[HowTo] Block unwanted calls - create blacklist

[Br1]

I've been using this script handled by upstart for a week, I have not detected abnormal battery consumption, the call block is so fast that my Xiaomi MI A2 does not ring ... should also work on other devices.

• Create a new contact and call it SPAM, add to it the numbers you want to block

• Create a script
  "nano /home/phablet/.myscripts/calls_blocker.sh"
  and make it executable (chmod u+x)

#!/bin/bash

# Intercepts every incoming call addressed to SPAM contact and terminates it

interface=org.freedesktop.DBus.Properties
member=Set

sudo dbus-monitor --system interface=$interface member=$member | awk '/SPAM/ {
    system("dbus-send --system --print-reply --dest=org.ofono /ril_0/voicecall01 org.ofono.VoiceCall.Hangup") 1>/dev/null
  }'

my data SIM in in slot 1(ril_0) if your data SIM is in slot 2 change "/ril_0" to "/ril_1"
(check with : nmcli c)

• you need to run sudo dbus-monitor without password, to do this, mount system in rw mode (1) :

sudo mount -o remount,rw /

• run sudo visudo add this line and save

phablet ALL=(ALL) NOPASSWD: /usr/bin/dbus-monitor

• Create an upstart session job
  "nano /home/phablet/.config/upstart/calls-blocker.conf"

description "Calls Blocker"

start on started dbus
stop on stopped dbus

exec /home/phablet/.myscripts/calls_blocker.sh

• Start it

start calls-blocker

other upstart commands here

(1) These changes can cause problems with OTA updates, you must keep track of all changes and restore the operating system before the OTA updates

Thanks to @c4pp4 for this topic

[Moem]

Wow! If someone could make a GUI for this*, that would be gold :1st_place_medal:

*and solve that OTA problem somehow

[Emphrath]

@br1 Well, next OTA is not a thing to worry about for a while ^^ I think I'll use that script for now. But yeah, GUI implementation is a must. You're the best !

[klh]

@moem This is a hack, let it stay hacky (you can't really solve the OTA problem, but @kugiigi has a "hack manager" that would at least make it a bit safer)

A proper solution is to do what Sailfish did (literally, using their implementation) - there might even be a GUI for it somewhere waiting for focal :winking_face:

Security stuff

The visudo change means that anyone can run dbus-monitor without entering a password - this is super unsafe as it would allow anyone with access to the device shell (ssh, adb, the terminal app or any unconfined app) to listen in on all dbus traffic (and afaik the keyboard sends keystrokes using dbus)

[Moem]

@klh said in [HowTo] Block unwanted calls - create blacklist:

@moem This is a hack, let it stay hacky :grinning_face_with_big_eyes:

Fair enough! No call blocking for me, then... for now. :smiling_face_with_halo:

[Br1]

@klh

this is super unsafe as it would allow anyone with access to the device shell (ssh, adb, the terminal app or any unconfined app) to listen in on all dbus traffic

adb and terminal app require physical access to the device(if someone has your device you already have a bigger problem) ssh with private key is safe, in my opinion the risk is very low ... everyone can evaluate risks and benefits.

[klh]

@br1 Which is why I posted what the risks are - this is not mentioned in the original post. It's still much safer than paying for an unconfined proprietary app

Also, since you already have to mess with the rootfs and run it as root, you might as well move the upstart job to /etc/init and not mess with the sudoers file.

[Br1]

--------- update ---------

To fix security issue mentioned by @klh, I have created an init.d service.

• Create a new contact and call it SPAM, add to it the numbers you want to block

• First script
  nano /home/phablet/.myscripts/calls_blocker.sh
  and make it executable (chmod u+x)

#!/bin/bash

# Intercepts every incoming call addressed to SPAM contact and terminates it

interface=org.freedesktop.DBus.Properties
member=Set

dbus-monitor --system interface=$interface member=$member | awk '/SPAM/ {
    system("dbus-send --system --print-reply --dest=org.ofono /ril_0/voicecall01 org.ofono.VoiceCall.Hangup") 1>/dev/null
  }'

• Second script
  nano /home/phablet/.myscripts/stop_blocker.sh
  (chmod u+x)

#!/bin/bash

# stop process gracefully

pkill dbus-monitor

exit

• mount system in rw mode

sudo mount -o remount,rw /

• create service
  sudo nano /etc/init.d/blacklist
  and set permissions (sudo chmod 755)

#! /bin/bash

### BEGIN INIT INFO
# Provides:          blacklist
# Required-Start:    dbus
# Required-Stop:     dbus
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Blocks calls
# Description:       Daemon that blocks unwanted calls
### END INIT INFO

# Written by Br1 <br1@spacelinux.it>

case "$1" in
  start)
    echo "Starting blacklist service ..."
    bash -c 'cd /home/phablet/.aa_myscripts/ && ./calls_blocker.sh &'
    ;;
  stop)
    echo "Stopping blacklist service ..."
    bash -c 'cd /home/phablet/.aa_myscripts/ && ./stop_blocker.sh &'
    sleep 2
    ;;
  *)
    echo "Usage: /etc/init.d/blacklist {start|stop}"
    exit 1
    ;;
esac

exit 0

• start or stop service with

sudo service blacklist start 
# or
sudo service blacklist stop

• enable service auto start on boot up

sudo update-rc.d blacklist defaults

• if you want disable service auto start on boot up

sudo update-rc.d -f blacklist remove

• check if service/dbus-monitor is running

ps -e | grep dbus-monitor

[_Joao_]

@br1 Thanks it works perfectly

[_Joao_]

The problem is the battery consumption, it lasts 2 hours with the scripts activated on my nexus.

[Emphrath]

@joao-0 u sure it's the script ? Nexus has catastrophic battery life

[_Joao_]

@emphrath yes I am sure

[Br1]

--------- UPDATE ---------
New version to install/uninstall with single command, see here for further information.

The old version has to be manually uninstalled before.

There are no new features but should be running much faster and draw less battery power (*)

three steps :

1 - download (just click) blacklist.1.01.tar.gz from here

2 - open file manager, go to Downloads click blacklist.1.01.tar.gz and extract archive

3 - open terminal and type :

sudo /home/phablet/Downloads/blacklist.1.01/blist-install

type 1 to install
type 2 to uninstall
type 3 to exit

That's all.

Preview of install/uninstall script (blist-install) :

#!/bin/bash

BLSERV=/etc/init.d/blacklist ;

# Make sure only root can run this script
if [ "$(id -u)" != "0" ]; then
   echo "    Must be run as root, you must prepend sudo !" 1>&2 ; exit 1
fi

echo -e '\n - Install/uninstall BlackList :\n' ;

PS3='Please enter your choice : '
options=("Install" "Uninstall" "Quit")
select opt in "${options[@]}"
do
	case $opt in
	"Install")

 			echo -e '\n Installation in progress ...\n' ;

			# change the working directory
			cd /home/phablet/Downloads/blacklist.1.01/ ;
			
			# create directory
			mkdir -p /home/phablet/.blacklist ;

			# copy scripts to directory just created 			
			cp *.sh /home/phablet/.blacklist/ ;
			
			# mount root in read/write mode
			mount -o remount,rw / ;
			
			# copy blacklist service
			cp blacklist /etc/init.d/ ;
			
			# enable autostart
			update-rc.d blacklist defaults ;
			
			# start service
			service blacklist start
			
			# roll back root in read only mode
			mount -o remount,ro / ;

			echo -e '\n Done, Blacklist installed !\n'
			
			exit 0

		;;

	"Uninstall")

			# check status
			if [ ! -f "$BLSERV" ]; then

			echo -e '\n Blacklist is not installed !\n' ;

			else

			# mount root in read/write mode
			mount -o remount,rw / ;

			# stop blacklist service, disable autostart and remove file
			service blacklist stop ; update-rc.d -f blacklist remove ; rm /etc/init.d/blacklist ;

			# roll back root in read only mode
			mount -o remount,ro / ;

			# delete scripts and remove directory
			rm -rf /home/phablet/.blacklist/* ; rmdir /home/phablet/.blacklist ;

			echo -e '\n Blacklist uninstalled !\n'

			exit 0

			fi

		;;

        "Quit")
			exit 0
		;;
			*) echo "invalid option $REPLY"
		;;
    esac
done

• small changes to make more efficient the script (now named sr-kill.sh) useful to stop blacklist service from command line :

#!/bin/sh

# stop blacklist service

# get pid of the script
scPID=$(pidof -x calls_blocker.sh)

# kill script and child processes
pkill -P $scPID

exit

(*) Now the always running script (calls_blocker.sh) is executed by dash shell which is much faster and requires fewer resources than bash shell, see benchmark , here is the preview :

#!/bin/sh

# Intercepts every incoming call addressed to SPAM contact and terminates it

interface=org.freedesktop.DBus.Properties
member=Set

sudo dbus-monitor --system interface=$interface member=$member | awk '/SPAM/ {
   system("dbus-send --system --print-reply --dest=org.ofono /ril_0/voicecall01 org.ofono.VoiceCall.Hangup") }' >/dev/null 2>&1

[_Joao_]

This post is deleted!

[_Joao_]

This post is deleted!

[_Joao_]

Hello the program works perfectly. The autonomy is frankly superior to the old version, the application consumes 9% per hour on my nexus 5 with a new battery. Without the appication my nexus 5 consumes 3% per hour. It's a bit fair but as you say the nexus has a limited basic autonomy.
Thanks, great job.

[Br1]

OTA-25 --- You can reinstall, no changes are necessary.

[Br1]

---- UPDATE OTA-2 Focal ----
---- Stable Channel ----

Usual three steps :

1 - download (just tap) blacklist-ota.2 from here

2 - open file manager, go to Downloads tap blacklist-ota.2.tar.gz and tap extract archive

3 - open terminal, type :

sudo Downloads/blacklist-ota.2/blist-install

and hit enter,

type 1 + enter to install

type 2 + enter to uninstall

reboot not required.

---

Blacklist only consist of three files :

preview of blist-install :

#!/bin/bash

BLSERV=/usr/lib/systemd/system/blacklist.service ;

# Make sure only root can run this script
if [ "$(id -u)" != "0" ]; then
   echo "    Must be run as root, you must prepend sudo !" 1>&2 ; exit 1
fi

echo -e '\n  -  Install-Uninstall BlackList :\n' ;

PS3=$'
Please enter your choice : '
options=("  Install    -       " "  Uninstall  -       " "  Quit       -       ")

select opt in "${options[@]}"
do
	case $opt in
	"  Install    -       ")

 			echo -e '\n Installation in progress ...\n' ;

			# change the working directory
			cd /home/phablet/Downloads/blacklist-ota.2/ ;

			# create directory
			mkdir -p /home/phablet/.blacklist ;

			# copy scripts to directory just created
			cp calls_blocker.sh /home/phablet/.blacklist/ ;

			# mount root in read/write mode
			mount -o remount,rw / ;

			# copy blacklist service
			cp blacklist.service /usr/lib/systemd/system/ ;

			# enable and start service
			systemctl enable --now blacklist > /dev/null 2>&1 ;

			# roll back root in read only mode
			mount -o remount,ro / ;

			echo -e '\n Done, Blacklist installed !\n'

			exit 0

		;;

	"  Uninstall  -       ")

			# check status
			if [ ! -f "$BLSERV" ]; then

			echo -e '\n Blacklist is not installed !\n' ;

			else

			# mount root in read/write mode
			mount -o remount,rw / ;

			# stop and disable blacklist service
			systemctl disable --now blacklist > /dev/null 2>&1 ;

			# remove file
			rm /usr/lib/systemd/system/blacklist.service ;

			# roll back root in read only mode
			mount -o remount,ro / ;

			# delete scripts and remove directory
			rm -rf /home/phablet/.blacklist/* ; rmdir /home/phablet/.blacklist ;

			echo -e '\n Blacklist uninstalled !\n'

			exit 0

			fi

		;;

        "  Quit       -       ")
			echo -e '\n - OS unchanged !\n'

			exit 0
		;;
			*) echo "invalid option $REPLY"
		;;
    esac
done

preview of blacklist.service :

[Unit]
Description=Calls Blacklist

[Service]
Type=simple
ExecStart=/home/phablet/.blacklist/calls_blocker.sh
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target

calls_blocker.sh script has not changed.

The script to stop service is no longer necessary, blacklist now is a systemd service and can be managed with systemctl commands, example :

systemctl stop blacklist

improved legibility :

[Br1]

I can’t test ota 3 update, install at your own risk.

[Br1]

OTA 3 Stable channel --- You can reinstall, no changes are necessary.