1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
# $OpenBSD: forward-control.sh,v 1.12 2023/07/28 05:33:15 djm Exp $
# Placed in the Public Domain.
tid="sshd control of local and remote forwarding"
LFWD_PORT=3320
RFWD_PORT=3321
CTL=$OBJ/ctl-sock
WAIT_SECONDS=20
wait_for_process_to_exit() {
_pid=$1
_n=0
while kill -0 $_pid 2>/dev/null ; do
test $_n -eq 1 && trace "waiting for $_pid to exit"
_n=`expr $_n + 1`
test $_n -ge $WAIT_SECONDS && return 1
sleep 1
done
return 0
}
mux_cmd() {
${SSH} -F $OBJ/ssh_proxy -S $CTL -O $1 host 2>&1
}
controlmaster_pid() {
mux_cmd check | cut -f2 -d= | cut -f1 -d')'
}
# usage: check_lfwd Y|N message
check_lfwd() {
_expected=$1
_message=$2
${SSH} -F $OBJ/ssh_proxy \
-L$LFWD_PORT:127.0.0.1:$PORT \
-o ExitOnForwardFailure=yes \
-MS $CTL -o ControlPersist=yes \
-Nf host
mux_cmd check >/dev/null || fatal "check_lfwd ssh fail: $_message"
${SSH} -F $OBJ/ssh_config -p $LFWD_PORT \
-oConnectionAttempts=10 host true >/dev/null 2>&1
_result=$?
_sshpid=`controlmaster_pid`
mux_cmd exit >/dev/null
wait_for_process_to_exit $_sshpid
if test "x$_expected" = "xY" -a $_result -ne 0 ; then
fail "check_lfwd failed (expecting success): $_message"
elif test "x$_expected" = "xN" -a $_result -eq 0 ; then
fail "check_lfwd succeeded (expecting failure): $_message"
elif test "x$_expected" != "xY" -a "x$_expected" != "xN" ; then
fatal "check_lfwd invalid argument \"$_expected\""
else
verbose "check_lfwd done (expecting $_expected): $_message"
fi
}
# usage: check_rfwd Y|N message
check_rfwd() {
_expected=$1
_message=$2
${SSH} -F $OBJ/ssh_proxy \
-R127.0.0.1:$RFWD_PORT:127.0.0.1:$PORT \
-o ExitOnForwardFailure=yes \
-MS $CTL -o ControlPersist=yes \
-Nf host
mux_cmd check >/dev/null
_result=$?
_sshpid=`controlmaster_pid`
if test $_result -eq 0; then
${SSH} -F $OBJ/ssh_config -p $RFWD_PORT \
-oConnectionAttempts=10 host true >/dev/null 2>&1
_result=$?
mux_cmd exit >/dev/null
wait_for_process_to_exit $_sshpid
fi
if test "x$_expected" = "xY" -a $_result -ne 0 ; then
fail "check_rfwd failed (expecting success): $_message"
elif test "x$_expected" = "xN" -a $_result -eq 0 ; then
fail "check_rfwd succeeded (expecting failure): $_message"
elif test "x$_expected" != "xY" -a "x$_expected" != "xN" ; then
fatal "check_rfwd invalid argument \"$_expected\""
else
verbose "check_rfwd done (expecting $_expected): $_message"
fi
}
start_sshd
cp ${OBJ}/sshd_proxy ${OBJ}/sshd_proxy.bak
cp ${OBJ}/authorized_keys_${USER} ${OBJ}/authorized_keys_${USER}.bak
# Sanity check: ensure the default config allows forwarding
check_lfwd Y "default configuration"
check_rfwd Y "default configuration"
# Usage: lperm_tests yes|local|remote|no Y|N Y|N Y|N Y|N Y|N Y|N
lperm_tests() {
_tcpfwd=$1
_plain_lfwd=$2
_plain_rfwd=$3
_nopermit_lfwd=$4
_nopermit_rfwd=$5
_permit_lfwd=$6
_permit_rfwd=$7
_badfwd1=127.0.0.1:22
_badfwd2=127.0.0.2:22
_goodfwd=127.0.0.1:${PORT}
cp ${OBJ}/authorized_keys_${USER}.bak ${OBJ}/authorized_keys_${USER}
_prefix="AllowTcpForwarding=$_tcpfwd"
# No PermitOpen
( cat ${OBJ}/sshd_proxy.bak ;
echo "AllowTcpForwarding $_tcpfwd" ) \
> ${OBJ}/sshd_proxy
check_lfwd $_plain_lfwd "$_prefix"
check_rfwd $_plain_rfwd "$_prefix"
# PermitOpen via sshd_config that doesn't match
( cat ${OBJ}/sshd_proxy.bak ;
echo "AllowTcpForwarding $_tcpfwd" ;
echo "PermitOpen $_badfwd1 $_badfwd2" ) \
> ${OBJ}/sshd_proxy
check_lfwd $_nopermit_lfwd "$_prefix, !PermitOpen"
check_rfwd $_nopermit_rfwd "$_prefix, !PermitOpen"
# PermitOpen via sshd_config that does match
( cat ${OBJ}/sshd_proxy.bak ;
echo "AllowTcpForwarding $_tcpfwd" ;
echo "PermitOpen $_badfwd1 $_goodfwd $_badfwd2" ) \
> ${OBJ}/sshd_proxy
check_lfwd $_plain_lfwd "$_prefix, PermitOpen"
check_rfwd $_plain_rfwd "$_prefix, PermitOpen"
# permitopen keys option.
# NB. permitopen via authorized_keys should have same
# success/fail as via sshd_config
# permitopen via authorized_keys that doesn't match
sed "s/^/permitopen=\"$_badfwd1\",permitopen=\"$_badfwd2\" /" \
< ${OBJ}/authorized_keys_${USER}.bak \
> ${OBJ}/authorized_keys_${USER} || fatal "sed 1 fail"
( cat ${OBJ}/sshd_proxy.bak ;
echo "AllowTcpForwarding $_tcpfwd" ) \
> ${OBJ}/sshd_proxy
check_lfwd $_nopermit_lfwd "$_prefix, !permitopen"
check_rfwd $_nopermit_rfwd "$_prefix, !permitopen"
# permitopen via authorized_keys that does match
sed "s/^/permitopen=\"$_badfwd1\",permitopen=\"$_goodfwd\" /" \
< ${OBJ}/authorized_keys_${USER}.bak \
> ${OBJ}/authorized_keys_${USER} || fatal "sed 2 fail"
( cat ${OBJ}/sshd_proxy.bak ;
echo "AllowTcpForwarding $_tcpfwd" ) \
> ${OBJ}/sshd_proxy
check_lfwd $_permit_lfwd "$_prefix, permitopen"
check_rfwd $_permit_rfwd "$_prefix, permitopen"
# Check port-forwarding flags in authorized_keys.
# These two should refuse all.
sed "s/^/no-port-forwarding /" \
< ${OBJ}/authorized_keys_${USER}.bak \
> ${OBJ}/authorized_keys_${USER} || fatal "sed 3 fail"
( cat ${OBJ}/sshd_proxy.bak ;
echo "AllowTcpForwarding $_tcpfwd" ) \
> ${OBJ}/sshd_proxy
check_lfwd N "$_prefix, no-port-forwarding"
check_rfwd N "$_prefix, no-port-forwarding"
sed "s/^/restrict /" \
< ${OBJ}/authorized_keys_${USER}.bak \
> ${OBJ}/authorized_keys_${USER} || fatal "sed 4 fail"
( cat ${OBJ}/sshd_proxy.bak ;
echo "AllowTcpForwarding $_tcpfwd" ) \
> ${OBJ}/sshd_proxy
check_lfwd N "$_prefix, restrict"
check_rfwd N "$_prefix, restrict"
# This should pass the same cases as _nopermit*
sed "s/^/restrict,port-forwarding /" \
< ${OBJ}/authorized_keys_${USER}.bak \
> ${OBJ}/authorized_keys_${USER} || fatal "sed 5 fail"
( cat ${OBJ}/sshd_proxy.bak ;
echo "AllowTcpForwarding $_tcpfwd" ) \
> ${OBJ}/sshd_proxy
check_lfwd $_plain_lfwd "$_prefix, restrict,port-forwarding"
check_rfwd $_plain_rfwd "$_prefix, restrict,port-forwarding"
}
# permit-open none mismatch match
# AllowTcpForwarding local remote local remote local remote
lperm_tests yes Y Y N Y Y Y
lperm_tests local Y N N N Y N
lperm_tests remote N Y N Y N Y
lperm_tests no N N N N N N
# Usage: rperm_tests yes|local|remote|no Y|N Y|N Y|N Y|N Y|N Y|N
rperm_tests() {
_tcpfwd=$1
_plain_lfwd=$2
_plain_rfwd=$3
_nopermit_lfwd=$4
_nopermit_rfwd=$5
_permit_lfwd=$6
_permit_rfwd=$7
_badfwd1=127.0.0.1:22
_badfwd2=127.0.0.2:${RFWD_PORT}
_goodfwd=127.0.0.1:${RFWD_PORT}
cp ${OBJ}/authorized_keys_${USER}.bak ${OBJ}/authorized_keys_${USER}
_prefix="AllowTcpForwarding=$_tcpfwd"
# PermitListen via sshd_config that doesn't match
( cat ${OBJ}/sshd_proxy.bak ;
echo "AllowTcpForwarding $_tcpfwd" ;
echo "PermitListen $_badfwd1 $_badfwd2" ) \
> ${OBJ}/sshd_proxy
check_lfwd $_nopermit_lfwd "$_prefix, !PermitListen"
check_rfwd $_nopermit_rfwd "$_prefix, !PermitListen"
# PermitListen via sshd_config that does match
( cat ${OBJ}/sshd_proxy.bak ;
echo "AllowTcpForwarding $_tcpfwd" ;
echo "PermitListen $_badfwd1 $_goodfwd $_badfwd2" ) \
> ${OBJ}/sshd_proxy
check_lfwd $_plain_lfwd "$_prefix, PermitListen"
check_rfwd $_plain_rfwd "$_prefix, PermitListen"
}
# permit-remote-open none mismatch match
# AllowTcpForwarding local remote local remote local remote
rperm_tests yes Y Y Y N Y Y
rperm_tests local Y N Y N Y N
rperm_tests remote N Y N N N Y
rperm_tests no N N N N N N
|
