| 1 | m4_divert(-1) ### -*-m4-*- |
| 2 | ### SSH server configuration skeleton. |
| 3 | ### |
| 4 | ### This file is maintained on ibanez: edit it there and run `update-slaves'. |
| 5 | |
| 6 | ### Diversion map. |
| 7 | ### |
| 8 | ### 10 general networking |
| 9 | ### 20 host keys and certificates |
| 10 | ### 30 local system configuration |
| 11 | ### 40 authentication |
| 12 | ### 50 permitted user environment |
| 13 | ### 60 subsystems |
| 14 | ### 90 match blocks |
| 15 | |
| 16 | ###-------------------------------------------------------------------------- |
| 17 | ### Do-not-edit banners. |
| 18 | |
| 19 | m4_divert(0)m4_dnl |
| 20 | ### -*-conf-*- GENERATED FROM sshd_config.m4: DO NOT EDIT! |
| 21 | ### |
| 22 | ### SSH server configuration. |
| 23 | |
| 24 | m4_divert(100)m4_dnl |
| 25 | ### GENERATED FROM sshd_config.m4: NO NOT EDIT! |
| 26 | m4_divert(-1) |
| 27 | |
| 28 | ###-------------------------------------------------------------------------- |
| 29 | ### M4 machinery. |
| 30 | |
| 31 | m4_changequote([, ]) |
| 32 | m4_define([nl], [ |
| 33 | ]) |
| 34 | |
| 35 | ## FOREACH(what, list) |
| 36 | ## |
| 37 | ## The LIST is a comma-separated list of things, like an m4 argument list. |
| 38 | ## For each item in the list, expand WHAT as if it's the body of a macro with |
| 39 | ## the list item as its arguments. In other words, the list item itself can |
| 40 | ## be a list of comma-separated items, which are available as $1, $2, ..., |
| 41 | ## within WHAT. |
| 42 | m4_define([_FOREACH], [m4_dnl |
| 43 | m4_ifelse([$#], [1], [_foreach_func($1)], |
| 44 | [_foreach_func($1)[]_FOREACH(m4_shift($@))])]) |
| 45 | m4_define([FOREACH], [m4_dnl |
| 46 | m4_pushdef([_foreach_func], [$1])m4_dnl |
| 47 | _FOREACH($2)[]m4_dnl |
| 48 | m4_popdef([_foreach_func])]) |
| 49 | |
| 50 | ## KEYTYPE(type) |
| 51 | ## |
| 52 | ## Declare a key type TYPE. This sets a server key and selects a |
| 53 | ## certificate. |
| 54 | m4_define([KEYTYPE], [m4_dnl |
| 55 | HostKey /etc/ssh/ssh_host_$1_key |
| 56 | HostCertificate /etc/ssh/ssh_host_$1_key-cert.pub]) |
| 57 | |
| 58 | ###-------------------------------------------------------------------------- |
| 59 | ### Meta-configuration. |
| 60 | |
| 61 | ## Ports to listen on. |
| 62 | m4_define([PORTS], [22]) |
| 63 | |
| 64 | ###-------------------------------------------------------------------------- |
| 65 | ### Include any local overides. |
| 66 | |
| 67 | m4_sinclude([/etc/ssh/sshd_config.local.m4])m4_divert(-1) |
| 68 | |
| 69 | m4_divert(10)m4_dnl |
| 70 | ###-------------------------------------------------------------------------- |
| 71 | ### General network matters. |
| 72 | |
| 73 | ## Listening port. Don't set an address here: sshd listens on INADDR_ANY by |
| 74 | ## default, and this is good; it also lets a host-specific file override it |
| 75 | ## for special effects (e.g., if covering for another server). |
| 76 | FOREACH([Port $1 |
| 77 | ], [PORTS])m4_dnl |
| 78 | |
| 79 | ## Protocol version. |
| 80 | Protocol 2 |
| 81 | |
| 82 | ## Don't use TCP keepalives: they break connections for no especially good |
| 83 | ## reason. Users can use protocol-level keepalives to keep NAT in line; |
| 84 | ## attackers can use other protocols to chew up TCP connections. |
| 85 | TCPKeepAlive no |
| 86 | |
| 87 | ## On the other hand, suppose that a client opens a number of SSH sessions |
| 88 | ## and then crashes. If there's no output from the server side, the server |
| 89 | ## will never notice that these connections are dead, so they'll consume |
| 90 | ## process slots and (worse) ptys forever. We could fix this by turning |
| 91 | ## TCP-level keepalives on, but they fire too rapidly in the case where the |
| 92 | ## client is suspended or off-net for a while. Instead, get the server to |
| 93 | ## send application-level keepalives after 36 hours. The count max isn't |
| 94 | ## relevant because the TCP session will break before a second keepalive |
| 95 | ## is sent, if the client really is unresponsive. |
| 96 | ClientAliveInterval 129600 |
| 97 | |
| 98 | ## Be relatively generous about authenticating connections. Allow 10 |
| 99 | ## concurrent connections, and start randomly rejecting connections until we |
| 100 | ## top out at 60. |
| 101 | MaxStartups 10:1:60 |
| 102 | |
| 103 | ## Allow heavy multiplexing. It's the users' fault if they overload the |
| 104 | ## connection. |
| 105 | MaxSessions 64 |
| 106 | |
| 107 | m4_divert(20)m4_dnl |
| 108 | ###-------------------------------------------------------------------------- |
| 109 | ### Host keys and certificates. |
| 110 | |
| 111 | ## We strongly prefer RSA keys. OpenSSH hasn't yet caught up with FIPS186--3 |
| 112 | ## and larger DSA keys, but allow it anyway for the sake of compatibility. |
| 113 | ## Later versions allow elliptic curves which is an improvement but not one |
| 114 | ## we can rely on yet. |
| 115 | KEYTYPE(rsa) |
| 116 | KEYTYPE(dsa) |
| 117 | |
| 118 | m4_divert(30)m4_dnl |
| 119 | ###-------------------------------------------------------------------------- |
| 120 | ### Other local system configuration. |
| 121 | |
| 122 | ## Privilege separation doesn't seem to have any obvious downsides. |
| 123 | UsePrivilegeSeparation yes |
| 124 | |
| 125 | ## Logging. |
| 126 | SyslogFacility AUTH |
| 127 | LogLevel INFO |
| 128 | |
| 129 | ## Don't be picky about file modes. |
| 130 | StrictModes no |
| 131 | |
| 132 | m4_divert(40)m4_dnl |
| 133 | ###-------------------------------------------------------------------------- |
| 134 | ### Authentication. |
| 135 | |
| 136 | ## Permitted kinds of authentication. Cryptographic authentication has |
| 137 | ## always been good; passwords are awful but unfortunately necessary. Don't |
| 138 | ## try to do the bizarre cryptographically-reinforced host-based |
| 139 | ## authentication: it's just more painful than necessary. Permit Kerberos |
| 140 | ## authentication via GSS, including key exchange. If hosts need to be |
| 141 | ## revoked then that can be done centrally at the KDC: if anything, it's |
| 142 | ## even easier than the signature-based scheme. |
| 143 | RSAAuthentication yes |
| 144 | PubkeyAuthentication yes |
| 145 | ##GSSAPIAuthentication yes |
| 146 | ##GSSAPIKeyExchange yes |
| 147 | IgnoreRhosts yes |
| 148 | RhostsRSAAuthentication no |
| 149 | HostbasedAuthentication no |
| 150 | |
| 151 | ## Password configuration. Turn off PAM challenge/response authentication |
| 152 | ## (somewhat sadly) because it can override some of our other policy |
| 153 | ## settings. Don't actually allow passwords here: we'll allow them from |
| 154 | ## trusted hosts later. |
| 155 | PasswordAuthentication no |
| 156 | LoginGraceTime 120 |
| 157 | PermitEmptyPasswords no |
| 158 | ChallengeResponseAuthentication no |
| 159 | m4_ifelse(m4_esyscmd([uname]), [OpenBSD]nl, [m4_dnl], [UsePAM yes]) |
| 160 | |
| 161 | ## Don't allow root in here. We can override this setting in a per-host |
| 162 | ## match later. |
| 163 | PermitRootLogin no |
| 164 | |
| 165 | ## Authentication attempts. Users get little control over this if they have |
| 166 | ## a lot of private keys lying around, so be generous. |
| 167 | MaxAuthTries 16 |
| 168 | |
| 169 | m4_divert(50)m4_dnl |
| 170 | ###-------------------------------------------------------------------------- |
| 171 | ### Permitted user environment. |
| 172 | |
| 173 | ## Allow users to set environment variables in their local configuration |
| 174 | ## files. They're already on this side of the airtight hatchway. |
| 175 | PermitUserEnvironment yes |
| 176 | |
| 177 | ## X and agent forwarding are allowed (but users should be careful not to |
| 178 | ## forward me things I shouldn't be allowed to mess with). |
| 179 | AllowAgentForwarding yes |
| 180 | X11Forwarding yes |
| 181 | X11DisplayOffset 10 |
| 182 | |
| 183 | ## Port forwarding is OK. |
| 184 | AllowTcpForwarding yes |
| 185 | GatewayPorts clientspecified |
| 186 | |
| 187 | ## Don't print a message-of-the-day (PAM has probably already done it). |
| 188 | PrintMotd no |
| 189 | |
| 190 | ## Do print last-login information. |
| 191 | PrintLastLog yes |
| 192 | |
| 193 | ## Environment variables. Accept locale-related things and time-zone |
| 194 | ## selection. |
| 195 | AcceptEnv LANG LC_* TZ |
| 196 | |
| 197 | m4_divert(60)m4_dnl |
| 198 | ###-------------------------------------------------------------------------- |
| 199 | ### SSH subsystem configuration. |
| 200 | |
| 201 | ## SFTP. |
| 202 | Subsystem sftp /usr/lib/openssh/sftp-server |
| 203 | m4_define([_KERMIT_SSHSUB], m4_esyscmd([ |
| 204 | sub=none |
| 205 | for i in /usr/local/bin /usr/bin; do |
| 206 | if test -x $i/kermit-sshsub; then sub=$i/kermit-sshsub; break; fi |
| 207 | done |
| 208 | printf "%s" $sub]))m4_dnl |
| 209 | m4_ifelse(_KERMIT_SSHSUB, [none], [], [m4_dnl |
| 210 | Subsystem kermit _KERMIT_SSHSUB |
| 211 | ])m4_dnl |
| 212 | |
| 213 | m4_divert(90)m4_dnl |
| 214 | ###-------------------------------------------------------------------------- |
| 215 | ### Specific match blocks. |
| 216 | |
| 217 | m4_divert(95)m4_dnl |
| 218 | ## Allow root logins from within the trusted network. This is needed to let |
| 219 | ## ibanez do its administration thang. |
| 220 | Match Address 62.49.204.144/28,212.13.198.64/28,172.29.199.0/24,m4_dnl |
| 221 | 2001:470:1f09:1b98::/64,2001:470:9740::/49,m4_dnl |
| 222 | 2001:ba8:0:1d9::/64,2001:ba8:1d9::/49 |
| 223 | PermitRootLogin without-password |
| 224 | PasswordAuthentication yes |
| 225 | |
| 226 | m4_divert(99)m4_dnl |
| 227 | ###------ That's all, folks -------------------------------------------------- |