Commit | Line | Data |
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b147e573 | 1 | #! /bin/sh |
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2 | ### |
3 | ### SSH forced-command script for establishing dynamic associations. | |
4 | ### | |
5 | ### (c) 2012 Mark Wooding | |
6 | ### | |
7 | ||
8 | ###----- Licensing notice --------------------------------------------------- | |
9 | ### | |
10 | ### This file is part of Trivial IP Encryption (TrIPE). | |
11 | ### | |
12 | ### TrIPE is free software: you can redistribute it and/or modify it under | |
13 | ### the terms of the GNU General Public License as published by the Free | |
14 | ### Software Foundation; either version 3 of the License, or (at your | |
15 | ### option) any later version. | |
16 | ### | |
17 | ### TrIPE is distributed in the hope that it will be useful, but WITHOUT | |
18 | ### ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
19 | ### FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
20 | ### for more details. | |
21 | ### | |
22 | ### You should have received a copy of the GNU General Public License | |
23 | ### along with TrIPE. If not, see <https://www.gnu.org/licenses/>. | |
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24 | |
25 | set -e | |
26 | ||
27 | ### This script performs the passive side of a dynamic association. It is | |
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28 | ### intended to be set as the forced command in an `.ssh/authorized_keys' |
29 | ### file. Specifically, for each dynamic peer, add a line to | |
30 | ### `.ssh/authorized_keys' of the form | |
b147e573 | 31 | ### |
0f51cf5a | 32 | ### environment="TRIPE_USER=PEER" ssh-rsa ... |
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33 | ### |
34 | ### There's an additional wrinkle. Suppose that the passive TrIPE endpoint | |
35 | ### is behind a NAT, and the SSH gateway is on a different machine. The | |
36 | ### gateway should have its own `tripe' user, and this script should again be | |
37 | ### its shell. On the gateway, add a `.ssh/authorized_keys' entry | |
38 | ### | |
0f51cf5a | 39 | ### environment="TRIPE_USER=tripe@SERVER:PEER" ssh-rsa ... |
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40 | ### |
41 | ### for the dynamic endpoint. On the passive endpoint itself, you need an | |
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42 | ### entry for the gateway's `tripe' user's key, with `TRIPE_GATEWAY' set to |
43 | ### any value, like | |
44 | ### | |
45 | ### environment="TRIPE_GATEWAY=t" ssh-rsa ... | |
46 | ### | |
47 | ### For backwards compatibility, it can also be set as the `tripe' user's | |
48 | ### shell, with the `[tripe@SERVER:]PEER' indicator set as the forced | |
49 | ### command. If there are no forced command or `TRIPE_*' environment | |
50 | ### variables then it is assumed that a gateway is calling. | |
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51 | |
52 | : ${prefix=@prefix@} ${exec_prefix=@exec_prefix@} | |
53 | : ${bindir=@bindir@} | |
54 | : ${TRIPEDIR=@configdir@} ${TRIPESOCK=@socketdir@/tripesock} | |
55 | : ${tripectl=$bindir/tripectl} | |
56 | export TRIPEDIR TRIPESOCK | |
57 | ||
d3731285 | 58 | ## Make sure we're being called properly, and figure out the peer identity. |
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59 | case "${TRIPE_USER+t},${TRIPE_GATEWAY+t},$#,$1" in |
60 | t,,0,) set -- "$TRIPE_USER" ;; | |
61 | ,t,0,) set -- $SSH_ORIGINAL_COMMAND; unset SSH_ORIGINAL_COMMAND ;; | |
62 | ,,2,-c) ;; | |
d3731285 | 63 | *) |
0f51cf5a | 64 | echo >&2 "usage: $0 -c [SERVER:]PEER [ACTION]" |
d3731285 | 65 | exit 1 |
b147e573 | 66 | ;; |
d3731285 | 67 | esac |
b147e573 | 68 | |
d3731285 MW |
69 | ## Examine the peer identifier and work out how to proceed. |
70 | case "$#,$1" in | |
0f51cf5a | 71 | 0,*) echo >&2 "missing peer identifier"; exit 1 ;; |
d3731285 MW |
72 | *:*) mode=proxy server=${1%:*} user=${1##*:} ;; |
73 | *) mode=local user=$1 ;; | |
74 | esac | |
75 | shift | |
b147e573 | 76 | |
0f51cf5a | 77 | ## Fetch the optional command from where SSH stashed it. |
d3731285 MW |
78 | case "$#" in 0) set -- $SSH_ORIGINAL_COMMAND ;; esac |
79 | case "$#,$1" in | |
80 | 0, | 1,hello) act=hello ;; | |
81 | 1,goodbye) act=goodbye ;; | |
82 | *) echo >&2 "$0: unknown action spec \`$*'"; exit 1 ;; | |
83 | esac | |
84 | ||
85 | ## Now actually do something. | |
86 | case "$mode,$act" in | |
87 | proxy,*) | |
88 | exec ssh "$server" "$user" "$act" | |
89 | ;; | |
90 | local,hello) | |
91 | exec $tripectl SVCSUBMIT connect passive "$user" | |
92 | ;; | |
93 | local,goodbye) | |
94 | peer=$($tripectl SVCSUBMIT connect userpeer "$user") | |
95 | exec $tripectl KILL "$peer" | |
96 | ;; | |
b147e573 | 97 | *) |
d3731285 | 98 | echo >&2 "$0: unknown mode/action $mode/$act" |
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99 | exit 1 |
100 | ;; | |
b147e573 | 101 | esac |