jailsetup.sh

   1 #!/bin/sh
   2 # The Girocco jail setup script
   3 #
   4 # If the first parameter is "dbonly", setup the database only
   5 #
   6 # We are designed to set up the chroot based on the output of
   7 # `uname -s` by sourcing a suitable system-specific script.
   8 # Unrecognized systems will generate an error.  When using
   9 # "dbonly" the setup of the chroot binaries is skipped so the
  10 # output of `uname -s` does not matter in that case.
  11
  12 set -e
  13
  14 curdir="`pwd`"
  15 srcdir="$curdir/src"
  16 getent="$srcdir/getent"
  17 . ./shlib.sh
  18
  19 dbonly=''
  20 [ "$1" != "dbonly" ] || dbonly=1
  21
  22 reserved_users="root sshd _sshd mob git lock bundle nobody everyone $cfg_cgi_user $cfg_mirror_user"
  23
  24 # Require either sshd or _sshd user unless "dbonly"
  25 sshd_user=sshd
  26 if ! "$getent" passwd sshd >/dev/null && ! "$getent" passwd _sshd >/dev/null; then
  27         if [ -n "$dbonly" ]; then
  28                 if [ ! -s etc/passwd ]; then
  29                         # Only complain on initial etc/passwd creation
  30                         echo "WARNING: no sshd or _sshd user, omitting entries from chroot etc/passwd"
  31                 fi
  32                 sshd_user=
  33         else
  34                 echo "*** Error: You do not have required sshd or _sshd user in system." >&2
  35                 exit 1
  36         fi
  37 else
  38         "$getent" passwd sshd >/dev/null || sshd_user=_sshd
  39 fi
  40
  41 # Verify we have all we need
  42 if ! "$getent" passwd "$cfg_mirror_user" >/dev/null; then
  43         echo "*** Error: You do not have \"$cfg_mirror_user\" user in system yet." >&2
  44         exit 1
  45 fi
  46 if ! "$getent" passwd "$cfg_cgi_user" >/dev/null; then
  47         echo "*** Error: You do not have \"$cfg_cgi_user\" user in system yet." >&2
  48         exit 1
  49 fi
  50 if [ -n "$dbonly" -a -z "$cfg_owning_group" ]; then
  51         cfg_owning_group="$("$getent" passwd "$cfg_mirror_user" | cut -d : -f 4)"
  52 elif ! "$getent" group "$cfg_owning_group" >/dev/null; then
  53         echo "*** Error: You do not have \"$cfg_owning_group\" group in system yet." >&2
  54         exit 1
  55 fi
  56
  57 # One last paranoid check before we go writing all over everything
  58 if [ -z "$cfg_chroot" -o "$cfg_chroot" = "/" ]; then
  59         echo "*** Error: chroot location is not set or is invalid." >&2
  60         echo "*** Error: perhaps you have an incorrect Config.pm?" >&2
  61         exit 1
  62 fi
  63
  64 umask 022
  65 mkdir -p "$cfg_chroot"
  66 cd "$cfg_chroot"
  67 chmod 755 "$cfg_chroot" ||
  68         echo "WARNING: Cannot chmod $cfg_chroot"
  69
  70 mkdir -p var/empty
  71 chmod 0555 var/empty ||
  72         echo "WARNING: Cannot chmod a=rx $cfg_chroot/var/empty"
  73
  74 # Set up basic user/group configuration; if there isn't any already
  75 mobpass=''
  76 [ -n "$cfg_mob" ] || mobpass='x'
  77 mkdir -p etc
  78 if [ ! -s etc/passwd ]; then
  79         cat >etc/passwd <<EOT
  80 root:x:0:0:system administrator:/var/empty:/bin/false
  81 nobody:x:$("$getent" passwd nobody | cut -d : -f 3-4):unprivileged user:/var/empty:/bin/false
  82 EOT
  83         [ -z "$sshd_user" ] || cat >>etc/passwd <<EOT
  84 sshd:x:$("$getent" passwd $sshd_user | cut -d : -f 3-4):privilege separation:/var/empty:/bin/false
  85 _sshd:x:$("$getent" passwd $sshd_user | cut -d : -f 3-4):privilege separation:/var/empty:/bin/false
  86 EOT
  87         cat >>etc/passwd <<EOT
  88 $cfg_cgi_user:x:$("$getent" passwd "$cfg_cgi_user" | cut -d : -f 3-5):/:/bin/true
  89 $cfg_mirror_user:x:$("$getent" passwd "$cfg_mirror_user" | cut -d : -f 3-5):/:/bin/true
  90 everyone:x:65537:$("$getent" group "$cfg_owning_group" | cut -d : -f 3):every user:/:/bin/false
  91 mob:$mobpass:65538:$("$getent" group "$cfg_owning_group" | cut -d : -f 3):the mob:/:/bin/git-shell-verify
  92 EOT
  93 elif [ -z "$dbonly" ]; then
  94         # Make sure an sshd entry is present
  95         if ! grep -q '^sshd:' etc/passwd; then
  96                 echo "*** Error: chroot etc/passwd exists but lacks sshd entry." >&2
  97                 exit 1
  98         fi
  99 fi
 100
 101 if [ ! -s etc/group ]; then
 102         cat >etc/group <<EOT
 103 _repo:x:$("$getent" group "$cfg_owning_group" | cut -d : -f 3):$cfg_mirror_user
 104 EOT
 105 fi
 106
 107 # Set up basic default Git configuration; if there isn't any already
 108 mkdir -p etc/girocco
 109 if [ ! -s etc/girocco/.gitconfig ]; then
 110         cat >etc/girocco/.gitconfig <<EOT
 111 [http]
 112         lowSpeedLimit = 1
 113         lowSpeedTime = 600
 114 EOT
 115 fi
 116
 117 mkdir -p etc/sshkeys etc/sshcerts etc/sshactive
 118 for ruser in $reserved_users; do
 119         touch etc/sshkeys/$ruser
 120 done
 121 chgrp $cfg_owning_group etc etc/sshkeys etc/sshcerts etc/sshactive ||
 122         echo "WARNING: Cannot chgrp $cfg_owning_group the etc directories"
 123 chgrp $cfg_owning_group etc/passwd ||
 124         echo "WARNING: Cannot chgrp $cfg_owning_group $cfg_chroot/etc/passwd"
 125 chgrp $cfg_owning_group etc/group ||
 126         echo "WARNING: Cannot chgrp $cfg_owning_group $cfg_chroot/etc/group"
 127 chgrp $cfg_owning_group etc/girocco etc/girocco/.gitconfig ||
 128         echo "WARNING: Cannot chgrp $cfg_owning_group $cfg_chroot/etc/girocco"
 129 chmod g+s etc etc/sshkeys etc/sshcerts etc/sshactive ||
 130         echo "WARNING: Cannot chmod g+s the etc directories"
 131 chmod g+w etc etc/sshkeys etc/sshcerts etc/sshactive ||
 132         echo "WARNING: Cannot chmod g+w the etc directories"
 133 chmod g+w etc/passwd etc/group ||
 134         echo "WARNING: Cannot chmod g+w the etc/passwd and/or etc/group files"
 135 chmod go-w etc/passwd etc/girocco etc/girocco/.gitconfig ||
 136         echo "WARNING: Cannot chmod go-w etc/girocco and/or etc/girocco/.gitconfig"
 137 chmod a-w etc/girocco ||
 138         echo "WARNING: Cannot chmod a-w etc/girocco"
 139 chmod -R g+w etc/sshkeys etc/sshcerts etc/sshactive 2>/dev/null ||
 140         echo "WARNING: Cannot chmod g+w the sshkeys, sshcerts and/or sshactive files"
 141
 142 # Note time of last install
 143 > etc/sshactive/_install
 144
 145 [ -z "$dbonly" ] || exit 0
 146
 147 # Make sure the system type is supported for chroot
 148 sysname="$(uname -s | tr A-Z a-z || :)"
 149 : ${sysname:=linux}
 150 nosshdir=
 151 # These equivalents may need to be expanded at some point
 152 case "$sysname" in
 153         *kfreebsd*)
 154                 sysname=linux;;
 155         *darwin*)
 156                 sysname=darwin;;
 157         *freebsd*)
 158                 sysname=freebsd;;
 159         *linux*)
 160                 sysname=linux;;
 161 esac
 162
 163 chrootsetup="$curdir/chrootsetup_$sysname.sh"
 164 if ! [ -r "$chrootsetup" -a -s "$chrootsetup" ]; then
 165         echo "*** Error: $chrootsetup not found" >&2
 166         echo "*** Error: creating a chroot for a `uname -s` system is not supported" >&2
 167         exit 1
 168 fi
 169
 170 # validate reporoot, chroot and jailreporoot before doing anything more
 171
 172 # validates the passed in dir if a second argument is not empty dir must NOT
 173 # start with / otherwise it must.  A trailing '/' is removed and any duplicated
 174 # // are removed and a sole / or empty is disallowed.
 175 make_valid_dir() {
 176         _check="$(echo "$1" | tr -s /)"
 177         _check="${_check%/}"
 178         [ -z "$_check" -o "$_check" = "/" ] && return 1
 179         if [ -z "$2" ]; then
 180                 # must start with '/'
 181                 case "$_check" in /*) :;; *) return 1; esac
 182         else
 183                 # must NOT start with '/'
 184                 case "$_check" in /*) return 1; esac
 185         fi
 186         echo "$_check"
 187 }
 188
 189 if ! reporoot="$(make_valid_dir "$cfg_reporoot")"; then
 190         echo "*** Error: invalid Config::reporoot: $cfg_reporoot" >&2
 191         echo "*** Error: MUST start with '/' and MUST NOT be '/'" >&2
 192         exit 1
 193 fi
 194 if ! chroot="$(make_valid_dir "$cfg_chroot")"; then
 195         echo "*** Error: invalid Config::chroot: $cfg_chroot" >&2
 196         echo "*** Error: MUST start with '/' and MUST NOT be '/'" >&2
 197         exit 1
 198 fi
 199 if ! jailreporoot="$(make_valid_dir "$cfg_jailreporoot" 1)"; then
 200         echo "*** Error: invalid Config::jailreporoot: $cfg_jailreporoot" >&2
 201         echo "*** Error: MUST NOT start with '/' and MUST NOT be ''" >&2
 202         exit 1
 203 fi
 204
 205 # chroot MUST NOT be reporoot
 206 if [ "$chroot" = "$reporoot" ]; then
 207         echo "*** Error: invalid Config::reporoot: $cfg_reporoot" >&2
 208         echo "*** Error: invalid Config::chroot: $cfg_chroot" >&2
 209         echo "*** Error: reporoot and chroot MUST NOT be the same" >&2
 210         exit 1
 211 fi
 212
 213 # chroot MUST NOT be a subdirectory of reporoot
 214 case "$chroot" in "$reporoot"/*)
 215         echo "*** Error: invalid Config::reporoot: $cfg_reporoot" >&2
 216         echo "*** Error: invalid Config::chroot: $cfg_chroot" >&2
 217         echo "*** Error: chroot MUST NOT be a subdirectory of reporoot" >&2
 218         exit 1
 219 esac
 220
 221 # chroot/jailreporoot MUST NOT be a subdirectory of reporoot
 222 case "$chroot/$jailreporoot" in "$reporoot"/*)
 223         echo "*** Error: invalid Config::reporoot: $cfg_reporoot" >&2
 224         echo "*** Error: invalid Config::chroot: $cfg_chroot" >&2
 225         echo "*** Error: invalid Config::jailreporoot: $cfg_jailreporoot" >&2
 226         echo "*** Error: chroot/jailreporoot MUST NOT be a subdirectory of reporoot" >&2
 227         exit 1
 228 esac
 229
 230 # reporoot MUST NOT be a subdirectory of chroot/jailreporoot
 231 case "$reporoot" in "$chroot/$jailreporoot"/*)
 232         echo "*** Error: invalid Config::reporoot: $cfg_reporoot" >&2
 233         echo "*** Error: invalid Config::chroot: $cfg_chroot" >&2
 234         echo "*** Error: invalid Config::jailreporoot: $cfg_jailreporoot" >&2
 235         echo "*** Error: reporoot MUST NOT be a subdirectory of chroot/jailreporoot" >&2
 236         exit 1
 237 esac
 238
 239 # Set the user and group on the top of the chroot before creating anything else
 240 chown 0:0 "$chroot"
 241
 242 # When we create a fork, the alternates always have an absolute path.
 243 # If reporoot is not --bind mounted at the same location in chroot we must
 244 # create a suitable symlink so the absolute path alternates continue to work
 245 # in the ssh chroot or else forks will be broken in there.
 246 if [ "$reporoot" != "/$jailreporoot" ]; then
 247         mkdirp="$(dirname "${reporoot#/}")"
 248         [ "$mkdirp" = "." ] && mkdirp=
 249         lnback=
 250         [ -z "$mkdirp" ] || lnback="$(echo "$mkdirp/" | sed -e 's,[^/]*/,../,g')"
 251         [ -z "$mkdirp" ] || mkdir -p "$chroot/$mkdirp"
 252         (umask 0; ln -s -f -n "$lnback$jailreporoot" "$chroot$reporoot")
 253         [ $? -eq 0 ] || exit 1
 254 fi
 255
 256 # First, setup basic platform-independent directory structure
 257 mkdir -p bin dev etc lib sbin var/empty var/run "$jailreporoot"
 258 chmod 0555 var/empty
 259 rm -rf usr
 260 ln -s . usr
 261
 262 # Now source the platform-specific script that is responsible for dev device
 263 # setup, proc setup (if needed), lib64 setup (if needed) and basic library
 264 # installation to make a chroot operational.  Additionally it will define a
 265 # pull_in_bin function that can be used to add executables and their library
 266 # dependencies to the chroot and finally will install a suitable nc.openbsd
 267 # compatible version of netcat that supports connections to unix sockets.
 268 . "$chrootsetup"
 269
 270 # Now, bring in sshd, sh etc.
 271 # The $chrootsetup script should have already provided a suitable nc.openbsd
 272 install -p "$cfg_basedir/bin/git-shell-verify" bin
 273 install -p "$cfg_basedir/bin/git-askpass-password" bin
 274 pull_in_bin "$cfg_basedir/bin/can_user_push" bin
 275 pull_in_bin /bin/sh bin
 276 pull_in_bin /bin/date bin
 277 pull_in_bin /bin/mv bin
 278 pull_in_bin /bin/rm bin
 279 pull_in_bin /usr/sbin/sshd sbin
 280
 281 # ...and the bits of git we need,
 282 # being sure to use the configured git and its --exec-path to find the pieces
 283 for i in git git-index-pack git-receive-pack git-shell git-update-server-info git-upload-archive \
 284         git-upload-pack git-unpack-objects git-config git-for-each-ref git-rev-list; do
 285         pull_in_bin "$var_git_exec_path/$i" bin git
 286 done
 287
 288 # Note time of last jailsetup
 289 > etc/sshactive/_jailsetup
 290
 291 # Update permissions on the database files
 292 chown $cfg_cgi_user:$cfg_owning_group etc/passwd etc/group
 293 chown -R $cfg_cgi_user:$cfg_owning_group etc/sshkeys etc/sshcerts etc/sshactive
 294 chown $cfg_mirror_user:$cfg_owning_group etc etc/girocco etc/girocco/.gitconfig
 295
 296 # Set up basic sshd configuration:
 297 if [ -n "$nosshdir" ]; then
 298         rm -rf etc/ssh
 299         ln -s . etc/ssh
 300         [ ! -f /etc/moduli ] || { cp -p /etc/moduli etc/; chown 0:0 etc/moduli; }
 301 else
 302         [ ! -e etc/ssh -o -d etc/ssh ] || rm -rf etc/ssh
 303         mkdir -p etc/ssh
 304         [ ! -f /etc/ssh/moduli ] || { cp -p /etc/ssh/moduli etc/ssh/; chown 0:0 etc/ssh/moduli; }
 305 fi
 306 mkdir -p var/run/sshd
 307 if [ ! -s etc/ssh/sshd_config ]; then
 308         cat >etc/ssh/sshd_config <<EOT
 309 Protocol                2
 310 Port                    $cfg_sshd_jail_port
 311 UsePAM                  no
 312 X11Forwarding           no
 313 AllowAgentForwarding    no
 314 AllowTcpForwarding      no
 315 PermitTunnel            no
 316 IgnoreUserKnownHosts    yes
 317 PrintLastLog            no
 318 PrintMotd               no
 319 UseDNS                  no
 320 PermitRootLogin         no
 321 UsePrivilegeSeparation  yes
 322
 323 HostKey                 /etc/ssh/ssh_host_rsa_key
 324 EOT
 325 if [ -z "$cfg_disable_dsa" ]; then
 326         cat >>etc/ssh/sshd_config <<EOT
 327 HostKey                 /etc/ssh/ssh_host_dsa_key
 328 EOT
 329 fi
 330         cat >>etc/ssh/sshd_config <<EOT
 331 AuthorizedKeysFile      /etc/sshkeys/%u
 332 StrictModes             no
 333
 334 # mob user:
 335 PermitEmptyPasswords    yes
 336 ChallengeResponseAuthentication no
 337 PasswordAuthentication  yes
 338 EOT
 339 fi
 340 if [ ! -s etc/ssh/ssh_host_rsa_key ]; then
 341         bits=2048
 342         if [ "$cfg_rsakeylength" -gt "$bits" ] 2>/dev/null; then
 343                 bits="$cfg_rsakeylength"
 344         fi
 345         yes | ssh-keygen -b "$bits" -t rsa -N "" -C Girocco -f etc/ssh/ssh_host_rsa_key
 346 fi
 347 if [ -z "$cfg_disable_dsa" -a ! -s etc/ssh/ssh_host_dsa_key ]; then
 348         # ssh-keygen can only create 1024 bit DSA keys
 349         yes | ssh-keygen -b 1024 -t dsa -N "" -C Girocco -f etc/ssh/ssh_host_dsa_key
 350 fi
 351
 352 # Set the final permissions on the binaries and perform any final twiddling
 353 chroot_update_permissions
 354
 355 # Change the owner of the sshd-related files
 356 chown 0:0 etc/ssh/ssh_* etc/ssh/sshd_*
 357
 358 echo "--- Add to your boot scripts: mount --bind $reporoot $chroot/$jailreporoot"
 359 echo "--- Add to your boot scripts: mount --bind /proc $chroot/proc"
 360 echo "--- Add to your syslog configuration: listening on socket $chroot/dev/log"
 361 echo "--- To restart a running jail's sshd: sudo kill -HUP \`cat $chroot/var/run/sshd.pid\`"