initramfs init-bottom script: Wait for drobear to start before bringing the network down.

    (Closes: #934146)

  * debian/initramfs/dropbear-hook: Don't mention cryptroot in warning

    messages, only SSH login.

  * debian/initramfs/bottom-dropbear: Wait for drobear to start before

    bringing the network down. This avoids a race where the network stack were

    fully not configured yet by the time the execution is handed over to the

    main system. (Closes: #943459)

 -- Guilhem Moulin <guilhem@debian.org>  Wed, 07 Aug 2019 16:14:58 +0200

. /scripts/functions

EXE="$(readlink -f /sbin/dropbear)" && [ -f "$EXE" ] || exit 1

PIDFILE="/run/dropbear.pid"

# delete authorized_keys(5) file to forbid new SSH sessions

rm -f ~root/.ssh/authorized_keys

if PID="$(cat /run/dropbear.pid)" 2>/dev/null &&

        [ "$(readlink -f "/proc/$PID/exe")" = "$EXE" ]; then

wait_for_dropbear() {

    local pid exe timer=60

    pid="$(cat "$PIDFILE" 2>/dev/null)" || return 1

    # when configure_networking() is run asynchronously dropbear might

    # not have started yet; ipconfig doesn't react to SIGTERM so we wait

    # for the network stack to be configured (and dropbear to start)

    # rather than terminating the shell and its children

    while [ $timer -gt 0 ] && exe="$(readlink -f "/proc/$pid/exe" 2>/dev/null)"; do

        if [ "$exe" = "$EXE" ]; then

            echo "$pid"

            return 0

        fi

        sleep 1

        timer=$(( timer - 1))

    done

    return 1

}

if PID="$(wait_for_dropbear)"; then

    log_begin_msg "Stopping dropbear"

    # Kill all process groups the leader of which is a child of the