unsafe-browser

#!/bin/sh

set -e

CMD=$(basename ${0})
LOCK=/var/lock/${CMD}

. gettext.sh
TEXTDOMAIN="tails"
export TEXTDOMAIN

CONF_DIR=/var/lib/unsafe-browser
COW=${CONF_DIR}/cow
CHROOT=${CONF_DIR}/chroot
BROWSER_USER=clearnet

# Import tor_is_working()
. /usr/local/lib/tails-shell-library/tor.sh

# Import the TBB_INSTALL, TBB_EXT and TBB_PROFILE variables, and
# exec_firefox(), configure_xulrunner_app_locale() and
# guess_best_tor_browser_locale()
. /usr/local/lib/tails-shell-library/tor-browser.sh

. /usr/local/lib/tails-shell-library/chroot-browser.sh

WARNING_PAGE='/usr/share/doc/tails/website/misc/unsafe_browser_warning'
LANG_CODE="$(echo ${LANG} | head -c 2)"
if [ -r "${WARNING_PAGE}.${LANG_CODE}.html" ]; then
   START_PAGE="${WARNING_PAGE}.${LANG_CODE}.html"
else
   START_PAGE="${WARNING_PAGE}.en.html"
fi

if [ -e /var/lib/gdm3/tails.camouflage ]; then
    CAMOUFLAGE=yes
fi

cleanup () {
    try_cleanup_browser_chroot ${CHROOT} ${COW} ${BROWSER_USER}
}

error () {
    local cli_text="${CMD}: `gettext \"error:\"` ${@}"
    local dialog_text="<b><big>`gettext \"Error\"`</big></b>

${@}"
    echo "${cli_text}" >&2
    sudo -u ${SUDO_USER} zenity --error --title "" --text "${dialog_text}"
    exit 1
}

verify_start () {
    # Make sure the user really wants to start the browser
    local dialog_msg="<b><big>`gettext \"Do you really want to launch the Unsafe Browser?\"`</big></b>

`gettext \"Network activity within the Unsafe Browser is <b>not anonymous</b>. Only use the Unsafe Browser if necessary, for example if you have to login or register to activate your Internet connection.\"`"
    local launch="`gettext \"_Launch\"`"
    local exit="`gettext \"_Exit\"`"
    # Since zenity can't set the default button to cancel, we switch the
    # labels and interpret the return value as its negation.
    if sudo -u ${SUDO_USER} zenity --question --title "" --ok-label "${exit}" \
       --cancel-label "${launch}" --text "${dialog_msg}"; then
        exit 0
    fi
}

show_start_notification () {
    local title="`gettext \"Starting the Unsafe Browser...\"`"
    local body="`gettext \"This may take a while, so please be patient.\"`"
    tails-notify-user "${title}" "${body}" 10000
}

configure_chroot () {
    echo "* Configuring chroot"

    # Set the chroot's DNS servers to those obtained through DHCP
    rm -f ${CHROOT}/etc/resolv.conf
    for NS in ${IP4_NAMESERVERS}; do
        echo "nameserver ${NS}" >> ${CHROOT}/etc/resolv.conf
    done
    chmod a+r ${CHROOT}/etc/resolv.conf

    # Create a fresh browser profile for the clearnet user
    BROWSER_CONF="${CHROOT}/home/${BROWSER_USER}/.tor-browser"
    BROWSER_PROFILE="${BROWSER_CONF}/profile.default"
    BROWSER_EXT="${BROWSER_PROFILE}"/extensions
    mkdir -p "${BROWSER_EXT}"
    cp -Pr "${TBB_PROFILE}"/extensions/langpack-*.xpi "${BROWSER_EXT}"

    BROWSER_PREFS="${BROWSER_PROFILE}"/preferences/prefs.js
    mkdir -p "$(dirname "${BROWSER_PREFS}")"
    cp /usr/share/tails/unsafe-browser/unsafe-browser.js "${BROWSER_PREFS}"

    # Localization
    BEST_LOCALE="$(guess_best_tor_browser_locale)"
    configure_xulrunner_app_locale "${BROWSER_PROFILE}" "${BEST_LOCALE}"

    # Set the name (e.g. window title) of the browser
    set_chroot_browser_name ${CHROOT} "`gettext \"Unsafe Browser\"`" "${BEST_LOCALE}"

    # Set start page to something that explains what's going on
    echo 'user_pref("browser.startup.homepage", "'${START_PAGE}'");' >> \
        "${BROWSER_PREFS}"
    BROWSER_CHROME="${BROWSER_PROFILE}/chrome/userChrome.css"
    mkdir -p "$(dirname "${BROWSER_CHROME}")"
    cp /usr/share/tails/unsafe-browser/userChrome.css ${BROWSER_CHROME}

    # Remove all bookmarks
    rm -f ${CHROOT}/"${TBB_PROFILE}"/bookmarks.html
    rm -f ${BROWSER_PROFILE}/bookmarks.html
    rm -f ${BROWSER_PROFILE}/places.sqlite

    chown -R ${BROWSER_USER}:${BROWSER_USER} "${BROWSER_CONF}"

    # Set a scary theme (except if we're using Windows
    # camouflage). Note that the tails-activate-win8-theme script that
    # we may run below requires that the browser profile is writable
    # by the user running the script (i.e. clearnet).
    if [ -z "${CAMOUFLAGE}" ]; then
        cat /usr/share/tails/unsafe-browser/unsafe-browser-theme.js >> "${BROWSER_PREFS}"
    else
        # The camouflage activation script requires a dbus server for
        # properly configuring GNOME, so we start one in the chroot
        chroot ${CHROOT} sudo -H -u ${BROWSER_USER} sh -c 'eval `dbus-launch --auto-syntax`; tails-activate-win8-theme' || :
    fi

}

show_shutdown_notification () {
    local title="`gettext \"Shutting down the Unsafe Browser...\"`"
    local body="`gettext \"This may take a while, and you may not restart the Unsafe Browser until it is properly shut down.\"`"
    tails-notify-user "${title}" "${body}" 10000
}

maybe_restart_tor () {
    # Restart Tor if it's not working (a captive portal may have prevented
    # Tor from bootstrapping, and a restart is the fastest way to get
    # wheels turning)
    if ! tor_is_working; then
        echo "* Restarting Tor"
        restart-tor
        if ! service tor status >/dev/null; then
            error "`gettext \"Failed to restart Tor.\"`"
        fi
    fi
}

# Prevent multiple instances of the script.
exec 9>${LOCK}
if ! flock -x -n 9; then
    error "`gettext \"Another Unsafe Browser is currently running, or being cleaned up. Please retry in a while.\"`"
fi

# Get the DNS servers that was obtained from NetworkManager, if any...
NM_ENV=/var/lib/NetworkManager/env
if [ -r "${NM_ENV}" ]; then
    . ${NM_ENV}
fi
# ... otherwise fail.
# FIXME: Or would it make sense to fallback to Google's DNS or OpenDNS?
# Some stupid captive portals may allow DNS to any host, but chances are
# that only the portal's DNS would forward to the login page.
if [ -z "${IP4_NAMESERVERS}" ]; then
    error "`gettext \"No DNS server was obtained through DHCP or manually configured in NetworkManager.\"`"
fi

verify_start
show_start_notification
echo "* Setting up chroot"
setup_browser_chroot ${CHROOT} ${COW} || \
    error "`gettext \"Failed to setup chroot.\"`"
configure_chroot
echo "* Starting Unsafe Browser"
run_chroot_browser ${CHROOT} ${BROWSER_USER} ${SUDO_USER}
show_shutdown_notification
maybe_restart_tor

exit 0