proxmark3/doc/termux_notes.md

Proxmark 3 on Android

Table of Contents

• Proxmark 3 on Android
  • Table of Contents
  • Requirements
  • Notes
  • Setup
    • Setting up Termux
    • Install Proxmark3 package which follows tagged releases
    • Optional: Install Proxmark3 package which offers a more up to date version from git master branch
    • Optional: Building Proxmark3 client from source
  • PC-like method
    • Specific requirements
    • USB_ACM
      • Enable the driver
      • Building the kernel
      • Flashing the kernel
      • Testing
      • Troubleshooting
  • TCP/UDP bridge method
    • USB connection
      • USB-UART Bridge Application for TCP to USB bridging
      • USB-UART Bridge Application for UDP to USB bridging
    • Bluetooth connection
      • BT-UART Bridge Application for TCP to BT bridging
    • TCP connection
    • UDP connection
    • Troubleshooting
      • BTADDON Missing in Firmware of PM3
  • Compiling and Flashing a Proxmark3 Firmware from non-root Android
    • Compiling the Proxmark3 Firmware
    • Flashing the Proxmark3 Firmware

Requirements

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• Android phone
• F-Droid
• Termux
• Proxmark3
• Blueshark Standalone Module (ONLY if using Bluetooth)
• Proxmark with BTADDON compiled Firmware (ONLY if using Bluetooth)

Notes

^Top From official Proxmark3 wiki:

In any case, you would need a USB-C to A or USB-OTG cable to connect Proxmark3 to your Android device. Some Android devices may not supply enough power (USB-OTG = 100mA), and need a USB Y-cable and external battery, otherwise they will get strange failures. ref : https://github.com/Proxmark/proxmark3/wiki/android

Setup

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Setting up Termux

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Use F-Droid to install Termux and start it.

It is recommended to use the F-Droid version of Termux as it will be the latest. The Play Store version is not maintained (as stated in the description: "Updates over Google Play [are] currently halted due to technical reasons").

Install Proxmark3 package which follows tagged releases

^Top

Run the following commands:

pkg install proxmark3

Optional: Building Proxmark3 client from source

pkg install make clang readline libc++ git binutils
git clone https://github.com/RfidResearchGroup/proxmark3.git
cd proxmark3
make clean && make client

PC-like method

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Specific requirements

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• Kernel with one of:
  • USB_ACM driver
  • module loading enabled
  • published sources
• Root

termux shell:

pkg install tsu

USB_ACM

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You need the USB_ACM driver enabled and working to communicate with the Proxmark3. To see if it's working, run tsudo ls /dev/tty* and it should list /dev/ttyACM0 (or similar). If you see this, congratulations, skip this step!

Enable the driver

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If your kernel has module loading enabled, you should be able to build the module separately and load it on your system without any changes. Otherwise, grab your kernel sources and edit your build config to include CONFIG_USB_ACM=y. On the tested kernel, this was under: android_kernel_oneplus_msm8998/arch/arm64/configs/omni_oneplus5_defconfig

Building the kernel

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If using a custom kernel, refer to the build instructions provided by its maintainer. Otherwise, follow the standard Linux kernel build procedure

Flashing the kernel

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You can flash the kernel however it suits you. On the tested device, this was achieved using TWRP, the most popular custom recovery

Testing

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Open Termux and start the Proxmark3 client:

tsudo proxmark3/client/proxmark3 /dev/ttyACM0

Everything should work just like if it was your PC!

Troubleshooting

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• dmesg | grep usb - useful debug info
• /proc/config.gz - contains your kernel's build configuration. Look for CONFIG_USB_ACM, which should be enabled

TCP/UDP bridge method

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Termux doesn't come with usb serial neither bluetooth serial drivers. However, it is fully integrated with phone's network, so we need to talk to the proxmark using serial to TCP/UDP sockets (carried out by other android apps).

|Client in Termux| <--TCP/UDP--> |Bridge App| <--USB/Bluetooth--> |Proxmark3| 

USB connection

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USB-UART Bridge Application for TCP to USB bridging

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Install this free TCPUART app on the Play Store

The app lets you choose the baudrate. Default value (115 200 baud) is fine. Plug the PM3 in and click connect. Set the toggle in server mode and choose a random port not used by system (e.g. 4321) and start the server.

Alternatively, use the paid version of the BT/USB/TCP Bridge app which includes USB bridge as well.

In this app, select TCP server as 'Device A' and choose an unused port (e.g. 4321). Choose your registered PM3 device as 'Device B' -> 'Connect to USB device'. Ensure 'Retransmission' is set to 'both ways'. It is possible to record the config as autostart, cf 'Settings' -> 'Autostart setting'.

USB-UART Bridge Application for UDP to USB bridging

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Install this free SerialPipe app on F-Droid. You can download the apk on this website without installing F-Droid.

The app lets you choose the baudrate. Default value (115 200 baud) is fine. Plug the PM3 in and click Connect. Choose a random port not used by system (e.g. 4321) and click Start Server.

Note: This app uses foreground service to keep the connection alive, so you can safely put it in the background without suspending the transmission. However, you will see a dummy notification in the status bar which is required for foreground service.

Bluetooth connection

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BT-UART Bridge Application for TCP to BT bridging

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Install this free app or the paid version (which includes usb bridge)

You need to pair the proxmark3 in the Android settings. In the app, select TCP server as 'Device A' and choose an unused port (e.g. 4321). Choose your registered PM3 device as 'Device B' -> 'Connect to classic Bluetooth device'. Ensure 'Retransmission' is set to 'both ways'. It is possible to record the config as autostart, cf 'Settings' -> 'Autostart setting'.

TCP connection

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Start a new session, then:

proxmark3 tcp:localhost:<chosenPort>

Alternatively, if you have made the client in the git repo:

./client/proxmark3 tcp:localhost:<chosenPort>

If the last colon and the chosen port are missing, the client will use 18888 as the default port.

UDP connection

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Start a new session, then:

proxmark3 udp:localhost:<chosenPort>

Alternatively, if you have made the client in the git repo:

./client/proxmark3 udp:localhost:<chosenPort>

If the last colon and the chosen port are missing, the client will use 18888 as the default port.

You can also specify the outbound port for UDP connections, which might be required for some UDP to USB/BT bridge app as the target port of it.
The format is

proxmark3 udp:localhost:<chosenPort>,bind=:<outboundPort>

Some examples:

# The bridge app listens on Port 12345, and the client listens on Port 12355
proxmark3 udp:localhost:12345,bind=:12355

# 127.0.0.1 is also a valid local address
proxmark3 udp:127.0.0.1:12345,bind=:12355

# The bridge app listens on the default port 18888, and the client listens on Port 12355
proxmark3 udp:127.0.0.1,bind=:12355

# OutboundPort is randomly picked by the system, which requires the "UDP server" mode for the bridge app
proxmark3 udp:localhost:12345

Troubleshooting

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BTADDON Missing in Firmware of PM3

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1. Phone and pm3 are connected, blue led is on and not blinking
2. BTUART Tool TCP Server at Port 4321
3. Using proxmark3 in termux shows the following error message:

$ proxmark3 tcp:localhost:4321

[=] Session log /data/data/com.termux/files/home/.suroot /.proxmark3/log_20210519.txt

[=] Loading Preferences...

[+] loaded from JSON file /data/data/com.termux/files/ho me/.suroot/.proxmark3/preferences.json

Using UART port tcp:localhost:4321

[!!] ERROR: cannot communicate with the Proxmark3

Solution:

Make sure you have installed a firmware with BTADDON compiled. See: https://github.com/RfidResearchGroup/proxmark3/blob/master/doc/md/Use_of_Proxmark/4_Advanced-compilation-parameters.md#platform_extras

Compiling and Flashing a Proxmark3 Firmware from non-root Android

READ ME:

• If you can compile and flash your device from a PC, do it! It's probably much confortable than following this method.
• Flashing is possible only via USB-UART, not via BT-UART
• Avoid flashing the Bootloader from non-root Android as the connection is probably less stable than with pure USB and you don't want to brick your device...

Compiling the Proxmark3 Firmware

Assuming we're using the Github repo sources as explained above.

pkg install make clang readline libc++ git binutils
cd
git clone https://github.com/RfidResearchGroup/proxmark3.git
cd proxmark3
make clean && make -j client

Termux doesn't have the ARM cross-compiler, so we'll install a Debian within Termux.

$ pkg install proot-distro
$ proot-distro install debian
$ proot-distro login debian --termux-home

At this point we should be on a Debian root prompt in the user directory. We install only the requirements to compile the Proxmark3 firmware.

# apt-get update
# apt-get install -y --no-install-recommends make gcc g++ libc6-dev gcc-arm-none-eabi libnewlib-dev
# cd proxmark3
# make -j fullimage
# exit

At this point we're back to the Termux prompt.

Flashing the Proxmark3 Firmware

Plug the Proxmark3 while pressing the button, to enter into bootloader mode manually.

Activate the USB-UART to TCP Bridge with one of the applications as explained above.

cd proxmark3
./client/proxmark3 tcp:localhost:<chosenPort> --flash --image armsrc/obj/fullimage.elf

Once the Proxmark3 has rebooted, reconnect it to the bridge in the app. The freshly flashed device is now ready to be used.

./client/proxmark3 tcp:localhost:<chosenPort>