#!/usr/bin/ksh
#
# SCRIPT: keyit
# AUTHOR: Randy Michael
# DATE: 7/31/2007
# REV: 1.0
# PLATFORM: Not platform dependent
# REQUIREMENTS: OpenSSH
#
# PURPOSE: This script is used to set up
# encryption keypairs between two hosts.
#
# set -x # Uncomment to debug this script
#
# set -n # Uncomment to check script syntax
#        # without any execution. Do not
#        # forget to add the comment back,
#        # or the script will never execute.
#
# USAGE:  keyit remote_host username
#
#######################################
# DEFINE FILES AND VARIABLES HERE
#######################################

RHOST=$1
THIS_USER=$2
THIS_SCRIPT=$(basename $0)
THIS_HOST=$(hostname)

#######################################
# DEFINE FUNCTIONS HERE
#######################################

usage ()
{
echo "\nUSAGE: $THIS_SCRIPT \
remote_host username\n"
}

#######################################

success_message ()
{
KTYPE=$1
echo "\nSUCCESS: $KTYPE key pairs configured for $THIS_USER on $RHOST"
echo "\n$THIS_USER should no longer require an SSH password on $RHOST"
echo "when logging in directly, however, using the ssh commands:\n"
echo "\tssh -l $THIS_USER $RHOST\nAND\n\tssh ${THIS_USER}@${RHOST}"
echo "\nWHILE LOGGED IN LOCALLY AS ANOTHER USER will still not work"
echo "without a valid user password\n"
}

#######################################

failure_message ()
{
echo "\nERROR: Setting up the $KEYTYPE key pairs failed"
echo "Ensure that OpenSSH is installed and running"
echo "on both hosts. Then ensure that the user has"
echo "a .ssh directory in their \$HOME directory."
echo "See the man page on ssh and ssh-keygen"
echo "for more details and manual setup\n"
}

#######################################

keyit_dsa ()
{
# Append the local public key to the same user's
# authorized_users file

cat ~${THIS_USER}/.ssh/id_dsa.pub | ssh ${THIS_USER}@$RHOST \
"cat >> ~${THIS_USER}/.ssh/authorized_keys"

if (( $? == 0 ))
then
    success_message dsa
else
    failure_message
fi
}

#######################################

keyit_rsa ()
{
# Append the local public key to the same user's
# authorized_users file

cat ~${THIS_USER}/.ssh/id_rsa.pub | ssh ${THIS_USER}@$RHOST \
"cat >> ~${THIS_USER}/.ssh/authorized_keys"

if (( $? == 0 ))
then
    success_message rsa
else
    failure_message
fi
}

#######################################
# BEGINNING OF MAIN
#######################################

# Ensure the user $THIS_USER exists on the local system

if ! $(/usr/bin/id $THIS_USER >/dev/null 2>&1)
then
    echo "\nERROR: $THIS_USER is not a valid user on $THIS_HOST\n"
    usage
    exit 1
fi

# Ensure ssh is installed locally

if [[ ! -x /usr/bin/ssh && ! -x /usr/local/bin/ssh ]]
then
    echo "\nERROR: SSH does not appear to be installed on this machine"
    echo "This script requires SSH...Exiting...\n"
    usage
    exit 2
fi

# Check for proper usage 

if ! [ $2 ]
then
   usage
   exit 1
fi

# Ping the remote host 1 ping

if ! $(ping -c1 $RHOST >/dev/null 2>&1)
then
    echo "\nERROR: $RHOST is not pingable...Exiting...\n"
    exit 2
fi

# Set up the key pairs for the configured key(s)

SET=0

if [ -s ~$THIS_USER/.ssh/id_dsa.pub ]
then
   keyit_dsa
   SET=1
fi

if [ -s ~$THIS_USER/.ssh/id_rsa.pub ]
then
   keyit_rsa
   SET=2
fi

if (( SET == 0 ))
then
   echo "\nERROR: SSH public key is not set for $THIS_USER..."
   echo "\nTo Configure Run: ssh-keygen -t type"
   echo "Where type is rsa or dsa encryption\n"
   echo "Would you like to set up the keys now? (y/n): \c"
   read REPLY
   case $REPLY in
   y|Y) if $(id $THIS_USER >/dev/null 2>&1)
        then
           echo "\nEncryption Type: (dsa or rsa?): \c"
           read KEYTYPE
           case "$KEYTYPE" in
           +([d|Ds|Sa|A])) KEYTYPE=dsa
              ;;
           +([r|Rs|Sa|A])) KEYTYPE=rsa
              ;;
           *) echo "\nERROR: Invalid entry...Exiting..."
              exit 1
              ;;
           esac
           echo "\nAccept the defaults and do not enter a passphrase...\n"
           su - $THIS_USER "-c ssh-keygen -t $KEYTYPE"
           if (( $? == 0 ))
           then
              echo "\nSuccess, keying $THIS_USER on $RHOST\n"
              keyit_${KEYTYPE} $KEYTYPE
           fi
        else 
           echo "\nERROR: $THIS_USER username does not exist\n" 
        fi
       ;;
     *) # Do nothing
        :  # A colon, :, is a "no-op"
        ;;
   esac
fi

#########################################
# END OF KEYIT SCRIPT
#########################################