[org/gnome/login-screen]
banner-message-enable=true

/org/gnome/login-screen/banner-message-enable

#!/bin/bash

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'gdm3' 2>/dev/null | grep -q installed; then

mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/user

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:local" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:local\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/local.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)
mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/gdm

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:gdm" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:gdm\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/gdm.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)
# Duplicate the setting also in 'greeter.dconf-defaults' for consistency with
# 'dconf_gnome_login_banner_text' and better alignment with STIG V1R1.
if [ -e "/etc/gdm3/greeter.dconf-defaults" ] ; then
    
    LC_ALL=C sed -i "/^\s*banner\-message\-enable/Id" "/etc/gdm3/greeter.dconf-defaults"
else
    touch "/etc/gdm3/greeter.dconf-defaults"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/gdm3/greeter.dconf-defaults"

cp "/etc/gdm3/greeter.dconf-defaults" "/etc/gdm3/greeter.dconf-defaults.bak"
# Insert after the line matching the regex '\[org/gnome/login-screen\]'
line_number="$(LC_ALL=C grep -n "\[org/gnome/login-screen\]" "/etc/gdm3/greeter.dconf-defaults.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '\[org/gnome/login-screen\]', insert at
    # the end of the file.
    printf '%s\n' "banner-message-enable=true" >> "/etc/gdm3/greeter.dconf-defaults"
else
    head -n "$(( line_number ))" "/etc/gdm3/greeter.dconf-defaults.bak" > "/etc/gdm3/greeter.dconf-defaults"
    printf '%s\n' "banner-message-enable=true" >> "/etc/gdm3/greeter.dconf-defaults"
    tail -n "+$(( line_number + 1 ))" "/etc/gdm3/greeter.dconf-defaults.bak" >> "/etc/gdm3/greeter.dconf-defaults"
fi
# Clean up after ourselves.
rm "/etc/gdm3/greeter.dconf-defaults.bak"


# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" \
                                | grep -v 'distro\|ibus\|gdm.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/gdm.d/00-security-settings"
DBDIR="/etc/dconf/db/gdm.d"

mkdir -p "${DBDIR}"

# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
    if grep -q "^\\s*banner-message-enable\\s*=" "${SETTINGSFILES[@]}"
    then
        
        sed -Ei "s/(^\s*)banner-message-enable(\s*=)/#\1banner-message-enable\2/g" "${SETTINGSFILES[@]}"
    fi
fi

[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/login-screen\\]" "${DCONFFILE}"
then
    printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
fi

escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
if grep -q "^\\s*banner-message-enable\\s*=" "${DCONFFILE}"
then
        sed -i "s/\\s*banner-message-enable\\s*=\\s*.*/banner-message-enable=${escaped_value}/g" "${DCONFFILE}"
    else
        sed -i "\\|\\[org/gnome/login-screen\\]|a\\banner-message-enable=${escaped_value}" "${DCONFFILE}"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/login-screen/banner-message-enable$" "/etc/dconf/db/" \
            | grep -v 'distro\|ibus\|gdm.d' | grep ":" | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/gdm.d/locks"

mkdir -p "${LOCKSFOLDER}"

# Comment out the configurations in databases different from the target one
if [[ ! -z "${LOCKFILES}" ]]
then
    sed -i -E "s|^/org/gnome/login-screen/banner-message-enable$|#&|" "${LOCKFILES[@]}"
fi

if ! grep -qr "^/org/gnome/login-screen/banner-message-enable$" /etc/dconf/db/gdm.d/
then
    echo "/org/gnome/login-screen/banner-message-enable" >> "/etc/dconf/db/gdm.d/locks/00-security-settings-lock"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi