#!/bin/sh
#
# (c) Copyright by Wolfgang Fuschlberger
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#    ( http://www.fsf.org/licenses/gpl.txt )

# first Release: 2004-07-30
# latest update: 2006-07-17
#
# The latest version of the script is available at
#   http://www.fuschlberger.net/programs/ssh-scp-chroot-jail/
#
# Feedback is welcome!
#
# Thanks for Bugfixes / Enhancements to 
# Michael Prokop <http://www.michael-prokop.at/chroot/>,
# Randy K., Randy D. and Jonathan Hunter.

#
# Features:
# - enable scp and sftp in the chroot-jail
# - use one directory (default /home/jail/) as chroot for all users
################################################################################

# Check if we are called with username or update
if [ -z "$1" ] ; then
  echo
  echo "Error: Parameter missing. Did you forget the username?"
  echo "-------------------------------------------------------------"
  echo "Creating new chrooted account:"
  echo "Usage: $0 username"
  echo
  echo "or specify \$SHELL and path where the jail should be located:"
  echo "Usage: $0 username [/path/to/chroot-shell [/path/to/jail]]"
  echo "Default shell       = /bin/chroot-shell"
  echo "Default chroot-path = /home/jail"
  echo "-------------------------------------------------------------"
  echo "Updating files in the chroot-jail:"
  echo "Usage: $0 update [/path/to/chroot-shell [/path/to/jail]]"
  echo "-------------------------------------------------------------"
  echo "To uninstall: # userdel \$USER"
  echo "              # rm -rf /home/jail"
  echo "              # rm -f /bin/chroot-shell"
  echo "              delete the User's line from /etc/sudoers"
  exit
fi

echo "Am I root?  "
if [ "$(whoami &2>/dev/null)" != "root" ] && [ "$(id -un &2>/dev/null)" != "root" ] ; then
  echo "  NO!

Error: You must be root to run this script."
  exit 1
fi
echo "  OK";

# Check existence of necessary files
echo "Checking distribution... "
if [ -f /etc/debian_version ];
  then echo "  Supported Distribution found"
       echo -e "  System is running Debian Linux\n"
       DISTRO=DEBIAN;
elif [ -f /etc/SuSE-release ];
  then echo "  Supported Distribution found"
       echo -e "  System is running SuSE Linux\n"
       DISTRO=SUSE;
elif [ -f /etc/fedora-release ];
  then echo "  Supported Distribution found"
       echo -e "  System is running Fedora Linux\n"
       DISTRO=FEDORA;
elif [ -f /etc/redhat-release ];
  then echo "  Supported Distribution found"
       echo -e "  System is running Red Hat Linux\n"
       DISTRO=REDHAT;
else echo -e "  failed...........\nThis script works best on Debian, Red Hat and SuSE Linux!\nLet's try it nevertheless....\n"
#exit 1
fi

# Specify the apps you want to copy to the jail
if [ "$DISTRO" = SUSE ]; then
  APPS="/bin/bash /bin/cp /usr/bin/dircolors /bin/ls /bin/mkdir /bin/mv /bin/rm /bin/rmdir /bin/sh /bin/su /usr/bin/groups /usr/bin/id /usr/bin/netcat /usr/bin/rsync /usr/bin/ssh /usr/bin/scp /sbin/unix_chkpwd /usr/lib/ssh/sftp-server"
elif [ "$DISTRO" = FEDORA ]; then
  APPS="/bin/bash /bin/cp /usr/bin/dircolors /bin/ls /bin/mkdir /bin/mv /bin/rm /bin/rmdir /bin/sh /bin/su /usr/bin/groups /usr/bin/id /usr/bin/nc /usr/bin/rsync /usr/bin/ssh /usr/bin/scp /sbin/unix_chkpwd /usr/libexec/openssh/sftp-server"
elif [ "$DISTRO" = REDHAT ]; then
  APPS="/bin/bash /bin/cp /usr/bin/dircolors /bin/ls /bin/mkdir /bin/mv /bin/rm /bin/rmdir /bin/sh /bin/su /usr/bin/groups /usr/bin/id /usr/bin/nc /usr/bin/rsync /usr/bin/ssh /usr/bin/scp /sbin/unix_chkpwd /usr/libexec/openssh/sftp-server"
elif [ "$DISTRO" = DEBIAN ]; then
  APPS="/bin/bash /bin/cp /usr/bin/dircolors /bin/ls /bin/mkdir /bin/mv /bin/rm /bin/rmdir /bin/sh /bin/su /usr/bin/groups /usr/bin/id /usr/bin/rsync /usr/bin/ssh /usr/bin/scp /sbin/unix_chkpwd /usr/lib/sftp-server"
else
  APPS="/bin/bash /bin/cp /usr/bin/dircolors /bin/ls /bin/mkdir /bin/mv /bin/rm /bin/rmdir /bin/sh /bin/su /usr/bin/groups /usr/bin/id /usr/bin/rsync /usr/bin/ssh /usr/bin/scp /usr/sbin/unix_chkpwd /usr/lib/misc/sftp-server"
fi

# Check existence of necessary files
echo "Checking for chroot..." 
if [ `which chroot` ];
  then echo "  OK";
  else echo "  failed

Please install chroot-package/binary!
"
exit 1
fi

echo "Checking for sudo..." 
if [ `which sudo` ]; then
  echo "  OK
";
else 
  echo "  failed

Please install sudo-package/binary!
"
exit 1
fi

# Get accountname to create
CHROOT_USERNAME=$1

if ! [ -z "$2" ] ; then
  SHELL=$2
else
  SHELL=/bin/chroot-shell
fi

if ! [ -z "$3" ] ; then
  JAILPATH=$3
else
  JAILPATH=/home/jail
fi

# Exit if user already exists
id $CHROOT_USERNAME > /dev/null 2>&1 && { echo "User exists."; echo "Exiting."; exit 1; }

# Create $SHELL (shell for jailed accounts)
if [ -f ${SHELL} ] ; then
  echo "$SHELL exists. Don't want to overwrite it.
Please delete it before running the script."
  exit 1
else
  echo "Creating $SHELL"
  echo '#!/bin/sh' > $SHELL
  echo "`which sudo` `which chroot` $JAILPATH /bin/su - \$USER" \"\$@\" >> $SHELL
  chmod 755 $SHELL
fi

# make common jail for everybody if inexistent
if [ ! -d $JAILPATH ] ; then
  mkdir -p $JAILPATH
  echo "Creating $JAILPATH"
fi
cd $JAILPATH

# Create directories in jail that do not exist yet
JAILDIRS="dev etc etc/pam.d bin home sbin usr usr/bin"
for directory in $JAILDIRS ; do
  if [ ! -d "$JAILPATH/$directory" ] ; then
    mkdir $JAILPATH/"$directory"
    echo "Creating $JAILPATH/$directory"
  fi
done
echo

# Comment in the following lines if your apache can't read the directories and
# uses the security contexts
# Fix security contexts so Apache can read files
#CHCON=$(`which chcon`)
#if [ -n "$CHCON" ] && [ -x $CHCON ]; then
#    $CHCON -t home_root_t $JAILPATH/home
#    $CHCON -t user_home_dir_t $JAILPATH/home/$CHROOT_USERNAME
#fi

# Creating necessary devices
[ -r $JAILPATH/dev/urandom ] || mknod $JAILPATH/dev/urandom c 1 9
[ -r $JAILPATH/dev/null ]    || mknod -m 666 $JAILPATH/dev/null    c 1 3
[ -r $JAILPATH/dev/zero ]    || mknod -m 666 $JAILPATH/dev/zero    c 1 5
[ -r $JAILPATH/dev/tty ]     || mknod -m 666 $JAILPATH/dev/tty     c 5 0 

# if we only want to update the files in the jail
# skip the creation of the new account
if [ "$1" != "update" ]; then

# Modifiy /etc/sudoers to enable chroot-ing for users
# must be removed by hand if account is deleted
echo "Modifying /etc/sudoers"
echo "$CHROOT_USERNAME       ALL=NOPASSWD: `which chroot`, /bin/su - $CHROOT_USERNAME" >> /etc/sudoers

# Define HomeDir for simple referencing
HOMEDIR="$JAILPATH/home/$CHROOT_USERNAME"

# Create new account, setting $SHELL to the above created script and
# $HOME to $JAILPATH/home/*
echo "Adding User \"$CHROOT_USERNAME\" to system"
useradd -m -d "$HOMEDIR" -s "$SHELL" $CHROOT_USERNAME && chmod 700 "$HOMEDIR"
# Enter password for new account
passwd $CHROOT_USERNAME
echo

# Create /usr/bin/groups in the jail
echo "#!/bin/bash" > usr/bin/groups
echo "id -Gn" >> usr/bin/groups
chmod 755 usr/bin/groups

# Add users to etc/passwd
#
# check if file exists (ie we are not called for the first time)
# if yes skip root's entry and do not overwrite the file
if [ ! -f etc/passwd ] ; then
 grep /etc/passwd -e "^root" > etc/passwd
fi
if [ ! -f etc/group ] ; then
 grep /etc/group -e "^root" > etc/group
# add the group for all users to etc/group (otherwise there is a nasty error
# message and probably because of that changing directories doesn't work with
# winSCP)
 grep /etc/group -e "^users" >> etc/group
fi

# grep the username which was given to us from /etc/passwd and add it
# to ./etc/passwd replacing the $HOME with the directory as it will then 
# appear in the jail
echo "Adding User $CHROOT_USERNAME to jail"
grep -e "^$CHROOT_USERNAME:" /etc/passwd | \
 sed -e "s#$JAILPATH##"      \
     -e "s#$SHELL#/bin/bash#"  >> etc/passwd

# if the system uses one account/one group we write the
# account's group to etc/group
grep -e "^$CHROOT_USERNAME:" /etc/group >> etc/group

# write the user's line from /etc/shadow to /home/jail/etc/shadow
grep -e "^$CHROOT_USERNAME:" /etc/shadow >> etc/shadow

# endif for =! update
fi

# Copy the apps and the related libs
echo "Copying necessary library-files to jail (may take some time)"

# The original code worked fine on RedHat 7.3, but did not on FC3.
# On FC3, when the 'ldd' is done, there is a 'linux-gate.so.1' that 
# points to nothing (or a 90xb.....), and it also does not pick up
# some files that start with a '/'. To fix this, I am doing the ldd
# to a file called ldlist, then going back into the file and pulling
# out the libs that start with '/'
# 
# Randy K.
#
# The original code worked fine on 2.4 kernel systems. Kernel 2.6
# introduced an internal library called 'linux-gate.so.1'. This 
# 'phantom' library caused non-critical errors to display during the 
# copy since the file does not actually exist on the file system. 
# To fix re-direct output of ldd to a file, parse the file and get 
# library files that start with /
#
if [ -x ${HOME}/ldlist ]; then 
   mv ${HOME}/ldlist ${HOME}/ldlist.bak
fi
if [ -x ${HOME}/lddlist2 ]; then 
   mv ${HOME}/lddlist2 ${HOME}/lddlist2.bak
fi

for app in $APPS;  do

    # First of all, check that this application exists
    if [ -x $app ]; then
        # Check that the directory exists; create it if not.
        app_path=`echo $app | sed -e 's#\(.\+\)/[^/]\+#\1#'`
        if ! [ -d .$app_path ]; then
            mkdir -p .$app_path
        fi

		# If the files in the chroot are on the same file system as the
		# original files you should be able to use hard links instead of
		# copying the files, too. Symbolic links cannot be used, because the
		# original files are outside the chroot.
		cp -p $app .$app

        # get list of necessary libraries
        ldd $app >> ${HOME}/ldlist
    fi
done

# Clear out any old temporary file before we start
if [ -e ${HOME}/ldlist2 ]; then
    rm ${HOME}/ldlist2
fi
for libs in `cat /root/ldlist`; do
   frst_char="`echo $libs | cut -c1`"
   if [ "$frst_char" = "/" ]; then
     echo "$libs" >> /root/ldlist2
   fi
done
for lib in `cat /root/ldlist2`; do
    mkdir -p .`dirname $lib` > /dev/null 2>&1

	# If the files in the chroot are on the same file system as the original
	# files you should be able to use hard links instead of copying the files,
	# too. Symbolic links cannot be used, because the original files are
	# outside the chroot.
    cp $lib .$lib
done

#
# Now, cleanup the 2 files we created for the library list
#
/bin/rm -f ${HOME}/ldlist
/bin/rm -f ${HOME}/ldlist2

# Necessary files that are not listed by ldd
if [ "$DISTRO" = SUSE ]; then
  cp /lib/libnss_compat.so.2 /lib/libnss_files.so.2 /lib/libnss_dns.so.2 /lib/libxcrypt.so.1 ${JAILPATH}/lib/
elif [ "$DISTRO" = FEDORA ]; then
  cp /lib/libnss_compat.so.2 /lib/libnsl.so.1 /lib/libnss_files.so.2 /lib/ld-linux.so.2 /lib/ld-ldb.so.3 /lib/libnss_dns.so.2 /lib/libxcrypt.so.1 ${JAILPATH}/lib/
  cp /lib/*.* ${JAILPATH}/lib/
elif [ "$DISTRO" = REDHAT ]; then
  cp /lib/libnss_compat.so.2 /lib/libnsl.so.1 /lib/libnss_files.so.2 /lib/ld-linux.so.2 /lib/ld-lsb.so.1 /lib/libnss_dns.so.2 /lib/libxcrypt.so.1 ${JAILPATH}/lib/
  # needed for scp on RHEL
  echo "export LD_LIBRARY_PATH=/usr/kerberos/lib" >> ${JAILPATH}/etc/profile
elif [ "$DISTRO" = DEBIAN ]; then
  cp /lib/libnss_compat.so.2 /lib/libnsl.so.1 /lib/libnss_files.so.2 /lib/libcap.so.1 /lib/libnss_dns.so.2 ${JAILPATH}/lib/
else
  cp /lib/libnss_compat.so.2 /lib/libnsl.so.1 /lib/libnss_files.so.2 /lib/libcap.so.1 /lib/libnss_dns.so.2 ${JAILPATH}/lib/
fi

# if you are using a 64 bit system and have strange problems with login comment
# the following lines in, perhaps it works then (motto: if you can't find the
# needed library just copy all of them)
#
#cp /lib/*.* ${JAILPATH}/lib/
#cp /lib/lib64/*.* ${JAILPATH}/lib/lib64/ 

# if you are using PAM you need stuff from /etc/pam.d/ in the jail,
echo "Copying files from /etc/pam.d/ to jail"
cp /etc/pam.d/* ${JAILPATH}/etc/pam.d/

# ...and of course the PAM-modules...
echo "Copying PAM-Modules to jail"
cp -r /lib/security ${JAILPATH}/lib/

# ...and something else useful for PAM
cp -r /etc/security ${JAILPATH}/etc/
cp /etc/login.defs ${JAILPATH}/etc/

if [ -f /etc/DIR_COLORS ] ; then
  cp /etc/DIR_COLORS ${JAILPATH}/etc/
fi 

exit