contrib/cygwin/ssh-host-config

#!/bin/bash
#
# ssh-host-config, Copyright 2000-2009 Red Hat Inc.
#
# This file is part of the Cygwin port of OpenSSH.
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  
# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   
# IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   
# DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    
# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    
# THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               

# ======================================================================
# Initialization
# ======================================================================
PROGNAME=$(basename $0)
_tdir=$(dirname $0)
PROGDIR=$(cd $_tdir && pwd)

CSIH_SCRIPT=/usr/share/csih/cygwin-service-installation-helper.sh

# Subdirectory where the new package is being installed
PREFIX=/usr

# Directory where the config files are stored
SYSCONFDIR=/etc
LOCALSTATEDIR=/var

source ${CSIH_SCRIPT}

port_number=22
privsep_configured=no
privsep_used=yes
cygwin_value=""
user_account=
password_value=
opt_force=no

# ======================================================================
# Routine: create_host_keys
# ======================================================================
create_host_keys() {
  if [ ! -f "${SYSCONFDIR}/ssh_host_key" ]
  then
    csih_inform "Generating ${SYSCONFDIR}/ssh_host_key"
    ssh-keygen -t rsa1 -f ${SYSCONFDIR}/ssh_host_key -N '' > /dev/null
  fi

  if [ ! -f "${SYSCONFDIR}/ssh_host_rsa_key" ]
  then
    csih_inform "Generating ${SYSCONFDIR}/ssh_host_rsa_key"
    ssh-keygen -t rsa -f ${SYSCONFDIR}/ssh_host_rsa_key -N '' > /dev/null
  fi

  if [ ! -f "${SYSCONFDIR}/ssh_host_dsa_key" ]
  then
    csih_inform "Generating ${SYSCONFDIR}/ssh_host_dsa_key"
    ssh-keygen -t dsa -f ${SYSCONFDIR}/ssh_host_dsa_key -N '' > /dev/null
  fi
} # --- End of create_host_keys --- #

# ======================================================================
# Routine: update_services_file
# ======================================================================
update_services_file() {
  local _my_etcdir="/ssh-host-config.$$"
  local _win_etcdir
  local _services
  local _spaces
  local _serv_tmp
  local _wservices

  if csih_is_nt
  then
    _win_etcdir="${SYSTEMROOT}\\system32\\drivers\\etc"
    _services="${_my_etcdir}/services"
    # On NT, 27 spaces, no space after the hash
    _spaces="                           #"
  else
    _win_etcdir="${WINDIR}"
    _services="${_my_etcdir}/SERVICES"
    # On 9x, 18 spaces (95 is very touchy), a space after the hash
    _spaces="                  # "
  fi
  _serv_tmp="${_my_etcdir}/srv.out.$$"

  mount -o text,posix=0,noacl -f "${_win_etcdir}" "${_my_etcdir}"

  # Depends on the above mount
  _wservices=`cygpath -w "${_services}"`

  # Remove sshd 22/port from services
  if [ `grep -q 'sshd[ \t][ \t]*22' "${_services}"; echo $?` -eq 0 ]
  then
    grep -v 'sshd[ \t][ \t]*22' "${_services}" > "${_serv_tmp}"
    if [ -f "${_serv_tmp}" ]
    then
      if mv "${_serv_tmp}" "${_services}"
      then
	csih_inform "Removing sshd from ${_wservices}"
      else
	csih_warning "Removing sshd from ${_wservices} failed!"
      fi
      rm -f "${_serv_tmp}"
    else
      csih_warning "Removing sshd from ${_wservices} failed!"
    fi
  fi

  # Add ssh 22/tcp  and ssh 22/udp to services
  if [ `grep -q 'ssh[ \t][ \t]*22' "${_services}"; echo $?` -ne 0 ]
  then
    if awk '{ if ( $2 ~ /^23\/tcp/ ) print "ssh                22/tcp'"${_spaces}"'SSH Remote Login Protocol\nssh                22/udp'"${_spaces}"'SSH Remote Login Protocol"; print $0; }' < "${_services}" > "${_serv_tmp}"
    then
      if mv "${_serv_tmp}" "${_services}"
      then
	csih_inform "Added ssh to ${_wservices}"
      else
	csih_warning "Adding ssh to ${_wservices} failed!"
      fi
      rm -f "${_serv_tmp}"
    else
      csih_warning "Adding ssh to ${_wservices} failed!"
    fi
  fi
  umount "${_my_etcdir}"
} # --- End of update_services_file --- #

# ======================================================================
# Routine: sshd_privsep
#  MODIFIES: privsep_configured  privsep_used
# ======================================================================
sshd_privsep() {
  local sshdconfig_tmp

  if [ "${privsep_configured}" != "yes" ]
  then
    if csih_is_nt
    then
      csih_inform "Privilege separation is set to yes by default since OpenSSH 3.3."
      csih_inform "However, this requires a non-privileged account called 'sshd'."
      csih_inform "For more info on privilege separation read /usr/share/doc/openssh/README.privsep."
      if csih_request "Should privilege separation be used?"
      then
	privsep_used=yes
	if ! csih_create_unprivileged_user sshd
	then
  	  csih_warning "Couldn't create user 'sshd'!"
	  csih_warning "Privilege separation set to 'no' again!"
	  csih_warning "Check your ${SYSCONFDIR}/sshd_config file!"
  	  privsep_used=no
	fi
      else
	privsep_used=no
      fi
    else
      # On 9x don't use privilege separation.  Since security isn't
      # available it just adds useless additional processes.
      privsep_used=no
    fi
  fi

  # Create default sshd_config from skeleton files in /etc/defaults/etc or
  # modify to add the missing privsep configuration option
  if cmp "${SYSCONFDIR}/sshd_config" "${SYSCONFDIR}/defaults/${SYSCONFDIR}/sshd_config" >/dev/null 2>&1
  then
    csih_inform "Updating ${SYSCONFDIR}/sshd_config file"
    sshdconfig_tmp=${SYSCONFDIR}/sshd_config.$$
    sed -e "s/^#UsePrivilegeSeparation yes/UsePrivilegeSeparation ${privsep_used}/
  	  s/^#Port 22/Port ${port_number}/
  	  s/^#StrictModes yes/StrictModes no/" \
	< ${SYSCONFDIR}/sshd_config \
	> "${sshdconfig_tmp}"
    mv "${sshdconfig_tmp}" ${SYSCONFDIR}/sshd_config
  elif [ "${privsep_configured}" != "yes" ]
  then
    echo >> ${SYSCONFDIR}/sshd_config
    echo "UsePrivilegeSeparation ${privsep_used}" >> ${SYSCONFDIR}/sshd_config
  fi
} # --- End of sshd_privsep --- #

# ======================================================================
# Routine: update_inetd_conf
# ======================================================================
update_inetd_conf() {
  local _inetcnf="${SYSCONFDIR}/inetd.conf"
  local _inetcnf_tmp="${SYSCONFDIR}/inetd.conf.$$"
  local _inetcnf_dir="${SYSCONFDIR}/inetd.d"
  local _sshd_inetd_conf="${_inetcnf_dir}/sshd-inetd"
  local _sshd_inetd_conf_tmp="${_inetcnf_dir}/sshd-inetd.$$"
  local _with_comment=1

  if [ -d "${_inetcnf_dir}" ]
  then
    # we have inetutils-1.5 inetd.d support
    if [ -f "${_inetcnf}" ]
    then
      grep -q '^[ \t]*ssh' "${_inetcnf}" && _with_comment=0

      # check for sshd OR ssh in top-level inetd.conf file, and remove
      # will be replaced by a file in inetd.d/
      if [ `grep -q '^[# \t]*ssh' "${_inetcnf}"; echo $?` -eq 0 ]
      then
	grep -v '^[# \t]*ssh' "${_inetcnf}" >> "${_inetcnf_tmp}"
	if [ -f "${_inetcnf_tmp}" ]
	then
	  if mv "${_inetcnf_tmp}" "${_inetcnf}"
	  then
  	    csih_inform "Removed ssh[d] from ${_inetcnf}"
	  else
  	    csih_warning "Removing ssh[d] from ${_inetcnf} failed!"
	  fi
	  rm -f "${_inetcnf_tmp}"
	else
	  csih_warning "Removing ssh[d] from ${_inetcnf} failed!"
	fi
      fi
    fi

    csih_install_config "${_sshd_inetd_conf}"   "${SYSCONFDIR}/defaults"
    if cmp "${SYSCONFDIR}/defaults${_sshd_inetd_conf}" "${_sshd_inetd_conf}" >/dev/null 2>&1
    then
      if [ "${_with_comment}" -eq 0 ]
      then
	sed -e 's/@COMMENT@[ \t]*//' < "${_sshd_inetd_conf}" > "${_sshd_inetd_conf_tmp}"
      else
	sed -e 's/@COMMENT@[ \t]*/# /' < "${_sshd_inetd_conf}" > "${_sshd_inetd_conf_tmp}"
      fi
      mv "${_sshd_inetd_conf_tmp}" "${_sshd_inetd_conf}"
      csih_inform "Updated ${_sshd_inetd_conf}"
    fi

  elif [ -f "${_inetcnf}" ]
  then
    grep -q '^[ \t]*sshd' "${_inetcnf}" && _with_comment=0

    # check for sshd in top-level inetd.conf file, and remove
    # will be replaced by a file in inetd.d/
    if [ `grep -q '^[# \t]*sshd' "${_inetcnf}"; echo $?` -eq 0 ]
    then
      grep -v '^[# \t]*sshd' "${_inetcnf}" >> "${_inetcnf_tmp}"
      if [ -f "${_inetcnf_tmp}" ]
      then
	if mv "${_inetcnf_tmp}" "${_inetcnf}"
	then
	    csih_inform "Removed sshd from ${_inetcnf}"
	else
	    csih_warning "Removing sshd from ${_inetcnf} failed!"
	fi
	rm -f "${_inetcnf_tmp}"
      else
	csih_warning "Removing sshd from ${_inetcnf} failed!"
      fi
    fi

    # Add ssh line to inetd.conf
    if [ `grep -q '^[# \t]*ssh' "${_inetcnf}"; echo $?` -ne 0 ]
    then
      if [ "${_with_comment}" -eq 0 ]
      then
	echo 'ssh  stream  tcp     nowait  root    /usr/sbin/sshd sshd -i' >> "${_inetcnf}"
      else
	echo '# ssh  stream  tcp     nowait  root    /usr/sbin/sshd sshd -i' >> "${_inetcnf}"
      fi
      csih_inform "Added ssh to ${_inetcnf}"
    fi
  fi
} # --- End of update_inetd_conf --- #

# ======================================================================
# Routine: install_service
#   Install sshd as a service
# ======================================================================
install_service() {
  local run_service_as
  local password

  if csih_is_nt
  then
    if ! cygrunsrv -Q sshd >/dev/null 2>&1
    then
      echo
      echo
      csih_warning "The following functions require administrator privileges!"
      echo
      echo -e "${_csih_QUERY_STR} Do you want to install sshd as a service?"
      if csih_request "(Say \"no\" if it is already installed as a service)"
      then
	csih_get_cygenv "${cygwin_value}"

	if ( csih_is_nt2003 || [ "$csih_FORCE_PRIVILEGED_USER" = "yes" ] )
	then
	  csih_inform "On Windows Server 2003, Windows Vista, and above, the"
	  csih_inform "SYSTEM account cannot setuid to other users -- a capability"
	  csih_inform "sshd requires.  You need to have or to create a privileged"
	  csih_inform "account.  This script will help you do so."
	  echo

	  [ "${opt_force}" = "yes" ] && opt_f=-f
	  [ -n "${user_account}" ] && opt_u="-u ""${user_account}"""
	  csih_select_privileged_username ${opt_f} ${opt_u} sshd

	  if ! csih_create_privileged_user "${password_value}"
	  then
	    csih_error_recoverable "There was a serious problem creating a privileged user."
	    csih_request "Do you want to proceed anyway?" || exit 1
	  fi
	fi

	# never returns empty if NT or above
	run_service_as=$(csih_service_should_run_as)

	if [ "${run_service_as}" = "${csih_PRIVILEGED_USERNAME}" ]
	then
	  password="${csih_PRIVILEGED_PASSWORD}"
	  if [ -z "${password}" ]
	  then
	    csih_get_value "Please enter the password for user '${run_service_as}':" "-s"
	    password="${csih_value}"
	  fi
	fi

	# at this point, we either have $run_service_as = "system" and $password is empty,
	# or $run_service_as is some privileged user and (hopefully) $password contains
	# the correct password.  So, from here out, we use '-z "${password}"' to discriminate
	# the two cases.

	csih_check_user "${run_service_as}"

	if [ -n "${csih_cygenv}" ]
	then
	  cygwin_env=( -e "CYGWIN=${csih_cygenv}" )
	fi
	if [ -z "${password}" ]
	then
	  if cygrunsrv -I sshd -d "CYGWIN sshd" -p /usr/sbin/sshd \
			    -a "-D" -y tcpip "${cygwin_env[@]}"
	  then
	    echo
	    csih_inform "The sshd service has been installed under the LocalSystem"
	    csih_inform "account (also known as SYSTEM). To start the service now, call"
	    csih_inform "\`net start sshd' or \`cygrunsrv -S sshd'.  Otherwise, it"
	    csih_inform "will start automatically after the next reboot."
	  fi
	else
	  if cygrunsrv -I sshd -d "CYGWIN sshd" -p /usr/sbin/sshd \
			    -a "-D" -y tcpip "${cygwin_env[@]}" \
			    -u "${run_service_as}" -w "${password}"
	  then
	    echo
	    csih_inform "The sshd service has been installed under the '${run_service_as}'"
	    csih_inform "account.  To start the service now, call \`net start sshd' or"
	    csih_inform "\`cygrunsrv -S sshd'.  Otherwise, it will start automatically"
	    csih_inform "after the next reboot."
	  fi
	fi

	# now, if successfully installed, set ownership of the affected files
	if cygrunsrv -Q sshd >/dev/null 2>&1
	then
	  chown "${run_service_as}" ${SYSCONFDIR}/ssh*
	  chown "${run_service_as}".544 ${LOCALSTATEDIR}/empty
	  chown "${run_service_as}".544 ${LOCALSTATEDIR}/log/lastlog
	  if [ -f ${LOCALSTATEDIR}/log/sshd.log ]
	  then
	    chown "${run_service_as}".544 ${LOCALSTATEDIR}/log/sshd.log
	  fi
	else
	  csih_warning "Something went wrong installing the sshd service."
	fi
      fi # user allowed us to install as service
    fi # service not yet installed
  fi # csih_is_nt
} # --- End of install_service --- #

# ======================================================================
# Main Entry Point
# ======================================================================

# Check how the script has been started.  If
#   (1) it has been started by giving the full path and
#       that path is /etc/postinstall, OR
#   (2) Otherwise, if the environment variable
#       SSH_HOST_CONFIG_AUTO_ANSWER_NO is set
# then set auto_answer to "no".  This allows automatic
# creation of the config files in /etc w/o overwriting
# them if they already exist.  In both cases, color
# escape sequences are suppressed, so as to prevent
# cluttering setup's logfiles.
if [ "$PROGDIR" = "/etc/postinstall" ]
then
  csih_auto_answer="no"
  csih_disable_color
  opt_force=yes
fi
if [ -n "${SSH_HOST_CONFIG_AUTO_ANSWER_NO}" ]
then
  csih_auto_answer="no"
  csih_disable_color
  opt_force=yes
fi

# ======================================================================
# Parse options
# ======================================================================
while :
do
  case $# in
  0)
    break
    ;;
  esac

  option=$1
  shift

  case "${option}" in
  -d | --debug )
    set -x
    csih_trace_on
    ;;

  -y | --yes )
    csih_auto_answer=yes
    opt_force=yes
    ;;

  -n | --no )
    csih_auto_answer=no
    opt_force=yes
    ;;

  -c | --cygwin )
    cygwin_value="$1"
    shift
    ;;

  -p | --port )
    port_number=$1
    shift
    ;;

  -u | --user )
    user_account="$1"
    shift
    ;;
    
  -w | --pwd )
    password_value="$1"
    shift
    ;;

  --privileged )
    csih_FORCE_PRIVILEGED_USER=yes
    ;;

  *)
    echo "usage: ${progname} [OPTION]..."
    echo
    echo "This script creates an OpenSSH host configuration."
    echo
    echo "Options:"
    echo "  --debug  -d            Enable shell's debug output."
    echo "  --yes    -y            Answer all questions with \"yes\" automatically."
    echo "  --no     -n            Answer all questions with \"no\" automatically."
    echo "  --cygwin -c <options>  Use \"options\" as value for CYGWIN environment var."
    echo "  --port   -p <n>        sshd listens on port n."
    echo "  --user   -u <account>  privileged user for service."
    echo "  --pwd    -w <passwd>   Use \"pwd\" as password for privileged user."
    echo "  --privileged           On Windows NT/2k/XP, require privileged user"
    echo "                         instead of LocalSystem for sshd service."
    echo
    exit 1
    ;;

  esac
done

# ======================================================================
# Action!
# ======================================================================

# Check for running ssh/sshd processes first. Refuse to do anything while
# some ssh processes are still running
if ps -ef | grep -q '/sshd\?$'
then
  echo
  csih_error "There are still ssh processes running. Please shut them down first."
fi

# Check for ${SYSCONFDIR} directory
csih_make_dir "${SYSCONFDIR}" "Cannot create global configuration files."
chmod 775 "${SYSCONFDIR}"
setfacl -m u:system:rwx "${SYSCONFDIR}"

# Check for /var/log directory
csih_make_dir "${LOCALSTATEDIR}/log" "Cannot create log directory."
chmod 775 "${LOCALSTATEDIR}/log"
setfacl -m u:system:rwx "${LOCALSTATEDIR}/log"

# Create /var/log/lastlog if not already exists
if [ -e ${LOCALSTATEDIR}/log/lastlog -a ! -f ${LOCALSTATEDIR}/log/lastlog ]
then
  echo
  csih_error_multi "${LOCALSTATEDIR}/log/lastlog exists, but is not a file." \
		   "Cannot create ssh host configuration."
fi
if [ ! -e ${LOCALSTATEDIR}/log/lastlog ]
then
  cat /dev/null > ${LOCALSTATEDIR}/log/lastlog
  chmod 644 ${LOCALSTATEDIR}/log/lastlog
fi

# Create /var/empty file used as chroot jail for privilege separation
csih_make_dir "${LOCALSTATEDIR}/empty" "Cannot create ${LOCALSTATEDIR}/empty directory."
chmod 755 "${LOCALSTATEDIR}/empty"
setfacl -m u:system:rwx "${LOCALSTATEDIR}/empty"

# host keys
create_host_keys

# use 'cmp' program to determine if a config file is identical
# to the default version of that config file
csih_check_program_or_error cmp diffutils


# handle ssh_config
csih_install_config "${SYSCONFDIR}/ssh_config"   "${SYSCONFDIR}/defaults"
if cmp "${SYSCONFDIR}/ssh_config" "${SYSCONFDIR}/defaults/${SYSCONFDIR}/ssh_config" >/dev/null 2>&1
then
  if [ "${port_number}" != "22" ]
  then
    csih_inform "Updating ${SYSCONFDIR}/ssh_config file with requested port"
    echo "Host localhost" >> ${SYSCONFDIR}/ssh_config
    echo "    Port ${port_number}" >> ${SYSCONFDIR}/ssh_config
  fi
fi

# handle sshd_config (and privsep)
csih_install_config "${SYSCONFDIR}/sshd_config"   "${SYSCONFDIR}/defaults"
if ! cmp "${SYSCONFDIR}/sshd_config" "${SYSCONFDIR}/defaults/${SYSCONFDIR}/sshd_config" >/dev/null 2>&1
then
  grep -q UsePrivilegeSeparation ${SYSCONFDIR}/sshd_config && privsep_configured=yes
fi
sshd_privsep



update_services_file
update_inetd_conf
install_service

echo
csih_inform "Host configuration finished. Have fun!"