Commit | Line | Data |
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775bd287 | 1 | ### -*-sh-*- |
bfdc045d MW |
2 | ### |
3 | ### Failsafe prologue for firewall scripts | |
4 | ### | |
5 | ### (c) 2008 Mark Wooding | |
6 | ### | |
7 | ||
8 | ###----- Licensing notice --------------------------------------------------- | |
9 | ### | |
10 | ### This program is free software; you can redistribute it and/or modify | |
11 | ### it under the terms of the GNU General Public License as published by | |
12 | ### the Free Software Foundation; either version 2 of the License, or | |
13 | ### (at your option) any later version. | |
14 | ### | |
15 | ### This program is distributed in the hope that it will be useful, | |
16 | ### but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | ### GNU General Public License for more details. | |
19 | ### | |
20 | ### You should have received a copy of the GNU General Public License | |
21 | ### along with this program; if not, write to the Free Software Foundation, | |
22 | ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
23 | ||
24 | m4_divert(10)m4_dnl | |
25 | ###-------------------------------------------------------------------------- | |
26 | ### Failsafe prologue. | |
27 | ||
28 | revert () { | |
d8eafff6 MW |
29 | escape=$1 badness=$2 |
30 | ## Report a firewall script failure and retreat to a safe place. | |
31 | ||
32 | echo "$2! Retreating to safe version..." | |
2a41fec3 MW |
33 | if [ -f /var/run/firewall.save ] && [ -f /var/run/firewall6.save ]; then |
34 | echo "Trying to loading saved firewall state..." | |
35 | if iptables-restore </var/run/firewall.save && | |
36 | ip6tables-restore </var/run/firewall6.save; then | |
37 | echo "Previous firewall state restored." | |
38 | return | |
39 | else | |
40 | echo "Failed! Falling back to plan B." | |
41 | fi | |
42 | fi | |
d8eafff6 | 43 | if ! "$1" revert; then |
bfdc045d MW |
44 | echo >&2 "Safe firewall failed. You're screwed. Good luck." |
45 | exit 1 | |
46 | fi | |
47 | echo >&2 "Phew! Fallback to safe version successful." | |
48 | exit 1 | |
49 | } | |
50 | ||
51 | finished () { | |
52 | echo "Done." | |
53 | exit 0 | |
54 | } | |
55 | ||
d8eafff6 MW |
56 | try () { |
57 | old=$1 new=$2 | |
58 | ## Install the NEW firewall rules. If it fails, revert to the OLD ones. | |
59 | ## Updating firewall rules can fail spectacularly, so be careful. Leave a | |
60 | ## timebomb in the form of NEW.errors: if this isn't removed in 10 seconds | |
61 | ## after the NEW rules complete successfully, then revert. Write errors to | |
62 | ## NEW.errors. | |
63 | ||
64 | ## Make sure we have an escape route. | |
2a41fec3 MW |
65 | iptables-save >/var/run/firewall.save.new |
66 | ip6tables-save >/var/run/firewall6.save.new | |
67 | mv /var/run/firewall.save.new /var/run/firewall.save | |
68 | mv /var/run/firewall6.save.new /var/run/firewall6.save | |
d8eafff6 MW |
69 | |
70 | ## Clear the air and make the errors file. | |
71 | rm -f "$new.errors" "$new.timebomb" "$new.grabbed" | |
72 | exec >"$new.errors" 2>&1 | |
73 | ||
74 | ## Now try to install the new firewall. | |
75 | "$new" install || revert "$old" "Failed" | |
76 | ||
77 | ## Set up the time bomb. Leave the errors file there if we failed. | |
78 | (sleep 10 | |
79 | if [ -f "$new.errors" ]; then | |
80 | mv "$new.errors" "$new.timebomb" | |
81 | revert "$old" "Time bomb" | |
82 | fi)& | |
83 | } | |
84 | ||
85 | catch () { | |
86 | new=$1 | |
87 | ## Report successful installation of the script. | |
88 | ||
89 | if mv "$new.errors" "$new.grabbed" 2>/dev/null; then | |
90 | rc=0 | |
91 | echo "Installed OK." | |
92 | else | |
93 | mv "$new.timebomb" "$new.grabbed" | |
94 | echo "Timebomb went off." | |
95 | rc=1 | |
96 | fi | |
97 | cat "$new.grabbed" >&2 | |
98 | rm -f "$new.grabbed" | |
99 | return $rc | |
100 | } | |
101 | ||
bfdc045d MW |
102 | exit_after_clearing=: |
103 | export FWCOOKIE=magical | |
d8eafff6 MW |
104 | case "$#,${1-update}" in |
105 | 1,start | 1,restart | 1,reload | 1,force-reload) | |
bfdc045d | 106 | echo -n "Starting up firewall... " |
d8eafff6 | 107 | "$firewall_script" install || revert "$firewall_failsafe" "Failed" |
bfdc045d MW |
108 | finished |
109 | ;; | |
d8eafff6 | 110 | 1,stop) |
bfdc045d MW |
111 | echo -n "Shutting down firewall... " |
112 | exit_after_clearing=finished | |
113 | ;; | |
d8eafff6 MW |
114 | 1,replace | 1,test) |
115 | echo -n "Running new firewall... " | |
116 | if ! (try "$firewall_script" "$0"); then | |
117 | echo "FAILED." | |
118 | cat "$0.errors" >&2 | |
119 | exit | |
120 | fi | |
121 | echo "done." | |
bfdc045d | 122 | echo "Can you hear me?" |
d8eafff6 MW |
123 | (trap 'exit 127' TERM |
124 | while :; do | |
125 | if [ -f "$0.timebomb" ]; then | |
126 | kill $$ | |
127 | echo "Timebomb went off!" | |
128 | cat "$0.timebomb" | |
129 | exit 1 | |
130 | fi | |
131 | sleep 1 | |
132 | done)& | |
bfdc045d | 133 | read answer |
d8eafff6 MW |
134 | kill $! |
135 | catch "$0" | |
136 | case "$1,$answer" in | |
137 | replace,y* | replace,Y*) | |
138 | install -m755 "$0" "$firewall_script" | |
139 | echo "Cool. Firewall script replaced." | |
bfdc045d MW |
140 | exit 0 |
141 | ;; | |
d8eafff6 MW |
142 | test,y* | test,Y*) |
143 | echo "Cool. Everything seems good." | |
144 | exit 0 | |
145 | ;; | |
146 | *) | |
147 | revert "$firewall_script" "Bogus" | |
148 | ;; | |
bfdc045d | 149 | esac |
bfdc045d | 150 | ;; |
d8eafff6 MW |
151 | 1,remote-prepare) |
152 | try "$firewall_script" "$0" | |
153 | exit 0 | |
154 | ;; | |
155 | 1,remote-commit) | |
156 | catch "$0" | |
157 | install -m755 "$0" "$firewall_script" | |
158 | exit 0 | |
159 | ;; | |
160 | 1,install | 1,revert) | |
bfdc045d MW |
161 | ;; |
162 | *) | |
d8eafff6 MW |
163 | cat >&2 <<EOF |
164 | Usage: | |
165 | $0 start|stop|reload|restart|force-reload | |
166 | $0 replace|test|remote-prepare|remote-commit | |
167 | EOF | |
bfdc045d MW |
168 | exit 1 |
169 | ;; | |
170 | esac | |
171 | ||
172 | m4_divert(-1) | |
173 | ###----- That's all, folks -------------------------------------------------- |