this if your Unix lacks
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/dev/random.
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--with-prngd-port=portnum allows you to enable EGD or PRNGD support
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and to specify a EGD localhost TCP port. Use this if your Unix lacks
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/dev/random.
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--with-lastlog=FILE will specify the location of the lastlog file.
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./configure searches a few locations for lastlog, but may not find
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it if lastlog is installed in a different place.
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--without-lastlog will disable lastlog support entirely.
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--with-osfsia, --without-osfsia will enable or disable OSF1's Security
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Integration Architecture. The default for OSF1 machines is enable.
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--with-tcp-wrappers will enable TCP Wrappers (/etc/hosts.allow|deny)
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support.
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--with-md5-passwords will enable the use of MD5 passwords. Enable this
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if your operating system uses MD5 passwords and the system crypt() does
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not support them directly (see the crypt(3/3c) man page). If enabled, the
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resulting binary will support both MD5 and traditional crypt passwords.
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--with-utmpx enables utmpx support. utmpx support is automatic for
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some platforms.
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--without-shadow disables shadow password support.
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--with-ipaddr-display forces the use of a numeric IP address in the
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$DISPLAY environment variable. Some broken systems need this.
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--with-default-path=PATH allows you to specify a default $PATH for sessions
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started by sshd. This replaces the standard path entirely.
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--with-pid-dir=PATH specifies the directory in which the sshd.pid file is
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created.
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--with-xauth=PATH specifies the location of the xauth binary
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--with-ssl-dir=DIR allows you to specify where your Libre/OpenSSL
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libraries are installed.
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--with-ssl-engine enables Libre/OpenSSL's (hardware) ENGINE support
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--with-4in6 Check for IPv4 in IPv6 mapped addresses and convert them to
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real (AF_INET) IPv4 addresses. Works around some quirks on Linux.
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If you need to pass special options to the compiler or linker, you
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can specify these as environment variables before running ./configure.
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For example:
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CC="/usr/foo/cc" CFLAGS="-O" LDFLAGS="-s" LIBS="-lrubbish" ./configure
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3. Configuration
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----------------
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The runtime configuration files are installed by in ${prefix}/etc or
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whatever you specified as your --sysconfdir (/usr/local/etc by default).
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The default configuration should be instantly usable, though you should
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review it to ensure that it matches your security requirements.
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To generate a host key, run "make host-key". Alternately you can do so
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manually using the following commands:
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ssh-keygen -t [type] -f /etc/ssh/ssh_host_key -N ""
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for each of the types you wish to generate (rsa, dsa or ecdsa) or
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ssh-keygen -A
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to generate keys for all supported types.
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Replacing /etc/ssh with the correct path to the configuration directory.
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(${prefix}/etc or whatever you specified with --sysconfdir during
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configuration)
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If you have configured OpenSSH with EGD support, ensure that EGD is
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running and has collected some Entropy.
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For more information on configuration, please refer to the manual pages
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for sshd, ssh and ssh-agent.
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4. (Optional) Send survey
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-------------------------
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$ make survey
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[check the contents of the file "survey" to ensure there's no information
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that you consider sensitive]
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$ make send-survey
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This will send configuration information for the currently configured
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host to a survey address. This will help determine which configurations
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are actually in use, and what valid combinations of configure options
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exist. The raw data is available only to the OpenSSH developers, however
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summary data may be published.
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5. Problems?
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------------
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If you experience problems compiling, installing or running OpenSSH.
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Please refer to the "reporting bugs" section of the webpage at
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https://www.openssh.com/
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