rsync-ssl

   1 #!/usr/bin/env bash
   2
   3 # This script uses openssl, gnutls, or stunnel to secure an rsync daemon connection.
   4
   5 # By default this script takes rsync args and hands them off to the actual
   6 # rsync command with an --rsh option that makes it open an SSL connection to an
   7 # rsync daemon.  See the rsync-ssl manpage for usage details and env variables.
   8
   9 # When the first arg is --HELPER, we are being used by rsync as an --rsh helper
  10 # script, and the args are (note the trailing dot):
  11 #
  12 #    rsync-ssl --HELPER HOSTNAME rsync --server --daemon .
  13 #
  14 # --HELPER is not a user-facing option, so it is not documented in the manpage.
  15
  16 # The first SSL setup was based on:  http://dozzie.jarowit.net/trac/wiki/RsyncSSL
  17 # Note that an stunnel connection requires at least version 4.x of stunnel.
  18
  19 function rsync_ssl_run {
  20     case "$*" in
  21     *rsync://*) ;;
  22     *::*) ;;
  23     *)
  24         echo "You must use rsync-ssl with a daemon-style hostname." 1>&2
  25         exit 1
  26         ;;
  27     esac
  28
  29     exec rsync --rsh="$0 --HELPER" "${@}"
  30 }
  31
  32 function rsync_ssl_helper {
  33     if [[ -z "$RSYNC_SSL_TYPE" ]]; then
  34         found=`path_search openssl stunnel4 stunnel` || exit 1
  35         if [[ "$found" == */openssl ]]; then
  36             RSYNC_SSL_TYPE=openssl
  37             RSYNC_SSL_OPENSSL="$found"
  38         elif [[ "$found" == */gnutls-cli ]]; then
  39             RSYNC_SSL_TYPE=gnutls
  40             RSYNC_SSL_GNUTLS="$found"
  41         else
  42             RSYNC_SSL_TYPE=stunnel
  43             RSYNC_SSL_STUNNEL="$found"
  44         fi
  45     fi
  46
  47     case "$RSYNC_SSL_TYPE" in
  48         openssl)
  49             if [[ -z "$RSYNC_SSL_OPENSSL" ]]; then
  50                 RSYNC_SSL_OPENSSL=`path_search openssl` || exit 1
  51             fi
  52             optsep=' '
  53             ;;
  54         gnutls)
  55             if [[ -z "$RSYNC_SSL_GNUTLS" ]]; then
  56                 RSYNC_SSL_GNUTLS=`path_search gnutls-cli` || exit 1
  57             fi
  58             optsep=' '
  59             ;;
  60         stunnel)
  61             if [[ -z "$RSYNC_SSL_STUNNEL" ]]; then
  62                 RSYNC_SSL_STUNNEL=`path_search stunnel4 stunnel` || exit 1
  63             fi
  64             optsep=' = '
  65             ;;
  66         *)
  67             echo "The RSYNC_SSL_TYPE specifies an unknown type: $RSYNC_SSL_TYPE" 1>&2
  68             exit 1
  69             ;;
  70     esac
  71
  72     if [[ -z "$RSYNC_SSL_CERT" ]]; then
  73         certopt=""
  74         gnutls_cert_opt=""
  75     else
  76         certopt="cert$optsep$RSYNC_SSL_CERT"
  77         gnutls_cert_opt="--x509keyfile=$RSYNC_SSL_CERT"
  78     fi
  79
  80     if [[ -z ${RSYNC_SSL_CA_CERT+x} ]]; then
  81         # RSYNC_SSL_CA_CERT unset - default CA set AND verify:
  82         # openssl:
  83         caopt="-verify_return_error -verify 4"
  84         # gnutls:
  85         gnutls_opts=""
  86         # stunnel:
  87         # Since there is no way of using the default CA certificate collection,
  88         # we cannot do any verification. Thus, stunnel should really only be
  89         # used if nothing else is available.
  90         cafile=""
  91         verify=""
  92     elif [[ "$RSYNC_SSL_CA_CERT" == "" ]]; then
  93         # RSYNC_SSL_CA_CERT set but empty -do NO verifications:
  94         # openssl:
  95         caopt="-verify 1"
  96         # gnutls:
  97         gnutls_opts="--insecure"
  98         # stunnel:
  99         cafile=""
 100         verify="verifyChain = no"
 101     else
 102         # RSYNC_SSL_CA_CERT set - use CA AND verify:
 103         # openssl:
 104         caopt="-CAfile $RSYNC_SSL_CA_CERT -verify_return_error -verify 4"
 105         # gnutls:
 106         gnutls_opts="--x509cafile=$RSYNC_SSL_CA_CERT"
 107         # stunnel:
 108         cafile="CAfile = $RSYNC_SSL_CA_CERT"
 109         verify="verifyChain = yes"
 110     fi
 111
 112     port="${RSYNC_PORT:-0}"
 113     if [[ "$port" == 0 ]]; then
 114         port="${RSYNC_SSL_PORT:-874}"
 115     fi
 116
 117     # If the user specified USER@HOSTNAME::module, then rsync passes us
 118     # the -l USER option too, so we must be prepared to ignore it.
 119     if [[ "$1" == "-l" ]]; then
 120         shift 2
 121     fi
 122
 123     hostname="$1"
 124     shift
 125
 126     if [[ -z "$hostname" || "$1" != rsync || "$2" != --server || "$3" != --daemon ]]; then
 127         echo "Usage: rsync-ssl --HELPER HOSTNAME rsync --server --daemon ." 1>&2
 128         exit 1
 129     fi
 130
 131     if [[ $RSYNC_SSL_TYPE == openssl ]]; then
 132         exec $RSYNC_SSL_OPENSSL s_client $caopt $certopt -quiet -verify_quiet -servername $hostname -connect $hostname:$port
 133     elif [[ $RSYNC_SSL_TYPE == gnutls ]]; then
 134         exec $RSYNC_SSL_GNUTLS --logfile=/dev/null $gnutls_cert_opt $gnutls_opts $hostname:$port
 135     else
 136         # devzero@web.de came up with this no-tmpfile calling syntax:
 137         exec $RSYNC_SSL_STUNNEL -fd 10 11<&0 <<EOF 10<&0 0<&11 11<&-
 138 foreground = yes
 139 debug = crit
 140 connect = $hostname:$port
 141 client = yes
 142 TIMEOUTclose = 0
 143 $verify
 144 $certopt
 145 $cafile
 146 EOF
 147     fi
 148 }
 149
 150 function path_search {
 151     IFS_SAVE="$IFS"
 152     IFS=:
 153     for prog in "${@}"; do
 154         for dir in $PATH; do
 155             [[ -z "$dir" ]] && dir=.
 156             if [[ -f "$dir/$prog" && -x "$dir/$prog" ]]; then
 157                 echo "$dir/$prog"
 158                 IFS="$IFS_SAVE"
 159                 return 0
 160             fi
 161         done
 162     done
 163
 164     IFS="$IFS_SAVE"
 165     echo "Failed to find on your path: $*" 1>&2
 166     echo "See the rsync-ssl manpage for configuration assistance." 1>&2
 167     return 1
 168 }
 169
 170 if [[ "$#" == 0 ]]; then
 171     echo "Usage: rsync-ssl [--type=SSL_TYPE] RSYNC_ARG [...]" 1>&2
 172     echo "The SSL_TYPE can be openssl or stunnel"
 173     exit 1
 174 fi
 175
 176 if [[ "$1" = --help || "$1" = -h ]]; then
 177     exec rsync --help
 178 fi
 179
 180 if [[ "$1" == --HELPER ]]; then
 181     shift
 182     rsync_ssl_helper "${@}"
 183 fi
 184
 185 if [[ "$1" == --type=* ]]; then
 186     export RSYNC_SSL_TYPE="${1/--type=/}"
 187     shift
 188 fi
 189
 190 rsync_ssl_run "${@}"