summaryrefslogtreecommitdiff
path: root/debian/openssh-server.postinst
blob: a438a4e0661bbde9121684b814dffdb333cb0162 (plain)
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
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
#!/bin/sh -e

action="$1"
oldversion="$2"

umask 022


get_config_option() {
	option="$1"

	[ -f /etc/ssh/sshd_config ] || return

	# TODO: actually only one '=' allowed after option
	perl -lne 's/\s+/ /g; print if s/^\s*'"$option"'[[:space:]=]+//i' \
	   /etc/ssh/sshd_config
}


set_config_option() {
	option="$1"
	value="$2"

	perl -le '
		$option = $ARGV[0]; $value = $ARGV[1]; $done = 0;
		while (<STDIN>) {
			chomp;
			(my $match = $_) =~ s/\s+/ /g;
			if ($match =~ s/^\s*\Q$option\E\s+.*/$option $value/) {
				$_ = $match;
				$done = 1;
			}
			print;
		}
		print "$option $value" unless $done;' \
		"$option" "$value" \
		< /etc/ssh/sshd_config > /etc/ssh/sshd_config.dpkg-new
	chown --reference /etc/ssh/sshd_config /etc/ssh/sshd_config.dpkg-new
	chmod --reference /etc/ssh/sshd_config /etc/ssh/sshd_config.dpkg-new
	mv /etc/ssh/sshd_config.dpkg-new /etc/ssh/sshd_config
}


rename_config_option() {
	oldoption="$1"
	newoption="$2"

	value="$(get_config_option "$oldoption")"
	[ "$value" ] || return 0

	perl -le '
		$oldoption = $ARGV[0]; $newoption = $ARGV[1];
		while (<STDIN>) {
			chomp;
			(my $match = $_) =~ s/\s+/ /g;
			# TODO: actually only one "=" allowed after option
			if ($match =~ s/^(\s*)\Q$oldoption\E([[:space:]=]+)/$1$newoption$2/i) {
				$_ = $match;
			}
			print;
		}' \
		"$oldoption" "$newoption" \
		< /etc/ssh/sshd_config > /etc/ssh/sshd_config.dpkg-new
	chown --reference /etc/ssh/sshd_config /etc/ssh/sshd_config.dpkg-new
	chmod --reference /etc/ssh/sshd_config /etc/ssh/sshd_config.dpkg-new
	mv /etc/ssh/sshd_config.dpkg-new /etc/ssh/sshd_config
}


host_keys_required() {
	hostkeys="$(get_config_option HostKey)"
	if [ "$hostkeys" ]; then
		echo "$hostkeys"
	else
		# No HostKey directives at all, so the server picks some
		# defaults depending on the setting of Protocol.
		protocol="$(get_config_option Protocol)"
		[ "$protocol" ] || protocol=1,2
		if echo "$protocol" | grep 1 >/dev/null; then
			echo /etc/ssh/ssh_host_key
		fi
		if echo "$protocol" | grep 2 >/dev/null; then
			echo /etc/ssh/ssh_host_rsa_key
			echo /etc/ssh/ssh_host_dsa_key
			echo /etc/ssh/ssh_host_ecdsa_key
		fi
	fi
}


create_key() {
	msg="$1"
	shift
	hostkeys="$1"
	shift
	file="$1"
	shift

	if echo "$hostkeys" | grep -x "$file" >/dev/null && \
	   [ ! -f "$file" ] ; then
		echo -n $msg
		ssh-keygen -q -f "$file" -N '' "$@"
		echo
		if which restorecon >/dev/null 2>&1; then
			restorecon "$file.pub"
		fi
	fi
}


create_keys() {
	hostkeys="$(host_keys_required)"

	create_key "Creating SSH1 key; this may take some time ..." \
		"$hostkeys" /etc/ssh/ssh_host_key -t rsa1

	create_key "Creating SSH2 RSA key; this may take some time ..." \
		"$hostkeys" /etc/ssh/ssh_host_rsa_key -t rsa
	create_key "Creating SSH2 DSA key; this may take some time ..." \
		"$hostkeys" /etc/ssh/ssh_host_dsa_key -t dsa
	create_key "Creating SSH2 ECDSA key; this may take some time ..." \
		"$hostkeys" /etc/ssh/ssh_host_ecdsa_key -t ecdsa
}


fix_loglevel_silent() {
	if [ "$(get_config_option LogLevel)" = SILENT ]; then
		set_config_option LogLevel QUIET
	fi
}


create_sshdconfig() {
	if [ -e /etc/ssh/sshd_config ] ; then
	    # Upgrade an existing sshd configuration.

	    # This option was renamed in 3.8p1, but we never took care
	    # of adjusting the configuration file until now.
	    if dpkg --compare-versions "$oldversion" lt 1:4.7p1-8; then
		rename_config_option KeepAlive TCPKeepAlive
	    fi

	    # 'LogLevel SILENT' is now equivalent to QUIET.
	    if dpkg --compare-versions "$oldversion" lt 1:5.4p1-1; then
		fix_loglevel_silent
	    fi

	    return 0
	fi

	cat <<EOF > /etc/ssh/sshd_config
# Package generated configuration file
# See the sshd_config(5) manpage for details

# What ports, IPs and protocols we listen for
Port 22
# Use these options to restrict which interfaces/protocols sshd will bind to
#ListenAddress ::
#ListenAddress 0.0.0.0
Protocol 2
# HostKeys for protocol version 2
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_dsa_key
HostKey /etc/ssh/ssh_host_ecdsa_key
#Privilege Separation is turned on for security
UsePrivilegeSeparation yes

# Lifetime and size of ephemeral version 1 server key
KeyRegenerationInterval 3600
ServerKeyBits 768

# Logging
SyslogFacility AUTH
LogLevel INFO

# Authentication:
LoginGraceTime 120
PermitRootLogin yes
StrictModes yes

RSAAuthentication yes
PubkeyAuthentication yes
#AuthorizedKeysFile	%h/.ssh/authorized_keys

# Don't read the user's ~/.rhosts and ~/.shosts files
IgnoreRhosts yes
# For this to work you will also need host keys in /etc/ssh_known_hosts
RhostsRSAAuthentication no
# similar for protocol version 2
HostbasedAuthentication no
# Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication
#IgnoreUserKnownHosts yes

# To enable empty passwords, change to yes (NOT RECOMMENDED)
PermitEmptyPasswords no

# Change to yes to enable challenge-response passwords (beware issues with
# some PAM modules and threads)
ChallengeResponseAuthentication no

# Change to no to disable tunnelled clear text passwords
#PasswordAuthentication yes

# Kerberos options
#KerberosAuthentication no
#KerberosGetAFSToken no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes

# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes

X11Forwarding yes
X11DisplayOffset 10
PrintMotd no
PrintLastLog yes
TCPKeepAlive yes
#UseLogin no

#MaxStartups 10:30:60
#Banner /etc/issue.net

# Allow client to pass locale environment variables
AcceptEnv LANG LC_*

Subsystem sftp /usr/lib/openssh/sftp-server

# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
# be allowed through the ChallengeResponseAuthentication and
# PasswordAuthentication.  Depending on your PAM configuration,
# PAM authentication via ChallengeResponseAuthentication may bypass
# the setting of "PermitRootLogin without-password".
# If you just want the PAM account and session checks to run without
# PAM authentication, then enable this but set PasswordAuthentication
# and ChallengeResponseAuthentication to 'no'.
UsePAM yes
EOF
}

fix_statoverride() {
# Remove an erronous override for sshd (we should have overridden ssh)
	if [ -x /usr/sbin/dpkg-statoverride ]; then
		if dpkg-statoverride --list /usr/sbin/sshd >/dev/null ; then
			dpkg-statoverride --remove /usr/sbin/sshd
		fi
	fi
}

setup_sshd_user() {
	if ! getent passwd sshd >/dev/null; then
		adduser --quiet --system --no-create-home --home /var/run/sshd --shell /usr/sbin/nologin sshd
	fi
}

remove_old_init_links() {
	# Yes, this only works with the SysV init script layout. I know.
	# The important thing is that it doesn't actually *break* with
	# file-rc ...
	if [ -e /etc/rc2.d/S20ssh ]; then
		update-rc.d -f ssh remove >/dev/null 2>&1
	fi
	rm -f /etc/rc0.d/K??ssh /etc/rc1.d/K??ssh /etc/rc6.d/K??ssh
}

if [ "$action" = configure ]; then
	create_sshdconfig
	create_keys
	fix_statoverride
	setup_sshd_user
	if dpkg --compare-versions "$2" lt 1:5.2p1-1; then
	    remove_old_init_links
	fi
	# Renamed to /etc/ssh/moduli in 2.9.9 (!)
	if dpkg --compare-versions "$2" lt 1:4.7p1-1; then
	    rm -f /etc/ssh/primes
	fi
	if dpkg --compare-versions "$2" lt 1:5.5p1-6; then
	    rm -f /var/run/sshd/.placeholder
	fi
fi

#DEBHELPER#

exit 0