| 1 | #! /bin/sh |
| 2 | |
| 3 | set -e |
| 4 | |
| 5 | ### This script performs the passive side of a dynamic association. It is |
| 6 | ### intended to be set as the forced command in an `.ssh/authorized_keys' |
| 7 | ### file. Specifically, for each dynamic peer, add a line to |
| 8 | ### `.ssh/authorized_keys' of the form |
| 9 | ### |
| 10 | ### environment="TRIPE_USER=PEER" ssh-rsa ... |
| 11 | ### |
| 12 | ### There's an additional wrinkle. Suppose that the passive TrIPE endpoint |
| 13 | ### is behind a NAT, and the SSH gateway is on a different machine. The |
| 14 | ### gateway should have its own `tripe' user, and this script should again be |
| 15 | ### its shell. On the gateway, add a `.ssh/authorized_keys' entry |
| 16 | ### |
| 17 | ### environment="TRIPE_USER=tripe@SERVER:PEER" ssh-rsa ... |
| 18 | ### |
| 19 | ### for the dynamic endpoint. On the passive endpoint itself, you need an |
| 20 | ### entry for the gateway's `tripe' user's key, with `TRIPE_GATEWAY' set to |
| 21 | ### any value, like |
| 22 | ### |
| 23 | ### environment="TRIPE_GATEWAY=t" ssh-rsa ... |
| 24 | ### |
| 25 | ### For backwards compatibility, it can also be set as the `tripe' user's |
| 26 | ### shell, with the `[tripe@SERVER:]PEER' indicator set as the forced |
| 27 | ### command. If there are no forced command or `TRIPE_*' environment |
| 28 | ### variables then it is assumed that a gateway is calling. |
| 29 | |
| 30 | : ${prefix=@prefix@} ${exec_prefix=@exec_prefix@} |
| 31 | : ${bindir=@bindir@} |
| 32 | : ${TRIPEDIR=@configdir@} ${TRIPESOCK=@socketdir@/tripesock} |
| 33 | : ${tripectl=$bindir/tripectl} |
| 34 | export TRIPEDIR TRIPESOCK |
| 35 | |
| 36 | ## Make sure we're being called properly, and figure out the peer identity. |
| 37 | case "${TRIPE_USER+t},${TRIPE_GATEWAY+t},$#,$1" in |
| 38 | t,,0,) set -- "$TRIPE_USER" ;; |
| 39 | ,t,0,) set -- $SSH_ORIGINAL_COMMAND; unset SSH_ORIGINAL_COMMAND ;; |
| 40 | ,,2,-c) ;; |
| 41 | *) |
| 42 | echo >&2 "usage: $0 -c [SERVER:]PEER [ACTION]" |
| 43 | exit 1 |
| 44 | ;; |
| 45 | esac |
| 46 | |
| 47 | ## Examine the peer identifier and work out how to proceed. |
| 48 | case "$#,$1" in |
| 49 | 0,*) echo >&2 "missing peer identifier"; exit 1 ;; |
| 50 | *:*) mode=proxy server=${1%:*} user=${1##*:} ;; |
| 51 | *) mode=local user=$1 ;; |
| 52 | esac |
| 53 | shift |
| 54 | |
| 55 | ## Fetch the optional command from where SSH stashed it. |
| 56 | case "$#" in 0) set -- $SSH_ORIGINAL_COMMAND ;; esac |
| 57 | case "$#,$1" in |
| 58 | 0, | 1,hello) act=hello ;; |
| 59 | 1,goodbye) act=goodbye ;; |
| 60 | *) echo >&2 "$0: unknown action spec \`$*'"; exit 1 ;; |
| 61 | esac |
| 62 | |
| 63 | ## Now actually do something. |
| 64 | case "$mode,$act" in |
| 65 | proxy,*) |
| 66 | exec ssh "$server" "$user" "$act" |
| 67 | ;; |
| 68 | local,hello) |
| 69 | exec $tripectl SVCSUBMIT connect passive "$user" |
| 70 | ;; |
| 71 | local,goodbye) |
| 72 | peer=$($tripectl SVCSUBMIT connect userpeer "$user") |
| 73 | exec $tripectl KILL "$peer" |
| 74 | ;; |
| 75 | *) |
| 76 | echo >&2 "$0: unknown mode/action $mode/$act" |
| 77 | exit 1 |
| 78 | ;; |
| 79 | esac |