Commit | Line | Data |
---|---|---|
53263601 MW |
1 | #! /bin/sh |
2 | ### | |
3 | ### Reveal shares of a secret distributed among keepers | |
4 | ### | |
5 | ### (c) 2011 Mark Wooding | |
6 | ### | |
7 | ||
8 | ###----- Licensing notice --------------------------------------------------- | |
9 | ### | |
599c8f75 MW |
10 | ### This file is part of the distorted.org.uk key management suite. |
11 | ### | |
12 | ### distorted-keys is free software; you can redistribute it and/or modify | |
53263601 MW |
13 | ### it under the terms of the GNU General Public License as published by |
14 | ### the Free Software Foundation; either version 2 of the License, or | |
15 | ### (at your option) any later version. | |
16 | ### | |
599c8f75 | 17 | ### distorted-keys is distributed in the hope that it will be useful, |
53263601 MW |
18 | ### but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | ### GNU General Public License for more details. | |
21 | ### | |
22 | ### You should have received a copy of the GNU General Public License | |
599c8f75 | 23 | ### along with distorted-keys; if not, write to the Free Software Foundation, |
53263601 MW |
24 | ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
25 | ||
26 | set -e | |
27 | case "${KEYSLIB+t}" in t) ;; *) echo >&2 "$0: KEYSLIB unset"; exit 1 ;; esac | |
28 | . "$KEYSLIB"/keyfunc.sh | |
29 | ||
30 | defhelp <<HELP | |
d516ebd0 | 31 | RECOV KEEPER |
53263601 MW |
32 | Reveal a share of a recovery key distributed among keepers. |
33 | ||
34 | If enough shares have been revealed, reconstruct the recovery private key. | |
d516ebd0 | 35 | The keeper nub is read from stdin. |
53263601 | 36 | HELP |
53263601 MW |
37 | |
38 | ## Parse the command line. | |
d516ebd0 | 39 | case $# in 2) ;; *) usage_err ;; esac |
53263601 | 40 | recov=$1 keeper=$2; shift 2 |
599c8f75 | 41 | checklabel "recovery key" "$recov" |
53263601 | 42 | case "$recov" in |
599c8f75 MW |
43 | */*) ;; |
44 | *) recov=$recov/current ;; | |
53263601 MW |
45 | esac |
46 | checkword "keeper set label" "$keeper" | |
47 | ||
c47f2aba MW |
48 | ## Check that this is a sensible thing to do. |
49 | if [ ! -f $KEYS/keeper/$keeper/meta ]; then | |
50 | echo >&2 "$quis: unknown keeper set \`$keeper'" | |
51 | exit 1 | |
52 | fi | |
53 | if [ ! -d $KEYS/recov/$recov ]; then | |
54 | echo >&2 "$quis: unknown recovery key \`$recov'" | |
55 | exit 1 | |
56 | fi | |
57 | if [ ! -f $KEYS/recov/$recov/$keeper.param ]; then | |
58 | echo >&2 "$quis: recovery key \`$recov' not kept by keeper set \`$keeper'" | |
59 | exit 1 | |
60 | fi | |
61 | ||
53263601 | 62 | ## Grab the key, because we'll need to read it several times. |
c47f2aba | 63 | mktmp |
d516ebd0 | 64 | cat >$tmp/secret |
53263601 MW |
65 | |
66 | ## Read the threshold from the recovery metadata. | |
2661d8aa | 67 | t=$(sharethresh $KEYS/recov/$recov/$keeper.param) |
53263601 MW |
68 | |
69 | ## Find out which keeper index it corresponds to. | |
70 | read n hunoz <$KEYS/keeper/$keeper/meta | |
71 | i=0 | |
72 | foundp=nil | |
73 | while [ $i -lt $n ]; do | |
c47f2aba MW |
74 | c_sysprepare $KEYS/keeper/$keeper/$i |
75 | nubbin=$(nubid <$tmp/secret) | |
76 | nubid=$(cat $KEYS/keeper/$keeper/$i/nubid) | |
77 | case "$nubbin" in "$nubid") foundp=t; break ;; esac | |
78 | i=$(( $i + 1 )) | |
53263601 MW |
79 | done |
80 | case $foundp in | |
c47f2aba | 81 | nil) echo >&2 "$quis: nub doesn't match keeper \`$keeper'"; exit 1 ;; |
53263601 MW |
82 | esac |
83 | ||
84 | ## Establish the recovery staging area. See whether we've done enough | |
85 | ## already. | |
c47f2aba | 86 | reqsafe |
53263601 | 87 | tag=$(echo $recov | tr / .) |
c47f2aba MW |
88 | mkdir -p -m700 $SAFE/keys.reveal |
89 | reveal=$SAFE/keys.reveal/$tag | |
599c8f75 MW |
90 | if [ ! -d $reveal ]; then mkdir -m700 $reveal; fi |
91 | cd $reveal | |
c47f2aba MW |
92 | if [ -f nub ]; then |
93 | echo >&2 "$quis: recovery key \`$recov' already revealed" | |
53263601 MW |
94 | exit 1 |
95 | fi | |
96 | ||
97 | ## Decrypt the share. | |
599c8f75 | 98 | umask 077 |
c47f2aba MW |
99 | if [ -f $keeper.$i.share ]; then |
100 | echo >&2 "$quis: share $i already revealed" | |
101 | else | |
102 | c_sysdecrypt $KEYS/keeper/$keeper/$i $tmp/secret \ | |
103 | <$KEYS/recov/$recov/$keeper.$i.share \ | |
104 | >$keeper.$i.new | |
105 | mv $keeper.$i.new $keeper.$i.share | |
106 | fi | |
53263601 MW |
107 | |
108 | ## See if there's enough for a recovery. | |
109 | n=0 | |
c47f2aba | 110 | for j in $keeper.*.share; do if [ -f "$j" ]; then n=$(( $n + 1 )); fi; done |
53263601 | 111 | if [ $n -lt $t ]; then |
c47f2aba | 112 | echo >&2 "$quis: share $i revealed; $(( $t - $n )) more required" |
53263601 | 113 | else |
c47f2aba | 114 | cat $KEYS/recov/$recov/$keeper.param $keeper.*.share >$keeper.shares |
5c30c6e6 | 115 | $bindir/shamir recover <$keeper.shares >nub.new |
c47f2aba MW |
116 | c_sysprepare $KEYS/recov/$recov/store |
117 | nubbin=$(nubid <nub.new) | |
118 | nubid=$(cat $KEYS/recov/$recov/store/nubid) | |
119 | case "$nubbin" in | |
120 | "$nubid") ;; | |
53263601 | 121 | *) |
c47f2aba | 122 | echo >&2 "$quis: recovered nub doesn't match stored hash" |
53263601 MW |
123 | exit 1 |
124 | ;; | |
125 | esac | |
c47f2aba MW |
126 | mv nub.new nub |
127 | rm -f $keeper.* | |
128 | echo >&2 "$quis: recovery key \`$recov' revealed" | |
53263601 MW |
129 | fi |
130 | ||
131 | ###----- That's all, folks -------------------------------------------------- |