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 $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 umask 022
  58 mkdir -p "$cfg_chroot"
  59 cd "$cfg_chroot"
  60 chmod 755 "$cfg_chroot" ||
  61         echo "WARNING: Cannot chmod $cfg_chroot"
  62
  63 # Set up basic user/group configuration; if there isn't any already
  64 mobpass=''
  65 [ -n "$cfg_mob" ] || mobpass='x'
  66 mkdir -p etc
  67 if [ ! -s etc/passwd ]; then
  68         cat >etc/passwd <<EOT
  69 root:x:0:0:system administrator:/var/empty:/bin/false
  70 EOT
  71         [ -z "$sshd_user" ] || cat >>etc/passwd <<EOT
  72 sshd:x:$("$getent" passwd $sshd_user | cut -d : -f 3-4):privilege separation:/var/empty:/bin/false
  73 _sshd:x:$("$getent" passwd $sshd_user | cut -d : -f 3-4):privilege separation:/var/empty:/bin/false
  74 EOT
  75         cat >>etc/passwd <<EOT
  76 $cfg_cgi_user:x:$("$getent" passwd "$cfg_cgi_user" | cut -d : -f 3-5):/:/bin/true
  77 $cfg_mirror_user:x:$("$getent" passwd "$cfg_mirror_user" | cut -d : -f 3-5):/:/bin/true
  78 mob:$mobpass:65538:$("$getent" group "$cfg_owning_group" | cut -d : -f 3):the mob:/:/bin/git-shell-verify
  79 EOT
  80 elif [ -z "$dbonly" ]; then
  81         # Make sure an sshd entry is present
  82         if ! grep -q '^sshd:' etc/passwd; then
  83                 echo "*** Error: chroot etc/passwd exists but lacks sshd entry." >&2
  84                 exit 1
  85         fi
  86 fi
  87
  88 if [ ! -s etc/group ]; then
  89         cat >etc/group <<EOT
  90 _repo:x:$(getent group "$cfg_owning_group" | cut -d : -f 3):$cfg_mirror_user
  91 EOT
  92 fi
  93
  94 mkdir -p etc/sshkeys etc/sshcerts
  95 for ruser in $reserved_users; do
  96         touch etc/sshkeys/$ruser
  97 done
  98 chgrp $cfg_owning_group etc etc/sshkeys etc/sshcerts ||
  99         echo "WARNING: Cannot chgrp $cfg_owning_group the etc directories"
 100 chgrp $cfg_owning_group etc/passwd ||
 101         echo "WARNING: Cannot chgrp $cfg_owning_group $cfg_chroot/etc/passwd"
 102 chgrp $cfg_owning_group etc/group ||
 103         echo "WARNING: Cannot chgrp $cfg_owning_group $cfg_chroot/etc/group"
 104 chmod g+s etc etc/sshkeys etc/sshcerts ||
 105         echo "WARNING: Cannot chmod g+s the etc directories"
 106 chmod g+w etc etc/sshkeys etc/sshcerts ||
 107         echo "WARNING: Cannot chmod g+w the etc directories"
 108 chmod g+w etc/passwd etc/group ||
 109         echo "WARNING: Cannot chmod g+w the etc/passwd and/or etc/group files"
 110 chmod -R g+w etc/sshkeys etc/sshcerts 2>/dev/null ||
 111         echo "WARNING: Cannot chmod g+w the sshkeys and/or sshcerts files"
 112
 113 [ -z "$dbonly" ] || exit 0
 114
 115 # Make sure the system type is supported for chroot
 116 sysname="$(uname -s | tr A-Z a-z || :)"
 117 : ${sysname:=linux}
 118 nosshdir=
 119 # These equivalents may need to be expanded at some point
 120 case "$sysname" in
 121         *kfreebsd*)
 122                 sysname=linux;;
 123         *darwin*)
 124                 sysname=darwin;;
 125         *freebsd*)
 126                 sysname=freebsd;;
 127         *linux*)
 128                 sysname=linux;;
 129 esac
 130
 131 chrootsetup="$curdir/chrootsetup_$sysname.sh"
 132 if ! [ -r "$chrootsetup" -a -s "$chrootsetup" ]; then
 133         echo "*** Error: $chrootsetup not found"
 134         echo "*** Error: creating a chroot for a `uname -s` system is not supported"
 135         exit 1
 136 fi
 137
 138 # Set the user and group on the top of the chroot before creating anything else
 139 chown 0:0 "$cfg_chroot"
 140
 141 # First, setup basic platform-independent directory structure
 142 mkdir -p bin dev etc lib sbin var/empty var/run ${cfg_jailreporoot#/}
 143 rm -rf usr
 144 ln -s . usr
 145
 146 # Now source the platform-specific script that is responsible for dev device
 147 # setup, proc setup (if needed), lib64 setup (if needed) and basic library
 148 # installation to make a chroot operational.  Additionally it will define a
 149 # pull_in_bin function that can be used to add executables and their library
 150 # dependencies to the chroot and finally will install a suitable nc.openbsd
 151 # compatible version of netcat that supports connections to unix sockets.
 152 . "$chrootsetup"
 153
 154 # Now, bring in sshd, sh etc.
 155 # The $chrootsetup script should have already provided a suitable nc.openbsd
 156 install -p "$cfg_basedir/bin/git-shell-verify" bin
 157 pull_in_bin "$cfg_basedir/bin/can_user_push" bin
 158 pull_in_bin /bin/sh bin
 159 pull_in_bin /bin/date bin
 160 pull_in_bin /bin/mv bin
 161 pull_in_bin /bin/rm bin
 162 # If /sbin/sshd is already running within the chroot, we get Text file busy
 163 pull_in_bin /usr/sbin/sshd sbin || :
 164
 165 # ...and the bits of git we need,
 166 # being sure to use the configured git and its --exec-path to find the pieces
 167 git_exec_path="$("$cfg_git_bin" --exec-path)"
 168 for i in git git-index-pack git-receive-pack git-shell git-update-server-info git-upload-archive \
 169         git-upload-pack git-unpack-objects git-show-ref git-config git-for-each-ref; do
 170         pull_in_bin "$git_exec_path/$i" bin
 171 done
 172
 173 # Update permissions on the database files
 174 chown $cfg_cgi_user:$cfg_owning_group etc etc/passwd etc/group
 175 chown -R $cfg_cgi_user:$cfg_owning_group etc/sshkeys etc/sshcerts
 176
 177 # Set up basic sshd configuration:
 178 if [ -n "$nosshdir" ]; then
 179         rm -rf etc/ssh
 180         ln -s . etc/ssh
 181         [ ! -f /etc/moduli ] || { cp -p /etc/moduli etc/; chown 0:0 etc/moduli; }
 182 else
 183         [ ! -e etc/ssh -o -d etc/ssh ] || rm -rf etc/ssh
 184         mkdir -p etc/ssh
 185         [ ! -f /etc/ssh/moduli ] || { cp -p /etc/ssh/moduli etc/ssh/; chown 0:0 etc/ssh/moduli; }
 186 fi
 187 mkdir -p var/run/sshd
 188 if [ ! -s etc/ssh/sshd_config ]; then
 189         cat >etc/ssh/sshd_config <<EOT
 190 Protocol        2
 191 Port            22
 192 UsePAM          no
 193 X11Forwarding   no
 194 PermitRootLogin no
 195 UsePrivilegeSeparation yes
 196
 197 AuthorizedKeysFile      /etc/sshkeys/%u
 198 StrictModes     no
 199
 200 # mob user:
 201 PermitEmptyPasswords    yes
 202 ChallengeResponseAuthentication no
 203 PasswordAuthentication  yes
 204 EOT
 205 fi
 206 if [ ! -s etc/ssh/ssh_host_dsa_key ]; then
 207         yes | ssh-keygen -N "" -C Girocco -t dsa -f etc/ssh/ssh_host_dsa_key
 208 fi
 209 if [ ! -s etc/ssh/ssh_host_rsa_key ]; then
 210         yes | ssh-keygen -N "" -C Girocco -t rsa -f etc/ssh/ssh_host_rsa_key
 211 fi
 212
 213 # Set the final permissions on the binaries and perform any final twiddling
 214 chroot_update_permissions
 215
 216 # Change the owner of the sshd-related files
 217 chown 0:0 etc/ssh/ssh_* etc/ssh/sshd_*
 218
 219 echo "--- Add to your boot scripts: mount --bind $cfg_reporoot $cfg_chroot/$cfg_jailreporoot"
 220 echo "--- Add to your boot scripts: mount --bind /proc $cfg_chroot/proc"
 221 echo "--- Add to your syslog configuration: listening on socket $cfg_chroot/dev/log"