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 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 $cfg_chroot"
  69
  70 # Set up basic user/group configuration; if there isn't any already
  71 mobpass=''
  72 [ -n "$cfg_mob" ] || mobpass='x'
  73 mkdir -p etc
  74 if [ ! -s etc/passwd ]; then
  75         cat >etc/passwd <<EOT
  76 root:x:0:0:system administrator:/var/empty:/bin/false
  77 nobody:x:$("$getent" passwd nobody | cut -d : -f 3-4):unprivileged user:/var/empty:/bin/false
  78 EOT
  79         [ -z "$sshd_user" ] || cat >>etc/passwd <<EOT
  80 sshd:x:$("$getent" passwd $sshd_user | cut -d : -f 3-4):privilege separation:/var/empty:/bin/false
  81 _sshd:x:$("$getent" passwd $sshd_user | cut -d : -f 3-4):privilege separation:/var/empty:/bin/false
  82 EOT
  83         cat >>etc/passwd <<EOT
  84 $cfg_cgi_user:x:$("$getent" passwd "$cfg_cgi_user" | cut -d : -f 3-5):/:/bin/true
  85 $cfg_mirror_user:x:$("$getent" passwd "$cfg_mirror_user" | cut -d : -f 3-5):/:/bin/true
  86 everyone:x:65537:$("$getent" group "$cfg_owning_group" | cut -d : -f 3):every user:/:/bin/false
  87 mob:$mobpass:65538:$("$getent" group "$cfg_owning_group" | cut -d : -f 3):the mob:/:/bin/git-shell-verify
  88 EOT
  89 elif [ -z "$dbonly" ]; then
  90         # Make sure an sshd entry is present
  91         if ! grep -q '^sshd:' etc/passwd; then
  92                 echo "*** Error: chroot etc/passwd exists but lacks sshd entry." >&2
  93                 exit 1
  94         fi
  95 fi
  96
  97 if [ ! -s etc/group ]; then
  98         cat >etc/group <<EOT
  99 _repo:x:$("$getent" group "$cfg_owning_group" | cut -d : -f 3):$cfg_mirror_user
 100 EOT
 101 fi
 102
 103 # Set up basic default Git configuration; if there isn't any already
 104 mkdir -p etc/girocco
 105 if [ ! -s etc/girocco/.gitconfig ]; then
 106         cat >etc/girocco/.gitconfig <<EOT
 107 [http]
 108         lowSpeedLimit = 1
 109         lowSpeedTime = 600
 110 EOT
 111 fi
 112
 113 mkdir -p etc/sshkeys etc/sshcerts etc/sshactive
 114 for ruser in $reserved_users; do
 115         touch etc/sshkeys/$ruser
 116 done
 117 chgrp $cfg_owning_group etc etc/sshkeys etc/sshcerts etc/sshactive ||
 118         echo "WARNING: Cannot chgrp $cfg_owning_group the etc directories"
 119 chgrp $cfg_owning_group etc/passwd ||
 120         echo "WARNING: Cannot chgrp $cfg_owning_group $cfg_chroot/etc/passwd"
 121 chgrp $cfg_owning_group etc/group ||
 122         echo "WARNING: Cannot chgrp $cfg_owning_group $cfg_chroot/etc/group"
 123 chgrp $cfg_owning_group etc/girocco etc/girocco/.gitconfig ||
 124         echo "WARNING: Cannot chgrp $cfg_owning_group $cfg_chroot/etc/girocco"
 125 chmod g+s etc etc/sshkeys etc/sshcerts etc/sshactive ||
 126         echo "WARNING: Cannot chmod g+s the etc directories"
 127 chmod g+w etc etc/sshkeys etc/sshcerts etc/sshactive ||
 128         echo "WARNING: Cannot chmod g+w the etc directories"
 129 chmod g+w etc/passwd etc/group ||
 130         echo "WARNING: Cannot chmod g+w the etc/passwd and/or etc/group files"
 131 chmod go-w etc/passwd etc/girocco etc/girocco/.gitconfig ||
 132         echo "WARNING: Cannot chmod go-w etc/girocco and/or etc/girocco/.gitconfig"
 133 chmod a-w etc/girocco ||
 134         echo "WARNING: Cannot chmod a-w etc/girocco"
 135 chmod -R g+w etc/sshkeys etc/sshcerts etc/sshactive 2>/dev/null ||
 136         echo "WARNING: Cannot chmod g+w the sshkeys, sshcerts and/or sshactive files"
 137
 138 # Note time of last install
 139 > etc/sshactive/_install
 140
 141 [ -z "$dbonly" ] || exit 0
 142
 143 # Make sure the system type is supported for chroot
 144 sysname="$(uname -s | tr A-Z a-z || :)"
 145 : ${sysname:=linux}
 146 nosshdir=
 147 # These equivalents may need to be expanded at some point
 148 case "$sysname" in
 149         *kfreebsd*)
 150                 sysname=linux;;
 151         *darwin*)
 152                 sysname=darwin;;
 153         *freebsd*)
 154                 sysname=freebsd;;
 155         *linux*)
 156                 sysname=linux;;
 157 esac
 158
 159 chrootsetup="$curdir/chrootsetup_$sysname.sh"
 160 if ! [ -r "$chrootsetup" -a -s "$chrootsetup" ]; then
 161         echo "*** Error: $chrootsetup not found" >&2
 162         echo "*** Error: creating a chroot for a `uname -s` system is not supported" >&2
 163         exit 1
 164 fi
 165
 166 # validate reporoot, chroot and jailreporoot before doing anything more
 167
 168 # validates the passed in dir if a second argument is not empty dir must NOT
 169 # start with / otherwise it must.  A trailing '/' is removed and any duplicated
 170 # // are removed and a sole / or empty is disallowed.
 171 make_valid_dir() {
 172         _check="$(echo "$1" | tr -s /)"
 173         _check="${_check%/}"
 174         [ -z "$_check" -o "$_check" = "/" ] && return 1
 175         if [ -z "$2" ]; then
 176                 # must start with '/'
 177                 case "$_check" in /*) :;; *) return 1; esac
 178         else
 179                 # must NOT start with '/'
 180                 case "$_check" in /*) return 1; esac
 181         fi
 182         echo "$_check"
 183 }
 184
 185 if ! reporoot="$(make_valid_dir "$cfg_reporoot")"; then
 186         echo "*** Error: invalid Config::reporoot: $cfg_reporoot" >&2
 187         echo "*** Error: MUST start with '/' and MUST NOT be '/'" >&2
 188         exit 1
 189 fi
 190 if ! chroot="$(make_valid_dir "$cfg_chroot")"; then
 191         echo "*** Error: invalid Config::chroot: $cfg_chroot" >&2
 192         echo "*** Error: MUST start with '/' and MUST NOT be '/'" >&2
 193         exit 1
 194 fi
 195 if ! jailreporoot="$(make_valid_dir "$cfg_jailreporoot" 1)"; then
 196         echo "*** Error: invalid Config::jailreporoot: $cfg_jailreporoot" >&2
 197         echo "*** Error: MUST NOT start with '/' and MUST NOT be ''" >&2
 198         exit 1
 199 fi
 200
 201 # chroot MUST NOT be reporoot
 202 if [ "$chroot" = "$reporoot" ]; then
 203         echo "*** Error: invalid Config::reporoot: $cfg_reporoot" >&2
 204         echo "*** Error: invalid Config::chroot: $cfg_chroot" >&2
 205         echo "*** Error: reporoot and chroot MUST NOT be the same" >&2
 206         exit 1
 207 fi
 208
 209 # chroot MUST NOT be a subdirectory of reporoot
 210 case "$chroot" in "$reporoot"/*)
 211         echo "*** Error: invalid Config::reporoot: $cfg_reporoot" >&2
 212         echo "*** Error: invalid Config::chroot: $cfg_chroot" >&2
 213         echo "*** Error: chroot MUST NOT be a subdirectory of reporoot" >&2
 214         exit 1
 215 esac
 216
 217 # chroot/jailreporoot MUST NOT be a subdirectory of reporoot
 218 case "$chroot/$jailreporoot" in "$reporoot"/*)
 219         echo "*** Error: invalid Config::reporoot: $cfg_reporoot" >&2
 220         echo "*** Error: invalid Config::chroot: $cfg_chroot" >&2
 221         echo "*** Error: invalid Config::jailreporoot: $cfg_jailreporoot" >&2
 222         echo "*** Error: chroot/jailreporoot MUST NOT be a subdirectory of reporoot" >&2
 223         exit 1
 224 esac
 225
 226 # reporoot MUST NOT be a subdirectory of chroot/jailreporoot
 227 case "$reporoot" in "$chroot/$jailreporoot"/*)
 228         echo "*** Error: invalid Config::reporoot: $cfg_reporoot" >&2
 229         echo "*** Error: invalid Config::chroot: $cfg_chroot" >&2
 230         echo "*** Error: invalid Config::jailreporoot: $cfg_jailreporoot" >&2
 231         echo "*** Error: reporoot MUST NOT be a subdirectory of chroot/jailreporoot" >&2
 232         exit 1
 233 esac
 234
 235 # Set the user and group on the top of the chroot before creating anything else
 236 chown 0:0 "$chroot"
 237
 238 # When we create a fork, the alternates always have an absolute path.
 239 # If reporoot is not --bind mounted at the same location in chroot we must
 240 # create a suitable symlink so the absolute path alternates continue to work
 241 # in the ssh chroot or else forks will be broken in there.
 242 if [ "$reporoot" != "/$jailreporoot" ]; then
 243         mkdirp="$(dirname "${reporoot#/}")"
 244         [ "$mkdirp" = "." ] && mkdirp=
 245         lnback=
 246         [ -z "$mkdirp" ] || lnback="$(echo "$mkdirp/" | sed -e 's,[^/]*/,../,g')"
 247         [ -z "$mkdirp" ] || mkdir -p "$chroot/$mkdirp"
 248         (umask 0; ln -s -f -n "$lnback$jailreporoot" "$chroot$reporoot")
 249         [ $? -eq 0 ] || exit 1
 250 fi
 251
 252 # First, setup basic platform-independent directory structure
 253 mkdir -p bin dev etc lib sbin var/empty var/run "$jailreporoot"
 254 chmod 0444 var/empty
 255 rm -rf usr
 256 ln -s . usr
 257
 258 # Now source the platform-specific script that is responsible for dev device
 259 # setup, proc setup (if needed), lib64 setup (if needed) and basic library
 260 # installation to make a chroot operational.  Additionally it will define a
 261 # pull_in_bin function that can be used to add executables and their library
 262 # dependencies to the chroot and finally will install a suitable nc.openbsd
 263 # compatible version of netcat that supports connections to unix sockets.
 264 . "$chrootsetup"
 265
 266 # Now, bring in sshd, sh etc.
 267 # The $chrootsetup script should have already provided a suitable nc.openbsd
 268 install -p "$cfg_basedir/bin/git-shell-verify" bin
 269 pull_in_bin "$cfg_basedir/bin/can_user_push" bin
 270 pull_in_bin /bin/sh bin
 271 pull_in_bin /bin/date bin
 272 pull_in_bin /bin/mv bin
 273 pull_in_bin /bin/rm bin
 274 pull_in_bin /usr/sbin/sshd sbin
 275
 276 # ...and the bits of git we need,
 277 # being sure to use the configured git and its --exec-path to find the pieces
 278 git_exec_path="$("$cfg_git_bin" --exec-path)"
 279 for i in git git-index-pack git-receive-pack git-shell git-update-server-info git-upload-archive \
 280         git-upload-pack git-unpack-objects git-show-ref git-config git-for-each-ref git-rev-list; do
 281         pull_in_bin "$git_exec_path/$i" bin git
 282 done
 283
 284 # Note time of last jailsetup
 285 > etc/sshactive/_jailsetup
 286
 287 # Update permissions on the database files
 288 chown $cfg_cgi_user:$cfg_owning_group etc/passwd etc/group
 289 chown -R $cfg_cgi_user:$cfg_owning_group etc/sshkeys etc/sshcerts etc/sshactive
 290 chown $cfg_mirror_user:$cfg_owning_group etc etc/girocco etc/girocco/.gitconfig
 291
 292 # Set up basic sshd configuration:
 293 if [ -n "$nosshdir" ]; then
 294         rm -rf etc/ssh
 295         ln -s . etc/ssh
 296         [ ! -f /etc/moduli ] || { cp -p /etc/moduli etc/; chown 0:0 etc/moduli; }
 297 else
 298         [ ! -e etc/ssh -o -d etc/ssh ] || rm -rf etc/ssh
 299         mkdir -p etc/ssh
 300         [ ! -f /etc/ssh/moduli ] || { cp -p /etc/ssh/moduli etc/ssh/; chown 0:0 etc/ssh/moduli; }
 301 fi
 302 mkdir -p var/run/sshd
 303 if [ ! -s etc/ssh/sshd_config ]; then
 304         cat >etc/ssh/sshd_config <<EOT
 305 Protocol                2
 306 Port                    $cfg_sshd_jail_port
 307 UsePAM                  no
 308 X11Forwarding           no
 309 AllowAgentForwarding    no
 310 AllowTcpForwarding      no
 311 PermitTunnel            no
 312 IgnoreUserKnownHosts    yes
 313 PrintLastLog            no
 314 PrintMotd               no
 315 UseDNS                  no
 316 PermitRootLogin         no
 317 UsePrivilegeSeparation  yes
 318
 319 HostKey                 /etc/ssh/ssh_host_rsa_key
 320 EOT
 321 if [ -z "$cfg_disable_dsa" ]; then
 322         cat >>etc/ssh/sshd_config <<EOT
 323 HostKey                 /etc/ssh/ssh_host_dsa_key
 324 EOT
 325 fi
 326         cat >>etc/ssh/sshd_config <<EOT
 327 AuthorizedKeysFile      /etc/sshkeys/%u
 328 StrictModes             no
 329
 330 # mob user:
 331 PermitEmptyPasswords    yes
 332 ChallengeResponseAuthentication no
 333 PasswordAuthentication  yes
 334 EOT
 335 fi
 336 if [ ! -s etc/ssh/ssh_host_rsa_key ]; then
 337         bits=2048
 338         if [ "$cfg_rsakeylength" -gt "$bits" ] 2>/dev/null; then
 339                 bits="$cfg_rsakeylength"
 340         fi
 341         yes | ssh-keygen -b "$bits" -t rsa -N "" -C Girocco -f etc/ssh/ssh_host_rsa_key
 342 fi
 343 if [ -z "$cfg_disable_dsa" -a ! -s etc/ssh/ssh_host_dsa_key ]; then
 344         # ssh-keygen can only create 1024 bit DSA keys
 345         yes | ssh-keygen -b 1024 -t dsa -N "" -C Girocco -f etc/ssh/ssh_host_dsa_key
 346 fi
 347
 348 # Set the final permissions on the binaries and perform any final twiddling
 349 chroot_update_permissions
 350
 351 # Change the owner of the sshd-related files
 352 chown 0:0 etc/ssh/ssh_* etc/ssh/sshd_*
 353
 354 echo "--- Add to your boot scripts: mount --bind $reporoot $chroot/$jailreporoot"
 355 echo "--- Add to your boot scripts: mount --bind /proc $chroot/proc"
 356 echo "--- Add to your syslog configuration: listening on socket $chroot/dev/log"
 357 echo "--- To restart a running jail's sshd: sudo kill -HUP \`cat $chroot/var/run/sshd.pid\`"